In response to feedback from other scientists, the authors of the paper “The economic commitment of climate change” at the Potsdam Institute for Climate Impact Research (PIK) have revised their analysis and are making it open access for the wider scientific community to engage with.
PIK welcomes the critical scrutiny published as a “Matters Arising” in Nature as an important part of the scientific debate and is committed to continuing to uphold the highest standards of research integrity and transparency.
The core findings hold: economic damages from climate change till mid-century are substantial and outweigh the costs of mitigation, they are mainly driven by temperature changes and affect regions with low incomes and low historical emissions most. These findings are broadly consistent with wider evidence (1, 2, 3, 4, 5) on the magnitude of economic impacts from climate change and the benefits of emission reductions.
In the study, the research team used historical data to project how changes in temperature and precipitation will affect economic growth. The analysis extended prior work in three innovative ways: by estimating climate impacts at the sub-national rather than the country level, by exploring the effects of daily weather variability in addition to average conditions, and by assessing the duration of climate impacts on economic growth rates. Prior to publication in April 2024, the paper and data underwent peer review, to ensure that data analysis and methodology were sound.
Bearpark, Hogan and Hsiang, the authors of the Matters Arising, highlight errors in the underlying economic data from Uzbekistan in the period 1995-1999, which had a disproportionate influence on the results. They further argue that correlations across regions imply larger statistical uncertainties, an issue also raised with the authors independently by a colleague. The authors’ revised version corrects the underlying economic data, introduces additional controls to limit the influence of data anomalies and accounts for correlations across regions.
The revised analysis in response to the critique indicates that:
• Global economic output in the middle of this century could be 17 percent lower than without further climate change, instead of the 19 percent found in the original calculation (populated-weighted average of the percentage losses in all regions worldwide).
• The unequal distribution of damages across the globe is now found to be even more pronounced, with poorer regions suffering more in percentage terms. This results in lower global damages when expressed in dollar terms: 32 trillion 2005 purchasing power adjusted “international” US dollars – instead of 38 trillion as found in the original calculation.
• Annual global climate damages in dollars in the middle of this century are about five times higher – instead of six times as found in the original calculation – than the abatement costs associated with limiting global warming to 2°C.
The revised results and data are online for others to engage with, though the authors emphasise they have not yet undergone peer review.
The authors and PIK welcome and appreciate the feedback from the wider scientific community and take responsibility for the oversights that led to this critique.