Michael Mann
Critique of his article on Bill Gates in The Bulletin of Atomic Scientists
Mann’s attack piece on Bill Gates was published in the Bulletin of the Atomic Scientists. I remain deeply concerned by Michael Mann’s refusal to engage seriously with scientific information about the feasibility of rival climate policies. His article contains serious errors and misleading claims.
A few key points:
“if your only tool is technology, every problem appears to have a technofix.”
The thrust of this argument is that solar geoengineering is not needed. That ignores findings – referenced in his own paper - that albedo loss is now contributing more to the acceleration of warming than the greenhouse effect from new emissions. The only way to restore planetary albedo is through technology. Planetary darkening cannot be slowed by carbon action. In effect, Mann is saying we must do nothing about planetary albedo. Mann’s rhetoric slides from the true point that technology cannot fix all ills to the false claim that cooling technology is not necessary. He treats efforts to develop sunlight-reflection tools as misconceived, when in reality we face a risk–risk trade-off. It is not a choice between a safe option (decarbonisation) and a reckless one (geoengineering).
On the albedo-carbon comparison, CERES satellite data from NASA shows that since 2000, planetary darkening has increased absorbed solar radiation by 0.8–1.0 W/m². That is up to 60% more than the extra greenhouse forcing from new emissions over the same period (≈0.6–0.8 W/m²). That justifies the view that albedo is a more serious climate problem than new emissions.
“a major new climate report (disclaimer: I was a co-author) entitled “A Planet On The Brink” was published… The legacy media is apparently more interested in the climate musings of an erstwhile PC mogul than a sober assessment by the world’s leading climate scientists.”
A Planet on the Brink is not a neutral “sober assessment.” It doubles down on the familiar line that we must rapidly decarbonise, while saying almost nothing about the tools needed to manage the planetary energy imbalance on timescales that matter. If media are cool towards this style of messaging, one possible reason is that it is heard as yet another demand for revolutionary economic restructuring with no credible back-up plan or transition strategy. Especially when set against the UN’s 2021 call to halve global emissions by 2030, which is broadly seen as politically and practically impossible. Mann’s report does acknowledge that “warming may be accelerating, likely driven by reduced aerosol cooling, strong cloud feedbacks, and a darkening planet.” But it fails to follow through on that unduly caveated admission by treating albedo restoration as an urgent climate task.
“modular nuclear reactors that couldn’t possibly be scaled up over the time frame in which the world must transition off fossil fuels.”
And he thinks decarbonisation can rapidly achieve climate relevant scale? Mann asserts that “the world must transition off fossil fuels” within a very tight timeframe – while providing no account of what happens when we inevitably don’t. That is a key reason for geoengineering. There is no evidence-based pathway in which fossil fuel use vanishes fast enough to avoid dangerous warming without direct climate cooling. We also need a lot more energy, including nuclear, ocean thermal and other low-emission firm sources. Dismissing options like advanced modular nuclear on ideological grounds leaves us with an energy system that is fragile, expensive, politically brittle and highly unsafe in the context of worsening climate change.
“Gates … has financed for-profit schemes to implement geoengineering interventions that involve spraying massive amounts of sulfur dioxide into the stratosphere to block out sunlight and cool the planet.”
This claim about Bill Gates is factually wrong and should be corrected if the Bulletin wants to be seen as a trusted forum on planetary-scale interventions. Gates has funded preliminary scientific research on solar geoengineering through philanthropic donations (e.g. FICER, Harvard’s Solar Geoengineering Research Program, the proposed SCoPEx experiment). These projects do not aim at commercial deployment as Mann wrongly suggests. SCoPEx proposed releasing a few kilograms of calcium carbonate, not “massive amounts of sulfur dioxide,” and has not proceeded. Fact-checkers have found claims that “Bill Gates is spraying the sky / blocking the sun” to be false and conspiratorial. Gates funds research, not large-scale or pilot deployment of stratospheric SO₂ injection. Mann’s claims do not match what Gates has actually funded.
“technofixes for the climate, in fact, lead us down a dangerous road, both because they displace far safer and more reliable options—namely the clean energy transition—and because they provide an excuse for business-as-usual burning of fossil fuels.”
Here again, Mann wrongly frames the choice as if we have a safe, reliable path (clean energy) and a dangerous one (sunlight reflection). My view is that treating clean energy as a primary climate strategy is a major security threat, bound to fail, and so highly unsafe and unreliable. Emissions and temperatures are still rising, destabilising key tipping elements. Betting everything on emissions reduction alone while refusing to develop sunlight-reflection technologies is delusional. Recent work on the planetary energy imbalance shows that albedo loss is now a major driver of warming. Treating albedo as off-limits is not caution, it is a refusal to engage on climate science. The hope that nonlinear feedbacks will stay within manageable bounds leaves the world without any ability to reflect incoming sunlight and fails the precautionary principle. On Mann’s ‘excuse’ claim, the moral-hazard literature around geoengineering is highly partisan. It does not justify the claim that sunlight reflection is more dangerous than decarbonisation. Its claim that banning SRM would somehow enhance political will for emissions cuts is little more than political cover for renewable energy subsidies. Fossil-fuel demand is driven by entrenched economic interests, not by hypothetical SRM projects.
“The only safe and reliable way out when you find yourself in a climate hole is to stop digging—and burning—fossil fuels.”
This “law of holes” metaphor is wrong. In a medical emergency, the priority is not to tweak your long-term lifestyle, it is to stabilise the patient. Likewise, in the current climate emergency, reducing actions that gradually worsen the problem (cutting emissions) is useful, but not sufficient. We also have to correct the acute radiative imbalance that is driving extreme weather and risks of systemic disruption. The real “hole” we are now in is the entrenched belief that renewable energy transition is the primary climate solution. There are strong commercial and ideological interests in continuing to dig that hole. Calling a combustion ban “the only safe and reliable way” without any back-up plan for cooling is dangerous rhetoric, not risk management.
Mann says “Gates does an injustice to the very dramatic inroads that renewable energy and energy efficiency are making…”. He refers to studies claiming “very credible” pathways to 100 percent non-carbon energy by 2050 that are “easily scalable”. He asserts “the obstacles aren’t technological. They’re political.”
These pathway studies are disputed. “100% renewables by 2050” roadmaps are criticised by energy-system modelers for errors, implausible assumptions and underestimation of challenges and costs. Even the IPCC acknowledges that the ability to overcome economic, regulatory, social and operational challenges to high renewable energy market penetration is not fully understood. Political backlash against renewable rollout is driven by valid concerns about cost, reliability, integration, land use and climate impact. The obstacles are not purely political, as Mann claims. They are primarily technical, economic, scientific and social.
Mann’s attack on geoengineering dismisses and misrepresents the major risks of putting all eggs in the decarbonization basket in a world that is already dangerously warmed. Preventing COCAWKI – collapse of civilization as we know it – requires a careful, experimental program to develop sunlight-reflection capabilities under robust international governance. The Montreal Protocol is a useful model for an Albedo Accord. Mann’s misinformed polemics sow confusion and delay effective climate action in a way that is not compatible with scientific method.