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Climate change poses major threat to United States, new government report concludes

Climate change is already being felt in communities across the United States, and will cause growing harm to the economy, infrastructure, and human and ecological health—unless the United States and other nations take concerted action to reduce emissions of warming gases and adapt to a warmer world.

That is the sobering message sent by a major federal report released today that examines climate change impacts on different U.S. regions, economic sectors, and ecosystems.

“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 concludes. “The impacts of global climate change are already being felt in the United States and are projected to intensify in the future—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.”

Efforts to address climate change “have expanded in the last five years, but not at the scale needed to avoid substantial damages to the economy, environment, and human health over the coming decades,” it states. And without “substantial and sustained global efforts,” climate change will “cause growing losses to American infrastructure and property and impede the rate of economic growth over this century.” U.S. gross domestic product could be reduced by 10% or more under some scenarios, with annual losses in some economic sectors reaching “hundreds of billions of dollars by the end of the century—more than the current gross domestic product (GDP) of many U.S. states.”

The new report is designed to be “policy relevant,” but does not make specific policy recommendations, federal officials associated with the U.S. Global Change Research Program in Washington, D.C., noted in a teleconference today. Still, its findings offer a stark contrast to positions taken by President Donald Trump and many of his top officials. They have repeatedly downplayed or rejected warnings from experts that climate change poses a serious threat to national security. And the administration plans to withdraw from the Paris climate accord, an international effort to cut emissions of warming gases, and has moved to roll back a wide array of domestic climate regulations.

The report also comes just weeks before Democrats are poised to take control of the U.S. House of Representatives. Incoming House leaders have promised to make climate change a priority, and have already announced a series of hearings early next year on the topic.

Representative Eddie Bernice Johnson (D–TX), who is expected become the chair of the House science committee in January 2019, said in a statement that the report’s conclusions, “as we’ve sadly grown accustomed to, are quite terrifying—increased wildfires, more damaging storms, dramatic sea level rise, more harmful algal blooms, disease spread, dire economic impacts, the list goes on and on. That being said, all hope is not lost, but we must act now. We have to reduce greenhouse gas emissions, work on adaptation and mitigation, and explore technology solutions such as geoengineering and carbon capture and sequestration.”

The 29-chapter report, formally known as Volume II of the Fourth National Climate Assessment, is a follow-up to the assessment’s first volume, released a year ago, which summarized the state of climate science. The reports are required by a 1990 law that orders federal agencies to report at least every 4 years on the status and potential impacts of climate change. They were assembled by some 300 experts, about half of whom work outside the federal government. The process of preparing the report, which was led by the National Oceanic and Atmospheric Administration, involved collecting public comment at events in more than 40 cities.

Over the past year, some climate advocates had expressed concern that the Trump administration would attempt to alter or censor the report. But federal scientists emphasized that there was no outside interference. “The report has not been altered in any way to reflect political considerations,” said Virginia Burkett, a climate scientist with the U.S. Geological Survey who worked on the effort. Many climate advocates have noted, however, that the administration chose to release the report late on the Friday after Thanksgiving, when the attention of the public and the press may be elsewhere.

“How many wake-up calls do we need?” Carol Werner, executive director of the Environmental and Energy Study Institute, a policy nonprofit in Washington, D.C., asked in a statement. “Every new National Climate Assessment has built on the previous one, confirming that climate change is already happening and that we need to act. Time is running out. … Sadly, the fact that the administration released this important report on the Friday after Thanksgiving clearly shows its desire to squelch its impact.”