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Abstract
While the scientific community has established a fairly clear consensus on the threat of
climate change, policymakers and journalists often suggest that the economic community
lacks a consensus view on climate change risks and appropriate policy responses. We
conducted a survey of 1,103 experts on the economics of climate change – all those who
have authored an article related to climate change in a highly ranked economics or
environmental economics journal since 1994 – and our results reveal several areas where
expert consensus exists, and others where more research is necessary. In casting a wider
net than many previous surveys of economists on climate change, we avoid many of the
pitfalls of previous studies.
Of the 1,103 experts that received the survey, 365 responded – a response rate of
approximately 33%. Though the response rate varied from question to question –
particularly for open-ended questions – it never dipped below 20%. There are several key
takeaways from our results, particularly with respect to the magnitude of the social cost of
carbon. Economic experts believe that climate change will begin to have a net negative
impact on the global economy very soon – the median estimate was “by 2025.” On average,
economists also predict far higher economic impacts from climate change than the
estimates found in landmark surveys from the 1990s (Nordhaus, 1994; Schauer, 1995).
Also while experts on climate economics did not support a constant discount rate
calibrated to market rates – the current methodology employed to estimate the US social
cost of carbon –respondents recommended rates lower than (or roughly equal to the lower
ranges of) those used by the U.S. government in these calculations. Given these results, it is
unsurprising that our findings revealed a strong consensus that the SCC should be greater
than or equal to the current $37 estimate. While these results indicate a growing consensus
that current damage and SCC impacts are too low, the high variance of our results indicate
that considerable work is still necessary to improve the values used for discount rates and
climate impact assumptions.
From a policy perspective, our findings also strongly suggest that U.S. policymakers should
be concerned about a lack of action on climate change. Experts believe that the United
States may be able to strategically induce other nations to reduce GHG emissions by
adopting policies to reduce U.S. emissions. Respondents also support unilateral emission
reductions by the United States, regardless of the actions other nations have taken. These
results appear to confirm an economic consensus that domestic climate policies should be
enacted immediately to address climate change.