Geoengineering Quackery
(Adapted from The Climate Pandemic: How Climate Disruption Threatens Human Survival)
What would your gut reaction be to the following schemes?
If your reaction to these schemes is disbelief, you are not alone. In fact, almost all climate researchers, after careful study and analysis, have concluded that incredulity is the appropriate reaction to such geoengineering proposals.
Such “solar radiation management” schemes “introduce a widespread range of new risks to people and ecosystems, which are not well understood,” concluded a landmark 2022 report of the UN Intergovernmental Panel on Climate Change (IPCC). The report cited “large uncertainties and knowledge gaps” in the approaches, and pointed out that they would “not stop atmospheric CO2 concentrations from increasing or reduce resulting ocean acidification.”[8]
Another report by the National Academies of Sciences, Engineering, and Medicine warned that such technologies could cause “significant potential for unanticipated, unmanageable, and regrettable consequences . . . including political, social, legal, economic, and ethical dimensions . . .”[9]
One group of scientists has called for an international non-use agreement for solar geoengineering. The agreement would ban funding, experiments, patents, deployment, or international institutional support. The group argues that solar engineering’s risks are unknowable; that it will tempt government and industry to delay decarbonization; and that the “current global governance system is unfit to develop and implement” the agreements to control deployment.[10]
“Barking mad” idea
“The idea of ‘fixing’ the climate by hacking the Earth’s reflection of sunlight is wildly, utterly, howlingly barking mad,” declared geophysicist Raymond Pierrehumbert, a co-author of the National Academies report. He wrote in an article in Slate:
Engineering is something you do to a system you understand very well, where you can try out new techniques thoroughly at a small scale before staking peoples’ lives on them. Hacking the climate is different—we have only one planet to live on, and can’t afford any big mistakes. Many of the climate “engineering” proposals are akin to turning the world’s whole population into passengers on a largely untested new fleet of hypersonic airplanes.[11]
One engineering team listed the profound unknowns of atmospheric aerosol injection.[12] They declared that nobody knows:
Nevertheless, some scientists have advocated proceeding with major research on albedo modification, despite its obvious barriers. Those scientists include the authors of a dubious National Academies report that called for a major research initiative into albedo modification.[13]
The report does not cite any new insights into geoengineering to justify such research, but only “an urgency reinforced by the world’s slow progress on climate.”
And the report presents no deep analysis of research needs, but rather “suggests [emphasis added] that a reasonable initial investment in [solar geoengineering] research is in the range of $100–200 million total over five years.”
The proposed budget is essentially fiscal hand-waving. Any budget analyst would judge as highly suspect a proposal that “suggests” such a large expenditure range, and one that is vaguely round-numbered. What’s more, this investment is only an “initial” one—sure to raise red flags in a budget office.
The report concluded that only extensive research could determine whether geoengineering could be “effective, affordable, safe, and publicly acceptable” or whether it “would be ineffective, too costly, or would raise unacceptable technical or social risks.”
The latter is the case, as the discussion that follows makes clear.
Insurmountable barriers
Any global geoengineering scheme would cost many billions of dollars and require the unlikely approval of every country in the world. Human rights advocates would certainly bitterly oppose any geoengineering, given that scientists would discover that some schemes would, in effect, kill people and would more heavily affect poorer countries and people.
For example, injecting particles into the atmosphere over the Northern Hemisphere would increase drought risk in the semi-arid Sahel region of Africa, imperiling the lives of millions, found one computer modeling study.[14]
Another computer model revealed that aerosol injection would weaken storm tracks in temperate latitudes, reducing storm severity. However, such weakening would also stagnate circulation causing more intense heat waves, higher air pollution, and altered ocean circulation.[15]
A catch-22 barrier is that only monumentally scaled geoengineering experiments could detect global-sized pitfalls. But monumentally scaled experiments are by definition global already. So the only way to study such schemes is to carry them out, thus potentially causing massive impacts on weather, agriculture, oceans, people—basically the entire Earth system.[16]
Public fears would make any global geoengineering scheme political poison. Scientists planning geoengineering experiments are already dogged by “chemtrails” conspiracy theorists. They believe that jet airplanes are secretly spewing chemicals into the atmosphere for weather or mind control.[17] Any global geoengineering plan would cause such fears to mushroom into a political movement that would thwart that plan.
Colossal injections
A global atmospheric geoengineering scheme would require gargantuan injections of material. For example, cutting global heating in half would initially require jets to deliver 25,000 metric tons of sulfuric acid a year into the stratosphere, estimated physicist David Keith.[18] To compensate for rising CO2 levels, this amount would have to increase to 250,000 metric tons by 2040.
Engineers would have to invent an entirely new tanker aircraft to carry such massive loads, calculated aviation and climate economists.[19] The airliner-sized, four-engine plane would have double the wingspan of a conventional commercial airplane. It would cost billions of dollars to develop, and the thousands of flights a year required for an injection program would cost some $2 billion a year, they calculated.
The injections would also have to continue in perpetuity. Limiting global heating to 2°C would require 160 years of sulfur injections, beginning in 2040, found calculations by atmospheric scientists. The peak injection rate would have to be about 8 million tons a year. Calculations showed that 1°C of cooling would require 6,700 flights a day, costing $20 billion a year.[20]
In fact, stopping such massive injections—quite likely given the fickleness of governments—would trigger rapid warming that would devastate the planet’s ecosystems, found another analysis. The researchers predicted that stopping suddenly would increase ocean and land temperatures more than twice as fast as either in the past or expected future.[21]
Of course, any sunlight-reducing scheme would reduce the output of solar panels, compromising that carbon-free energy source.
Seeding high-altitude heat-trapping cirrus clouds with sulfuric or nitric acid to thin them out has been another proposal to reduce global heating. Reducing cirrus clouds would allow the heat they trap to radiate back into space, the theory goes. But over-seeding might actually form more cirrus clouds, concluded atmospheric scientists. Thus, they declared the uncertainties mean that, “for the time being, cirrus cloud thinning should be viewed as a thought experiment.”[22]
Even a limited geoengineering scheme would be costly. For example, the sand-spreading scheme, called the Arctic Ice Project, would cost an estimated $300 million. It would involve spreading tons of silica microspheres—now used in toothpaste and milkshake mixes—over vast areas of Arctic ice.[23] [24]
Some advocates have argued that global geoengineering might be launched to battle a climate emergency such as melting polar ice, tropical deforestation, or a tipping point. But, as one group of geoecologists point out, such tipping points are irreversible and tend to lag the forces that triggered them.[25] They wrote that:
By the time tipping is perceived, their original state may have long since lost its stability. This means that excessive climate engineering—that is, over-cooling the planet—is likely to be required to recover their original state (and even then it may not work).
Any research program that gave geoengineering the fig leaf of validity might discourage countries from reducing greenhouse emissions, charged climatologist Michael Mann.[26] He accused geoengineering advocates as being “engaged in the kinder gentler form of denialism . . . [that] it won't be that bad, and if we stop burning carbon it's going to hurt our economy.” He wrote that “When you look in detail at these schemes, in many cases they could make us much worse off than if we hadn't engaged in these interventions at all.”
[1] Niemeier, Ulrike, and Simone Tilmes. “Sulfur Injections for a Cooler Planet.” Science 357, no. 6348 ( July 21, 2017).
[2] Gao, Ru-Shan, Karen H. Rosenlof, Bernd Kärcher, Simone Tilmes, Owen B. Toon, Christopher Maloney, and Pengfei Yu. “Toward Practical Stratospheric Aerosol Albedo Modification: Solar-Powered Lofting.” Science Advances 7, no. 20 (May 14, 2021).
[3] Pultarova, Tereza. “Clouds of Self-Levitating Soot Might Help Halt Global Warming.” Space.com (May 19, 2021).
[4] Wood, Robert. “Marine Cloud Brightening Program.”
[5] Geoengineering Monitor. “Ocean Fertilization” (January 2021).
[6] Sánchez, Joan-Pau, and Colin R. McInnes. “Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point.” PLOS One (August 26, 2015).
[7] Arctic Ice Project. Arctic Ice Project website.
[8] IPCC, Climate Change 2022: Impacts, Adaptation and Vulnerability: Summary for Policymakers. From: IPCC Sixth Assessment Report: Impacts, Adaptation and Vulnerability. (February 27, 2022).
[9] National Academies of Sciences, Engineering, and Medicine. Reflecting Sunlight to Cool Earth. The National Academies Press, 2015.
[10] Solar Geoengineering Non-Use Agreement. “We Call for an International Non-Use Agreement on Solar Geoengineering.”
[11] Pierrehumbert, Raymond T. “Climate Hacking is Barking Mad.” Slate (February 10, 2015).
[12] McMartin, Douglas, Ben Kravitz, Jane C. S. Long, and Philip J. Rasch. “Geoengineering With Stratospheric Aerosols: What Do We Not Know After A Decade Of Research?” Earth’s Future 4, no. 11 (November, 18, 2016).
[13] National Academies of Sciences, Engineering, and Medicine. Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance. The National Academies Press, 2021.
[14] Jones, Anthony C., James M. Haywood, Nick Dunstone, Kerry Emanuel, Matthew K. Hawcroft, Kevin I. Hodges, and Andy Jones. “Impacts of Hemispheric Solar Geoengineering on Tropical Cyclone Frequency.” Nature Communications 8 (November 14, 2017).
[15] Gertier, Charles G., Paul A. O'Gorman, Ben Kravitz, John C. Moore, Steven J. Phipps, and Shingo Watanabe. “Weakening of the Extratropical Storm Tracks in Solar Geoengineering Scenarios.” Geophysical Research Letters 47, no. 11 (April 23, 2020).
[16] Robock, Alan, Martin Bunzl, Ben Kravitz, and Georgiy L. Stenchikov. “A Test for Geoengineering?” Science 327, no. 5965 (January 29, 2010).
[17] Beaumont, Hilary. “Chemtrails Conspiracy Theorists are Sending Death Threats to Climate Scientists.” Vice News (November 22, 2017).
[18] Rotman, David. “A Cheap and Easy Plan to Stop Global Warming.” Technology Review (February 8, 2013).
[19] Smith, Wake and Gernot Wagner. “Stratospheric Aerosol Injection Tactics and Costs in the First 15 Years of Deployment.” Environmental Research Letters 13, no. 12 (November 23, 2018).
[20] Niemeier, Ulrike and Simone Tilmes. “Sulfur Injections for a Cooler Planet.” Science 357, no. 6348 (July 21, 2017).
[21] Trisos, Christopher H., Giuseppe Amatulli, Jessica Gurevitch, Alan Robock, Lili Xia, and Brian Zambri. “Potentially Dangerous Consequences for Biodiversity of Solar Geoengineering Implementation and Termination.” Nature Ecology & Evolution (January 22, 2018).
[22] Lohmann, Ulrike and Blaž Gasparini. “A Cirrus Cloud Climate Dial?” Science 357, no. 6348 (July 21, 2017).
[23] Arctic Ice Project. Arctic Ice Project website.
[24] Niiler, Eric. “Can Tiny Glass Beads Keep Arctic Ice from Melting? Maaaybe.” Wired (October 18, 2019).
[25] Stillman, Jana, Timothy M. Lenton, Anders Levermann, Konrad Ott, Mike Hulme, François Benduhn, and Joshua B. Horton. “Climate Emergencies Do Not Justify Engineering the Climate.” Nature Climate Change 5 (April 2015).
[26] Curwood, Steve. “America's Climate Denial Madhouse: Interview with Michael Mann.” Living on Earth (December 30, 2016).