Gernot Wagner

AP: "Researchers slightly lower study’s estimate of drop in global income due to climate change"

Gernot Wagner, a climate economist at Columbia Business School who wasn’t involved with the research, said the thrust of the Potsdam Institute’s work remains the same “no matter which part of the range the true figure will be.”

“Climate change already hits home, quite literally. Home insurance premiums across the U.S. have already seen, in part, a doubling over the past decade alone,” Wagner said. “Rapidly accumulating climate risks will only make the numbers go up even more.”

Quoted in: "Researchers slightly lower study’s estimate of drop in global income due to climate change" by Alexa St. John, Associated Press (3 December 2025).

Washington Post: "Private companies have raised millions to block the sun. What could go wrong?"

Make Sunsets has released just over 240 pounds of sulfur dioxide this year — well short of the millions of tons a year it would take to change global temperatures. Reaching that scale would require thousands of flights per year from specialized planes and at least the quiet tolerance of governments deciding to look the other way, said Gernot Wagner, a climate economist at Columbia Business School and a co-author on the 2018 study on the costs of geoengineering.

“There is no Silicon Valley venture capitalist who is able to do this, full stop. Even the billionaire who has hundreds of billions of dollars is running out of money sooner or later,” Wagner said. “But there are dozens of countries out there whose military air force budget alone could cover this. That’s what I’m really, really worried about: Not every one of these countries might have a democratically elected government acting in the best interest of the planet.”

Quoted in: "Private companies have raised millions to block the sun. What could go wrong?" by Nicolás Rivero, Washington Post (3 December 2025).

Washington Post: "On Giving Tuesday, how to make small donations with big climate impact"

Give to the planet by giving to yourself

Gernot Wagner, a climate economist at Columbia Business School, calculates that the most effective investment in the climate involves decarbonizing your home.

Some improvements, like sealing a leaky door to improve your energy efficiency, may only cost a few dollars. But many clean technologies, such as heat pumps and induction stoves, still carry a “green premium.” The up-front cost is higher than conventional technologies, even if operational costs are lower.

Installing those sorts of technologies before they become mainstream, Wagner argues, helps expand the market, puts downward pressure on their costs and edges your neighborhood closer to low or zero emissions.

Wagner just finished a multiyear odyssey retrofitting his 750-square-foot loft and helping to make his 200-year-old, seven-household co-op building more energy efficient. He finally sealed off the building’s gas line earlier this year after going all-electric.

“How do you spend your hundred bucks? How do you spend your thousand bucks?” he asked. “Spend it on overcoming this initial hurdle [of a green premium]. In this case, spending it on yourself might be the most philanthropic thing you can do.”

Quoted in: "On Giving Tuesday, how to make small donations with big climate impact" by Michael Coren, Washington Post Climate Coach (2 December 2025).

Behavioral economics of climate action

Abstract:

Behavioral economics plays a key role in explaining the lack of current climate action and in facilitating effective future interventions. For instance, it can help us evaluate the efficacy and efficiency of policy instruments and institutions, understand the effectiveness of “hard” and “soft” interventions, and estimate pro-environmental preferences. In this editorial, we provide examples for some of the contributions of behavioral economics to the study of climate action and review the eight studies published in this collection. These studies introduce “social tipping points”, study related aspects of international organizations, explore the relationship between pro-environmental behaviors and individual well-being, investigate the effect of “Veggie Days” on emissions in German university cafeterias, test whether an intervention can increase the adoption of certified solar devices for refugees in Uganda, conduct a systematic review and a meta-analysis of public support for carbon pricing policies, examine arguments for and against the use of pricing instruments to mitigate emissions, and analyze social media communications of three groups of stakeholders.

Full text: "Behavioral economics of climate action" [PDF] (editorial; 4 December 2025)

Introduction to special issue on "Behavioral economics of climate action."

CSEi Seminar: "Engineering and logistical concerns add practical limitations to stratospheric aerosol injection strategies"

Title: Engineering and logistical concerns add practical limitations to stratospheric aerosol injection strategies

Abstract: The use of reflective aerosols in the upper atmosphere (stratospheric aerosol injections, SAI) to limit incoming sunlight has been proposed as a potential means of countering anthropogenic climate change. Such a strategy ideates from observed cooling effects due to sulfate aerosol formation following volcanic eruptions. Solid mineral candidates have been proposed as a sulfate alternative, potentially lowering environmental risks like ozone epletion and absorption of radiation. The bulk of SAI modeling literature focuses on optimal deployment scenarios, in which practical constraints – microphysical, geopolitical, and economic – are not considered. Here, we explore several key micro- and macroscopic aspects of deployment that may directly increase risk, and the degree to which technical and governance approaches could be levied to offset it. We find that the risk and design space for SAI may be considerably constrained by factors like supply chains and governance. Logistical and technical considerations, most significantly difficulties in dispersing solid aerosols at scale in the desired size range, and the radiative properties of potentially formed aggregates, notably introduce uncertainties in the outcomes of solid-based SAI strategies more so than sulfate. We conclude that the design space for a “low-risk” SAI strategy, particularly with solid aerosol, may be more limited than current literature reflects.

The CSEi Seminar Series brings researchers from the natural and social sciences, industry practitioners, and policymakers to the University of Chicago to explore critical questions in climate systems engineering. The series is intended to stimulate new research collaborations on campus and build connections with experts outside the university.

Event info; paper (joint with Miranda Hack, V. Faye McNeill & Dan Steingart).