WASHINGTON — Climate change, driven by greenhouse gas emissions, is causing the Arctic to warm “faster than any other region on Earth,” according to a new international assessment. The thaw there is expected to have “major consequences for ecosystems and society,” potentially costing tens of trillions of dollars by the end of this century.

“The Arctic is showing clear evidence of evolving into a new state before mid-century,” with warmer, wetter and more variable conditions, according to the report from the Arctic Monitoring and Assessment Program.

By the late 2030s, the report suggests the Arctic could be completely free of summer sea ice, likely resulting in more extreme weather in southern latitudes. Without immediate action to curb greenhouse gas emissions, the melting of land-based Arctic ice could raise global sea levels an estimated 10 inches by 2100, threatening coastal communities around the globe.

“The changes are cumulative, and so what we do in the next five years is really important to slowing down the changes that will happen in the next 30 or 40 years,” James Overland, an oceanographer at the National Oceanic and Atmospheric Administration and an author of the report, said during a media briefing Tuesday. “The emphasis on action and immediacy is one of the key findings [of the report].”

It’s yet another terrifying reminder of what’s in store if humans continue with business as usual.

Wolfgang Kaehler/LightRocket via Getty Images A polar bear looks for food at the edge of the pack ice north of Svalbard, Norway.

The new report adds to the findings of the 2011 “Snow, Water, Ice, Permafrost in the Arctic” study, also coordinated by the Arctic Monitoring and Assessment Program. Dozens of scientists contributed to the latest assessment, which mainly covers the five years from 2011 to 2015.

The cumulative cost of the changes unfolding in the Arctic could range from $7 trillion to $90 trillion by 2100, researchers found.

The 200-plus page report calls on governments around the world to take immediate action to cut carbon emissions and to follow through on commitments made as part of the historic Paris climate pact. Such steps could stabilize Arctic temperatures in the later half of the century and prevent nearly 8 inches of additional sea level rise, according to the report.

“The main message that’s coming through in this report, the main message we’d like to convey, is that over the timescale of the next 50 to 100 years, human actions can make a difference in the trajectory of the Arctic climate system,” contributing author John Walsh, a chief scientist at the International Arctic Research Center at the University of Alaska, said in a video accompanying the report. “The way the cryosphere — ice and snow — will respond to climate change will depend a lot on the emissions scenarios, which basically are determined by human actions.”

The assessment comes as President Donald Trump moves to roll back Obama-era policies aimed at reducing the United States’ carbon footprint and fighting climate change. Trump previously vowed to withdraw the U.S. from the Paris Agreement, in which nearly 200 countries committed to cut carbon emissions (there is some indication that cooler heads may prevail). He has also dismissed climate change as “bullshit” and a “hoax.” And he has given encouragement to those who support oil and gas development in Arctic waters.

Margaret Williams, managing director of the World Wildlife Fund’s Arctic Program, said the new report underscores the urgency of reining in emissions and allowing only sustainable development in the Arctic.

“An intact Arctic is critical to our future, but the planet’s air conditioner is in jeopardy,” Williams, who was not involved in the study, said in a statement. “The staggering pace of Arctic warming reinforces the need for scientists to continually engage policymakers and the public about these changes. Smart Arctic policy will come from sound science and shared responsibility.”

Earlier this month, the International Union for Conservation of Nature called on world leaders to safeguard the Arctic from such threats as oil development and shipping. It highlighted seven marine areas worthy of protection.

This weekend, on Trump’s 100th day in office, thousands of Americans are expected to descend on Washington, D.C., to participate in the People’s Climate March, a demonstration against the president’s environmental policies.