The countries emitting the most climate-changing pollution today are not only jeopardizing the future of the global economy, they already have cost the world trillions of dollars in gross domestic production in recent years.

That finding comes from researchers at Dartmouth College in the United States. It should give nearly 190 other nations ample reason to turn up the heat on the big polluters. The study shows once again that climate change is not only a future threat. It has slowed the growth of the world economy by about 11 percent annually from 1990 to 2014.

The study was released shortly after the United States Supreme Court delivered another setback to the faltering response to global warming from the world’s largest historic source of greenhouse gas pollution. Like Sisyphus, the U.S. government has gained some ground on climate action over the years, only to see its efforts fall back to the starting line again and again.

Past presidents including Jimmy Carter, Bill Clinton, and Barack Obama have set national goals and created federal programs to reduce greenhouse gas pollution, only to have progress undone by Presidents George W. Bush and Donald Trump.

The current president, Joe Biden, has proposed the most aggressive package of funding and government programs ever introduced to the U.S. Congress, only to see them languish in the U.S. Senate.

In fact, Congress has failed to pass any significant legislation on climate change since it was first briefed on the science nearly 60 years ago. The failure is perverse testimony to the power of the oil, coal, and natural gas industries to spread doubt about the validity of climate science and the costs of transitioning to clean energy.

Frustrated by the lack of congressional action, the Obama administration proposed to regulate climate-changing pollution from power plants. But a month ago, the Supreme Court ruled presidents cannot limit that pollution without specific authorization from Congress. That sent climate action by the national government back to square one.

Trillions in lost GDP

The Dartmouth study found that greenhouse gas emissions in the United States cost the world economy more than $1.8 trillion from 1990 to 2014, while pollution in the biggest carbon-polluting nations – the U.S., China, India, Russia, and Brazil cost the world $6 trillion during that period.

The study also quantified the economic losses major emitters have caused in developing nations. For example, lost GDP amounted to more than $14 billion in Bangladesh during the 25-year period because of U.S. carbon pollution and another $13.6 billion due to China’s carbon pollution.

The lead author of the Dartmouth study said its findings provide a scientific basis for developing nations to establish the financial liability of major polluting countries for suppressing economic growth.

Fifteen years ago, the U.S. Supreme Court ruled the government was obligated to limit greenhouse gas pollution from power plants if it certified that the emissions endangered public health and welfare. The Obama administration made that determination, allowing regulation of greenhouse gas emissions to proceed.

Since then, however. President Trump was able to appoint three new conservative justices to the court, tipping the Supreme Court far to the right. The new conservative majority reversed the previous Court’s decision.

Congress could fix the problem by simply adding greenhouse gases to the list of pollutants itemized in the nation’s clean-air law. But oddsmakers are betting Republicans will become the majority party in Congress after elections this November.

What now?

This doesn’t mean the United States is completely stalled in doing its part to reduce global emissions. State governments have helped fill the leadership void in the past. They’ll have to continue leading. They deserve most of the credit for a 20 percent decline in America’s coal-generated electricity from 2019 to 2020, along with the near quadrupling of wind and solar power in the U.S. between 2011 and 2020.

But the U.S. agency in charge of monitoring energy use says that without significant changes in national policies, fossil fuels will still generate half of America's electricity in 2050, obviously an unacceptable outcome as the world tries to achieve a net-zero carbon economy by then.

The lesson here is that national sovereignty is fine, except when the actions of one or more countries pose an existential threat to all. If there is a way for the larger international community to pressure the world’s biggest greenhouse gas polluters into more aggressive carbon-cutting, now is the time to do it.