Earth's Energy Imbalance More Than Doubled in Recent Decades - 2025

[Renaud de RICHTER]

Earth's Energy Imbalance More Than Doubled in Recent Decades
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024AV001636

Abstract

Global warming results from anthropogenic greenhouse gas emissions which upset the delicate balance between the incoming sunlight, and the reflected and emitted radiation from Earth. The imbalance leads to energy accumulation in the atmosphere, oceans and land, and melting of the cryosphere, resulting in increasing temperatures, rising sea levels, and more extreme weather around the globe. Despite the fundamental role of the energy imbalance in regulating the climate system, as known to humanity for more than two centuries, our capacity to observe it is rapidly deteriorating as satellites are being decommissioned.

Key Points

• Earth's energy imbalance more than doubled in recent decades

• The large trend has taken us by surprise, and as a community we should strive to understand the underlying causes

• Our capability to observe the Earth's energy imbalance and budget terms is threatened as satellites are decommissioned

Plain Language Summary

Global warming is caused by the imbalance between the incoming radiation from the Sun and the reflected and outgoing infrared radiation from the Earth. The imbalance leads to energy accumulation in the atmosphere, oceans and land, and melting of the cryosphere, resulting in increasing temperatures, rising sea levels, and more extreme weather around the globe according the the United Nations Intergovernmental Panel on Climate Change (IPCC). Observations from space of the energy imbalance shows that it is rising much faster than expected, and in 2023 it reached values two times higher than the best estimate from IPCC. We argue that we must strive to better understand this fundamental change in Earth's climate state, and ensure our capacity to monitor it in the future.

[Ron Baiman]

Wow!  Thanks for sharing Renaud. I haven't read it but from the abstract  it (very unfortunate for all of us humans and most other species, but not really surprising for many of us humans) looks like forecasts of Hansen et al. 2024 are being vindicated!

Best,

Ron

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 Addressing the Urgent Need for Direct Climate Cooling: Rationale and Options

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]

Thank you LDM and Dan,

@LDM:

(IMO) Thanks for sharing!  IMO this recent Hansen and Kharecha Newsletter with further evidence supporting a climate sensitivity of 4.5 rather than the established IPCC value of 3.0 that is (as I understand it) embedded in most current climate models, is excellent and should be widely distributed, per these last two paragraphs:

"Criticisms of the Acceleration paper in the media did not address the physics in our three assessments of
climate sensitivity. Instead, criticisms were largely ad hoc opinions, even ad hominem attacks. How can
science reporting have descended to this level? Climate science is now so complex, with many sub-
disciplines, that the media must rely on opinions of climate experts. Although there are thousands of
capable scientists in these disciplines, the media have come to depend on a handful of scientists, a clique
of climate scientists who are willing, or even eager, to be the voice of the climate science community.
But are they representative of the total community, of capable scientists who focus on climate science?
We have lamented9 the absence of scientists with the breadth of understanding of say Jule Charney or
Francis Bretherton,10 or our beloved, sometimes crotchety, former colleague, Wally Broecker. However,
the truth is that there are many scientists out there with a depth of understanding at least as great as the
clique of scientists that the media rely on. Given the success of this clique in painting us as outliers, we
are dependent on the larger community being willing to help educate the media about the current climate
situation. For that purpose, we will discuss – one-by-one in upcoming communications – several of the
matters that are raised in our papers. Thanks for your attention."

@Dan:  Thanks for sharing!  I will definitely give this a listen!

Best,

Ron

On Sun, May 18, 2025 at 4:04 PM LDM <len...@gmail.com> wrote:

https://www.columbia.edu/~jeh1/mailings/2025/CloudFeedback.13May2025.pdf

Large Cloud Feedback Confirms High Climate Sensitivity 

James Hansen and Pushker Kharecha 

13 May 2025 

Abstract. 

Earth’s albedo (reflectivity) declined over the 25 years of precise satellite data, with the decline so large that this change must be mainly reduced reflection of sunlight by clouds. Part of the cloud change is caused by reduction of human-made atmospheric aerosols, which act as condensation nuclei for cloud formation, but most of the cloud change is cloud feedback that occurs with global warming. The observed albedo change proves that clouds provide a large, amplifying, climate feedback. This large cloud feedback confirms high climate sensitivity, consistent with paleoclimate data and with the rate of global warming in the past century.

https://youtu.be/NxV1IbHt7fU

When Will We Go Over 2ºC? & Hansen's Cloud Update

[Michael MacCracken]

Ron et al.--Just a note that the 3 C sensitivity is not "embedded" in the climate models. That is the value that emerges from the representations of the various physical processes that play out against each other. So, assuming the observations and resulting analyses are accurate, for there to be a higher sensitivity, it might be that some of the processes are not parameterized in a way that fully represents possibilities and realities (observations to calibrate parameterizations can be drawn from only the conditions we are experiencing), some processes are not represented at all (viewed as long-term such as isostatic rebound, etc.), the resolution of the models is not fine enough to treat aspects of the processes, etc. In any case, however, the 3 C sensitivity is not built into the models.

Mike

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[Ron Baiman]

Understood Mike! Perhaps a more accurate framing is that " ECS informs the parametrization" of climate models.  My understanding is that Hansen et al.  are suggesting that most current climate models (the not "hot" climate models based on roughly 3.0 ECS) are able to track past climate data by mistakenly underestimating two offsetting phenomena: a) GHG forcing and b) human aerosol produced cooling, and thus calibrating to past data  with lower ECS offset by lower aerosol cooling.  The problem of course is that this parametrization is not able to track the increased warming that we are experiencing going forward induced by a greater warming (as expected with a higher ECS) coupled with less cooling from reduced aerosol masking (as expected with a higher aerosol cooling parameterization).  My understanding from the latest May 2025 Hansen and Kharecha Newsletter and further elaborated on in Dan's most recent podcast that I'm in the middle of!). 

Best,

Ron

[James Hansen]

Hi Mike et al.,

I can't get involved in a back-and-forth -- we are in the process of moving back to NYC, to live in a Columbia apartment to avoid time wasted in commuting and taking care of a house/property. However, I'm surprised by your comment, Mike. Most GCM groups make hundreds, if not more, GCM runs between one IPCC report and the next, and there are hundreds, if not more, model parameters. There is a widespread, if not universal, tendency to prefer those model configurations that yield a magnitude of warming in the past 200 years that is consistent with observations. In this way, wittingly or not, the 3C sensitivity is "baked into" the models -- because, as we showed in our "Acceleration" the usual aerosol forcing employed is close to the IPCC best estimate for aerosol forcing. As shown by a graph in the Supplementary Information of our paper, the change of the IPCC aerosol forcing during the period of rapid warming is negligible. In such case, the climate sensitivity required to match the observed warming rate is ~3C for 2xCO2. However, if the aerosol forcing increased by ~0.5 W/m2 (became more negative) during 1970-2005, as simulated by Bauer et al. and as independently inferred in our paper, then a climate sensitivity of ~4.5C is required to match the observed warming.

However, the temperature change in the last 200 years is only one of the three independent ways that we obtain the 4.5C sensitivity, and the other two are much cleaner, independent of the GCM issues.

High climate sensitivity demanded by large cloud feedback, clearly shown by Earth's darkening in the past 25 years, is summarized in the recent communication to my email list.

The third method is described in our "Global warming in the pipeline" paper: comparison of equilibrium glacial and interglacial climates. For several decades, based largely on CLIMAP and "confirmed" by MARGO, it was believed that the LGM was only 3-4C colder than the Holocene. Thanks especially to Alan Seltzer, we now know that the LGM was 6-7C colder, which demands the higher ECS -- several new paleo studies confirm the high ECS.

Best, Jim

To view this discussion visit https://groups.google.com/d/msgid/geoengineering/4e23a031-1d90-429f-b962-a428e82fc7ac%40comcast.net.

--

Jim Hansen, Director

Climate Science, Awareness and Solutions Program

Columbia University Earth Institute

[Michael MacCracken]

Hi Jim--No need for a back and forth. I did not mean to dismiss your calculation of sensitivity possibly being 4.5 C and don't disagree that the set of parameters used in models now do tend toward yielding a 3 C sensitivity. Indeed, I found your latest results very interesting, high as the sensitivity seems if one goes back to when the CO2 concentration is thought to be 4 or more times preindustrial.

In my interactions with Ron and others, I was interpreting their remarks to be saying that the climate sensitivity was directly specified as 3 C in the models independent of how the processes work and come together, and I wanted to say that that is not the case. At least that was what I was intending to say. I should perhaps have made more clear your point that some of the parameters in the existing model should, based on the time history of observations and seeking to match the model results to them could well be indicating that different parameters regarding cloud feedback are likely the case and this could lead to the higher sensitivity and improved the match to the multiple types of observations that you consider.

Good luck for your move back to New York City.

Best, Mike

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[James Hansen]

o.k., well-taken -- I just wanted to make the point that, if you start out accepting IPCC's best estimate for aerosol forcing, there is a human tendency, given the choice of many models/parameters, to choose the model/parameters that yield realistic global warming -- and this is a way to "bake in" the ECS (3C for doubled CO2) that agrees with the assumed (IPCC) aerosol forcing.

Jim

[H simmens]

Jim,

I know that your time is short but if you have a few moments I’d love to get your response to Dr Anastassia Mararieva’s  (who has a PhD in atmospheric physics and formulated the concept of the biotic pump ) article on Substack published today. 

She argues that the biosphere is neglected in both your work and the work of most mainstream climate modelers and scientists (I’m oversimplifying her argument of course but it touches on ECS, aerosols,  clouds and much more.)

Thanks,

Herb

Thanks,

Herb

Herb Simmens
Author of A Climate Vocabulary of the Future

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

On May 19, 2025, at 8:39 PM, James Hansen <jimeh...@gmail.com> wrote:



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[Michael MacCracken]

Agreed.

Mike

[James Hansen]

Thanks, Dan.

It's a similar story with ECS implied by comparison of glacial and interglacial states.

The forcings that maintain the glacial-interglacial temperature change are almost entirely:

(1) Atmosphere: GHG change,  

(2) Surface: change of ice sheet size

Vegetation change also affects surface albedo, but it's a small effect and an estimate for it is included, even in our 1984 paper.

Biology affects aerosols, but glacial-interglacial aerosol change is a climate feedback, part of the cloud-aerosol feedback (not a forcing); the biology effect is included in the empirical global temperature change.

[Why is the biology effect (change of surface albedo due to change of vegetation distribution) included as a forcing, while the biology effect on aerosols is bookkept as a feedback? Because we have knowledge of the change of surface vegetation distribution, while the N aerosol types are unknown, especially their main effect, which would be via impact on clouds. So, the only choice is to leave it in the feedback category. These arbitrary forcing/feedback designations for vegetation and aerosols are small potatoes compared with GHG and ice sheet albedo changes.]

Biology was sure a BFD in maintaining the fiction of 3C sensitivity for several decades. CLIMAP and MARGO estimated that LGM cooling was only about 3.6C based on their assumption that the microscopic marine biology would migrate to stay in the same temperature range where they exist today. Actual LGM cooling was almost a factor of two larger.

Jim

On Tue, May 20, 2025 at 12:52 PM Dan Miller <d...@rodagroup.com> wrote:

Hi Herb:

I read Dr. Mararieva’s comments and I don’t believe she understood Jim’s recent communication fully.  I explain Jim’s latest communication it in my recent Climate Chat program.  In a nutshell, the Earth dimmed by 0.5% in the past 25 years.  There are 3 main causes: 1) Less sea ice, 2) changes to aerosols, and 3) could feedbacks.  We know (1) well from direct observation. The IPCC thinks (2) is less than Jim does, but if that it true then (3) is even bigger than Jim says.  The bottom line is that there are large cloud feedbacks (less clouds as the planet warms) which implies a large ECS (4.5ºC).  See my interview with George Tselioudis for more on cloud feedback: 

Global Warming➔Fewer Clouds➔More Warming! with George Tselioudis

https://youtube.com/live/suFZb2ViHoA 

While biological processes of course play a role in climate change, it’s hard to see how a biological process played a role in changing the Earth’s albedo by 0.5% in the past 25 years, unless such process plays a major role in short-term cloud cover.  Even if it did, it does not change Jim’s conclusions since he doesn’t say why the cloud feedback is so large, just that it is.

Dan

On May 19, 2025, at 6:09 PM, H simmens <hsim...@gmail.com> wrote:

Jim,

I know that your time is short but if you have a few moments I’d love to get your response to Dr Anastassia Mararieva’s  (who has a PhD in atmospheric physics and formulated the concept of the biotic pump ) article on Substack published today. 

She argues that the biosphere is neglected in both your work and the work of most mainstream climate modelers and scientists (I’m oversimplifying her argument of course but it touches on ECS, aerosols,  clouds and much more.)

Thanks,

Herb

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[Alan Gadian]

Jim,

I still argue water vapour 51% (62% no clouds ) and 19% ( 25%) contributes to IR warming and co2 increases now no longer dominate the rises. With es(T) at 7% for each degree rise in surface air temperatures, then by 2-3 C rise gives a huge positive feedback , clouds or no clouds. A plot on a Elsaser diagram shows this.  The radiative models don’t include it properly. Bignell’s water vapour continuum paper shows it works.  Study of the planets mars and venus shows it. 

Thus in my opinion ECS is bigger than 5 ( may be 8) C. Look at the steepness of the current temperature curve increase. If ECS was say 4 the hysterisis would start to flatten off and it’s not. 

Thus I do think lovelock ( re verge of gaia, 2009) is correct , catastrophic weather events start by 2035 and martyn rees ( astronomer royal’s ) prediction for the end of the century are in the right ball park. 

Best wishes

Alan 

T ---

Alan Gadian, UK.

Tel: +44 / 0  775 451 9009 

T ---

On 20 May 2025, at 20:57, James Hansen <jimeh...@gmail.com> wrote:



To view this discussion visit https://groups.google.com/d/msgid/geoengineering/CAEL%2B3vMiZP8F10jcFOhDVnrZH8XOZqp1DKitmpyE%2BYgwsGi8Pw%40mail.gmail.com.

[Ron Baiman]

Hi Herb et al.,

As you may recall, per Jim's comment, we discuss Makarieva's "biological pump" as a TRM  "Local-Regional" "Afforestation, Reforestation and Soil and Vegatation Restoration" (mostly authored by Suzanne) as one of 14 possible Direct Climate Cooling (DCC) approaches in our paper  in our cooling paper: https://academic.oup.com/oocc/article/4/1/kgae014/7731760 , see ref. 98 below:

"Afforestation, Reforestation, and Soil and Vegetation Restoration (ARSVR) can increase evapotranspiration that can reduce a region’s peak temperatures in a process sometimes referred to as “the terrestrial biotic pump” [95–98]. Increased evapotranspiration can also increase cloud formation in some regions, the increased albedo of which can add to the cooling influence. The extent to which afforestation reduces dryland albedo versus. decreasing thermal radiation and the timeframe over which these effects will occur influence its overall cooling potential [99]. The interaction of temperature, wind, vegetation species, soil water retention capacity, water availability, current land use albedo, and altitude are critical factors in determining where and how this solution could and should be applied [100–102]. Incorporating biochar into agricultural soils can increase soil water retention and thus increase the potential cooling influence via evapotranspiration [103].

• ARSVR involves both solar radiation and thermal radiation to exert a cooling influence. Additional co-benefits can include run-off and erosion reduction, flood protection, carbon drawdown and sequestration, and promotion of increased biodiversity [104, 105]. There is some tension between the need for agricultural land versus. afforestation considering the increasing demand for food and impacts on local economies. Implementation would best aim for a complementarity achieved through a global land stewardship approach that balances need while maximizing benefits of afforestation, reforestation, regenerative agriculture, and agroforestry [102, 106]."

• Best,
• Ron
• 
  

[Ron Baiman]

Dear Colleagues,

Alan's post has reminded me that while we're on the topic of the urgent need for near-term climate cooling,  it would be good to ask if any of you have any contacts with any International Maritime Organization (IMO) representatives or advisors in this document: https://drive.google.com/drive/folders/1Z1qaOARNFTpvkGKKhlABrsr8UB9FhqDx  who might be open to getting their delegations to support our open letter to the IMO: https://academic.oup.com/oocc/article/4/1/kgae008/7706251?searchresult=1?

The lead staff scientist at the IMO has encouraged us to find a country(s) or NGO(s) with IMO standing that would submit this to the IMO's Marine Environment Protection Committee (MEPC) of which she is the Secretary, but so far no luck!  Note that as the IMO office is in London some of the Reps are based there (UK based HPAC members have tried valiantly to get in touch with the UK Rep but also no luck).

Any help that any of you might be able to offer on this would be greatly appreciated!

Best,

Ron

[Ron Baiman]

Dear Colleagues,

My apologies!  It's been pointed out to me that I sent out the wrong IMO MEPC committee representatives and advisors link.  This is the correct one: 

https://drive.google.com/file/d/1wlKHNs3jwXIKFEn_GD0DSaLT-Luvscrq/view?usp=drivesdk

Best,

Ron