James Hansen – Hope vs Hopium in the acceleration of global warming

Accumulating evidence supports the interpretation in our Pipeline paper: decreasing human-made aerosols increased Earth’s energy imbalance and accelerated global warming in the past decade. Climate sensitivity and aerosol forcing, physically independent quantities, were tied together by United Nations IPCC climate assessments that rely excessively on global climate models (GCMs) and fail to measure climate forcing by aerosols. IPCC’s best estimates for climate sensitivity and aerosol forcing both understate reality.

By James Hansen, Makiko Sato, Pushker Kharecha 
Columbia University Climate Science, Awareness and Solutions

Preservation of global shorelines and global climate patterns – the world humanity is adapted to – likely will require at least partly reversing global warming. Required actions and time scale are undefined. A bright future for today’s young people is still possible, but its attainment is hampered by precatory (wishful thinking) policies that do not realistically account for global energy needs and aspirations of nations with emerging economies. An alternative is needed to the GCM-dominated perspective on climate science. We will bear a heavy burden if we stand silent or meek as the world continues on its present course.

Our paper, Global Warming in the Pipeline,[1] was greeted by a few scientists, among the most active in communication with the public, with denial. Our friend Michael Mann, e.g., with a large public following, refused to concede that global warming is accelerating. We mention Mike because we know that he won’t take this notation personally.

Accelerated global warming is the first significant change of global warming rate since 1970. It is important because it confirms the futility of “net zero” hopium that serves as present energy policy and because we are running short of time to avoid passing the point of no return. We will focus on advancing our research now and completing Sophie’s Planet in 2024, so we must limit our interactions this year. We will send out updates every other month for the remainder of this year, as described in a recent note.[2] This is the March update.

Global warming in 2010-2023 is 0.30°C/decade, 67% faster than 0.18°C/decade in 1970-2010 (Fig. 1). The recent warming is different, peaking at 30-60°N (Fig. 2); for clarity we show the zonal-mean temperature trend both linear in latitude and area-weighted. Such an acceleration of warming does not simply “happen” – it implies an increased climate forcing (imposed change of Earth’s energy balance). Greenhouse gas (GHG) forcing growth has been steady. Solar irradiance has zero trend on decadal time scales. Forcing by volcanic eruptions has been negligible for 30 years, including water vapor from the Honga Tunga eruption.4 The one potentially significant change of climate forcing is change of human-made aerosols. The large warming over the North Pacific and North Atlantic (Fig. 1) coincides with regions where ship emissions dominate sulfate aerosol production (Fig. 3, from Jin et al.3).

Aerosol climate forcing is unmeasured. (5) Inference of aerosol forcing is thus a herculean task
because (1) aerosol forcing operates mainly by altering clouds, (2) clouds are also a climate
feedback that is poorly quantified, and (3) clouds have large natural variability. Fortunately,
an indirect measure of aerosol forcing can be extracted from precise data for changes of
Earth’s absorbed solar radiation (ASR) and Earth’s energy imbalance (EEI). Unbroken time
series of ASR and EEI are available from March 2000 to the present from CERES (Clouds
and Earth’s Radiant Energy System) instruments6 with calibration via precise measurement of
changing ocean heat content over decades; the calibration depends primarily on an improving
global network of deep-diving Argo floats.7 Continuing data for ASR and EEI will be crucial
for guiding young people and future generations.(8)

Global absorbed solar radiation (ASR) has increased dramatically since 2010, more than 1.4
W/m2, equivalent to a CO2 increase of more than 100 ppm.(9) The ASR increase is not due to a
brightening Sun,(10) it is due to a darkening Earth. Our task is to learn how much of this
darkening is climate feedback (due to decreasing ice/snow and cloud albedo, i.e., reflectivity)
and how much is climate forcing (due to decreasing aerosols). In note, we use the
geographical distribution (global map) of ASR to infer that the forcing due to decreased ship
aerosols is at least ~0.5 W/m2. A smaller, additional, forcing is inferred from increased ASR
over Europe, which also is likely from reduced aerosols.

Zonal mean ASR (Fig. 4) provides insight. ASR increases strongly since 2020 at latitudes
30-60°N, the region of reduced aerosols we have discussed. In the region where ship aerosols
are expected to have a large effect (30-60°N) and in the entire region where ship effects may
be significant (30°S-60°N), ASR increases in 2015-2020 and increases more in 2020-2023.
The Arctic ASR maxima are associated with sea ice minima in 2007, 2012, 2015-16 and
2020, while the double maximum near Antarctica is caused by increasing polynya (open
water) near the Antarctic coast and decreasing ice cover at the northern boundary of Southern
Ocean sea ice. The region 30°S-60°S is unlikely to have much ship aerosol effect (Fig. 3), so
change of ASR there is more likely due to cloud feedback and unforced cloud variability.

The climate forcing at 30-60°N implied by ASR is so large that we should expect a detectable
surface temperature response. A major scientific issue has been raised by an unprecedented
increase of global sea surface temperature (SST) in 2023, so it is appropriate to ask whether
there is a relationship between the large increase in ASR and increased SST. Fig. 5 shows that
the pattern of temperature change corresponds with the location and temporal development of
the ASR anomaly. Coincidence does not prove causality, as high temperatures could cause
reduced cloud cover and increased ASR, so we must seek additional evidence.

However, first, let’s draw attention to important information in Fig. 5.

Much ado is being made about the increase of global SST in 2023. It suffices to reference a single article11 by Scott Dance, because Dance comprehensively describes fears and speculations of climate
researchers who describe ocean surface warming as inexplicable, suggesting that the climate
system may be undergoing some fundamental change in the way climate physics operates.
Fears are expressed that new climate patterns are being established that will be irreversible on
time scales from centuries to millennia. The scientists reject, without any evidence to the
contrary, the evidence we presented that IPCC’s best estimates for climate sensitivity and
human-made aerosol forcing are substantial underestimates. They rule out, without evidence,
our suggestion that decreases of aerosols, especially those produced by ships, are a significant
climate forcing that is causing global warming acceleration. Instead, they make a blatant error
by describing the current El Nino as historically strong and express concern that current
record warmth may persist even under La Nina conditions.

The largest SST change is at 30-60°N (Fig. 5), the region with decreased aerosols. That
SST increase did not appear suddenly in 2023 – it was well underway in 2020. During 2020-
2022 the tropics were in a La Nina cooling trend with the La Nina depth disguised by the
effect of accelerated global warming on the temperature of upper ocean layers. Global SST
made a big jump in 2023 because tropical, midlatitude, and polar temperature changes were
all suddenly in warming phase. There is no basis for fear that new physics has come into play.
The tropics will cool as the El Nino fades later this year, although the present large planetary
energy imbalance will inhibit the size of the global temperature decline.

Zonal-mean surface temperature (Fig. 6) based on the GISS temperature analysis(12,13) supports
the interpretation of global warming that we have presented here and elsewhere.1 Warming is
accelerating in the past 10-15 years, especially at midlatitudes in the Northern Hemisphere.

The fact that the climate physics is understandable is no reason to relax. On the contrary, we
have shown14 that the world is approaching a point of no return in which the overturning
ocean circulation may shut down as early as midcentury and sea level rise of many meters
will occur on a time scale of 50-150 years. Time is running short to make the public and
policymakers aware of the threat posed by the delayed response of our climate system and of
the actions that should replace present wishful thinking (hopium). This education will not
happen instantly, but it is realistic to hope that we can greatly improve understanding this
decade, a period that should be long enough to expose the fruitlessness of present policies, as
well as to verify the physics of ongoing climate change.

As an additional check on our understanding of the cause of global warming acceleration, we
examine global average absorbed solar radiation (ASR) and Earth’s energy imbalance (EEI).
Then we can be quantitative about the additional climate forcing that is needed to produce the
observed global warming acceleration and discuss implications for the future

Global ASR and EEI (Fig. 7) aid understanding of climate change. Increased solar heating
of Earth, i.e., increased ASR (Fig. 7a) is a darkening of Earth that must be the combination of
aerosol forcing and albedo feedbacks. However, albedo feedbacks contribute at most half of
the total (forcing + albedo feedback).15 So, at least half of the increased ASR since 2015, i.e.,
at least 0.7 W/m2 , is the added forcing. This comports with our estimate that added aerosol
forcing is at least 0.5 W/m2 based on changes of ASR in the areas of maximum ship effect, as
described in note

This estimate for the ship aerosol forcing is an order of magnitude (factor of ~10) greater than
what follows from IPCC estimates. The 2021 IPCC report (AR6) pegs total aerosol forcing as
1.06 W/m2 in 2019, with 0.22 direct aerosol forcing and 0.84 the indirect effect on clouds. A
2021 update16 reduces the aerosol forcing to 0.98 W/m2 (0.21 direct, 0.77 indirect). Based on
this small aerosol forcing, Hausfather and Forster17 obtain a forcing of 0.079 W/m2 for 100%
implementation of 2020 IMO18 ship emission limits. Our estimate of 0.5-0.7 W/m2
refers to the actual (~80%) reduction of sulfates from ships. The difference with the Hausfather and
Forster value is so large that it must be possible to resolve this issue within a few years.

Where did the IPCC aerosol forcing come from? Not from global measurements. As will be
described in Sophie’s Planet, such measurements were proposed19 and strongly supported by
engineers at Goddard Space Fight Center (GSFC). However, GSFC management and NASA
Headquarters viewed the proposed (Climsat) mission as a threat to the larger Earth Observing
System mission and Climsat was not approved. Aerosol forcing requires detailed knowledge
of the changing microphysics of both aerosol and cloud particles, which depends on precise
measurement of the polarization of reflected sunlight and the spectrum of emitted thermal
radiation measured with an infrared spectrometer (Michelson interferometer).(19)

In reality, the IPCC aerosol forcing is the forcing required for GCMs to yield global warming
comparable to observed warming. In the many years between successive IPCC reports, the
modeling groups make hundreds of climate simulations. Results reported to CMIP (climate
modeling intercomparison project) and used by IPCC tend to be model runs with global
warming comparable to observations. The ensemble of model results yields a fog of projected
future warming. The real world falls within the projected model fog because each successive
IPCC report has a new model fog consistent with the new models and updated observations

Knutti20 pointed out individual models in the model fog each tend to yield global warming
comparable to observations, even though the models differed in many ways and had a range
of climate sensitivities. This result is at least partially explained by the fact that the aerosol
forcing is not well constrained, which provides each GCM model a degree of freedom in the
choice of aerosol forcing. Knutti also pointed out that most GCM simulations did not even
include the aerosol indirect climate forcing (the effect of aerosols on cloud cover and cloud
albedo). Aerosol and cloud physicists who wrote the aerosol section of IPCC reports
suggested that the indirect effect was probably the larger aerosol forcing, yet this larger
(negative) aerosol forcing was not employed in most of the GCMs.

There were two reasons that the GCM modelers did not want to include the full aerosol
forcing in their models. First, many of the oceans in the GCMs tended to mix heat into the
deep ocean too effectively, which meant that the GCM needed a slightly exaggerated forcing
to match observed surface warming. Increased net forcing could be achieved with a smaller
(less negative) aerosol forcing. Second, and more important, the GCMs tended to have climate sensitivities in the neighborhood of 3°C for 2×CO2; with such climate sensitivity only
moderate aerosol forcing (~1-1.5 W/m2) is needed to match observed global warming.

[We are not suggesting that modelers were up to something nefarious. For example, the GISS
GCM21 in that era had sensitivity ~3°C for 2×CO2 and the aerosol forcing was −1.39 W/m2
(direct = −0.52, indirect = −0.87). It was admitted that we had no ability to compute aerosol
indirect forcing; instead, we used a global distribution from an aerosol model multiplied by a
factor intended to yield an indirect aerosol forcing of −1 W/m2 . When used in the GCM with
computed cloud cover, the aerosol indirect forcing turned out to be −0.87 W/m2
. Other GCM groups made their own choices, but no group had realistic aerosol-cloud modeling.]

The basic difficulty is that cloud modeling is hard and aerosol-cloud modeling is very hard.
The simplest cloud models, used for decades, yield climate sensitivity near 3°C for 2×CO2.
Several recent models that attempt to model cloud microphysics more realistically, including
mixed phase clouds, yield higher climate sensitivity, ~4-6°C for 2×CO2. Empirical evaluation
of climate sensitivity has finally been achieved thanks to accurate definition of ice age global
temperature by Seltzer et al. (22) and Tierney et al., (23) with the result that climate sensitivity is
4.8°C ± 0.6°C (1σ), with 3°C sensitivity excluded with 99.7% certainty.(1)

There is independent support for high climate sensitivity. In a webinar,24 George Tselioudis
showed figures of Zelinka et al. (25) and Jiang et al.(26) revealing that high sensitivity climate
models yield much better agreement with satellite observations of seasonal and latitudinal
cloud changes; the low sensitivity models do not have even the correct sense of the changes.
In addition, Williams et al. (27) show that the improved aerosol and cloud physics (particularly
production of liquid water in mixed phase clouds) in the British Met Office GCM (widely
agreed to be one of the most realistic GCMs) leads to an increase of the model’s sensitivity
from 3.2°C to 5.5°C for 2×CO2. As described also by Palmer,28 the physics changes that yield
the higher climate sensitivity also yield improved 6-hour tendencies in the GCM used for
short-term (weather) simulations, an insightful approach that has been recommended for
assessing the realism of supposed improvements in model physics.

High climate sensitivity is a double whammy. High sensitivity implies a large (negative)
aerosol forcing because aerosol forcing, unfortunately, so far has been an implied quantity,
not a directly measured quantity. Further evidence that IPCC underestimates aerosol forcing
is provided in our Pipeline paper.1 For example, greenhouse gas climate forcing increased by
0.5 W/m2 over the past 6000 years, yet global temperature held steady or declined slightly,
especially in the Northern Hemisphere. Given that greenhouse gases and aerosols are the two
significant global forcings and the fact that wood-burning was the fuel source as civilization
developed, we argue that the human-made aerosol forcing was already at least (negative) 0.5
W/m2 in 1750, when IPCC assumes that it was zero, and we argue that the release of aerosols
in burning of wood and other biofuels has not decreased globally since 1750.

Decreased aerosol forcing since 2010 accelerates global warming and, in combination with
a moderate El Nino, accounts for the magnitude and geographical location of unusual 2023
warming. There is no need for concern that the physics of the climate system has changed.

Little light is shed on global climate change by the IPCC model fog approach. Real world
global temperature change always is included within the projected model fog, as reset with
each successive assessment, but that does not expose the physics of the climate system.

The real world has its own fog: natural climate variability that makes it difficult to measure
human-driven climate change. El Nino/La Nina tropical variability is the main source of
global temperature variability. Jeremy Grantham(29) suggested a way to possibly detect and
measure global warming acceleration: compare global temperatures at the peaks of strong El
Ninos, which provide a well-defined point in the tropical cycle. The 1997-98 and 2015-16 super El Ninos were comparably strong, and the global temperature increase between them
provided a strong hint that global warming was beginning to accelerate.

Does the present El Nino provide a similar opportunity? We must first ask whether this El
Nino is of comparable strength to those two super El Ninos. NOAA declared that the 2023-24
El Nino is a super El Nino, based on the fact that the Nino3.4 temperature (of a small region
in the equatorial Pacific) reached 2.0°C. In desperate attempts to explain extreme global
temperatures of the past year, the present El Nino has been described as a “historically strong
El Nino.”11 Really? Is it a super El Nino?

Nino3.4 SST (sea surface temperature, Fig. 8a) implied that the current El Nino is almost as
strong as the super El Ninos. However, heat content data for the upper 300m of the equatorial
Pacific (Fig. 8b) show that this El Nino is a weak imposter, no super El Nino. The El Nino/La
Nina system operates as a discharge-recharge heat battery:31,32,33 heat builds up in the tropical
western Pacific during the La Nina phase, then, in the El Nino phase, heat moves eastward
across the Pacific and poleward within the ocean. Local SST increase causes heat loss to the
atmosphere mainly via enhanced evaporation, cooling the ocean, moistening the atmosphere,
invigorating convection and atmospheric teleconnections that dispense energy worldwide,
especially to the Atlantic and Indian Ocean regions, causing an overall global warming.34 Fig.
8b shows that the present El Nino started with a battery that was only half full. The heat loss
from the equatorial Pacific during the 1997-98 El Nino of the (20th) century was a cooling of
the upper 300 m of the ocean by in excess of 4.5°C (peak to trough change in Fig. 8b). The
battery discharged 3°C in the 2015-16 El Nino. How far the present El Nino will discharge
the battery remains to be seen, but it seems unlikely to approach even the 3°C level.

Fig. 9 confirms that the 2023-24 El Nino is only moderate. Although Nino 3.4 reached 2.0°C
in November and December 2023, the global maps show that temperatures throughout the
tropics (including the Nino3.4 area) are inflated from global warming by at least 0.6°C in
2023-24. Even with that inflation the narrow El Nino region is notably cooler than in the two
super El Ninos. The map in the lower right corner of Fig. 9 will show even less warming in
the El Nino region when the March data are added to that map. Consistent with the present El
Nino being weak, global temperature during Northern Hemisphere winter, when El Ninos
usually have the largest impact on global temperature, was barely larger in 2024 than it was
in 2016, despite the strong overall global warming of the past decade.

Even though the current El Nino is weak, we expect the peak global temperature produced by
the El Nino to help confirm global warming acceleration. The 12-month-mean is +1.5°C in
the GISS analysis through February (Fig. 10). The peak in 2016 was reached in March, but this year the 12-month mean may continue to rise as much as a few months longer due to the
extreme planetary energy imbalance. The pink range in the Fig. 10 projection was based on
Earth’s unprecedented energy imbalance and assumption that the current El Nino was similar
to the super El Ninos.35 This El Nino is actually half-baked, not a super El Nino, but the 12-
month mean global temperature may still approach ~1.6°C. Peak 12-month temperature
during the 2016 super El Nino was 1.34°C, so a 1.6°C El Nino peak would be a warming rate
between El Ninos (1.6-1.34)/(8 years) = 0.33°C/decade, an 84% acceleration over the
0.18°C/decade rate of 1970-2010, which is within the 50-100% acceleration expected due to
the observed doubling of Earth’s energy imbalance.1 Better assessment of acceleration –
independent of El Nino strength – will be provided by the average temperature of the El Nino
peak and the next La Nina valley. We expect the average of the El Nino maximum and the La
Nina minimum of global temperatures to be ~1.5°C. Given Earth’s huge energy imbalance –
more energy coming in than going out – it will be clear that for all practical purposes the
1.5°C global warming level has been reached in the mid-2020s.

Summary

1. Our Three-Pronged Research Approach

Our research approach38 gives comparable weight to paleoclimate, GCM modeling, and
observations of ongoing climate physics. Housing these three in the same university or the
same climate assessment report is not sufficient. They must be housed in the same brains.

IPCC’s overemphasis on GCMs, in contrast, causes IPCC to be purblind to evidence of
climate change, a slowness with grave consequences for effective policy-making because of
the delayed response of the climate system. Let’s give one pertinent example (another more
consequential one is discussed below under “point of no return”). As soon as paleoclimate
evidence made it clear that equilibrium climate sensitivity was greater than 3°C for 2×CO2,
alarm bells should have gone off: “Uh-oh, we also fxcked up on aerosol climate forcing!”

Aerosol physicists knew that aerosol forcing could be large because of the difficulty in
quantifying the effect of aerosols on cloud cover and cloud lifetime. But GCM modelers, of
course, tended to employ an aerosol forcing that allowed their models to approximately
reproduce global warming of the past century. Sometimes this was explicitly admitted, e.g., in
a review39 that concluded aerosol forcing had to be smaller than 1.6 W/m2
because otherwise the GCMs would not yield observed global warming. The IPCC modeling community
dressed this up with a sophisticated appellation “emergent constraint,” preferring that to its
more useful description in the olden days as an adjustable “fudge factor.”

The result is that two independent physical quantities, climate sensitivity and aerosol forcing,
were tied together via excessive reliance on GCMs as a basis for climate assessment. One
response of modelers has been: oh, well, it doesn’t really matter – the policy requirement is
still that we must reduce greenhouse gas emissions rapidly; everybody must promise to have
zero “net emissions” by mid-century. Oh, boy. That’s another story. Enough on this for now.

2. Global Warming Is Accelerating

Fig. 1 shows that global warming accelerated since 2010, especially in regions where aerosol
forcing is believed to have declined due to IMO fuel restrictions. Based on the increase of
absorbed solar radiation (ASR) in these regions, we estimated an increase of aerosol forcing
of at least 0.5 W/m2 . Based on the 1.4 W/m2 global increase of ASR, and expectation that
only about half of this could be feedbacks on the short time scale of change, we estimate an
aerosol forcing near 0.7 W/m2 . The increase of ASR is the reason Earth’s energy imbalance
(EEI) since 2020 is nearly double what it was in the first decade of the 21st century. From this
increased energy imbalance, we conclude that global warming in 2010-2030 should be 50-
100 percent greater than the warming rate in 1970-2010. This acceleration follows from the
climate response function for a high climate sensitivity,1 without the need to run a GCM.

Coincidence of regions of strong warming with regions of aerosol reduction does not prove
causality. Anomalous ocean circulation, for example, may have produced hot regions in the
North Pacific and North Atlantic. If high SSTs led to reduced cloud cover, this might explain
increased ASR. Fig. 5, repeated here for convenience, suggests how unusual this ocean
dynamical explanation is, needing to produce an unprecedented hot spot in the midlatitudes
of the Northern Hemisphere. For this ocean dynamics explanation to be taken seriously,
evidence for and explanation of the ocean circulation change should be presented

Instead, Fig. 5 suggests that the sudden increase of global SST in 2023 was the combination of two phenomena: (1) growth over the past decade, especially since 2020, of warming due to decreased aerosols with the maximum effect where expected, at northern midlatitudes, and (2) the switch in mid-2023 from a prolonged, strong, La Nina to a moderate El Nino. This obvious interpretation of Fig. 5 allows us to dispense with the notion that new climate physics is required to explain the sudden increase of global warmth in the past 12 months.

Additional insights are contained in Fig. 5. The apparent strength of the 2015-16 and 2023-24
El Ninos relative to the 1997-98 El Nino of the century is misleading because it results from
the more recent El Ninos being bathed in growing, widespread, global warming. Fig. 5 also
suggests a delayed spreading of El Nino warmth to higher latitude ocean areas. El Nino ocean
heat is transported between ocean basins via interesting atmospheric teleconnections.40 The
warming in Southern Hemisphere midlatitudes is likely to include significant amplifying
cloud feedback because high climate sensitivity implies amplifying cloud feedback and the
southern midlatitudes are the main region of stronger positive cloud feedback in the increased
sensitivity CMIP6 model ensemble.(25)

A feature of special note in Fig. 5 is the lack of warming in the Southern Ocean at latitudes
near 60°S. This feature is an indicator of approach to the point of no return.

3. The Point of No Return

The “tipping point” concept, implying an unstable climate response, is misused and overused,
thus encouraging a fatalistic public response or climate change denial. (41) Most phenomena described as tipping points are amplifying, reversible, feedbacks, not runaway processes. Take melting permafrost and decreasing Arctic sea ice; these amplifying feedbacks increase regional and global climate change on decadal and longer time scales. The feedbacks grow while Earth’s radiation balance is positive – more energy coming in than going out – but once we reduce the climate forcing enough that Earth’s energy imbalance becomes slightly negative, feedbacks will work in the opposite sense, helping us move global temperature and climate patterns back toward their condition before human alterations of the planet began.

Attention should be focused on the danger of passing the point of no return, when we lock in
disastrous consequences that cannot be reversed on any time scale humans care about. The
prime point of no return is collapse of the West Antarctic ice sheet. If we allow that to get
well underway, we will lose that entire ice sheet quickly (by paleo standards). That ice sheet
must have collapsed in the Eemian period, when global temperature was similar to today; sea
level rose several meters in less than a century.42 Moreover, today’s greenhouse gas level and
climate forcing now exceed even that of the early Pliocene, when sea level was 15-25 meters
(50-80 feet) higher than today. Thus, West Antarctic ice sheet collapse would initiate a long
period of continuously changing shorelines. Combined with shifting climate zones, greater
climate extremes, and increasingly inhospitable low latitudes, this is a picture of future
climate that must and can be avoided.

How close are we to locking in West Antarctic ice sheet collapse? Nobody knows for sure.
Better understanding of that issue was an objective of a proposal43 (unfunded) that we made a
few years ago. This topic provides an example of why our three-pronged research approach is
needed as a complement to the GCM-dominated IPCC approach. We concluded in our Ice
Melt paper,14 based on observed rates of ice shelf melting, that the world is nearing shutdown
of the Atlantic Overturning Meridional Circulation (AMOC) and shutdown of deepwater
formation near Antarctica (which we term SMOC for its analogy to the Northern Hemisphere
process), if the rate of ice melt continues to grow. AMOC shutdown occurs in midcentury in
our GCM simulations, if ice melt continues to grow. We interpret lack of real-world warming
in the Southern Ocean near Antarctica as a telltale sign that freshwater from melting ice
shelves is already slowing SMOC and beginning to reduce Southern Ocean SST. We describe
in Note2 how the GCM-dominated approach allows censorship of alternative perspectives,
when the models have a common, or at least widespread, problem: lack of realistic sensitivity
to injection of freshwater into the upper layers of the ocean.

What is a realistic timeframe on which “the point of no return” should be understood much
better and its implications communicated? By 2030, the date when nations are expected to
have made measurable progress in climate policies, it may, at long last, be recognized that the
“hopium” approach to climate policy – goals and promises of “net zero” emissions at some
distant date, without realistic plans for reliable, carbon-free, energy – is hopeless. By then
scientists need to have improved their communication with the public, especially with young
people, who, we will argue, have great potential to affect the future of their planet.

4. Communication

We need to communicate energy/climate science better. It is tempting to relax into comfort of
scientific reticence, described in section 7.2 of our Pipeline paper. But who is going to
communicate science to policymakers and the public if scientists retreat into reticence? It’s
especially important, we think, to communicate with young people to help them realize that
they have great potential to help assure that they have a bright future.

We became involved in the broad energy/climate problem more than 20 years ago after we
became concerned that the Kyoto Protocol was ineffectual and the climate scenarios being
considered by IPCC were all problematical. We wrote a paper, An Alternative Scenario,
(44) and organized two workshops(45) at the East-West Center in Hawaii to discuss the possibility of
addressing the problems of air pollution and climate simultaneously. What is the most useful
way to communicate the perspective that we gained in the following 20 years from our efforts
to understand the energy/climate problem? We think that completion of the long-planned
Sophie’s Planet might help the public understand the situation.

The potential political power of young people has been demonstrated. Without funding, but
communicating among themselves, they had a large role in elevating Barack Obama to his
nomination in the 2008 Democratic Presidential primary, and their support of Bernie Sanders
in 2016 almost led to the improbable nomination of a democratic socialist as a major party
nominee. College and high school students46 can understand the need for a simple, honest,
carbon fee-and-dividend that economists47 support. It’s also necessary, however, to have
insight about how the best interests of the public can be foiled by special financial interests.

Consider the example of nuclear power. When U.S. President Bill Clinton, in his first State of
the Union address following his 1992 election, declared “We are eliminating programs that
are no longer needed, such as nuclear power research and development,” he was acting under
the spell of Amory Lovins, whose policy prescriptions were based not on science but on a
vision, a vision of a world that needed no coal, no oil, no gas, no nuclear power, no large
hydro, no carbon tax – all that was needed was “soft” renewable energies such as solar panels
and windmills, and these renewables could totally replace all other energies by 2025.

Reality is different. Lovins’ later book, Reinventing Fire, (48) has a fawning Foreword written
by the President of Shell Oil Company, which is not surprising since Lovins had adjusted his
graphs so that fossil fuel phaseout was moved to 2050, and no doubt the phaseout in such
heuristic graphs can be moved further. It is unsurprising that annual reports of Lovins’ Rocky
Mountain Institute include Shell and BP among corporate donors providing minimum annual
support of $500,000 each. In defense of Lovins, we note his more recent op-ed49 in the New
York Times, expressed support for carbon fee-and-dividend, which he had categorically
dismissed as unnecessary a decade earlier in discussions with the first author (JEH).

One of the things that JEH learned from a conversation with the leader of one of the largest
“Big Green” environmentalist organizations is that Big Green cannot support nuclear power
because they would lose a substantial fraction of their donations if they did. The fossil fuel
industry is a significant contributor to the Big Green organizations, and many of these
organizations are financially invested in renewables and fossil fuels, so they do not want to
see nuclear power as a competitor. Big Green is green mainly as the shade of a dollar bill.

The 30-year delay in support for nuclear power denied the industry the R&D needed to
develop its potential. Based on the amount of material (steel, concrete, fuel, etc.) required for
a power plant, nuclear power should be our cheapest energy, if it was supported equally.
There is no need to cry over spilled milk, though. By 2030, there should be multiple options
for modern ultrasafe nuclear power that can serve as the needed complement to renewable
energies to produce carbon-free electricity.

In 2024 in the United States, the essential political need for the sake of the energy/climate
problem is preservation of democracy and thus the potential for future political influence.
However, once the 2024 election is over, our opinion is that young people need to reconsider
how to most effectively use their enormous potential political power. Is it really by joining
one of the sides in the cultural war that prevents effective governance? In Sophie’s Planet, we
will discuss some ideas that we believe are worth considering.

5. Funding

Most philanthropic organizations will not support organizations that are positive about
nuclear power, so we greatly appreciate the people who helped Climate Science, Awareness
and Solutions survive and even achieve some rejuvenation in the past year. It started with
Isabelle Sangha, who did the calculations for the Cenozoic Era section of the Pipeline paper
(there is still more to extract from that study – we will argue that it provides a more realistic
history of atmospheric CO2 than that from proxy CO2 measurements, as well as other
insights). Isabelle was taking a year off from studies after her BaSci; the bureaucracy for
creating a position at Columbia took so long that we employed her through CSAS.inc.
Isabelle is now off to Cambridge University in the UK for a Ph.D. program, but the Columbia
advertisement uncovered another gem, Joe Kelly, similarly in a period prior to Ph.D. studies.
Joe, under guidance of George Tselioudis, is making great progress in understanding cloud
behavior in the GISS climate models, and he produced the “good news” (item 6 below).

Makiko Sato will retire late this year. It is impossible to replace her, as her contributions are
spread widely across our program in data set compilations, climate analysis, graphics, and
keeping our group together. The crucial requirement is someone who can maintain, expand,
and work with climate data sets. We aim to find someone at an entry level position who is
eager to learn – in our view, working with data is at least as interesting and important as
climate modeling. If we can afford it, we would like to start someone this summer to have a
period of overlap with Makiko.

In the list of our major donors over the past several years, published at the end of the Pipeline
paper, we forgot to include the grant received from the Alex C. Walker Foundation, and since
Pipeline was published, we received a gift from Michael Dorrell. A list of those who have supported CSAS over the past several years, more complete than given in our Pipeline paper
is the Grantham Foundation, Frank Batten, Eric Lemelson, James and Krisann Miller, Carl
Page, Michael Dorrell, Alex C. Walker Foundation, Peter Joseph, Ian Cumming, Gary and
Claire Russell, Donald and Jeanne Keith Ferris, Aleksandar Totic, Chris Arndt, Larry Travis,
Jeffrey Miller, Ron and Gail Gester, Judy Lamana, Morris Bradley, and about 200 members
of the public to CSAS at Columbia University and about 100 contributors to CSAS.inc in
response to funding appeals.

The good news comes from Joe Kelly, who investigated the large “ultrafast” response of
Earth’s energy imbalance (EEI) to a 2×CO2 forcing in the GISS (2020) GCM. Specifically,
we reported in Pipeline that the initial 4 W/m2 imbalance dropped by about 30% (to 2.7 W/m2
) in year 1 after the forcing was imposed. A drop by 10-15% is not surprising, even expected, because land areas respond rapidly to a forcing, but 30% requires an additional explanation. For want of an alternative, we speculated that it may be a rapid cloud feedback.

Joe made 60 runs of the model from different points on the control run, finding year 1 responses ranging from 2.5 to 3.7 W/m2 , with an ensemble mean 3.1 W/m2 and standard deviation 0.3 W/m2
. He found no evidence of an immediate cloud adjustment. The large variability in the GISS (2020) GCM might be related to its excessive “Nino” variability.

In any case, there is an ultrafast response in many of the GISS models, which does limit the
rate at which the ocean takes up heat and restores planetary energy balance, but it is not likely
to be as large as found in the single run of the GISS (2020) model. It would be useful if all
GCMs reported both their temperature and EEI response functions.

FOOTNOTES:

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8 There are no convincing plans in place for long-term continuation of Earth radiation balance observations of sufficient quality. It’s bad enough that no effort was made to monitor global aerosol forcing. If precise satellite monitoring of Earth’s radiation balance is not continued, today’s young people will be up the proverbial shxt crick without a paddle, without tools needed to understand ongoing climate change.
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