Climate change is taking an increasing toll on the nation's environment, health and economy, and the damage will intensify over the century without swift action to slash greenhouse gas emissions, according to a major scientific report released Friday by federal agencies.

The congressionally mandated report by 13 federal agencies, the first of its kind under the Trump administration, found that climate change is already being felt in communities across the United States. It projects widespread and growing devastation as increasing temperatures, rising sea levels, worsening wildfires, more intense storms and other cascading effects harm our ecosystems, infrastructure and society.

The assessment paints a dire picture of the worsening effects of global warming as nearly every corner of the country grows more at risk from extreme heat, more devastating storms, droughts and wildfires, waning snowpack and other threats to critical infrastructure, air quality, water supplies and vulnerable communities. By century's end, the report projects thousands of additional deaths annually from worsening heat waves and air pollution, as well as declining crop yields and the loss of key coral reef and sea ice ecosystems.

Roughly $1 trillion in coastal real estate is threatened by rising sea levels, storm surges and high-tide flooding exacerbated by climate change, according to the report.

The report also warns of economic consequences of inaction. Without substantial global emissions reductions and local adaptation measures, the report says, "climate change is expected to cause growing losses to American infrastructure and property and impede the rate of economic growth over this century."

If emissions continue to climb, economic losses will be in the hundreds of billions annually in some sectors by the end of the century _ "more than the current gross domestic product (GDP) of many U.S. states," the report says.

The assessment found climate change already affecting California and the Southwest through extreme drought, rising sea levels, heat-related deaths increased wildfire risk. The area burned across the western U.S. from 1984 to 2015 was twice what it would have been if climate change had not occurred, according to analyses cited in the report.

The report also details regional-level climate impacts across the nation in an effort to provide local officials with tools to respond and adapt.

The assessment leaves no doubt that humans are to blame for the changing climate, and that extent of the harm we will experience depends on decisions we make today.

"Earth's climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities," the report says. "But the severity of future impacts will depend largely on actions taken to reduce greenhouse gas emissions and to adapt to the changes that will occur."

The assessment's dire conclusions are at odds with President Donald Trump's efforts to dismiss the threat of climate change and his administration's push to slash environmental regulations and allow more planet-warming pollution.

The Trump administration has moved to dismantle Obama-era climate regulations and replace them with fossil fuel-friendly policies that allow more planet-warming emissions from power plants, cars and trucks. Trump has vowed to pull out of the international Paris climate agreement, while seeking to cast doubt on the scientific consensus that climate change is accelerating and caused by human activity.

Earlier this week Trump mocked climate science, tweeting about cold weather in the Northeast and asking "Whatever happened to Global Warming?"

In a statement, White House spokeswoman Lindsay Walters said "to address future risks, the administration supports a strong economy and access to affordable, reliable energy, which are integral to advancing technology and innovation and the development of resilient, modern infrastructure."

She also said the climate report "is largely based on the most extreme scenario" and called for future installments to have "more transparent and data-driven process that includes fuller information on the range of potential scenarios and outcomes" _ a claim that one of report's lead authors said was "demonstrably false."

"I can confirm it considers all scenarios, from those where we go carbon negative before end of century to those where carbon emissions continue to rise," Texas Tech University climate scientist Katharine Hayhoe responded on Twitter.

The Trump administration did not block the release of the report, a product of more than two years of work by more than 300 of the nation's leading scientists both in and outside of government, and is one volume of the National Climate Assessment, which the federal government is required by law to produce every four years.

But federal officials faced criticism over its timing, with environmentalists, Democratic lawmakers and scientists among those accusing the Trump administration of trying to bury the report by releasing it early, on a slow news day the Friday after Thanksgiving.

The document's release was important in tackling a misconception by Americans that the changing climate doesn't harm them personally, instead "showing how climate change is already affecting each one of us, whether we live in Texas or Minnesota or Hawaii or Florida," said Hayhoe, the Texas Tech climate scientist.

"This report is clear: It's real. It's us. It's here. It's bad. It's getting worse. But our choices can and do make a difference. So: act now," Hayhoe tweeted.

Environmentalists said the assessment provides a mountain of evidence that climate change is not a political debate but an existential threat that warrants action to cut planet-warming pollution, before it's too late.

"With the lives and health of millions of Americans at risk from worsened hurricanes, droughts, wildfires and air pollution, we urge President Trump and his administration to heed the dire warnings in this report and reduce greenhouse gas emissions from power plants, vehicles and other sources to save American lives," said Harold P. Wimmer, national president of the American Lung Association.