Arctic ice and permafrost melt will add at least $24 trillion to the long-term costs of climate change, even if the Paris Agreement's goals are met, according to a study published in Nature Communications on Tuesday.

If we take no further action to curb greenhouse gases, that extra cost will climb to $67 trillion by 2300, the authors said.

Led by climate scientist Dmitry Yumashev of Lancaster University, the paper found that factoring in two Arctic feedback loops, regarded as key tipping points in the future of the Arctic climate, cloud inflate global temperatures and their costs by as much as 5 percent.

One is the permafrost carbon feedback, which is generated by greenhouse gas emissions released by the Arctic’s frozen soil as it thaws. The other is the surface albedo feedback, which refers to solar energy that is either absorbed by darker surfaces, such as ocean and dirt, or reflected by brighter surfaces, such as ice.

In the scenarios modeled by Yumashev’s team, the total global cost of climate change ranges from $600 to $2,100 trillion by 2300.

"Our findings support the need for more proactive mitigation measures to keep global temperature rise well below 2°C,” Yumashev said in a statement. Such measures include widespread adoption of renewable energies such as solar power, the study said.

While Yumashev’s team modeled future consequences of climate change, a study published Monday in the Proceedings of the National Academy of Sciences assesses the global economic damage that the problem has already caused.

Authors Noah Diffenbaugh and Marshall Burke, geoscientists at Stanford University, find that climate change has caused a 25 percent rise in global economic inequality since the 1960s.

The economic growth of warmer nations such as Sudan, India, Nigeria, and Brazil has been stunted by about 25-36 percent due to climate change, the study found. Meanwhile, colder nations like Norway, Canada, and Sweden are about 25-34 percent richer than they would have been without warmer global temperatures.

The team calculated these figures by examining long-term temperature and GDP measurements across 165 countries, to see if there is a link between economic growth and temperature fluctuations.

“Although between-country inequality has decreased over the past half century, there is ~90 percent likelihood that global warming has slowed that decrease,” the authors said. “The primary driver is the parabolic relationship between temperature and economic growth, with warming increasing growth in cool countries and decreasing growth in warm countries.”

Some proposals, such as the Green New Deal, have outlined measures that would rapidly reduce greenhouse gas emissions over the coming years. Opposition to these plans is often based on the costs involved in implementing them, but these two new studies offer a powerful counterpoint to that argument.

We still have a lot of work to do in figuring out the best way to curb climate change, but there is a clear consensus that the priciest option is to do nothing.