Worldwide income may fall by 19% by 2049 because of changes in climate.
That's according to a new study published in Nature. Poorer countries in the tropics that have historically contributed the least to greenhouse gas emissions will experience the greatest economic burden, researchers said.
The "huge" $38 trillion annual price tag of climate-related damages is 6 times greater than the cost of mitigating emissions to meet the targets in the Paris Agreement, said Anders Levermann, a climate scientist at the Potsdam Institute for Climate Impact Research and one of the study's authors. The treaty aims to limit global average temperatures to 1.5°C-2°C above preindustrial levels by 2100.
We won't be able to avoid most of the damages estimated in the study by 2049.
Previous research has shown a strong correlation between average annual temperature changes and economic growth. But climate change will also affect precipitation, driving more frequent droughts, extreme storms, and flooding. Any given region may see more or fewer wet days, and Levermann and his colleagues wanted to factor this, and newer findings about how these variations in weather affect business, into economic predictions.
The researchers incorporated data from climate simulations and historical data about the links between average and extreme temperatures and precipitation and projected that worldwide income is likely to fall by 11%-29% by 2049. The most likely outcome is somewhere in the middle, a 19% decrease. That's higher than previous estimates that looked at only average temperature increases, Levermann said.
The economy has a lot of inertia, and major changes such as getting to net zero carbon emissions take time. For that reason, the climate simulations, which considered various emissions pathways, don't diverge much in their predictions until mid-century. We won't be able to avoid most of the damages estimated in the study by 2049, Levermann explained. But he said he hopes the thought of economic risks will spur actions that will help later in the century.
Uneven Burden
Economic damages will not be distributed evenly, according to the projections. Poorer countries will experience 61% more income loss than richer countries will. And the effects will also fall disproportionately on those that have contributed relatively little to climate change: Countries with historically low emissions will face 40% more lost income than those whose emissions have been high.
"This is a call to action for adaptation," said Matteo Coronese, who studies climate change and economic inequality at the Scuola Superiore Sant'Anna in Pisa, Italy. Coronese was not involved with the study.
People living in sub-Saharan Africa are particularly vulnerable to climate change, Coronese said, because many work in agriculture, which relies on consistent rainfall. Adaptation measures must take different forms in different places, but in developing countries, supporting the development of decarbonized economic structures is key, he explained.
There is a lot of uncertainty in the study's estimates, Coronese noted. Climate simulations confidently predict rising average temperatures, but the effects of climate change on regional precipitation are more uncertain. Economic models also can't predict how people will behave. If the world rapidly and aggressively puts in place climate adaptation strategies, the economic damages could be lower.
Another unknown is how long a given weather event, such as a particularly dry year, will affect an economy. Some researchers assume that climate-related economic damages persist year to year, Levermann said. Others assume a rapid recovery, with people and systems adapting quickly. Levermann said he and his colleagues fall somewhere in between. There's good evidence that temperature-related economic damages persist for about 10 years and rainfall-related ones last for 4-8 years, he said.
"A lot of things can change in 30 or 40 years."
Past 2049, it's much more difficult to predict the costs of climate change. These kinds of studies assume that nothing is changing besides the climate, Coronese said. But these are not forecasts-they are projections. Adaptation measures could make things better.
"A lot of things can change in 30 or 40 years," he said.
It's impossible to predict human behavior, but the need to mitigate emissions and adapt to climate change is clear. "It's much cheaper to avoid the costs than to pay for the damages," Levermann said.