(CN) — It may be getting hotter around the world, but the global economy is cooling down. Heat waves felt worldwide have long been attributed to climate change effects and Dartmouth College researchers have now quantified how rising temperatures have caused trillions of dollars in losses worldwide in the past three decades.
Published on Friday in Science Advances, the study builds on previous research by Dartmouth researchers Christopher Callahan and Justin Mankin on the effects of climate change on the global economy. This new study estimates that the world economy has sustained a loss of approximately $16 trillion and highlights the outsized effect of global warming on regions that have contributed the least to greenhouse gas emissions globally.
Callahan, lead author of the study and doctoral student at Dartmouth, explained that higher temperatures have a direct impact on a country's economic output.
“Most severely, it destroys crops and makes outdoor labor very difficult. But there are a number of more subtle effects -- people become more aggressive on hot days, workplaces injuries go up, mental focus goes down, and so on. These individual effects likely interact and combine to produce the overall economy-wide effects that we see in our data,” he said in an email interview.
Researchers evaluated economic data on regional growth of GDP per capita collected by researchers in Germany against databases of global weather phenomena, centering on the severe heatwaves reported worldwide. Callahan and Mankin, assistant professor of geography at Dartmouth and senior author on the study, focused on the five hottest days of the year for different regions from 1992 to 2013. They found that those five days corresponded with particular economic variations throughout the world.
$16 trillion may not even be the full extent of climate changes economic damage, according to Callahan.
“There are a lot of things we did not look at in this study, such as the effect of other extremes like hurricanes and droughts. The true costs of warming are likely much higher than the ones we show here, and we are going to continue trying to assess these costs,” he said.
The most severe losses documented in the study came from nations in warmer tropical regions, which often coincide with some of the world’s poorest countries. These countries experienced an average of 6.7% in losses of GDP per capita, whereas wealthier countries that could use their resources to adapt to the climate effects came in at around 1.5% in losses, according to the study.
The study also discovered that wealthier countries may actually benefit from higher temperatures, but warns of a possible ripple effect that disruptions to the global supply chain caused by extreme temperatures that would eventually reach wealthy regions like Europe and the United States.
Currently, extreme heat waves have most affected already vulnerable areas of the world in the warm, lower-income regions — regions that have also emitted the least number of harmful pollutants. These findings emphasize, Callahan said, the disproportionate effect of global warming on the global economy.
“Our study is another illustration of the well-known pattern where the people generating greenhouse gas emissions are not bearing the costs of those emissions. Because of this, the United States and other major emitters have an ethical responsibility to both rapidly reduce their greenhouse gas emissions and assist lower-income regions in adapting to the effects of warming,” he explained.
Callahan and Mankin ultimately hope that their research may be able to help bolster climate liability claims against major carbon emitter countries and companies. Callahan references a 2018 lawsuit brought by a Peruvian farmer against a German power company for contributions to climate change.
“The success of these cases depends in part on our ability to quantitatively link individual actors (such as countries or fossil fuel companies) to the downstream economic or human costs of the warming those actors have caused. There are many barriers to this sort of litigation, but we hope that our work makes the impacts of global warming more tangible and thus makes the harm suffered by specific regions more easily valued in a legal setting,” he said.
The authors of the study have also published a July study detailing individual countries’ economic damages that found the United States among the world’s top 5 carbon emitters, along with China, Russia, Brazil and India, who have collectively cost the world $6 trillion in income losses.
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