Researchers at Stanford University have calculated that meeting the targets of the Paris climate agreement could save the world 20 trillion dollars.

The benefits of hitting the climate targets are 40 times larger than the costs of achieving those goals, the researchers show in their Nature study. And meeting the goals would benefit the economies of nearly all countries, from the poorest to the wealthiest.

The U.S. is the only country in the world that has refused to sign on to the Paris agreement, which aims to limit world warming to between 1.5 and 2 degrees Celsius above pre-industrial levels. The Trump administration’s rationale for pulling out was that the agreement hurts the U.S. economy. But the Stanford team finds that missing the most ambitious Paris targets would cost the U.S. economy $6 trillion in today’s dollars.

The new study is among the first to comprehensively estimate the economic benefits of meeting Paris goals. Marshall Burke and his colleagues analyzed historical temperatures and gross domestic products of 165 countries between 1960 and 2010. Data from these years show that as temperatures rise, the GDP falls in most nations. That’s because hotter weather decreases human productivity and agricultural output, and affects health and cognitive ability.

Projecting into the future using global climate models, the researchers found that about 90 percent of the world’s population would likely benefit from meeting the Paris goal of limiting warming to 1.5°C.

Poorest countries of the world, which also tend to be the hottest, would benefit most, the data shows. But beneficiaries also include the three biggest economies: China, Japan, and the U.S. Other big winners would be Middle Eastern countries, which face the dire threat of extreme heatwaves.

By the end of the century, meeting the 1.5°C target would lead to global benefits of $20 trillion. But missing the goal and hitting a warming of 3°C will cost an additional 5–10 percent of GDP relative to 2°C, which translates to tens of trillions of dollars. A previous study has shown that the estimated cost of meeting the 1.5°C target is about $0.5 trillion over the next 30 years.

“Thus, while acting on climate change will no doubt require substantial investment, doing nothing will be even more costly,” Burke said in a commentary published in The Hill.

Source: Marshall Burke et al. Large potential reduction in economic damages under UN mitigation targets. Nature, 2018.

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