Each metric ton of carbon dioxide that humans produce comes with a price. Not only is it costly financially due to the destruction caused by heat waves, floods and droughts, but also in terms of human lives. According to a new study, reducing carbon dioxide emissions could save millions of people from premature death over the next century.
Nature Communications published the research on Thursday. It includes a piece of the Social Cost of Carbon (SCC). This metric calculates future damages from carbon emitted in the present to establish a price for those emissions. The SCC assists governments to weigh the benefits and costs of climate regulations, mitigation programs, and fossil fuel infrastructure. Current efforts by the Biden administration to revise the U.S. Federal Governments estimate of this metric are underway. This is in line with recommendations made by a 2017 National Academies of Sciences, Engineering and Medicine report. Those impacts include expected premature deaths. Temporarily, the Biden administration has set its SCC estimate at $51 per metric tons. This is close to the Obama years before the Trump administration reduced it to $1 per tonne.
R. Daniel Bressler is a Columbia University Ph.D. Candidat and the author of the new study. He was interested in how SCC estimates might change if scientists included the latest science on climate-related deaths. To make the human toll more clear, he also separated that component. Bressler used a model by William Nordhaus, an economist who won the Nobel Prize in Economics for this model in 2018. This model effectively links different climate scenarios with their economic impacts to calculate carbon's social cost and determine the best plan to reduce emissions. Bressler had two goals: to make climate-related death a larger contributor to the overall cost associated with climate change, and to include extensive research. He says that there has been a lot of literature on the subject in the past decade.
Bressler used the newer research to calculate that if emissions continued to grow, every 4,434 metric tonnes of carbon dioxide in the atmosphere by 2020 would lead to one extra death worldwide by 2100. This is a comparison to the 3.5 million metric tons of CO2 that Americans produce in a lifetime. If we look at the bigger picture, 1 million metric tons CO2 emitted by 2020, which is equivalent to 35 commercial planes, 216,000 automobiles or 115,000 American homes emitting in a year, would cause 226 premature deaths by 2026.
The social cost of carbon rose from $37 per metric tons to $258 per metric tons when you include these deaths. It is therefore more economic to reduce emissions immediately. This makes it more cost-effective to reduce emissions quickly and decarbonize by 2050, as opposed to the more conservative Nordhauss model. Bressler states that the result is quite different from what the recommended climate policy is. A faster path to reduce emissions would be better than allowing them to continue growing unabated. This would decrease premature deaths by about 83 million to nine millions by 2100.
Bressler points out that there is a large uncertainty in his study and that mortality figures do not include deaths due to temperature. Although it is ideal to include disease transmission, floods, and other climate-related effects, these factors have limited research. Maureen Cropper from the University of Maryland, who was co-chair of the National Academies 2017 report, said that Bressler's work is similar in nature to other scientists. Because of his economic assumptions, Bressler's estimate of SCC is higher than Climate Impact Labs, but Cropper says it is worth translating this aspect from abstract dollar numbers. She says that it resonates when you think about people.