Here's what every degree of heat rise could do to the global economy

Even the most promising solutions to climate change often run smack into the challenge of how to pay for them. As the United Nations' COP26 summit kicks off in Scotland on Sunday, questions about whether poorer countries can afford to reduce their emissions for the global good and whether richer countries — which account for the vast majority of the world's carbon emissions — are doing enough to help them are expected to take center stage.

Yet the cost of fighting climate change must be weighed against the potential economic toll of losing the war, which climate experts warn would be staggering. Indeed, the financial damage from runaway climate change would surpass the amount of all the money that currently exists on the planet, according to one estimate.

As of 2017, global warming had already reduced U.S. economic output by about 1% — or nearly $200 billion, according to a study published at the time in the research publication outlet Science. But as the mercury rises, the costs increase exponentially. If the global temperature reaches 4 degrees Celsius by 2100 — described by experts as a catastrophic scenario — the costs per degree soar to as high as 5.6% of GDP, the same study predicts.