Climate change already having significant impact–US report

WASHINGTON—The government’s newest national assessment of climate change declares that increased global warming is affecting every part of the United States.

The report released on Tuesday cites wide and severe impacts: more sea-level rise, flooding, storm surges, precipitation and heat waves in the Northeast; frequent water shortages and hurricanes in the Southeast and the Caribbean; and more drought and wildfires in the Southwest.

“For a long time, we have perceived climate change as an issue that’s distant, affecting just polar bears or something that matters to our kids,” said Katharine Hayhoe, a Texas Tech University professor and a co-author of the report. “This shows it’s not just in the future; it matters today. Many people are feeling the effects.”

The federal climate assessment—the third since 2000—brought together hundreds of experts in academia and government to guide US policy based on the best available climate science. The authors of the more-than-800-page report said it aims to present “actionable science” and a road map for local leaders and average citizens to mitigate carbon and other gas emissions that warm the planet.

But the report ran immediately into conservative critics who called it a political document, aimed at giving President Barack Obama a leg up on regulating major polluters, such as power plants.

In their view, regulation costs jobs. Obama, who is increasingly focusing on climate change, spent part of the day talking about the report with television meteorologists from across the country.

Echoing the findings of a recent global report by climate scientists at the Intergovernmental Panel on Climate Change, US scientists said the climate is changing in the United States and that the warming of the past 50 years was primarily caused by emissions of heat-trapping gases released by humans.

Burning coal for electricity, using gasoline to fuel vehicles, clear-cutting forests and engaging in certain agricultural practices that remove carbon-trapping vegetation contribute to the problem, the assessment said.

By the end of the century, temperatures could be up to 5 degrees higher, even if the nation acts aggressively to reduce greenhouse-gas emissions. It could be up to 10 degrees hotter if emissions are high.

The higher the temperature, the more dire the impact. Extreme weather in the United States caused by climate change has increased in recent decades, the report said.

The decade starting in 2000 was the hottest on record, and 2012, the year Hurricane Sandy followed an epic summer drought, was the hottest ever recorded in the nation’s history, the report said. US temperatures are 1.3 degrees to 1.9 degrees Fahrenheit higher now than they were in 1895, and most of that increase—80 percent—occurred over the past 44 years, the assessment says.

Alaska warmed twice as fast as the rest of the country in the past 60 years, leading to permafrost thaw that is causing highways and even airport runways to sink.

The authors pointed to major concerns for mid-Atlantic areas.

“As sea levels rise, the Chesapeake Bay region is expected to experience an increase in coastal flooding and drowning of. . .wetlands” that protect against storm surge, the report said. That’s especially bad because the lower bay region is at higher risk as a result of of sinking land. Water quality would decline and low-oxygen dead zones would increase.

If there are higher greenhouse-gas emissions, the majority of Maryland and Delaware, and parts of West Virginia and New Jersey, are projected to have 60 extra days per year of temperatures topping 90 degrees starting around the middle of the century, the report said.

The impacts sound alarming, but there are reasons to be optimistic that they can be mitigated, said David Wolfe of Cornell University, a lead co-author of the report’s chapter on change in the Northeast.

Business leaders are looking more toward investments in renewable energy, he said. This report, unlike the first two, has a web site with interactive tools that show Americans how to reduce climate impacts.

“It will be a living document, a resource for people,” he said. “It’s a place to start.” –Darryl Fears / The Washington Post