The huge economic losses caused by sweltering temperatures caused by human-induced climate change are not just a problem in the distant future. The Dartmouth study, published Oct. 28 in the journal Science Advances, shows that more severe heat waves caused by global warming have already cost the global economy trillions of dollars since the early 1990s. It revealed that. The world's poorest countries with the lowest carbon emissions are the hardest hit. .
Geography professor Justin Mankin and doctoral candidate Christopher Callahan (Guarini '23) used newly available detailed economic data from around the world and the average temperature of the five hottest days (typically (used to measure heat intensity) were combined by region for each region. Every year. They found that from 1992 to 2013, heat waves statistically coincided with fluctuations in economic growth, with an estimated $16 trillion lost due to the effects of high temperatures on human health, productivity, and agricultural yields. discovered.
Quote
Our research shows that no place is well adapted to the current climate. …The true cost of climate change is much higher than previously calculated.
attribution
Justin Mankin, Assistant Professor of Geography
The findings highlight the urgent need for policies and technologies to protect people during the hottest months of the year, particularly in the tropics and Global South, where some of the world's warmest and most economically vulnerable countries are located. , the researchers report.
“Accelerating adaptation during the hottest months of the year could provide immediate economic benefits,” said Callahan, lead author of the study. “The amount of money spent on adaptation measures should not be evaluated solely by the price of the measure, but also against the cost of doing nothing. turns out to be quite costly.”
The study, “The Globally Unequal Impact of Heat Waves on Economic Growth,'' is one of the first to specifically examine how heat waves affect economic output, the study said. said Mankin, lead author and assistant professor of geography. “No one has shown independent evidence of extreme heat and the strength of its impact on economic growth. The true cost of climate change is much greater than we have ever calculated. It is.”
“Our study shows that no place is well adapted to our current climate,” Mankin says. “The world's lowest-income regions are the ones most affected by these heatwaves.As climate change increases the magnitude of heatwaves, it is reasonable to expect that the costs will continue to accumulate. .”
Callahan said climate models and previous studies included heat waves, among other extreme events caused by climate change, such as more frequent floods and more intense storms. But heatwaves have unique characteristics, he says. Because they occur on shorter time scales than droughts and human activities continue to drive climate change, temperatures on the hottest days of the year are projected to rise much faster than global average temperatures.
Geography professors Justin Mankin (left) and Christopher Callahan (Guarini ’23). (Photo courtesy of Lars Blackmore)
“Heatwaves are one of the most direct and tangible effects of climate change that people are feeling, but there is little understanding of what costs climate change has brought so far and what costs it will bring in the future. Heatwaves are not fully factored into our assessment,” Callaghan said. “We live in a world that has already been changed by greenhouse gas emissions. I think our research helps prove that.”
The findings highlight issues of climate justice and inequality, Mankin said. The economic costs of extreme heat, as well as the costs of adaptation, have been and continue to be borne disproportionately by the world's poorest countries in the tropics and the Global South. Most of these countries contribute the least to climate change.
Researchers found that economic losses from extreme heat averaged 1.5% of gross domestic product per capita in the world's richest regions, while low-income regions suffered losses of 6.7% of gross domestic product per capita. discovered.
Additionally, the study found that wealthy rural areas in Europe and North America, which are among the world's biggest carbon emitters, could theoretically benefit to some extent economically from continued warmer days. It became clear. The economies of other major emitters, such as China and India, would be adversely affected by more intense heat events, given their region's reference temperatures, the researchers found.
“We are now in a situation where the people who are causing changes in global warming and extreme heat have more resources to withstand, and in rare cases may benefit from, those changes. “There are,” Mankin said. “This is a massive international transfer of wealth from the world's poorest countries to the world's richest countries through climate change, and this transfer needs to be reversed.”
In July, Mankin and Callahan published a paper in the journal Climatic Change assessing the economic damage each country has inflicted on others by contributing to climate warming. This study provided the scientific basis on which countries need to assess their legal positions in order to claim economic damages from emissions and warming.
In this latest publication, Mankin and Callahan suggest that in addition to helping low-income countries develop low-emission economies, the world's major emitters should shoulder most of the costs of adapting to extreme heat. are doing. Mankin said sharing the costs of adaptation measures in the global economy would benefit rich and developing countries alike.
“Most countries on Earth have not benefited from the extreme heat that has occurred,” Mankin said. “Global events like the COVID-19 pandemic have revealed the close interconnectedness of supply chains and the global economy. Low-income countries have access to raw materials that are critical to global supply chains. It generates a disproportionate number of outdoor workers and there is absolutely an upward ripple effect.”
This research was funded by a National Science Foundation Graduate Research Fellowship. The Wright Center for Computational and Justice Community Research at Dartmouth's Neucom Institute for Computational Sciences. Nelson A. Rockefeller Center for Public Policy and Social Science.
