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Assessment paints stark picture of climate damage

WASHINGTON — The warming of Earth, with human consumption of fossil fuels as the main cause, will have severe consequences for every region of the United States, according to the Third National Climate Assessment released Tuesday morning by the Obama administration.

Mandated by Congress and published every four years, the report is a science-based resource that is meant to inform public policy and private sector decisions.

The report concludes that extreme weather events influenced by climate change have grown more frequent and intense, including heat waves, drought and severe precipitation. “These and other aspects of climate change are disrupting people’s lives and damaging some sectors of our economy,” the report said.

Most Americans believe that climate change is happening or will happen in their lifetimes, according to a March Gallup poll. But only one in three sees it as a “serious threat” to their way of life, the poll reported.

The climate assessment is meant, in part, to drive home the seriousness of the threat by focusing on local effects. The report sketches out sobering scenarios for different regions. The Northeast and Midwest, for instance, would see a huge increase in heavy downpours that could lead to flooding and erosion.

Read more: Climate change threatens forests, Great Lakes

“The overall message is that climate change is happening right now — we can’t think of this as an issue for future generations,” said Radley Horton, one of the lead authors and a climate scientist at the Earth Institute’s Center for Climate Systems Research at Columbia University. “We know that the effects on ecosystems, infrastructure, economics and public health are going to grow.”

The National Climate Assessment also assesses humanity’s contribution to climate change, the thorniest question tied to the issue and the one at the heart of political disputes. Very early on, the report states that many different kinds of evidence “confirm that human activities” have driven global warming over the past 50 years, specifically the emissions of heat-trapping greenhouse gases from burning coal, oil and gas.

Skeptics react

Skeptics attacked the report. The Cato Institute, a Washington-based libertarian research center, sent out its assessment Monday, saying the report “overly focuses on the supposed negative impacts from climate change while largely dismissing or ignoring the positives from climate change.”

It said the “bias … towards pessimism” has implications for the federal regulatory process because the report is cited as a primary source for the science of climate change in justifying federal regulations.

Since the U.S. National Climate Assessment “gets it wrong, so does everyone else,” Cato’s authors said.

The paper tackles in plain English and swift strokes the arguments that climate contrarians generally use to deny that man-made climate change is occurring. The report states, for example, that satellite data show that the warming has not been caused by greater solar activity or by volcanic eruptions. A pause in recent global average land temperatures “appears to be related to cyclic changes in the oceans and in the sun’s energy output,” the report said.

By the numbers

Written by more than 240 scientists, business people and other experts, the report explains that the U.S. annual mean temperature has risen by 1.3 to 1.9 degrees Fahrenheit since the late 19th century, with most of the increase occurring since 1970. “Temperatures are projected to rise another 2 degrees F to 4 degrees F in most areas” of the country over the next few decades, according to the report.

If the U.S. and other big emitters enact polices that would cut emissions considerably, U.S. temperatures would rise about 3 degrees to 5 degrees Fahrenheit by the end of the century. Under today’s “business-as-usual scenario,” U.S. average temperatures would rise by 5 degrees to 10 degrees, which means that summers in New Hampshire by the end of the century would be as hot as those in North Carolina now.

President acts

The climate assessment arrives amid increased efforts by the Obama administration to address climate change through the president’s Climate Action Plan, which was unveiled in June 2013 and focuses on executive actions Obama can use to rein in polluters. It will enter a new phase in June when the EPA proposes new emissions limits for the country’s power plants.

In February, the administration created climate hubs under the Agriculture Department to connect farmers and ranchers with universities, industry groups and federal agencies to help prepare for disasters worsened by climate change, such as wildfires, pests, flooding and drought.