Are emissions cuts on track to avoid catastrophic impacts? Live Discussion

[Ceri SRM360]

Can current emissions pledges keep us safe – or is the world heading for dangerous overshoot? And are additional climate interventions needed? 

The State of the Climate Report¹ warns that Earth’s “vital signs” are flashing red and that warming may even be accelerating as cleaner air reduces the planet’s reflectivity. Meanwhile, the UN Emissions Gap Report² projects roughly 2.8°C of warming based on current policies, citing a lack of political will to cut emissions even as climate risks intensify.

This evidence suggests a high likelihood of dangerous climate overshoot unless global action accelerates dramatically. This raises the question of whether additional tools, such as sunlight reflection methods, should be considered to reduce near-term risks. 

Live Discussion: Are emissions cuts on track to avoid catastrophic impacts? 

Hear from our expert panel: Simon Evans (Deputy Editor and Senior Policy Editor, Carbon Brief), David Keith (Professor of Geophysical Science and founding Faculty Director at the Climate Systems Engineering Initiative, University of Chicago), and Matt Burgess (Assistant Professor, University of Wyoming).

We’ll explore: 

- The latest data on global emissions and temperature trajectories. 

- What overshooting 1.5°C could mean for the planet. 

- The potential role of solar geoengineering. 

Live Discussion: Are emissions cuts on track to avoid catastrophic impacts? 

4 Dec 2025 

15.00 GMT/10.00 ET 

Can’t join us live? Register to receive the recording.

1.State of the Climate Report 2. Emissions Gap Report   

About SRM360

SRM360.org is a non-profit knowledge broker dedicated to informing people about solar geoengineering, so they can contribute to critical decisions about its research, development, and governance. SRM360 works with experts around the world to create clear accessible content and to bring more people into the conversation. 

Want to learn more? Read our guide: Could SRM Help Reduce Climate Risks? 

[John Nissen]

Hi Ceri,

Thanks for the invitation and I look forward to attending online.

You ask whether the world is heading for dangerous overshoot.  We believe the overshoot happened when global temperatures rose above 0.5C in the 80s and the Arctic sea ice volume started an exponential decline, demonstrating the positive feedback characteristic of a tipping process.

The Planetary Restoration Action Group (PRAG) has been looking at tipping elements in the Arctic to see how close they are to the point of no return at today's temperatures.  To our horror, we discovered that there are five tipping elements which are already activated and are proceeding inexorably towards a point of collapse.  Collapse is liable to produce abrupt and catastrophic climate change, or, in the case of the Greenland Ice Sheet, abrupt sea level rise of several metres.  

Some collapses could occur within a few decades.   Each is like a time bomb with the fuse burning.  Defusing will require powerful cooling, on a scale only practically achievable using Stratospheric Aerosol Injection (SAI).  Deployment is urgent, since every month's delay increases the risk of failure.  The situation is desperate, yet the climate community seems unaware of the extreme danger we all face.  They are still plugging emissions reduction, which cannot reduce temperatures on any meaningful timescale - and we are heading for 2.0C by 2040 with their strategy and 4.0C by 2100 is on the cards.

We therefore wrote to the Financial Times, in the hopes of their publishing our letter to be seen by business and financial people who would understand the security implications.  I have appended the letter to this email.  I am afraid that the logic is inescapable: we are in a crisis of unprecedented proportions and unprecedented cooling intervention is required to defuse the Arctic situation.

I cannot expect you to change your event to reflect this change in perspective; but I would appreciate some consideration by your organisation, whose remit is on SRM.  We are desperate to get our message across, as time is of the essence.  Since the FT has not responded in over a week, we would be delighted if you would publish the letter for us.

Best wishes, 

John Nissen

Chair PRAG

To: the editor of the Financial Times for publication

19/11/2025

 

The necessity for cooling intervention

 

Dear editor,

 

While COP30 focuses on CO2 emissions, the huge danger from Arctic meltdown is being ignored. Five critical “tipping elements” in the Arctic are threatening us: the Arctic sea ice; the Greenland ice sheet; the permafrost with its methane release; the polar vortex and jet stream; and the Atlantic meridional overturning circulation. In each case we are already seeing acceleration towards a point of collapse, threatening catastrophic climate change or sea level rise globally.

 

The most obvious global threat is from the Greenland ice sheet.  If its disintegration is not halted very soon, we could be committed to many metres of sea-level rise in the future, with partial collapse a real danger this century.  Even half a metre would be catastrophic for low-lying countries like Bangladesh and Vietnam; several metres would devastate coastal cities and agricultural land worldwide, with incalculable economic consequences.

 

If the Arctic temperature is to be reduced, the heating power from greenhouse gases and from loss of reflectivity as ice retreats has to be offset by even greater cooling power from solar geoengineering.  A rapid temperature reduction is needed to minimise risk from tipping element catastrophe.

 

In 2012, I and sea ice expert Peter Wadhams testified to the UK Environmental Audit Committee’s inquiry on Protecting the Arctic. We warned that geoengineering was already necessary to save the Arctic—and were openly ridiculed. Since then, Arctic temperatures have risen four times faster than the global average, and the danger from tipping elements has only grown.

 

We now face a planetary emergency. This justifies the immediate consideration of Stratospheric Aerosol Injection (SAI)—a solar geoengineering technique that mimics the cooling effect of large volcanic eruptions by injecting SO₂ into the stratosphere. Understandably, many find the idea of SAI alarming. But recent research shows that it can be deployed with minimal risk of serious side effects—especially compared to the risks from continued inaction.

 

SAI is the only scalable technique we currently possess to reduce the Arctic temperature in time to avert catastrophe. Its potential global benefits—to humanity, ecosystems, and the climate system—are immense. What we need now is leadership. Business and industry must step up and support the development pathway to rapid and safe SAI deployment.  Without such leadership, we may simply not act in time.

 

Yours sincerely,

John Nissen

[Address info omitted]

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