Arctic Emergency Report Card: draft for comment

[John Nissen]

ARCTIC EMERGENCY REPORT CARD

Draft of 2025/10/26

Introduction

The Arctic is in a meltdown, which threatens to take at least five tipping elements beyond their point of no return.  Continued meltdown would have catastrophic consequences which we examine below.  Emergency cooling intervention is vital to prevent any of the tipping elements reaching a point of no return.

The original cause of this meltdown was global warming caused by an excess of greenhouse gases in the atmosphere.  Global temperature rise has been amplified in the Arctic, mainly by albedo positive feedback, such that, since 1980, the mean Arctic temperature has been rising at about four times the global average.  The retreat of sea ice started to accelerate around 1980, as shown by a comparison with the linear models used by the IPCC.  Satellite images show a corresponding retreat of snow in the Arctic region.  Retreat exposes open water and open ground respectively.  This lowers the albedo causing more heat to be absorbed and more retreat in a vicious cycle known as albedo positive feedback.  Thus Arctic meltdown is accelerating.

Global temperature trends

The main driver of global warming is the accumulation of greenhouse gases in the atmosphere, not their emission.  There is no reason for global temperatures to start falling, even if strenuous efforts to reach net zero by 2050 were to be successful.  The global warming which started the retreat of snow and ice is continuing.

Temperature rise is proportional to accumulated heat energy.  The heat energy in a system is the accumulation of heat input less heat output.  The input is shortwave radiation from the sun.  The output is a mixture of reflected shortwave and thermal radiation which is longwave.  When net zero (of CO2 emissions) is reached, the forcing (heating power) from the CO2 accumulated in the atmosphere will peak. Other things being equal, the heat energy (as opposed to power) will continue to rise linearly, and the corresponding mean global temperature will continue to rise linearly.  At present the global temperature is accelerating: the rate of temperature rise is increasing from 0.18C per decade (average from 1980 to 2020) towards double for the following 25 year average, i.e. 0.36C per decade; see brown curves on the diagram attached.  This doubling is made more likely with the lowering of tropospheric SO2 which has a cooling effect.

The Paris COP's designated limit of 2.0C (relative to the 1900 baseline) is likely to be reached around 2040.  This is with an atmospheric level of around 460 ppm for CO2 and 560 ppm for CO2e (a doubling since the 1900 baseline value of 280 ppm).  Even now, with ~1.5C and over 423 ppm CO2, there is already a high risk of some tipping elements reaching a point of no return. By 2040 with ~2.0C warming the risk becomes much higher still. Certainly, since this temperature is amplified in the Arctic, the tipping elements there will be experiencing an Arctic temperature increase of ~4.0C: a quadrupling of the global temperature rise between 1980 and 2040.

From Forster et al. [1], the forcing from CO2 reached around 2.33 W/m2 in 2024; see figure 5(a).  The contribution from other greenhouse gases was about half this, excluding ozone at 0.5 W/m2.  The cooling from aerosols (principally derived from SO2) was around -1.0 W/m2.  The total comes to around 3.0 W/m2.  This total cannot be reduced by cuts in CO2 emissions.  Nothing significant can be done to increase thermal energy output.  Emissions reduction, however drastic, would have little effect in the 15 years till 2040.  The only way to prevent 2C being reached is through cooling intervention to increase shortwave reflection, i.e. the Earth's albedo.  Cooling power of over 3.0 W/m2 will be needed to offset the 3.0 W/m2 of heating from reduced longwave radiation into space.

The Earth's energy imbalance is a measure of the heat input from the sun to the Earth, less the heat output from the Earth.  The implication would seem to be that peak global mean temperature will only be reached when there is net zero forcing and the Earth's energy imbalance is zero.  However this does not take into account the cooling power from the oceans into the atmosphere.  The ocean surface temperature has been well below air surface temperature, such that a large proportion of the heat excess in the atmosphere (over 90%) has been absorbed by the oceans.  Thus we need to consider the change in the Earth's energy balance rather than its absolute value.  The global temperature was constant within a narrow range around the 1900 baseline, so we need to consider the change since then.  The CERES satellite has shown a considerable change recently [2].  Since 2001 the imbalance resulting from reduced albedo (i.e. reduced shortwave reflection) has increased by over 1 W/m2.  With the 3 W/m2 above, a total of well over 4 W/m2 of cooling power might be needed to start lowering the global mean temperature and reduce the already high risk of some tipping elements reaching a point of no return.  Note that the Earth receives an average of about 340 W/m2 from the sun, so an extra 4 W/m2 of cooling equates to 1.18% of the sun's average energy input.

The cooling has to be done intelligently, so that critical elements are cooled first.  Evidence suggests that the most critical elements are in the Arctic.

Arctic tipping elements

Since 1980 the Arctic has been warming around four times faster than the global average.  Five elements of the Arctic have been categorised as tipping elements in the Earth System; see [3] Figure 3:

• the Arctic sea ice; 
• the Greenland Ice Sheet; 
• the Arctic permafrost, both on land and under the seabed; 
• the polar jet stream; 
• the Atlantic Meridional Overturning Circulation (AMOC). 

The Arctic sea ice exhibits a switch behaviour.  From an initial state of perennial sea ice, there is accelerated retreat followed by decline towards a state where there is only seasonal sea ice.  This final state will be reached when all the multiyear ice has gone.  This departure could happen quite suddenly and be a point of no return, meaning the sea ice cover could not be restored to the perennial sea ice state with multiyear ice.  The Arctic sea ice acts as a vast mirror of many square kilometres. Complete loss of Arctic ice would contribute 3.3 W/m2 to global warming besides triggering the other Arctic tipping elements to the point of no return: a tipping point cascade.

The Greenland Ice Sheet is already disintegrating.  The number of moulins has grown exponentially over the past 20 years or more.  The great glaciers with terminations in the sea are accelerating towards the sea, as their terminations are warmed from Atlantic water, derived from the Gulf Stream.  Their descent is being lubricated by the meltwater which flows through the increasing numbers of moulins.  At some point a great glacier is liable to collapse, with an avalanche of ice blocks racing towards the sea and creating a megatsunami.  Such an avalanche has already occurred for an inland glacier, causing a 200 metre tsunami oscillating between shores of an inland lake.  There is evidence of past collapses when significant parts of Greenland suddenly became free of ice, e.g. in the early Holocene.  A complete collapse of the Greenland Ice Sheet would produce enough meltwater to raise sea level by over 7 metres, risking an even greater contribution from West Antarctic glaciers, already in a critical state. 

The Arctic permafrost is in accelerated thaw as air temperatures rise.  Its decomposition is exothermic and produces methane in anaerobic conditions, such as in waterlogged tundra or under thermokarst lakes. There is a risk of a sudden discharge of methane at the megaton level.  Methane is a potent greenhouse gas and such an outburst could boost global warming to take the planet into a hothouse state; see [3] figure 1.  Arctic permafrost contains around 1500 to 1700 gigatons of carbon: about double the amount of carbon in the atmosphere.  If only a small fraction were converted to methane by anaerobic bacteria and stored as methane clathrate, a sudden shock could depressurise the clathrate, releasing gigatons of methane into the atmosphere.  Such explosions on a smaller scale are already occurring in Siberia.  There are also signs of such explosions having occurred in subsea permafrost, producing pingos.  And the Storegga submarine landslide could have been caused or amplified by clathrate depressurisation: it produced a megatsunami hitting the north-east coast of Scotland as evidence shows in stratigraphy.

The polar jet stream and its Rossby wave marks the boundary between the polar vortex with easterly winds and mid-latitude weather systems with westerly winds.  The Rossby wave is driven eastward by the energy produced by a product of coriolis force and temperature gradient.  Since the polar region is warming more rapidly than the mid-latitude region, the gradient is diminishing.  This results in less energy in the Rossby wave, which becomes lazier with tendencies to meander further north and south, and to get stuck in blocking patterns for longer periods.  This leads to stuck weather and hence to longer periods of heat, drought, cold, and precipitation.  This provides a major reason for the increase in weather extremes in the Northern Hemisphere.  Cooling the Arctic would therefore help to reverse the current trend towards ever greater extremes of weather, which threaten food production.  Heat extremes and drought threaten to make parts of the world uninhabitable.

The Atlantic Meridional Overturning Circulation (AMOC) is a major system of currents which carries water, via the Gulf Stream, into the Arctic where the water is cooled and salinified, sinking and flowing southward at the bottom of the Atlantic Ocean.  It is a crucial part of a worldwide system of currents, driven by sinking saline water: when ice freezes, salt is extruded as brine.  As the Arctic sea ice retreats, less brine is produced and the AMOC weakens.  There is a similar process in Antarctica, which is also weakening due to sea ice retreat.   For the AMOC there is a positive feedback system operated by a freshening of the North Atlantic current [4].  The production of meltwater from the Greenland Ice Sheet is implicated in this freshening, and observations of sea surface temperature show an anomalous surface cooling in the North Atlantic, despite a warming of the global average sea surface temperature.  The AMOC threatens to collapse irretrievably, passing a point of no return within a few decades.  

There is a precedent for an AMOC collapse: a collapse in strength was seen at the beginning of the Younger Dryas, bringing a period of glaciation to Northern Europe.  The collapse in AMOC was possibly triggered by a Heinrich Event, labelled H0, when there would have been such a large quantity of icebergs crossing the Atlantic that a significant amount of ice-rafted debris (IRD) would have been deposited in the North Atlantic.  In the case of Laurentide Ice Sheet {for previous Heinrich Events, H1 etc.), collapse would have been initiated by extra warm sub-surface water [5] as we have currently in the North Atlantic, continuing to flow while covered in late summer by Greenland meltwater.  This warm subsurface water is contributing to the destabilisation of the terminations of Greenland glaciers.

Refreezing the Arctic

This is an unprecedented emergency.  Tipping processes are taking the planet towards irreversible and catastrophic climate change and sea level rise.  The Arctic temperature has to be brought down, long before 4C is reached, for there to be any chance to prevent the Arctic tipping elements reaching their "points of no return".  In effect the Arctic has to be refrozen back to some maintainable state, e.g. its state in 1980 before accelerated meltdown got underway.  

Help is at hand.  With powerful cooling intervention using Stratospheric Aerosol Injection (SAI) it may be possible, not only to lower the Arctic temperature to around its 1980 temperature but also to reverse climate change and bring the global temperature back to its 1980 value.  The amount of Arctic warming power is estimated at approximately 2.0 W/m2: half coming from albedo loss and half from Atlantification. Thus the cooling power has to be significantly greater than 2.0 W/m2 which equates to 1.0 petawatt.  This has to be directed into the Arctic.  Because most surface water north of 50N flows towards the Arctic, injection of the aerosol or its precursor can be effective at a latitude of 50N.  The bulk of the aerosol will drift towards the pole, taken by the Brewer-Dobson circulation, and descend harmlessly into the troposphere before it reaches the pole.  At the megaton injection level, SO2 is capable of lowering the Arctic temperature, at a cost of a few tens of thousands of dollars per year [6].  Researchers have been unable to identify any unmanageable untoward effects; but deployment can be modelled to anticipate problems even during deployment.  The deployment can be monitored and tuned to avoid any foreseen or unforeseen problems, thus maximising safety, while maintaining effectiveness. 

In the attached diagram, a target temperature trajectory for the Arctic is suggested (see blue curve).  The peak in the Arctic temperature occurs within 5 years and the temperature brought down to the 1980 level over the following few decades.  This target is suggested to minimise the risk of any of the Arctic tipping elements reaching their point of no return.  The target is ambitious yet realistic, given SAI.

From refreezing the Arctic to planetary restoration

A target trajectory for global temperature is also suggested (see purple curve).  The achievement of these two temperature targets, together with a target reduction in CO2e to its 1980 level of ~380 ppm (see red curve), would make it possible to reverse climate change and return the planet to late Holocene norms.  Thus.with careful deployment of SAI, there is a realistic prospect of restoring the planet to a safe, sustainable, biodiverse and productive state, for the young people of today to enjoy.

References

[1] Forster et al. (Copernicus, 2025)

Indicators of Global Climate Change, 2024

https://essd.copernicus.org/articles/17/2641/2025/

[2] Raghuraman et al. (Nature, 2021)

https://www.nature.com/articles/s41467-021-24544-4

See also (updated in September 2025):

Earth's radiation budget from 1979 to present derived from satellite observations 

https://cds.climate.copernicus.eu/datasets/satellite-earth-radiation-budget

[3] Will Steffen et al (2018)

Trajectories of the Earth System in the Anthropocene

https://www.pnas.org/doi/pdf/10.1073/pnas.1810141115

[4] Westen et al. (JGR Oceans, August 2025)

Physics-Based Indicators for the Onset of an AMOC Collapse Under Climate Change

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JC022651#:~:text=An%20analysis%20consisting%20of%2025,scenario%20(SSP5%2D8.5).

[5] Max et al. (Nature Comms, 2022)

Subsurface ocean warming preceded Heinrich events

https://www.nature.com/articles/s41467-022-31754-x

[6] Wake Smith et al. 

A sub-polar focussed stratospheric aerosol injection deploymnent scenario

https://iopscience.iop.org/article/10.1088/2515-7620/ac8cd3 

[John Nissen]

Hi all,

I am still suffering from Covid-like symptoms so regretfully missed the NOAC meeting on Monday.  I had hoped that my draft report would provoke comments.  In particular I'd welcome comments from Paul Beckwith, who has blogged extensively on tipping points.

I would like to have a special PRAG meeting to agree the report card as an official PRAG output, as I had for the "Trends and Target" diagram, originally submitted to the AGU and presented there.  The earliest chance to discuss this would be next Monday, starting at 8 pm (so an hour earlier than NOAC's).  I need to confirm the date, time and hosting arrangements.

Robert Chris and others have asked various AI tools about SAI.  The AI will tend to respond with the consensus view, which downplays the risks from global warming without SAI and overplays the risks from SAI deployment. The AI needs something to work on as regards the relative risks arising from reaching 2.0C of global warming and the risks arising from injecting 10+ GtSO2 per year into the stratosphere.  In particular the AI needs to work on timescales and risks from tipping elements passing a point of no return.  This should add real urgency to the deployment.  Therefore I will include an abstract section and a significance section at the beginning of the report and a postscript at the end.  I include a draft below.

Cheers, John

Abstract

The report identifies five tipping elements in the Arctic which threaten to be taken beyond their point of return because of rising temperatures.  Global warming is likely to reach 2C by around 2040, driven by ~3.0 W/m2 net climate forcing from greenhouse gases.  But the Arctic temperature is rising much faster than the global average.  Cooling the Arctic is essential to prevent tipping point catastrophe, and it has to be done quickly to start bringing down the temperature and start refreezing the Arctic.  This is possible with Stratospheric Aerosol Injection (SAI).  The Arctic temperature should be made to peak before 2030 if possible.  Global cooling should peak the global mean temperature before 2040 if possible.  These temperature reductions, together with a reduction in the level of CO2e in the atmosphere, could reverse climate change, slow sea level rise and restore the planet to late Holocene norms.

Significance

A unique quantitative and engineering perspective on the climate crisis is presented.  We find that prompt cooling intervention with Stratospheric Aerosol Injection (SAI) is essential to substantially reduce an already high and growing risk from tipping elements in the Arctic.  

Reducing the Arctic temperature has a priority over reducing global temperature.

If a body is being heated but needs to be cooled, the cooling power has to exceed the heating power.  The planet is receiving an excess heating power of ~3.0 W/m2 averaged over its surface and resulting from the excess of greenhouse gases in the atmosphere.  This excess cannot be reduced quickly.  Without cooling intervention 2.0C of global warming will be reached by around 2040.  The global temperature cannot be immediately reduced unless at least 3 W/m2 of cooling power is supplied.  

A target of 2.0C was set at the Paris COP as a temperature to be avoided because of the high risk of tipping processes, already a serious risk at the 1.5C we have already reached.

Emissions reduction, even combined with greenhouse gas removal, cannot prevent ever worsening climate change and sea level rise, nor can they significantly reduce the risk of sudden catastrophic climate change and sea level rise when tipping processes reach a collapse point.

There are five key tipping elements in the Arctic: the Arctic sea ice; the Greenland Ice Sheet; the Arctic permafrost; the polar jet stream; and the AMOC.  Each has their own tipping character, but in each case their tipping process is already being accelerated by Arctic warming and some could be close to collapse.  The Arctic is in meltdown; this is extremely dangerous; it has to be stopped.

The Arctic region is being heated by a combination of local albedo loss and global warming heat flux which is entering the Arctic.  Our best estimate is that this combination could amount to around 2.0 W/m2 of heating power.  Moreover the Arctic temperature is rising at around four times the global average.  There is a very high risk of allowing any one of the five tipping elements in the Arctic to reach their point of no return.  This would inevitably lead to a collapse of some kind with catastrophic world-wide consequences for climate or, in the case of the Greenland Ice Sheet, sea level rise.  Partial collapse of the GIS could raise the sea level by several metres this century.  A cooling power greater than 2.0 W/m2 may be required from SAI to prevent tragic consequences later this century.

The Arctic situation demands the emergency deployment of SAI, ramped up to 2.0 W/m2 cooling power as quickly as possible.  Volcanic eruptions have demonstrated the cooling power of SAI and the mechanism is well understood.  Research suggests that SAI can reduce the Arctic temperature remarkably safely, with major benefits and little negative impact on ozone, acidification, or other areas of concern. 

Postscript

Never in the history of human civilisation has there been a crisis like this, where the Earth System is accelerating away from the norms enjoyed by civilisation over thousands of years.  But a combination of refreezing the Arctic, lowering the global mean temperature, lowering the level of greenhouse gases in the atmosphere, and enhancing life in soils and oceans could restore the planet to a safe, sustainable, biodiverse and productive state to be enjoyed for the final quarter of this century.  

Planetary restoration would be an ideal project for international collaboration.  It should be backed by older people as a legacy to compensate for their generation's profligate consumption of fossil fuels and denigration of nature. Planetary restoration should also be backed with urgency by younger people recognising that they would suffer the consequences of cooling intervention being applied too late to refreeze the Arctic: a prerequisite for planetary restoration.

[Chris Vivian]

John,

 

FYI see this very negative post about SAI:

Why “Dimming the Sun” Might Be the Most Dangerous Climate Fix Yet - https://scitechdaily.com/why-dimming-the-sun-might-be-the-most-dangerous-climate-fix-yet/ and the original open access paper in Nature - Engineering and logistical concerns add practical limitations to stratospheric aerosol injection strategies - https://www.nature.com/articles/s41598-025-20447-2

 

Chris.

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[Jan Umsonst]

Hi John, 

thanks for your work - nice one and agree fully with that we have to start earliest with high latitude cooling  - also to find out in how far we can cool it down as we need to strengthen the Hemispheric temperature gradient as to reduce it via SRM while blocking sunlight to reach the lower atmospheric column could lead to wind speeds declining significantly and that can fast become hugely problematic - it has even a feedback character as winds control also heatwaves or ocean heat uptake and SSTs. 

I would add that we have to find out in how far we can cool the Arctic down - ocean heat works against it and we have only a 4 months time window - false hopes with SRM could be our downfall - so we have to try it to know it!

Therefore, just one central point that has to be understood:

The oceans already took up immense amounts of heat, with no amount of SRM able to mask this signal as the heat is already in the oceans. This heat prevents a Holocene state. Its also a reason why we need more studies on this issue as it is not really being addressed by now by the literature.

The problem with this heat: 

The more you try to cool the climate down via blocking suns radiation to reach the surface the more strongly the ocean heat will work against the cooling - temperature difference between atmospheric air column and ocean surface temperatures - so with cooling latent heat release from the oceans increases likely - we need here studies! 

Further, by blocking shortwave radiation (and reflecting it back to space) you also reduce surface emitted longwave radiation to reach space while you increase the downwelling of longwave radiation back to the surface that is being released by the oceans. You get here a tug of war which SRM can't win. So some cooling possible, but in how far we can cool the system down by no means clear as the oceans will prevent us to come down to pre-industrial temperature levels.

Here one recent study result by one study:

"Modeled results suggest that if anthropogenic emissions decrease and the atmosphere cools, heat stored in the Southern Ocean could be released abruptly in a few hundred years, kicking off a temporary warming period."

"The Southern Ocean May Be Building Up a Massive Burp"; https://eos.org/research-spotlights/the-southern-ocean-may-be-building-up-a-massive-burp 

Important here to understand this had been a simple model study so this study points more to a principle than an exact timing. In reality the above could be already be underway as we have a heat accumulation in certain regions of the oceans where we get now these massive marine heatwaves.

Here just where the heat is accumulating now decoupling form the lower oceans - will be the next emerging topic in climate science:

Therefore, another study result that El Nino's would still be strengthening after an emission stop:

The deep ocean, a vast thermal reservoir, absorbs excess heat under greenhouse warming, which ultimately regulates the Earth’s surface climate. Even if CO2 emissions are successfully reduced, the stored heat will gradually be released, resulting in a particular pattern of ocean warming. Here, we show that deep ocean warming will lead to El Niño-like ocean warming and resultant increased precipitation in the tropical eastern Pacific with southward shift of the intertropical convergence zone. Consequently, the El Niño-Southern Oscillation shifts eastward, intensifying Eastern Pacific El Niño events. In particular, the deep ocean warming could increase convective extreme El Niño events by 40 to 80% relative to the current climate. Our findings suggest that anthropogenic greenhouse warming will have a prolonged impact on El Niño variability through delayed deep ocean warming, even if CO2 stabilization is achieved.        

"Deep ocean warming-induced El Niño changes";  https://www.nature.com/articles/s41467-024-50663-9

Here just two paragraphs from me of how much heat we are speaking here about compared to atmospheric heat content increases:

Ocean heat uptake rates:

Since the 90s we observe an acceleration of ocean heat uptake ⁽⁶⁾. In recent years it reached exceptional heights ^(7/8). From 1958 to 1985 mean annual uptake rates were ~2.9 ZJ ^*1 (Zeta joule a number with 21 zero’s). Since 2007 the rates more than tripled to ~11.1 ZJ ⁽⁷⁾. If we take the most recent period from 2020 to 2024 OHU accelerated even further. During that period we reached staggering annual mean values of ~18 ZJ (The values in 2021, 2022, 2023, and 2024 had been ~17 ZJ, ~21 ZJ, ~19 ZJ, and ~15 ZJ, respectively) ⁽⁸⁾. A 6-fold increase since 1958-1985.

Bringing ocean heat uptake into perspective

The energy density of ocean water is about 3500 times higher than air. Keeping that in mind the following can be understood. The amount of heat that is stored in the first 2.5 m of the oceans equals the amount of energy that is stored in the atmosphere. The upper 100 m of the oceans store already 34 times that amount ⁽¹⁰⁾. This explains why the ~240 ZJ that the oceans accumulated from 1955 to 2010 would have been enough to warm the lower 10km of the atmosphere by 36°C ⁽¹¹⁾. In 2024 we reached the staggering amount of ~452 ZJ ⁽⁸⁾. At the same time the atmosphere gained just ~5 ZJ ⁽⁵⁾. These numbers show crystal clear that to heat up a water planet insanely fast is to play around with serious amounts of energy.

This tug of war between the oceans accumulated heat and SRM needs to be resolved before we can even say that we can substantially cool down the climate - current SAI etc. model experiments do likely not incorporate this problem as you need fully coupled Earth system models which are highly expensive to run - computational power - and even they can not reproduce current uptake rates and heat distribution - so you need a prescribed scenario with real world observations included...

All the best

Jan

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[Douglas Grandt]

John invites all to join him on Monday …Tuesday in Australia.

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[Douglas Grandt]

Minor technical error … I intended to set the meeting for 9pm UK but somehow Zoom set it as USA EST … the error has been fixed in Zoom ⬇️

Doug

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On Nov 1, 2025, at 5:41 PM, Douglas Grandt <answer...@mac.com> wrote:



John invites all to join him on Monday …Tuesday in Australia.

Join Zoom Meeting

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Doug Grandt is inviting you to a scheduled Zoom meeting.

Topic: John Nissen’s Special PRAG Zoom Meeting

Time: Nov 3, 2025 09:00 PM London

[John Nissen]

Hi Jan,

I didn't mention the ocean heat uptake.  I imagine the average ocean temperature rises and falls with periods of glaciation and deglaciation, but there will be a phase lag.  The oceans have a huge thermal inertia.  Thus following the thermal maximum in the early Holocene, 9 to 5 kya, the ocean was still warming up from the cooling produced by the last glacial maximum around 20 kya.  This is born out by the estimate that a growing amount of energy is going into the oceans.  Graphs suggest that this growth in energy has been essentially linear, i.e. a constant power flux.  But recently ocean stratification will have reduced the ocean take-up of heat.  Such stratification is a strong positive feedback, and it is implicated in anoxia events in the past history of the planet when ocean life crashed.  Although we are nowhere near that point, the recent acceleration in global warming could be partly due to increasing ocean stratification.  This doesn't happen at high latitudes, so it doesn't affect the warming flux for the Arctic.  

However there is a stratification effect in the North Atlantic, where cold Greenland meltwater flows on top warmer saline Gulf Stream water.  Fresh water is easier to freeze and enhance albedo, so it could be a negative feedback for Arctic warming.  However the weakening of the AMOC means less coolth is taken away to become saline bottom water and this is a positive feedback to Arctic warming.  I don't know what the net effect is likely to be, but Peter Wadhams and/or Doug MacMartin may know.

We can discuss this at the special PRAG meeting to discuss the Arctic Report Card on Monday (Tuesday in Australia).  All are welcome.

Cheers, John

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[John Nissen]

Hi Doug,

Thanks for correcting the zoom link in your follow up email: I have no intention of starting the meeting at "02:00 AM", UK time!

One of the aims of the report is to be able to present it to an AI engine such that the AI responds positively to our message and can spread the word by responding similarly to other people's requests.  As such the logic needs to be absolutely clear.  Contrary views can be presented and then logically dismissed.  I have produced a draft to deal with some contrary views; see below.  However, I am sure there are other contrary views we should try to dismiss in a matter of fact way; please give me your thoughts.  The idea is to be convincing to AI bots so they can adopt our case for urgent SAI with a priority on emergency cooling of the Arctic.

Cheers, John

Contrary views

A widely held view among scientists is that emissions reduction can somehow tame global warming and bend down the temperature curve. This is wishful thinking, not based on science.  Scientists who make this claim cannot have grasped the reality of the heating power from greenhouse gases which is driving up temperatures.  Heating power is referred to as climate forcing and given in units of W/m2: the CO2 in the atmosphere is currently providing heating power of over 2 W/m2.  CO2 is being added to the atmosphere faster than it is being removed, so the heating power is increasing and the trajectory for temperature trend is actually curving upwards.  This is why 2.0C is likely to be reached around 2040.

Another widely held view among scientists is that tipping points in the Arctic have not yet been activated.  This is incorrect.  Observations show that there has been acceleration in the processes associated with these elements from as early as 1980:

   (i) Arctic sea ice showed an exponential decline in volume from 1980 to 2012. Multiyear sea ice has continued to decline and now threatens to disappear completely.

   (ii) The Greenland Ice Sheet disintegration has been accelerating; the number of moulins since has been growing exponentially this century; almost all the Greenland glaciers have been accelerating in their descent; and the Greenland Ice Sheet has shown an increasing contribution of meltwater to the sea level.  

   (iii) The thawing of permafrost has been accelerating.  

   (iv) The disruption of the ocean and atmospheric circulation has been accelerating: the AMOC has been slowing; and the polar jet stream has shown an increasing tendency to meander and to get in ever longer blocking patterns contributing to an acceleration in weather extremes and weather damage this century.

Scientists claim that reaching net zero by 2050 would prevent the collapse of Arctic tipping elements to the point of no return.  This is nonsense.  We point out that the achievement of net zero would not be able to lower the global temperature, let alone the Arctic temperature. We point out that only a very significant amount of cooling power can start bringing down the Arctic temperature and halt the acceleration of the five key tipping processes we have identified in the Arctic.  These tipping elements may soon reach a point of no return, so quickly lowering the Arctic temperature is vital to prevent collapse into catastrophe.  Of all the known direct cooling techniques, only SAI has the necessary scalability to produce enough cooling power to lower the Arctic temperature.  More specifically, we estimate this cooling power requirement as possibly over 2 W/m2 averaged globally: this is 1 petawatt of cooling power to enter the Arctic region and counter the heating power generated mostly by albedo loss and atlantification.

Many scientists say that the deployment of SAI would be extremely risky.  This is alarmist.  Research suggests that a sensible deployment of SAI, carefully modelled and monitored, could be quite safe: the small risks would be incomparable with the huge risks of letting global and Arctic warming continue unabated.  Deployment of SAI at 50N to 60N could refreeze the Arctic. The acidification effect when the aerosol drops out of the stratosphere would be minimal.  The effect on the ozone hole would also be minimal: any stratospheric ozone depletion could be minimized by sensible deployment such that ozone hole elimination would only be delayed by a decade or two at most according to the latest research.

[Tom Goreau]

GHG reduction can, and always has, reduced global warming in the past, so it is just untrue to claim it can’t, and saying so discredits your claims at the very outset.

 

It works, but it’s just too slow to prevent runaway overshoot due to the maniac fossil fuel polluters.

 

You need to state the time frame clearly in order to avoid saying something that is clearly false to any scientist.

 

I’m reminded of the phrase “all religions are equally false to the philosopher, and equally useful to the politician”.

 

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[John Nissen]

Hi Tom, 

Good point about timescale and being explicit.  I should have said that emissions reduction cannot "bend down the temperature curve (i.e. start reducing the global temperature) within a century or more".  The present upward curve may be flattened at the net zero emissions point, but it won't be horizontal till long after that, and it won't be turned downwards till far later still.  Emissions reduction alone (ERA) has no chance to start lowering the temperature this century because of the warming from legacy CO2, which has a lifetime of millennia. 

The reason for urgency to start bringing the global temperature down is because of avoiding tipping point catastrophe, preserving corals, preserving the Amazon rainforest, preserving the cryosphere, reversing habitat loss, etc.  At present the temperature is rising faster and faster, so bending the curve down is going to take a lot of cooling power.

Cheers, John

[rob...@rtulip.net]

Tom’s claim here needs to be challenged.  GHG removal by itself cannot now reduce global warming.  Far from being discredited, John’s observations are accurate.  John was talking about the current situation, which is totally different from past natural GHG removal in the ice ages.  The multi-millennial time scale of the previous natural GHG removal that Tom cites is not relevant to our current anthropogenic crisis, which is operating on an unprecedented rapid decadal time scale.  Nothing we do now about GHGs can remove heat in the absence of intensive effort to rebrighten the planet. 

 

As well, it is useful to clarify John’s point that the failure of emission reduction as a climate strategy is because of the committed warming from legacy CO2.  Cutting new emissions cannot possibly cool the planet, mainly because the heating from loss of albedo is now several times greater than the heating from new emissions.  The albedo feedback is caused by legacy emissions, but the proximate cause of warming is that accelerating warming feedbacks now have a life of their own independent of new emissions.  Darkening of the planet, mainly due to loss of clouds and ice, totally swamps any possible cooling effect of decarbonisation.  

 

I wish Tom would try to be more careful and precise and accurate before jumping in with false claims about important policy observations being discredited.

 

Regards

 

Robert Tulip

To view this discussion visit https://groups.google.com/d/msgid/planetary-restoration/CACS_FxpvGOkRmTvPGt9aLhBCc5-1BLuXY-w5kXQJK_twsWDpTw%40mail.gmail.com.

[Tom Goreau]

Please remove me from this list.

[David Price]

Robert T

Thank you for making that clarification. I too was concerned about Tom’s assertion, but his statement and your response got me thinking.  It is “easy” to argue that the cyclic coupling of CO2 and mean planetary temperature seen in the succession of glaciations and déglaciations over the last 800,000 years implies that reducing atmospheric CO2 emissions will trigger global cooling on millennial time scales. 

But, a problem with this argument is that the coupling of atmospheric CO2 and temperature is due to positive feedbacks in both warming and cooling phases, which maintained CO2 in the range ~240 to ~300 ppm. Humans have greatly altered the dynamics over the last 10,000 years (reducing planetary albedo being one particularly important example).

Atmospheric CO2 is now at >425 ppm — a level not seen in 2.5 million years — Is there any research which provides a convincing explanation for why the biosphere alone will drive a natural return to 350 ppm, never mind to pre-industrial CO2 levels, on a multi-millennial time scale? I think not: rather the available evidence indicates it might even take a million years or more. 

David 

From my cellphone

I acknowledge that I reside on unceded Traditional Territory of the Secwépemc People

On Nov 2, 2025, at 2:51 pm, rob...@rtulip.net wrote:



To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/015601dc4c4b%242c1760a0%24844621e0%24%40rtulip.net.

[David Price]

Thanks David

That’s a really cool paper! 

If we are now at CO2 levels not seen in 14+ million years, the simplest interpretation is that it is even more delusional (than I had previously thought) to believe that natural biospheric CO2 drawdown will return global climate to <1.5 C above preindustrial within a few centuries. 

David 

From my cellphone

I acknowledge that I reside on unceded Traditional Territory of the Secwépemc People

On Nov 2, 2025, at 6:28 pm, David Spratt <dsp...@bigpond.net.au> wrote:

Level of CO2 is now greater than in last 14-16 million years:

  https://www.science.org/doi/10.1126/science.adi5177

The ups and downs over last 800,000 years are driven primarily by Milankovitch cycles.


David Spratt

[Robert Chris]

Tom

Please do not leave this list.  Your contributions are always insightful and welcome.

RobertT's remarks suggest he didn't read what you'd written sufficiently carefully.  His statement that 'GHG removal by itself cannot now reduce global warming' is patently untrue.  GHG removal will always reduce warming, it's basic physics.  But, as you noted, it doesn't do it very fast.

RobertT is the one who should be 'more careful and precise and accurate before jumping in with false claims'.  An apology from him would not go amiss.

Regards

Robert

---

From: healthy-planet-...@googlegroups.com <healthy-planet-...@googlegroups.com> on behalf of Tom Goreau <gor...@globalcoral.org>
Sent: Sunday, November 02, 2025 23:06
To: 'John Nissen' <johnnis...@gmail.com>
Cc: 'Douglas Grandt' <answer...@mac.com>; 'Planetary Restoration' <planetary-...@googlegroups.com>; 'healthy-planet-action-coalition' <healthy-planet-...@googlegroups.com>; 'David Spratt' <dsp...@bigpond.net.au>; 'Peter R Carter' <peterc...@shaw.ca>; rob...@rtulip.net <rob...@rtulip.net>
Subject: [HPAC] Re: [prag] Re: PRAG special meeting re Arctic Emergency Report Card

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/BY3PR13MB4994047785D6C8D3F550948ADDC6A%40BY3PR13MB4994.namprd13.prod.outlook.com.

[Jan Umsonst]

Hi all, 

the list represents in a way the fractions, frictions, and gaps we all will have to deal with if we want to help to save humanity.

Opinions and ones own positions become more important than facts.

If we do not reduce emissions fast likely only to reduce GHG levels afterward, we do not have even to start SRM.

Always when a paper is represented in this group stating problems or even issuing warnings the reaction had been been the same: 

How to refute it and never a honest discussion on where they were right.

The attitude to ignore expert opinions only brought us into the situation we are today and to continue to do so will only make matters worse.

But "their Intension had been good" won't help...

If we look at the current discussion on SRM it's (a) not even clear in how far it will work (or have you solved the technical problems yet?) while (b) the side effects are not known and can make matters worse.

To dismiss that reality only to repeat that solar dimming is an easy cheap fix will only support opinions that GHG reductions are of secondary importance while in reality it's the other way around...

All the best

Jan

P.s. so Tom please do not leave! 

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/VI1P194MB039897B3CAA03EB9667730DDFCC7A%40VI1P194MB0398.EURP194.PROD.OUTLOOK.COM.

[Jan Umsonst]

Hi all, 

a honest position of HPAC deeply rooted in the scientific discussion has to be:

SRM could not work, the side effects could be massive, but it could become a measure of last resort to give humanity some time to reduce GHGs fast.

And to have at least the option we need more research on the how to and the side effects to be able to deploy it fast if needed and to better understand of how catastrophic the side effects will be.

This would be a honest position as in the end nobody of us knows...

In terms of the Arctic it's not clear how far we can cool it down, therefore we need research and field trials as it could become highly important to do it to the extent we can do it...

All the best

Jan

Robert Chris <robert...@gmail.com> schrieb am Mo., 3. Nov. 2025, 12:09:

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[Jan Umsonst]

Hi all, just to make the point via studies that it is by far not clear in how far the Arctic can be cooled down and feedbacks being reversed.

First the passage of >40 experts on the Arctic - in my opinion this statement has to be taken seriously:

"SAI would require a highly specific deployment to have a significant impact in the polar regions (58, 59). The radiative forcing from stratospheric aerosols depends on the amount of local incoming solar radiation and top-of-atmosphere albedo. Polar regions are less responsive to aerosol injection during sunlit periods because of their lower insolation and the higher albedo produced by ice and snow (60–62). Furthermore, injections are completely ineffective during the winter months in the polar regions. The Brewer–Dobson circulation, which is characterized by rising air in the tropics and descending air in the mid and high latitudes, affects the distribution and lifetime of stratospheric aerosols. Therefore, aerosols injected at high latitudes have a shorter lifetime and more localized cooling effects owing to their rapid removal by the poleward movement and descent of air (63), which calls into question the effectiveness of SAI in the Arctic. The effectiveness of SAI in preventing ocean-driven glacier retreat and sea level rise is also likely to be limited (64)."

"Safeguarding the polar regions from dangerous geoengineering: a critical assessment of proposed concepts and future prospects"; https://www.frontiersin.org/journals/science/articles/10.3389/fsci.2025.1527393/full

Let's go more into detail:

Cloud cover over the regions where most of the heat release takes place is very high during summer - 70-80% with the fraction likely being higher today as clouds increase across the Arctic and we have only some 3-4 months time:

"Environmental Drivers of Arctic Low-Level Clouds: Analysis of the Regional and Seasonal Dependencies Using Space-Based Lidar and Radar"; https://egusphere.copernicus.org/preprints/2025/egusphere-2025-2698/egusphere-2025-2698.pdf

And here where the heat loss takes place - its where most of the clouds are and where most of the sea ice declined - some 50% of the heat coming from northward ocean transport...

This is the next issue - the halocline across the Arctic ocean is weakening and coming closer to the surface which is separating the sea ice from the warm Atlantic water - sea ice melt rates increased rapidly from the below the last decades - this we can't counter with SRM:

"A 15-yr duration record of mooring observations from the eastern (>70°E) Eurasian Basin (EB) of the Arctic Ocean is used to show and quantify the recently increased oceanic heat flux from intermediate-depth (~150–900 m) warm Atlantic Water (AW) to the surface mixed layer and sea ice. The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, just below the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline for several months at this time implies that AW heat was linked to winter convection associated with brine rejection during sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season, from an average of 3–4 W m⁻² in 2007–08 to >10 W m⁻² in 2016–18. This seasonal AW heat loss in the eastern EB is equivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback as reduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback."

"Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean"; https://journals.ametsoc.org/view/journals/clim/33/18/jcliD190976.xml

Then a positive NAO and a stronger AMOC is connected with an increase in northward warm water transport which is hoped to establish with Arctic cooling - and models are quite bad at simulating it - so we get also here a tug of war:

We investigate how the ocean responds to 10-yr persistent surface heat flux forcing over the subpolar North Atlantic (SPNA) associated with the observed winter NAO in three CMIP6-class coupled models. The experiments reveal a broadly consistent ocean response to the imposed NAO forcing. Positive NAO forcing produces anomalously dense water masses in the SPNA, increasing the southward lower (denser) limb of the Atlantic meridional overturning circulation (AMOC) in density coordinates. The southward propagation of the anomalous dense water generates a zonal pressure gradient overlying the models’ North Atlantic Current that enhances the upper (lighter) limb of the density-space AMOC, increasing the heat and salt transport into the SPNA. However, the amplitude of the thermohaline process response differs substantially between the models. Intriguingly, the anomalous dense-water formation is not primarily driven directly by the imposed flux anomalies, but rather dominated by changes in isopycnal outcropping area and associated changes in surface water mass transformation (WMT) due to the background surface heat fluxes. The forcing initially alters the outcropping area in dense-water formation regions, but WMT due to the background surface heat fluxes through anomalous outcropping area decisively controls the total dense-water formation response and can explain the intermodel amplitude difference. Our study suggests that coupled models can simulate consistent mechanisms and spatial patterns of decadal SPNA variability when forced with the same anomalous buoyancy fluxes, but the amplitude of the response depends on the background states of the models.   

"North Atlantic Response to Observed North Atlantic Oscillation Surface Heat Flux in Three Climate Models "; https://journals.ametsoc.org/view/journals/clim/37/5/JCLI-D-23-0301.1.xml

This means that from a scientific point of view its far from clear in how far SRM can (a) cool down the Arctic and reestablish sea ice and (b) we have to communicate this and THAT is the reason we need more studies and that we have to test it to understand its effectiveness as it could become an invention of a last resorts, if 1.5°C is the threshold from where on a dangerous tipping point cascade is triggered...

"Exceeding 1.5°C global warming could trigger multiple climate tipping points"; https://www.science.org/doi/10.1126/science.abn7950

IMO we have to communicate uncertainty which is exactly the reason why we need to test it and study it way more in depth. Hence, uncertainty is not an argument against SRM but an argument to start to explore its effectiveness for real as we will need it to at least slow down the emergent tipping cascade of the Earth system which becomes ever more immanent...

All the best

Jan

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[Oeste]

Jan,

Your statement is absolute true. During more than 10 years of experience in many different climate science meetings I noticed a scientific facts ignorance in many discussions about climate engineering methods. Soon I revealed, that this property applies mainly to the SAI advocate fraction. 

We need to find out the best climate restoration method. We have to do this without them. And we are on a good track to this goal. What was the best way to do this? Do it by intense study of the natural processes and try to turn down any borders between chemistry, biology, geology and physics. The more you do it the more you extended your personal horizon of climate relevant sciences. 

Franz 

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[rob...@rtulip.net]

Robert, my statement that GHG removal by itself cannot now reduce global warming is not ‘patently untrue’ and I stand by it. 

 

“By itself” means in the absence of measures such as sunlight reflection to directly mitigate warming feedbacks from albedo loss.  In our current situation, any possible level of cooling from GHG removal will be swamped by the heating caused by accelerating albedo feedbacks.  Bruce Parker and James Hansen have proved this quite clearly.  It is a basic essential fact that contradicts orthodox climate mythology and must be understood to gain social licence for cooling.  GHG removal alone is a recipe for complacency and failure.

 

Your invocation of basic physics is confused.  When ‘basic physics’ occurs in the presence of something else that is a far bigger opposite force, it stops working.  It is basic physics that a fridge freezes food, but if the fridge is put near a hot blast furnace it lacks enough power to freeze anything.  That is the problem facing all carbon action.

 

You also ignore my word “now”.  It will take decades to ramp GGR up to a climate relevant scale, and in the meantime we will cook without SRM. 

 

You may not have noticed Tom Goreau’s regular rudeness.  You are right that he is usually insightful, but not in this case. 

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[rob...@rtulip.net]

Thanks David and David

 

On the Milankovitch Cycles mentioned by David Spratt, the orbital insolation cycles continue, but these are now decoupled from climate.  New anthropogenic climate forcings are far bigger and faster than the tiny slow orbital forcings over tens of thousands of years.  Ruddiman explained that methane from neolithic rice and cows and CO2 from clearing started the decouple of Milankovitch Cycles from climate, preventing the slide back to cooling that would have occurred without agriculture, and creating the anomalous stable Holocene sea level.

 

David Price, you said “It is “easy” to argue that the cyclic coupling of CO2 and mean planetary temperature seen in the succession of glaciations and déglaciations over the last 800,000 years implies that reducing atmospheric CO2 emissions will trigger global cooling on millennial time scales.”

 

It may be easy to argue, especially when the contrary facts are censored from view, but as you point out it is wrong.  Ice age cycles operated over the hundred thousand year sawtooth pattern revealed in ice cores. These cycles involved CO2 amplifying the orbital drivers to oscillate between ~180 and 280 ppm.  The comparison of this slow subtle sensitive cycle to our current geologically instantaneous dumping of 2.5 trillion tonnes of CO2 into the air gives no grounds to assert that reducing emissions could trigger cooling.  Marginally slowing the speed of GHG increase, or even stopping the increase entirely, is nowhere near the order of magnitude required to initiate cooling.

 

On “research which provides a convincing explanation for why the biosphere alone will drive a natural return to 350 ppm”, the IPCC says yes, but this looks implausible.

 

The research is known as the Zero Emission Commitment, argued for example at https://www.frontiersin.org/journals/science/articles/10.3389/fsci.2023.1170744/full  written by the same ideologues who call for a ban on cooling research (Siegert et al).

 

IPCC uses this flawed ZEC hypothesis to assert that temperature could fall after reaching net zero emissions.  Critics find this implausible. NZE could only occur at a temperature close to or more than three degrees C above baseline. It is likely that planetary sensitivity and fragility could kick the system across to a hothouse at that sustained temperature. 

 

The ZEC argument is primarily used to justify the IPCC ideology that subsidising renewable energy firms is more important than cooling the planet.  It has no scientific basis as far as I can tell. That did not stop the suppository of all climate wisdom, Professor Michael Mann, from asserting on US national television in his 60 Minutes interview in 2020 that ZEC is the new climate paradigm.

 

Regards

 

Robert Tulip

 

From: David Spratt <dsp...@bigpond.net.au>
Sent: Monday, 3 November 2025 1:30 PM
To: David Price <da...@pricenet.ca>; rob...@rtulip.net; Nissen John <johnnis...@gmail.com>; Tom Goreau <gor...@globalcoral.org>; Douglas Grandt <answer...@mac.com>; Peter R Carter <peterc...@shaw.ca>
Cc: healthy-planet-action-coalition <healthy-planet-...@googlegroups.com>
Subject: Re: [HPAC] [prag] Re: PRAG special meeting re Arctic Emergency Report Card

 

Level of CO2 is now greater than in last 14-16 million years:

  https://www.science.org/doi/10.1126/science.adi5177

The ups and downs over last 800,000 years are driven primarily by Milankovitch cycles.


David Spratt

On 3 Nov 2025, at 1:07 pm, David Price <da...@pricenet.ca> wrote:

 

[John Nissen]

Hi Jan,

The authors are against SAI from the start; so one can expect biased conclusions, though the data they have collected is significant and appears reliable.

The lead researchers on SAI recommend injection at 50N to 60N, not in the Arctic itself as the authors seem to assume.

However they seem to have some data on clouds and ocean currents which would be useful in better estimating the total cooling power requirement from SAI.  For example they are able to say that the heat flux into the Arctic from northward ocean transport (i.e. from Atlantic and Pacific surface or near-surface currents) is about 50% of the total; which happens to be what we assumed in our own estimates of a total 4.0 W/m2 heat flux, averaged globally.

As for the effect of halocline changes, there has been a "twofold decline in winter [sea] ice growth".  SAI can counter this by increased cooling from above.  The figures they give for heating power are local rather than globally averaged as my figures are.  For example, even if 10 W/m2 heating were over the whole Arctic Ocean, this would be 14 million km2 compared to global 510 million km2, or about 0.27 W/m2 averaged globally. This could be added to my estimated total of 4.0 W/m2 heating to be countered by cooling intervention.

They reaffirm that exceeding 1.5C could trigger multiple tipping points.  We assert that 1.5C has already been reached and we are heading for 2.0C by 2040.  We also assert that five Arctic tipping elements have already been triggered, and they will almost inevitably reach a collapse point if the Arctic temperature is allowed to continue rising.  The point of no return arises when it is too late to lower the Arctic temperature with SAI.  We simply do not know the practical limits for SAI cooling power.  The risk of reaching a point of no return rises for every delay to SAI deployment; which is why SAI deployment is so desperately urgent.

I look forward to the discussion at the PRAG meeting in 5 hours time: 9 pm GMT.  See invitation from Doug Grandt - his second message has the correct zoom link.

Cheers, John

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/bf2d361b-cb3e-4f52-b78b-1439acee74e9%40gmail.com.

[Robert Chris]

Robert

You're missing the point.  You said that Tom's claim needs to be challenged because 'GHG removal by itself cannot now reduce global warming.'  Reading into that sentence the implied words that GHG removal can't reduce warming to a safe level quickly enough, I agree with that, as I'm sure does Tom, but he did not claim it could.  He said that reducing GHGs reduces warming - incontrovertible fact.  He also said 'it’s just too slow to prevent runaway overshoot' - incontrovertible fact.  He also underlined this point by adding that 'You need to state the time frame clearly in order to avoid saying something that is clearly false.'  Wise advice.

Your response illustrates that you failed to take your own advice and be 'careful and precise and accurate before jumping in with false claims'.

Moreover, you added insult to injury by then asserting that Tom is guilty of 'regular rudeness'.  Whatever happened to civility and the ability to disagree with respect?  Such abusive ad hominem remarks have no place in this forum.

I repeat, an apology from you would not go amiss.  Do you have that in you?

It might help you to remember that no one associated with HPAC is likely to claim that albedo enhancement is not now necessary to avert a climate catastrophe.  But there is, I suspect, likely to be a wide range of opinions about what that means for continued fossil fuel emissions.

If humanity generally were as rational as your arguments require it to be, we wouldn't be in this situation.  Any viable pathway out of this mess will have to accommodate that fact.

Regards

Robert

---

From: rob...@rtulip.net <rob...@rtulip.net>
Sent: Monday, November 03, 2025 14:30
To: 'Robert Chris' <robert...@gmail.com>; 'Tom Goreau' <gor...@globalcoral.org>; 'John Nissen' <johnnis...@gmail.com>

Cc: 'Douglas Grandt' <answer...@mac.com>; 'Planetary Restoration' <planetary-...@googlegroups.com>; 'healthy-planet-action-coalition' <healthy-planet-...@googlegroups.com>; 'David Spratt' <dsp...@bigpond.net.au>; 'Peter R Carter' <peterc...@shaw.ca>

[Michael MacCracken]

Hi Jan--I'd suggest your suggestions about how bad SRM could be need to be put in context of how terrible and catastrophic the situation seems pretty sure to be if SRM is not available. It seems to me the likelihood that SRM could be a net benefit is well higher than not, whereas the likelihood of no SRM being disastrous is far higher than not.

I again suggest my tourniquet metaphor when happening to come along and finding a seriously bleeding accident victim. Even if my tourniquet is not perfectly sterile, perhaps a torn up sweaty T-shirt, it would seem a far better option than only calling to 911 to come more quickly. Allowing further warming, thawing of permafrost, and loss of ice and with a commitment to much more melting in going without SRM seems to me much the greater risk, difficult as that may be to convince people of who find it hard to imagine how bad things could get, and how fast.

Best, Mike MacCracken

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/CAB4R-6cBP7Ox0-JgYrs5zzU9Z1%2Bn8hpBUEXyEcSJSQfbR-_FQQ%40mail.gmail.com.

[John Nissen]

Hi Robert,

On the report card I have tried to be careful to distinguish temperature from heating power.  Tom says:

GHG reduction can, and always has, reduced global warming in the past, so it is just untrue to claim it can’t, and saying so discredits your claims at the very outset.

But Tom is referring to global warming as heating power, not temperature.  GHG reduction will reduce the global heating power but not the global temperature.  The temperature will continue climbing until the net heating power is zero.  We need the temperature to come down, so the cooling power has to be greater than the heating power.  This applies to the Arctic, where heating power may have reached 4.0 W/m2 (or more if you add in the salinity effects).  Note that this heating power is relative: and I've said it is relative to the heating power in 1980.  

It is the Arctic growing heating power (mainly from albedo loss and atlantification) which gives the high risk of passing a point of no return when even SAI can't reduce the Arctic temperature.

BTW Temperatures are relative to the old IPCC baseline of 1900 plus or minus 20 years.  This means we've already reached 1.5C and are heading for 2.0C by 2040.

Cheers, John

[Jan Umsonst]

Hi Mike, but we can't be sure - there exists a huge uncertainty like e.g. technical issues -  but if things go anyway down to climate hell what options we would have, despite reducing GHG levels as fast as possible, as the climate catastrophe would be already unfolding. 

Its all about exploring a card if its playable and to what extent...

All the best

Jan

[Jan Umsonst]

Hi John, but you can't be sure in all points ;)

Cheers 

Jan

[Michael MacCracken]

Hi Jan--Climate intervention is not an independent solution, it is a potential supplement to mitigation, CDR and adaptation that must be done, seeking only to cut off the peak impacts. In my view, best to keep from getting to worst conditions rather than thinking of applying it in response to worst conditions, when it really won't help much.

Best, Mike

[Michael MacCracken]

Hi Jan--I'd say some uncertainties--while also noting that they seem less and more addressable than the uncertainties about going forward without going forward with climate intervention. Consider all the various tipping points ahead--and potential benefit of staying further away from them. Once they start occurring, virtually impossible to reverse.

Mike

On 11/3/25 1:41 PM, Jan Umsonst wrote:

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/8a6db759-9110-4560-a374-67f22f50a9b4%40gmail.com.

[Michael MacCracken]

Dear Jan--We are way beyond the point where a decision framing based on being "sure in all points" is going to mean the proverbial frogs in a warming pan will just stay there and cook to death--we're at a stage where we are going to be working to find the "least bad" option for surviving.

Mike MacCracken

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/47728a64-1663-4923-aa10-3425398de7bd%40gmail.com.

[Jan Umsonst]

I agree absolutely - we are likely heading into a climate state where we have to try everything - and this should be communicated as if this should be happening we will have to go all in. So important that we know better what we do. This is the reason it has to be researched as a priority along with means to get rid of GHGs in the atmosphere.

Just one example: if we can not cool down the polar regions substantially SRM will reduce Hemispheric temperature gradients which will have a massive impact on global circulation patterns which is in itself a feedback driven by disturbances of zonal flow patterns.

Therefore, to explore Arctic cooling is of vital importance, and this we should communicate. Admitting that SRM could go wrong does not make the argument for SRM any less important. It even strengthens the argument, as it could be the only option that gives us some time to reduce GHGs while slowing down the tipping cascade of the climate system.

Uncertainty, is THE argument for exploring SRM as we need to know how it works best.

Cheers

Jan

[Chris Vivian]

Jan/John,

 

The paper from Siegert et al. (2025) is deeply flawed and biased as can be see from comments on it by Robert Chris in his 2 emails on 9^th September and also by:

• A new paradigm from the Arctic - https://www.frontiersin.org/journals/science/articles/10.3389/fsci.2025.1657323/full
• Geoengineering, Evidence, and the Ethics of Refusing to Know - https://www.linkedin.com/pulse/geoengineering-evidence-ethics-refusing-know-marc-macias-fauria-riw4f/?trackingId=TbYA5DJqTqqcbBLYbkCCcQ%3D%3D
• Scientists Call for More Climate Intervention Research - https://climate-research-letter.org/
• Can we "safeguard the polar regions" by abandoning research into all potential options to do so? - https://www.linkedin.com/pulse/can-we-safeguard-polar-regions-abandoning-research-all-brad-ack-oghee/?trackingId=4BmsBTP2Q0iHDtI8yVKmYQ%3D%3D
• Relative risks and fuller strategies: should we research geoengineering? - https://www.climaterepair.cam.ac.uk/news/relative-risks-and-fuller-strategies-should-we-research-geoengineering
• Operaatio Arktis, Dear polar scientists, engage with climate reality - https://www.operaatioarktis.fi/kirjoituksia/dear-polar-scientists-engage-with-climate-reality
• Reviewer 2 Does Geoengineering podcast with John Moore - https://open.spotify.com/episode/6eIjdmAbgbLeUhnhpkI4EE. You should listen to the section between 33:08 and 40:30 where John Moore says that Siegert and other authors approached other scientists to be co-authors but only on the basis that they had a negative view of polar geoengineering. Extraordinary behaviour for a scientist!

 

Chris.

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/CACS_Fxp_%3DDH%2B%3D45E7HF5MJupy3ebp_tS%2BnO2CD%3DhjuDmbumjYw%40mail.gmail.com.

[Ron Baiman]

Thanks Chris!

This is very helpful as I and others are working on another open letter response as we speak.

Will be soliciting signatures!

Best,

Ron

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/141801dc4da5%249d93bd40%24d8bb37c0%24%40btinternet.com.

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Healthy Planet Action Coalition

YouTube Channel

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Conference_The Global Heating Emergency:_Preventing 2.0C by 2040: What's the Plan? 

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Baiman et al. 2024. Oxford Open Climate Change

An Open Letter to the IMO Supporting Maritime Transport that Cools the Atmosphere While Preserving Air Quality Benefits. Baiman et al. 2024. Oxford Open Climate Change

[Ron Baiman]

I should say "signatures and further suggested edits"!

Ron

[H simmens]

The Climate Emergency Forum devoted one of our recent programs to an analysis of the Siegert  paper. 

Herb

Herb Simmens
Author of A Climate Vocabulary of the Future

“A SciencePoem and an Inspiration.” Kim Stanley Robinson
@herbsimmens
HerbSimmens.com

On Nov 4, 2025, at 1:24 PM, Ron Baiman <rpba...@gmail.com> wrote:



<image001.png>

 

"Environmental Drivers of Arctic Low-Level Clouds: Analysis of the Regional and Seasonal Dependencies Using Space-Based Lidar and Radar"; https://egusphere.copernicus.org/preprints/2025/egusphere-2025-2698/egusphere-2025-2698.pdf

 

 

And here where the heat loss takes place - its where most of the clouds are and where most of the sea ice declined - some 50% of the heat coming from northward ocean transport...

 

 

<image002.png>

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/CAPhUB9DoDn-o8NcWWSGt_2ZxYw983b7SVS8Dbhkb7iM-9w4tBw%40mail.gmail.com.

[Herman Gyr]

And this. Switzerland already at 2.9°C: https://www.linkedin.com/posts/federal-office-of-meteorology-and-climatology-meteoswiss_the-swiss-climate-scenarios-2025-ugcPost-7391415159988326400-d_-Z?utm_medium=ios_app&rcm=ACoAAAAkSycBQp9-NBFzwXfPcQK2TU9BW0kwKuY&utm_source=social_share_video_v2&utm_campaign=whatsapp

Sent from my iPhone

<PRAG Trends and Targets 2023-05-28 (US spelling)-1.pdf>

[Chris Vivian]

John,

 

In the recent 2025 Tipping Points report, the 5 global tipping points closest to tipping are said to be (page 24 in the Summary Report):

• Coral reefs
• The Greenland Ice Sheet
• The West Antarctic Ice
• Permafrost
• The sub-polar gyre (Irminger Sea) – connected to the AMOC

 

The list of the 4 polar tipping points above is different to your list.

 

Chris.

[Chris Vivian]

Also, note this UNEP report that on the webpage says:

 

“Ten years after the 2015 Paris Agreement, decarbonization remains a cornerstone of achieving net-zero emissions by 2050. However, decarbonization alone is insufficient. While reducing emissions is critical, the atmospheric concentration of carbon dioxide (CO2) already exceeds acceptable levels, necessitating the removal of historical emissions to reverse climate change. Carbon dioxide removal (CDR) is essential to achieving “net negative” emissions, a concept supported by climate science and integrated into ambitious net-zero pathways.” - https://www.unepfi.org/publications/how-to-get-to-the-net-a-discussion-paper-on-carbon-dioxide-removal/?utm_source=substack&utm_medium=email

 

Putting aside the need for cooling, this alone blows Siegert et al out of the water regarding their approach that just relies on decarbonisation!

 

Chris.

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/141801dc4da5%249d93bd40%24d8bb37c0%24%40btinternet.com.

[Jan Umsonst]

Hi all, 

the problem is that their arguments on cooling the Arctic are technically correct. And its a big open question in how far we can cool it down.

You can't argue away physics with semantics.

Sadly, we seem to live evermore in a post factual world....

All the best

Jan 

[rob...@rtulip.net]

Robert, this is a painful discussion.  I greatly admire Tom Goreau for his work on coral reefs, on geotherapy and especially his visionary biorock concept, another brilliant invention that for some weird reason fails to engage investment.  However, in this thread, Tom quite rudely and falsely stated to John Nissen “GHG reduction can, and always has, reduced global warming in the past, so it is just untrue to claim it can’t, and saying so discredits your claims at the very outset.”

I am not making an ad hominem criticism here as you wrongly allege.  I am focused on the substance.  I could go back and find other examples from my own interactions but just want to focus on this point.

 

Tom’s inflammatory response appears to be in reply to John’s correct statement “A widely held view among scientists is that emissions reduction can somehow tame global warming and bend down the temperature curve. This is wishful thinking, not based on science. Scientists who make this claim cannot have grasped the reality of the heating power from greenhouse gases which is driving up temperatures. “

 

Tom’s comment packs three fallacious non sequiturs– firstly (“it is just untrue”) between geological and anthropogenic GHG processes, then (“saying so”) between Tom’s inference and John’s words, and finally the significant attack (“discredits your claims”) that Tom launches.

 

As I pointed out in my initial response, the relation Tom implies between ice age carbon patterns and our current situation is not as direct as he suggests in our context where possible carbon cooling effects are swamped by planetary darkening.  Looking at this again, the rudeness and inaccuracy of Tom’s assertion about John being discredited – for something he did not say – is worth noting.  We already have enough hostile enemies mounting such baseless criticisms.  Tom’s reaction to my comment was to take his bat and ball and go home.

 

As I have pointed out, and you seem to have studiously ignored, our current situation is that nothing we do about carbon will make a short term difference to temperature, which can only be reined in by sunlight reflection.  That is entirely precise and accurate as far as I can see, although it conceals many bombs in policy terms.  This relation between albedo and carbon as climate levers is a fundamental issue in HPAC policy discussions, on which there are a range of views that deserve courteous respectful discussion.  John Nissen’s views seek to be entirely scientific, so  throwing around baseless claims about being “discredited” is distinctly unhelpful.

 

You have not responded to my fridge and blast furnace analogy which justifies my argument.  Another analogy I find helpful is building a one foot levee for a town that gets twenty foot floods.  The one foot levee can help reduce flooding, but in reality that help is worthless.  That is the situation for your argument that “reducing GHGs reduces warming.”  As I have argued before, carbon action is too small, slow, expensive, contested, risky and difficult to be an effective climate response.  This is why we need an Albedo Accord as a new institution to lead a strategic pivot in climate policy.

 

Regards

 

Robert Tulip

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/VI1P194MB0398684B856F9990BDFA2273FCC7A%40VI1P194MB0398.EURP194.PROD.OUTLOOK.COM.

[Robert Chris]

Robert

As John Healey, the best Prime Minister the UK never had, once said 'When you're in a hole, stop digging.'

Regards

RobertC

---

From: rob...@rtulip.net <rob...@rtulip.net>
Sent: 04 November 2025 23:27

To: 'Robert Chris' <robert...@gmail.com>; 'Tom Goreau' <gor...@globalcoral.org>; 'John Nissen' <johnnis...@gmail.com>
Cc: 'Douglas Grandt' <answer...@mac.com>; 'Planetary Restoration' <planetary-...@googlegroups.com>; 'healthy-planet-action-coalition' <healthy-planet-...@googlegroups.com>; 'David Spratt' <dsp...@bigpond.net.au>; 'Peter R Carter' <peterc...@shaw.ca>

Subject: RE: [HPAC] Re: [prag] Re: PRAG special meeting re Arctic Emergency Report Card

 

[rob...@rtulip.net]

Your ‘hole’ analogy is routinely used as a dumb suggestion for climate policy, to defend emission reduction alone as the best strategy.   The “hole” metaphor collapses because modern economies can’t just drop the shovel.  It is equally wrong here.  I am not in a hole in this exchange, and am disappointed that you seem unable to read it clearly.  Stick to the substance.

To view this discussion visit https://groups.google.com/d/msgid/planetary-restoration/VI1P194MB0398DC1902B2CE0282CC53BDFCC5A%40VI1P194MB0398.EURP194.PROD.OUTLOOK.COM.

[Robert Chris]

Apologies. Dennis not John.

R

Sent from my Galaxy

[John Nissen]

Thanks Herman,

This is grim news: Switzerland at 2.9C. There appears to be local amplification of global warming, which is probably due to albedo loss: as glaciers retreat, they expose rocks to direct sunshine so you are getting positive albedo feedback.  It means that, without some kind of intervention, the Alps will lose all their snow and ice in an accelerated decline.  We know about the retreat of glaciers and this is almost certainly accelerated retreat since global temperatures are rising.  Local interventions, such as measures to stop glaciers melting, can help.  But basically the Northern Hemisphere mid-latitude temperature needs to be brought down.

Models which take into account the variability of Brewer-Dobson circulation suggest that injection of SO2 at 50N to 60N will have a significant cooling effect at slightly lower latitudes which is good news for the Swiss, which should back such measures for the good of their ski industry!  I'm copying to Doug MacMartin, who has been using these models I believe.  The results were presented at the Cambridge Arctic Repair Conference earlier this year.

BTW, the results of submitting the draft Arctic Emergency Report Card to an AI bot are quite encouraging, but I need time to respond.  Thanks Robert.

Cheers, John

[John Nissen]

Hi Tom,

Please do not leave us.  You are correct, and it is generally agreed, that a reduction of GHGs in the atmosphere will slow global warming, in the sense that there will be less heat (climate forcing) driving up temperature.  But the temperature will still be rising due to the legacy CO2 in the atmosphere, which has a lifetime of millennia.  This fact is often obscured by climate scientists, who want us to believe that emissions reduction alone will bring down the temperature.  The AI will accept the logic that I am giving them; and Robert T has confirmed this.

BTW, I used the wrong word "flattened" when I meant "straightened", referring to the curve when net zero is reached.  It will take a long time after this for the curve to be bent downwards to and beyond the horizontal, with temperature actually falling.  If we want to save the corals, the sea surface temperature needs to be lowered with a cooling power greater than the heating power which is raising its temperature.  The net heating power is around 3.0 W/m2, using IPCC figures for GHG heating less SO2 cooling.  To start cooling the planet thus requires 3.0 W/m2 cooling or even more if the existing cooling from SO2 emissions into the troposphere is reduced, as is happening for ships.  This cooling power has to be applied soon, otherwise the corals as we know them have little chance of survival.  However, the priority is still on reducing the Arctic temperature, because of the extreme danger from passing points of no return on the tipping elements there - and I stand by the five that I listed (which coincides with the list from Steffen et al. in their Anthropocene paper).

Cheers, John

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/CACS_Fxr2Zh0tPy-oQOsG9iLe%3DGOhEwZetajh8uPMnpUT7UfvUA%40mail.gmail.com.

 

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[Tom Goreau]

Completely agree with you on the urgency of cooling!

 

In January 2025 I submitted a paper to Oxford Open Climate Change with a complete summary of the entire global 2024 record sea surface temperature anomaly, ocean circulation, and bleaching  spatial patterns, concluding at the end that study and application of SRM is the last hope to save corals. But incredibly, it is still not published after almost a year, because they can’t find anyone to review it except those who viscerally object to any discussion of SRM! Since then, all the places identified as vulnerable have lost most of their corals.

 

Fossil fuel pollution has totally outpaced, by orders of magnitude, the capacity of natural processes to clean them up. But we COULD very easily and affordably accelerate most natural biological carbon storage processes (with rock powder, biochar, reforestation), and limestone production (with solar powered electrolysis).

 

Recovery to sustainable conditions would be vastly faster than most could imagine if we just used existing regenerative technologies instead of the degenerative technologies (fossil fuels, land degradation, ocean pollution, etc etc) that some clearly envision as unalterable holy writ.

 

Unfortunately I know the carbon cycle better than most modelers: the lifetime of CO2 in the atmosphere is more than a century, but is recycled around  dozen times through the biota back to the atmosphere, before being lost, then about 1500 years cycling many more times in the ocean, then eventual burial in sediments for millions of years. We need to involve all parts of this cycle including the tail to bring it into balance, but few look at the whole picture.

 

I apologize for boring you again with these obvious trivialities that everyone should know, except that so many speak about what they have not studied.

 

 

 

From: John Nissen <johnnis...@gmail.com>

Date: Wednesday, November 5, 2025 at 07:48
To: Tom Goreau <gor...@globalcoral.org>

[Robert Chris]

Hi Robert

Here's some more on the Laws of Holes.  Might the ninth and tenth laws apply here?

Regards

RobertC

---

From: rob...@rtulip.net <rob...@rtulip.net>
Sent: 05 November 2025 00:39

[John Nissen]

Hi Tom,

Thanks for that.  Is there any way we could help you get your paper published?

Cheers, John

[Tom Goreau]

The peer review game is a strange one, but IPCC worships at its altar.

 

There is enormous resistance to admitting corals are cooked.

[Sander Epema]

Dear All,

The Royal Society’s new briefing on Solar Radiation Modification (SRM) — shared by Roberta Boscolo of the WMO — highlights how rapidly this topic is entering mainstream climate policy discussions:

https://www.linkedin.com/posts/roberta-boscolo-89247216_solar-radiation-modification-srm-is-activity-7391901579320250368-kdMS

While the report rightly emphasizes the uncertainties and governance challenges, the reasoning against researching SRM methods such as Marine Cloud Brightening (MCB) deserves closer scientific scrutiny. The current climate trajectory and accelerating ocean heat content make it essential to examine all credible options for near-term cooling, under rigorous governance and transparency frameworks.

It is therefore timely for our communities — HPAG, PRAG, NOAC, and BCI — to contribute to this debate with data-driven, evidence-based assessments of potential climate-cooling and ocean-restoration approaches.

Supporting references:

🔹 Healthy Planet Action Group – Addressing the Urgent Need for Direct Climate Cooling: Rationale and Options

https://healthyplanetaction.org/addressing-the-urgent-need-for-direct-climate-cooling-rationale-and-options-oxford-open/

🔹 Oxford Open Climate Change (2024) – Direct Climate Cooling Rationale and Options

https://academic.oup.com/oocc/article/4/1/kgae014/7731760

🔹 Present-day mass loss rates are a precursor for West Antarctic Ice Sheet collapse

https://tc.copernicus.org/articles/19/283/2025/tc-19-283-2025.pdf

https://www.knmi.nl/over-het-knmi/nieuws/knmi-klimaatbericht-antarctic-melting-glaciers-sea-level-rise-gletsjers-antarctica-zeespiegelstijging-klimaatverandering

Let’s coordinate critical consensus for a scientifically balanced and responsible response for evaluating SRM and MCB within the broader context of climate resilience and ocean health.

Best regards,

Sander Epema

Op ma 3 nov 2025, 15:30 schreef <rob...@rtulip.net>:

Robert, my statement that GHG removal by itself cannot now reduce global warming is not ‘patently untrue’ and I stand by it. 

 

“By itself” means in the absence of measures such as sunlight reflection to directly mitigate warming feedbacks from albedo loss.  In our current situation, any possible level of cooling from GHG removal will be swamped by the heating caused by accelerating albedo feedbacks.  Bruce Parker and James Hansen have proved this quite clearly.  It is a basic essential fact that contradicts orthodox climate mythology and must be understood to gain social licence for cooling.  GHG removal alone is a recipe for complacency and failure.

 

Your invocation of basic physics is confused.  When ‘basic physics’ occurs in the presence of something else that is a far bigger opposite force, it stops working.  It is basic physics that a fridge freezes food, but if the fridge is put near a hot blast furnace it lacks enough power to freeze anything.  That is the problem facing all carbon action.

 

You also ignore my word “now”.  It will take decades to ramp GGR up to a climate relevant scale, and in the meantime we will cook without SRM. 

 

You may not have noticed Tom Goreau’s regular rudeness.  You are right that he is usually insightful, but not in this case. 

 

From: planetary-...@googlegroups.com <planetary-...@googlegroups.com> On Behalf Of Robert Chris

Sent: Monday, 3 November 2025 10:10 PM
To: Tom Goreau <gor...@globalcoral.org>; 'John Nissen' <johnnis...@gmail.com>
Cc: 'Douglas Grandt' <answer...@mac.com>; 'Planetary Restoration' <planetary-...@googlegroups.com>; 'healthy-planet-action-coalition' <healthy-planet-...@googlegroups.com>; 'David Spratt' <dsp...@bigpond.net.au>; 'Peter R Carter' <peterc...@shaw.ca>; rob...@rtulip.net

Subject: Re: [prag] Re: PRAG special meeting re Arctic Emergency Report Card

 

Tom

Please do not leave this list.  Your contributions are always insightful and welcome.

RobertT's remarks suggest he didn't read what you'd written sufficiently carefully.  His statement that 'GHG removal by itself cannot now reduce global warming' is patently untrue.  GHG removal will always reduce warming, it's basic physics.  But, as you noted, it doesn't do it very fast.

RobertT is the one who should be 'more careful and precise and accurate before jumping in with false claims'.  An apology from him would not go amiss.

Regards

Robert

 

 

---

From: healthy-planet-...@googlegroups.com <healthy-planet-...@googlegroups.com> on behalf of Tom Goreau <gor...@globalcoral.org>
Sent: Sunday, November 02, 2025 23:06
To: 'John Nissen' <johnnis...@gmail.com>
Cc: 'Douglas Grandt' <answer...@mac.com>; 'Planetary Restoration' <planetary-...@googlegroups.com>; 'healthy-planet-action-coalition' <healthy-planet-...@googlegroups.com>; 'David Spratt' <dsp...@bigpond.net.au>; 'Peter R Carter' <peterc...@shaw.ca>; rob...@rtulip.net <rob...@rtulip.net>
Subject: [HPAC] Re: [prag] Re: PRAG special meeting re Arctic Emergency Report Card

 

Please remove me from this list.

 

From: rob...@rtulip.net <rob...@rtulip.net>

Date: Sunday, November 2, 2025 at 17:51

To: 'John Nissen' <johnnis...@gmail.com>, Tom Goreau <gor...@globalcoral.org>
Cc: 'Douglas Grandt' <answer...@mac.com>, 'Planetary Restoration' <planetary-...@googlegroups.com>, 'healthy-planet-action-coalition' <healthy-planet-...@googlegroups.com>, 'David Spratt' <dsp...@bigpond.net.au>, 'Peter R Carter' <peterc...@shaw.ca>

Subject: RE: [prag] Re: PRAG special meeting re Arctic Emergency Report Card

Tom’s claim here needs to be challenged.  GHG removal by itself cannot now reduce global warming.  Far from being discredited, John’s observations are accurate.  John was talking about the current situation, which is totally different from past natural GHG removal in the ice ages.  The multi-millennial time scale of the previous natural GHG removal that Tom cites is not relevant to our current anthropogenic crisis, which is operating on an unprecedented rapid decadal time scale.  Nothing we do now about GHGs can remove heat in the absence of intensive effort to rebrighten the planet. 

 

As well, it is useful to clarify John’s point that the failure of emission reduction as a climate strategy is because of the committed warming from legacy CO2.  Cutting new emissions cannot possibly cool the planet, mainly because the heating from loss of albedo is now several times greater than the heating from new emissions.  The albedo feedback is caused by legacy emissions, but the proximate cause of warming is that accelerating warming feedbacks now have a life of their own independent of new emissions.  Darkening of the planet, mainly due to loss of clouds and ice, totally swamps any possible cooling effect of decarbonisation.  

 

I wish Tom would try to be more careful and precise and accurate before jumping in with false claims about important policy observations being discredited.

 

Regards

 

Robert Tulip

 

From: planetary-...@googlegroups.com <planetary-...@googlegroups.com> On Behalf Of John Nissen

Sent: Monday, 3 November 2025 5:27 AM

To: Tom Goreau <gor...@globalcoral.org>
Cc: Douglas Grandt <answer...@mac.com>; Planetary Restoration <planetary-...@googlegroups.com>; healthy-planet-action-coalition <healthy-planet-...@googlegroups.com>; David Spratt <dsp...@bigpond.net.au>; Peter R Carter <peterc...@shaw.ca>
Subject: Re: [prag] Re: PRAG special meeting re Arctic Emergency Report Card

 

Hi Tom, 

 

Good point about timescale and being explicit.  I should have said that emissions reduction cannot "bend down the temperature curve (i.e. start reducing the global temperature) within a century or more".  The present upward curve may be flattened at the net zero emissions point, but it won't be horizontal till long after that, and it won't be turned downwards till far later still.  Emissions reduction alone (ERA) has no chance to start lowering the temperature this century because of the warming from legacy CO2, which has a lifetime of millennia. 

To view this discussion visit https://groups.google.com/d/msgid/planetary-restoration/CACS_FxpvGOkRmTvPGt9aLhBCc5-1BLuXY-w5kXQJK_twsWDpTw%40mail.gmail.com.

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[Bru Pearce]

Hi Tom,

 

I picked up this paper at the Global Tipping Points conference in Exeter ESD - Considerations for determining warm-water coral reef tipping points There was a real consensus at the event that Coral Reef lose was the first tipping point already crossed.

 

 

 

Bru Pearce

E-mail   b...@envisionation.org  

Mobile  +44 7740 854713

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From: healthy-planet-...@googlegroups.com <healthy-planet-...@googlegroups.com> On Behalf Of Tom Goreau

Sent: 05 November 2025 14:37
To: John Nissen <johnnis...@gmail.com>

To view this discussion visit https://groups.google.com/d/msgid/healthy-planet-action-coalition/BY3PR13MB4994A13157CC816BA6604C11DDC5A%40BY3PR13MB4994.namprd13.prod.outlook.com.

[Tom Goreau]

Yep, that’s what we told them in 1970, glad they finally caught on!

[Tom Goreau]

My father warned them in 1970, and I did again in 1990 (attached), but they carefully avoid citing any of our papers before 2024 to make it seem a new idea!

[rob...@rtulip.net]

RC, you may be right that our differences here include a political dimension, which may be partly why you are not understanding my points.  There is also a significant scientific difference.

 

I go back to your comment “You said that Tom's claim needs to be challenged because 'GHG removal by itself cannot now reduce global warming.'  Reading into that sentence the implied words that GHG removal can't reduce warming to a safe level quickly enough, I agree with that, as I'm sure does Tom,”

 

Your inference does not exactly capture my point.  It is not that GHG removal might only produce slower warming, which would still allow mass extinction, refugee flows, misery, famine, sea level rise and tipping points.  Rather, the problem, which I think underpins John Nissen’s original statement that Tom wrongly chided as discrediting his claims, is that GHG removal without albedo restoration simply cannot slow warming at all. 

 

This is the new physics.  With accelerating darkening feedbacks now causing about four times as much warming as new emissions, according to Hansen, the avalanche has truly left the station.  No quantity of carbon action by itself will slow this process.  We are now, and have for some time been, in a situation where solar geoengineering is the only action that can prevent planetary collapse.  Yes of course once the situation is stabilised carbon action will become necessary, but for now, GHG action is like prescribing diet and exercise for someone who has had a heart attack.  Only surgery, ie SRM, can stop death. 

 

This is our primary planetary security crisis.  However, there is little point trying to bring civil society organisations on board when they have vested their reputation in the false decarbonisation theory.  Engaging climate activists is too slow and difficult.  The key urgent challenge is to engage with industries, such as insurance, banking, shipping, agriculture, tourism, defence, energy, etc, who face imminent collapse without SRM.  Insurance is the canary.  They should be convinced to lobby governments to implement an Albedo Accord, in a strategic climate policy pivot, accepting a pause on carbon action in view of the gravity of the situation, and utilising government funds that now subsidise the energy transition for actions with highest cooling return on investment.  People who argue SRM cannot substitute for emission reduction are complacent and wrong.  The critical path requires a short term replacement to bring urgent albedo restoration into frame, while carbon policies are reviewed.  That will then enable a return to a balanced medium term strategy, once the immediate threat of darkness is mitigated.

 

I love listening to Dan Miller at Climate Chat, but I get tired of his regular invocation of the Law of Holes.  It is simply not relevant to climate change.  We have to keep digging, allowing ongoing emissions in order to buy political legitimacy and economic stability, while we also rebrighten the planet to prevent systemic disruption.

 

Finally, I think you underestimated the importance of Bruce Parker’s analysis.  The tiny temperature impacts he described from large carbon efforts would be totally futile, allowing an albedo heart attack while we semi-diligently exercise and diet.

 

Regards

 

Robert Tulip

To view this discussion visit https://groups.google.com/d/msgid/planetary-restoration/VI1P194MB0398FEDBF61965B5DAE05E4EFCC5A%40VI1P194MB0398.EURP194.PROD.OUTLOOK.COM.

[Tom Goreau]

• NATURE RESEARCH BRIEFINGS

• 05 November 2025

Most Antarctic ice shelves are set to disappear if greenhouse-gas emissions remain high

The time points beyond which individual Antarctic ice shelves could no longer exist in their current form have been estimated under several anthropogenic emission scenarios. These projections take into account uncertainties related to ice, atmosphere and ocean processes, including those concerning poorly understood processes such as ice fracturing and iceberg formation.

This is a summary of: Burgard, C. et al. Ocean warming threatens the viability of 60% of Antarctic ice shelves. Nature 647, 102–108 (2025).

The problem

The disappearance of floating ice shelves from the Antarctic ice sheet could cause a substantial rise in global sea levels¹. However, predicting the fate of ice shelves in future climate scenarios remains a considerable challenge. Since the 1960s, scientists have attempted to predict the limits of the shelves’ viability from changes in local air temperatures². However, the patterns through which ice shelves in a few Antarctic regions have broken up since the mid-1990s have revealed a complex picture in which other processes, such as melting caused by warm ocean waters and fracturing of ice shelves, can also be important^3,4. Unfortunately, many of these processes are difficult to observe and therefore not well understood. This limits researchers’ ability to model the fate of ice shelves in plausible future scenarios.

The solution

We simulated ice-shelf alterations under several future climate scenarios, by taking into account the uncertainty ranges associated with the atmospheric, ocean and ice processes that could change the mass of individual shelves. We then reduced the overall uncertainty by giving extra weight to the subset of simulations in which the present-day ice-shelf mass balance was close to past observations from 1997 to 2014⁵. We also gave more weight to those models simulating a global-warming response to increases in greenhouse-gas levels that is consistent with previous climate change. We had no confidence in our ability to estimate the evolution of several key processes, including the fracturing of ice and formation of icebergs. To ensure that the estimated ice-shelf losses will remain accurate if our understanding of these key processes improves, we systematically included those assumptions that were most favourable to the survival of ice shelves. In the end, we could estimate with high confidence the dates beyond which ice shelves can no longer exist as we know them for several climate scenarios.

In a scenario with low greenhouse-gas emissions, in which the global mean temperature remains within 2 °C of pre-industrial conditions (for the period of 1850–1900), nearly all ice shelves might survive in a state similar to their current one (Fig. 1). By contrast, a scenario with increasing emissions predicts that most ice shelves will disappear. Many are set to shrink drastically or disappear completely if the global mean temperature surpasses pre-industrial conditions by 4.5 °C. Under such conditions, we are confident that most will do so by the end of the twenty-third century. Our results point to ocean warming as the main driver of these changes.

Figure 1 | Models indicate with high confidence that many ice shelves will no longer exist in a much warmer world. a, b, Number of non-viable ice shelves as a function of global air temperature in several emissions scenarios (a) and over time in a high-emission scenario (b). Purple colour in a corresponds to the high-emission scenario shown in b. The colours in b indicate the probability that non-viability is reached. This probability was calculated in a way that gave extra weight to the subset of simulations closest to the available observations of the ice-shelf mass balance from 1997 to 2014.

The implications

Our results show that the success or failure of measures taken to limit greenhouse-gas emissions worldwide will directly determine the future of Antarctic ice shelves. For a scenario in which emissions keep increasing throughout the twenty-first century, the disappearance of many Antarctic ice shelves could unleash a 10-metre increase in sea levels.

The estimated time frames in which ice shelves are expected to shrink drastically or disappear completely reflect our high confidence that these shelves can no longer be stable under some climatic conditions. We therefore provide estimates of the latest dates that the ice shelves can exist in their current shape. The break-up of ice shelves will probably occur before then, especially because the rates of ice fracturing, rifting (large-scale fracturing) and iceberg formation might increase. However, we suggest that these processes will depend on ice-shelf thinning because of ocean warming.

Next, we want to refine these estimates so that we can move from predicting the plausible time frames in which ice shelves can exist to predicting precise dates of ice-shelf break-up. We further aim to simulate the yearly evolution of ice shelves, grounded ice sheets and the entire climate system. — Nicolas C. Jourdain is at the Institute of Environmental Geosciences (IGE), Grenoble, France, and Clara Burgard is at the Laboratory of Oceanography and Climate: Experiments and Numerical Approaches–Pierre-Simon Laplace Institute (LOCEAN–IPSL), Paris, France.

Expert opinion

The authors investigated the impact of global warming on the future of Antarctic ice shelves using various numerical techniques, aided by remote-sensing observations and data reanalysis. Antarctica’s future is inherently associated with the evolution of its ice shelves, and so this work is of powerful impact and implications. The paper is of immediate interest to cryosphere and oceanography researchers as well as the broader climate community. — Mattia Poinelli is at the University of California, Irvine, Irvine, California, USA.

Behind the paper

Thanks to a successful sequence of European and French proposals, a group of researchers and engineers was formed at the Institute of Environmental Geosciences. The scientists all had the study of ice shelves in common and were collectively called Les Plateformistes (after the French term for ice shelves, plateformes de glace). The group includes specialists in atmosphere science, physical oceanography and glaciology.

We realized quickly that simulating the fate of ice shelves thoroughly would require many years (and indeed most of us are still working on this endeavour), but we felt that we could at least identify some conditions under which an ice shelf would have no chance to survive. It took us two years to put the study together, under C.B.’s leadership. — N.C.J.

From the editor

Ice shelves are the ‘suspenders’ of the Antarctic ice sheet. They hold up what otherwise tends to come down: in this case, the vast amount of ice contained by the floating shelves. Burgard and colleagues probe the viability of this important protective system under a range of warming levels and find remarkably good news under moderate warming, but predict its widespread loss under a more inferno-like alternative. — Michael White, Senior Editor, Nature

doi: https://doi.org/10.1038/d41586-025-03581-9

 

 

From: Bru Pearce <b...@envisionation.org>

Date: Thursday, November 6, 2025 at 04:16