Question A:
The OECD’s projected cumulative emissions of greenhouse gases from today until the year 2100 is 616.2 billion metric tons of CO2e, compared to 2,734 billion metric tons for the rest of the world - 82% of the total. (Larsen et al, Rhodium Group, 2024: https://climateoutlook.rhg.com/reports/rhodium-climate-outlook-2024-probabilistic-global-emissions-and-energy-projections)
The domestic net benefits of emissions reductions vary substantially across countries because of differences in income levels and exposure to climate risk.
Responses
Responses weighted by each expert's confidence
Question B:
In the absence of incentives from developed countries, developing countries will not reduce their emissions substantially in places where the private costs of fossil fuels remain meaningfully lower than those of zero-carbon fuels.
Responses
Responses weighted by each expert's confidence
Question C:
Providing incentives for developing countries to reduce their emissions through penalties (such as a carbon border adjustment mechanism or carbon club) is substantially less effective than providing equivalent incentives through subsidies (such as payments for climate damages in exchange for emissions reductions).
Responses
Responses weighted by each expert's confidence
Question A Participant Responses
| Participant | University | Vote | Confidence | Bio/Vote History |
|---|---|---|---|---|
 Daron Acemoglu |
MIT | Bio/Vote History | ||
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Internal political economy factors matter as well.
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 Mark Aguiar |
Princeton | Bio/Vote History | ||
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 Joseph Altonji |
Yale | Bio/Vote History | ||
 Alan Auerbach |
Berkeley | Bio/Vote History | ||
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 David Autor |
MIT | Bio/Vote History | ||
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Some countries will simply get a more temperate climate. Others will be submerged by rising seas.
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 Abhijit Banerjee |
MIT | Bio/Vote History | ||
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 Dirk Bergemann |
Yale | Bio/Vote History | ||
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 Marianne Bertrand |
Chicago | Bio/Vote History | ||
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 Markus Brunnermeier |
Princeton | Bio/Vote History | ||
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 Judith Chevalier |
Yale | Bio/Vote History | ||
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 David Cutler |
Harvard | Bio/Vote History | ||
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 Darrell Duffie |
Stanford | Bio/Vote History | ||
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I'm uncertain about net differences in exposure to climate damage relative to net income. Is the idea that lower-income countries are less exposed so benefit less? Anyway, there are clearly lots of differences in income and exposures.
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 Aaron Edlin |
Berkeley | Did Not Answer | Bio/Vote History | |
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 Barry Eichengreen |
Berkeley | Bio/Vote History | ||
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 Liran Einav |
Stanford | Bio/Vote History | ||
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 Ray Fair |
Yale | Bio/Vote History | ||
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 Edward Glaeser |
Harvard | Bio/Vote History | ||
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 Pinelopi Goldberg |
Yale | Did Not Answer | Bio/Vote History | |
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 Michael Greenstone |
University of Chicago | Bio/Vote History | ||
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Marginal utility of consumption higher in emerging countries so higher costs of carbon reduction policies there
Unequal projected climate damages with larger costs in hot/poor/hot & poor countries but domestic benefits small share of global benefits (mitigation is public good!)
-see background information here |
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 Oliver Hart |
Harvard | Bio/Vote History | ||
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 Caroline Hoxby |
Stanford | Bio/Vote History | ||
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 Hilary Hoynes |
Berkeley | Bio/Vote History | ||
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 Erik Hurst |
Chicago Booth | Bio/Vote History | ||
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 Kenneth Judd |
Stanford | Bio/Vote History | ||
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The variation is much greater than outlined in the Rhodium Report. It ignores uncertainty in economic growth. The Rhodium report ignores the upper 15% tail in possible warming. My DSICE model (joint with Yongyang Cai) demonstrates these facts.
-see background information here |
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 Steven Kaplan |
Chicago Booth | Bio/Vote History | ||
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 Anil Kashyap |
Chicago Booth | Bio/Vote History | ||
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This follows from any economic analysis of costs and benefits
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 Pete Klenow |
Stanford | Bio/Vote History | ||
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 Jonathan Levin |
Stanford | Bio/Vote History | ||
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 Eric Maskin |
Harvard | Bio/Vote History | ||
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 William Nordhaus |
Yale | Bio/Vote History | ||
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 Maurice Obstfeld |
Peterson Institute for International Economics | Bio/Vote History | ||
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 Parag Pathak |
MIT | Bio/Vote History | ||
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 Larry Samuelson |
Yale | Bio/Vote History | ||
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 José Scheinkman |
Columbia University | Bio/Vote History | ||
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Many lower income countries face serious financial constraints that make it extremely difficult to help fund a solution to a global problem which was overwhelmingly caused by OECD countries.
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 Richard Schmalensee |
MIT | Bio/Vote History | ||
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True for reductions in global emissions. The benefits of reductions of domestic emissions is essentially zero.
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 Fiona Scott Morton |
Yale | Bio/Vote History | ||
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 Carl Shapiro |
Berkeley | Bio/Vote History | ||
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 Robert Shimer |
University of Chicago | Bio/Vote History | ||
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 Stefanie Stantcheva |
Harvard | Bio/Vote History | ||
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 James Stock |
Harvard | Bio/Vote History | ||
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 Nancy Stokey |
University of Chicago | Bio/Vote History | ||
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 Chad Syverson |
Chicago Booth | Bio/Vote History | ||
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 Richard Thaler |
Chicago Booth | Did Not Answer | Bio/Vote History | |
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 Christopher Udry |
Northwestern | Bio/Vote History | ||
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There is enormous hetereogeneity within and especially across countries.
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 Ivan Werning |
MIT | Bio/Vote History | ||
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It is reasonable for the benefits to rise with income. Income differences are huge. Geographic exposure to climate change are also large and only add to this.
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Question B Participant Responses
| Participant | University | Vote | Confidence | Bio/Vote History |
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Daron Acemoglu |
MIT | Bio/Vote History | ||
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Mark Aguiar |
Princeton | Bio/Vote History | ||
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Joseph Altonji |
Yale | Bio/Vote History | ||
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Alan Auerbach |
Berkeley | Bio/Vote History | ||
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David Autor |
MIT | Bio/Vote History | ||
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Abhijit Banerjee |
MIT | Bio/Vote History | ||
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Dirk Bergemann |
Yale | Bio/Vote History | ||
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Marianne Bertrand |
Chicago | Bio/Vote History | ||
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Markus Brunnermeier |
Princeton | Bio/Vote History | ||
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new technology and new energy sources might lead to a leap frogging.
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Judith Chevalier |
Yale | Bio/Vote History | ||
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David Cutler |
Harvard | Bio/Vote History | ||
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Darrell Duffie |
Stanford | Bio/Vote History | ||
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Aaron Edlin |
Berkeley | Did Not Answer | Bio/Vote History | |
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Barry Eichengreen |
Berkeley | Bio/Vote History | ||
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Liran Einav |
Stanford | Bio/Vote History | ||
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Ray Fair |
Yale | Bio/Vote History | ||
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Edward Glaeser |
Harvard | Bio/Vote History | ||
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Pinelopi Goldberg |
Yale | Did Not Answer | Bio/Vote History | |
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Michael Greenstone |
University of Chicago | Bio/Vote History | ||
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Oliver Hart |
Harvard | Bio/Vote History | ||
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Caroline Hoxby |
Stanford | Bio/Vote History | ||
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Hilary Hoynes |
Berkeley | Bio/Vote History | ||
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Erik Hurst |
Chicago Booth | Bio/Vote History | ||
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Kenneth Judd |
Stanford | Bio/Vote History | ||
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Why would they? The rich countries put the CO2 in the atmosphere. Why should the poor sacrifice their economic growth to deal with a problem the rich created?
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Steven Kaplan |
Chicago Booth | Bio/Vote History | ||
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Anil Kashyap |
Chicago Booth | Bio/Vote History | ||
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It is hard to understand what has been going on over the last 15 years without recognizing the disparate incentives facing different countries. The advanced economies got rich on cheap fossil fuels. Hard to see the less developed countries won't want to do the same
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Pete Klenow |
Stanford | Bio/Vote History | ||
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Jonathan Levin |
Stanford | Bio/Vote History | ||
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Eric Maskin |
Harvard | Bio/Vote History | ||
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William Nordhaus |
Yale | Bio/Vote History | ||
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Maurice Obstfeld |
Peterson Institute for International Economics | Bio/Vote History | ||
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Parag Pathak |
MIT | Bio/Vote History | ||
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Larry Samuelson |
Yale | Bio/Vote History | ||
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José Scheinkman |
Columbia University | Bio/Vote History | ||
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In addition, financial constraints and cost of capital these countries face, make it difficult to fund the capital investments necessary to to switch energy production to clean fuels.
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Richard Schmalensee |
MIT | Bio/Vote History | ||
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Fiona Scott Morton |
Yale | Bio/Vote History | ||
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Carl Shapiro |
Berkeley | Bio/Vote History | ||
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Robert Shimer |
University of Chicago | Bio/Vote History | ||
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Stefanie Stantcheva |
Harvard | Bio/Vote History | ||
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James Stock |
Harvard | Bio/Vote History | ||
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Main exception is when substituting away from fossil fuels delivers substantial local public health benefits - cleaner cities from EVs, fewer deaths from particulates -witness China and EVs in cities, and India has (irregularly enforced) smokestack rules.
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Nancy Stokey |
University of Chicago | Bio/Vote History | ||
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Chad Syverson |
Chicago Booth | Bio/Vote History | ||
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I agree because this question conditions on "the private costs of fossil fuels remain[ing] meaningfully lower than those of zero-carbon fuels." Unconditionally, I think solar + batteries are becoming cheap enough to drive considerable cost-based shifts away from fossil fuels.
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Richard Thaler |
Chicago Booth | Did Not Answer | Bio/Vote History | |
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Christopher Udry |
Northwestern | Bio/Vote History | ||
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Ivan Werning |
MIT | Bio/Vote History | ||
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Agree HOWEVER: in principle, the free rider problem is broader, not directly affected by income (unlike country size)AS LONG as actors selfishly optimize. But everyone is not 100% selfish, many place direct value on "being green". If this value rises with income then:FULLY AGREE.
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Question C Participant Responses
| Participant | University | Vote | Confidence | Bio/Vote History |
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Daron Acemoglu |
MIT | Bio/Vote History | ||
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It's not either or. Positive incentives matter as well, but carbon tariffs are essential.
-see background information here |
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Mark Aguiar |
Princeton | Bio/Vote History | ||
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Joseph Altonji |
Yale | Bio/Vote History | ||
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Alan Auerbach |
Berkeley | Bio/Vote History | ||
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David Autor |
MIT | Bio/Vote History | ||
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Abhijit Banerjee |
MIT | Bio/Vote History | ||
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Dirk Bergemann |
Yale | Bio/Vote History | ||
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Marianne Bertrand |
Chicago | Bio/Vote History | ||
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Markus Brunnermeier |
Princeton | Bio/Vote History | ||
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Judith Chevalier |
Yale | Bio/Vote History | ||
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David Cutler |
Harvard | Bio/Vote History | ||
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Darrell Duffie |
Stanford | Bio/Vote History | ||
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Michael Greenstone has explained the benefit of a market-based approach to compensation for climate protection, tied to a developing country's adoption of a carbon tax.
-see background information here |
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Aaron Edlin |
Berkeley | Did Not Answer | Bio/Vote History | |
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Barry Eichengreen |
Berkeley | Bio/Vote History | ||
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Liran Einav |
Stanford | Bio/Vote History | ||
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Ray Fair |
Yale | Bio/Vote History | ||
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Edward Glaeser |
Harvard | Bio/Vote History | ||
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Pinelopi Goldberg |
Yale | Did Not Answer | Bio/Vote History | |
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Michael Greenstone |
University of Chicago | Bio/Vote History | ||
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Bad politics of CBAM in emerging economies- rich countries largely responsible for climate change to date & now CBAM is stick imposing their policies on emerging
Carrot would be to compensate emerging for damages caused by rich countries in exchange for adopting carbon pricing
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Oliver Hart |
Harvard | Bio/Vote History | ||
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A combination of lump sum transfers to developing countries and a carbon border adjustment mechanism might be best
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Caroline Hoxby |
Stanford | Bio/Vote History | ||
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Hilary Hoynes |
Berkeley | Bio/Vote History | ||
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Erik Hurst |
Chicago Booth | Bio/Vote History | ||
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Kenneth Judd |
Stanford | Bio/Vote History | ||
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Neither approach will do much. Penalities will encourage the poor countries to economic ties with oil producers, particularly those rich enough to buy the products of the poor countries. Subsidies will be difficult to effectively monitor.
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Steven Kaplan |
Chicago Booth | Bio/Vote History | ||
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Unclear what effective means. Unclear what costs and benefits of reducing emissions are. There is widespread disagreement and uncertainty on these. So imposing cost to reduce emissions is a fraught and uncertain exercise.
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Anil Kashyap |
Chicago Booth | Bio/Vote History | ||
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Pete Klenow |
Stanford | Bio/Vote History | ||
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Jonathan Levin |
Stanford | Bio/Vote History | ||
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Eric Maskin |
Harvard | Bio/Vote History | ||
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William Nordhaus |
Yale | Bio/Vote History | ||
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Too many uncertainties about exact policies to make a firm judgment.
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Maurice Obstfeld |
Peterson Institute for International Economics | Bio/Vote History | ||
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Parag Pathak |
MIT | Bio/Vote History | ||
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Larry Samuelson |
Yale | Bio/Vote History | ||
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I am less certain here, but suspect that carrots will work more efficiently that sticks.
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José Scheinkman |
Columbia University | Bio/Vote History | ||
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In contrast to carrots, sticks do not solve the constraints that these countries face.
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Richard Schmalensee |
MIT | Bio/Vote History | ||
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Not clear there is any evidence relevant to this proposition.
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Fiona Scott Morton |
Yale | Bio/Vote History | ||
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Carl Shapiro |
Berkeley | Bio/Vote History | ||
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Robert Shimer |
University of Chicago | Bio/Vote History | ||
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Stefanie Stantcheva |
Harvard | Bio/Vote History | ||
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James Stock |
Harvard | Bio/Vote History | ||
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Complicated. For mainly traded heavy industry CBAMs are being effective. For nontraded goods and services providing support for achieving GHG reductions combined with local pollutant reductions is promising, "subsidies" through international carbon markets can help in theory.
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Nancy Stokey |
University of Chicago | Bio/Vote History | ||
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Chad Syverson |
Chicago Booth | Bio/Vote History | ||
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Richard Thaler |
Chicago Booth | Did Not Answer | Bio/Vote History | |
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Christopher Udry |
Northwestern | Bio/Vote History | ||
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Subsidies or penalties can provide approximately similar incentives to reduce emissions. But it is crazy to penalize, say Niger, for emissions that would not be damaging but for the huge stock of carbon that we put in the atmosphere. So subsidize them to provide emissions cuts.
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Ivan Werning |
MIT | Bio/Vote History | ||
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Uncertain on pure static incentives: no clear asymmetry of carrot(1) vs stick(2). Income effects AT THE MARGIN (1 vs 2) are minor. Yet we may prefer 1 for other reasons: fairness considerations, enforcement issues, or even efficiency if they spur green innovation with spillovers.
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