"The model proposed by Hansen reveals ten degrees of heating is already baked into Earth’s surface temperature, but has been masked by aerosol cooling"
James Hansen has always been a good climate scientist searching for an even better editor. Scientists, engineers, writers and poets all train differently and may even have different thought patterns and gut microbiomes. Occasionally you get a hybrid—Neil deGrasse Tyson; Carl Sagan; James Burke—who can both do the nerdy computations and communicate to receptive ignoramuses. Hansen is not one of those. He follows the orthodox scientist cast—defensive; assertions couched in equivocation; tentative conclusions; arcane arithmetic and acronyms.
When President George W. Bush, in his second week in office, created the National Energy Policy Development Group, headed by Vice President Dick Cheney, the Veep realized NEPDG would need to mention the risk of climate change in its report. His predecessor Al Gore had bequeathed him that as a job description. So, Cheney asked Hansen to come to the White House and make his best case. It was a disaster. Cheney, an oil man like the President, had no interest in recommending anything other than more drilling. Hansen played right into that, giving a mind-numbing powerpoint about Watts per square meter, forcing and feedbacks, percentages of confidence, framed with the usual caveats of uncertainty and asking for more research funding for NASA, NOAH, and NAS. Committee eyes glazed over. He was politely ushered out. He was no Carl Sagan.lamented the lack of pretext for taking control of that. That was seven months before Saudi kamikaze pilots crashed hijacked planes into the World Trade Center and Pentagon.
Hansen can be forgiven this missed moment in history because his token appearance had been a set-up to begin with. He redeemed himself by getting arrested outside the White House and at the Keystone pipeline as a climate protester, over and over.
An extraterrestrial geosystems expert, his work for NASA Goddard Inst. for Space Studies (GISS) comparing Earth’s global temperature to that of Venus was first published in 1981 and updated in 1988. He risked his career testifying to Congress that year over the orders of his superiors. His testimony, that Earth had warmed 0.5-0.7°C in the previous 100 years, that the four warmest years on record were all in the 1980s, and that this warming was mostly man-made, poked a hornets’ nest. In June 2006, Hansen appeared on 60 Minutes stating that the George W. Bush White House had edited climate-related press releases reported by federal agencies to make global warming seem less threatening (like the phrase “global warming” itself). Physicist Freeman Dyson criticized Hansen's climate-change activism, alleging he “consistently exaggerates all the dangers.” New York Times columnist Andrew Revkin wrote, "Dr. Hansen has pushed far beyond the boundaries of the conventional role of scientists.” They tried to push the toothpaste back into the tube.
I have my own disagreements with Hansen, as I have said here before. He is absurd in his claims about safe, clean, nuclear energy. He underestimates the terrawatt potential and cost reductions of renewables at scale. But I respect his integrity and willingness to be jailed to make a dramatic point. I applaud his wordsmithing of the “Faustian Bargain” and “Young People’s Burden.” This is perhaps why I am a bit disappointed that his latest research paper, placed in the public domain for early review before formal journal peer-review has been completed, is so opaque and poorly crafted. It is 49 pages of superdense U-238 surrounding a plutonium core.
Here are the top takeaways from Hansen’s latest and in future posts I will dive a little more deeply and bring in a few other recent papers to lend color and texture. Warning: this is not for the faint at heart.
From Robert Chris, Visiting Fellow at the Department of Geography, The Open University, UK:
The core message is that both the magnitude and response times of human causes of climate change and responses to it have been seriously misrepresented by the scientific community. This has been due largely to inadequacy in the manner in which climate models have handled uncertainties relating to both the warming effect of a doubling of atmospheric greenhouse gases and the impact of human-generated aerosols.
The model proposed by Hansen and 14 co-authors drawn from the top ranks of the required specialties brings in previously neglected externalities and paleoclimate data to show ten degrees of heating is already baked into Earth’s surface temperature but has been masked by aerosol cooling (“global dimming”), delayed ocean mixing, and lag response time for large systems.
They estimate that by 2050 surface temperature will have increased by 2°C and 65% of the remaining 10°C could occur within a century assuming current CO2 and trace GHG emissions levels are maintained and the aerosols continue to be reduced until they are largely eliminated.
Equilibrium heating will not be reached by 2100, which is as far as the IPCC AR6 report and most studies go. By the end of this century, only half to two-thirds of the heating caused by our past emissions will have been felt. Full equilibrium heating will not be reached for approximately 6000 years.
Our pragmatic evaluation based on real-world data is an essential antidote to assessments associated with the annual United Nations COP (Conference of the Parties) meetings, which give the impression that much progress is being made and it is still feasible to limit global warming to as little as 1.5°C. Once governments and the public understand Fig. 1, they should recognize it as a wake-up call about the untenable situation that we are creating for young people.
Since anything above 5 degrees likely portends human extinction and anything above 3 degrees might irrevocably trigger tipping points that cascade to 5 degrees, urgent removal of the climate-forcing agents is required. Thus, carbon dioxide removal and solar radiation management are recommended.
While these are popularly labeled “geoengineering” and carry unquantified risks, Hansen points out that what we have been doing for the past 8000 years is also geoengineering with heretofore unquantified risks, so you should ask what is the risk of not acting to stop the forcing?
Personally, I think the term “geoengineering” has become politically charged and should be retired. Painting streets and buildings white, as they do in the Greek islands, is solar radiation management. Turning sewage sludge into biochar is carbon dioxide removal. What we want to avoid is uncontrolled experimentation with the entire planet’s homeostasis. Hansen agrees.
One key number is the rate of heating that can be expected once the concentration of greenhouse gases doubles. Svante Arrhenius was the first person to predict that emissions of carbon dioxide from the burning of fossil fuels and other combustion processes were large enough to cause global climate change. He calculated in 1906 that any doubling of the percentage of carbon dioxide in the air would raise the temperature of the Earth's surface by 4°C; and if the carbon dioxide were increased fourfold, the temperature would rise by 8°C.
As shown in Hansen’s Figure 2 chart taken from ice cores in Greenland and Antarctica, Earth's average temperature, including during ice ages, corresponds to 225 ppm CO2e (CO2e means for all greenhouse gases, including trace gases, expressed as equivalent to CO2). Average concentration at peak interglacials is about 278 ppm. The doubling threshold for a warm state would therefore be 556 ppm. Hansen’s paper calculates present CO2e to be 561 ppm. In 1979, Charney et al refined Arrhenius’s calculation to estimate a doubling temperature of 3 degrees. Hansen refines it again and arrives at 7 to 10°C, experiencing half of that this century and the remainder in later years.
Humans have been geoengineering the climate for at least 8000 years. The reason we are not entering another ice age now and had all those millennia of gorgeous, predictable weather and unvarying coastlines upon which to build cities and found civilizations was because we warmed the Earth ever so slightly by conversion of forest to farm starting 8000 years ago and the methane released by rice farming starting 6000 years ago. We also mined and burned peat, killed the great whales that ran the deep ocean carbon mixing, and domesticated animals. We actually, accidentally, achieved a beneficial climate stasis for the first time in Earth’s history. We just couldn’t leave well enough alone. We had to dig and drill up Earth’s stores of fossil carbon and litter the atmosphere and ocean with that, which is what got us into our present predicament.
With most of the heat due and payable but masked by air pollution, we are damned if we keep emitting and damned if we don’t. That’s the Faustian Bargain. In one fell stroke, Hansen and team validated both the Ruddiman Apostasy and the McPherson Paradox.
The release of these findings, soliciting public comment ahead of peer review, has been met with howls from scientists, influencers, and various interested parties. That firestorm is still raging at this writing. I will describe more about all this in our next installment.