White House climate report dire yet optimistic

Climate change is already making its presence felt in the Northwest through diminished snowpacks, more frequent forest fires and rising sea levels, but it’s not too late for the region and the nation to escape the worst effects of human-caused warming, scientists said Tuesday.

“The choices we’re making today will have a huge impact on what’s to come,” said Katharine Hayhoe, director of the Climate Science Center at Texas Tech and one of the authors of the National Climate Assessment, a scientific report released by the White House.

Carbon dioxide levels in the atmosphere have risen more than 40 percent since the beginning of the Industrial Revolution. Though it’s too late to halt climate change, some effects can be muted through a transition away from burning fossil fuels to other energy sources, the report’s authors said.

Both dire and optimistic, the National Climate Assessment lays out already observed effects of climate change across the country – from more drenching downpours in the Northeast to an increase in the number of days over 90 degrees in the South and hotter-burning Western wildfires. The 840-page report predicts that destructive weather-related events will become more frequent unless carbon emissions are curtailed.

More than 300 scientists and other experts worked on the recent assessment, which focuses on regional and state-level effects of global warming, as opposed to United Nations reports that look more broadly at North America. During a conference call, scientists said the assessment gives U.S. citizens a better idea of the social and economic impacts climate change is having on their regions.

The report illustrates the cost to the Northwest of inaction on climate, said Washington Gov. Jay Inslee, an advocate for a “carbon-free” grid, who appointed a task force last week to find ways to reduce the state’s greenhouse gas emissions.

“I’m glad to have a dedicated ally in President Barack Obama advancing his climate action plan at the federal level,” Inslee said in a statement.

However, some oil and gas groups, conservative think tanks and Republican senators immediately assailed the report as “alarmist.” Senate Republican leader Mitch McConnell of Kentucky said Obama was likely to “use the platform to renew his call for a national energy tax. And I’m sure he’ll get loud cheers from liberal elites – from the kind of people who leave a giant carbon footprint and then lecture everybody else about low-flow toilets.”

Since taking office, Obama has not proposed a specific tax on fossil fuel emissions. He has proposed a system that caps emissions and allows companies to trade carbon pollution credits, but it has failed in Congress. Later this summer, the administration plans to propose new regulations restricting emissions from existing coal-fired power plants.

In the Northwest, the report focuses on threats to coastal communities, water supply and forests.

“These three risks – to our water, to our oceans and to our forests – aren’t lurking on the horizon, they’re here,” said Philip Mote, an Oregon State University professor and a lead author for the report’s Northwest section.

As the ocean absorbs more carbon, the water becomes more acidic, which is already affecting Washington’s oyster industry. In addition, rising sea levels are putting billions of dollars of infrastructure at risk in Washington and Oregon’s coastal communities, the report said.

Climate change is also affecting water supplies for drinking, agriculture and fish.

Most of the region’s summer water supply comes from snowmelt, but warming temperatures are reducing the amount of winter precipitation that falls as snow, Mote said. This spring, Oregon had the surreal experience of simultaneously worrying about drought and flooding, he said. After a dry spell in early winter, storms brought heavy precipitation, but the moisture fell as rain.

“We didn’t produce any snow for summer use,” he said. “All the water rushed into the rivers right away.”

The altered flows are hurting the region’s iconic salmon, steelhead and trout fisheries. Winter flooding scours fish habitat while low summer flows heat streams to temperatures that can be lethal for salmon and trout, which are adapted to cold water.

Changing precipitation patterns are also affecting Northwest forests, where scientists say a long-term transition is underway. Tree mortality is expected to spike by the 2040s, and the region’s subalpine forests will virtually disappear by the 2080s.

Water-stressed trees are more susceptible to disease and insect attacks. And more intense, more frequent forest fires are burning larger areas and sterilizing soils, which makes tree regeneration more difficult.

Across the Intermountain West, “our purple mountain majesty is at risk,” said Gregg Garfin, a University of Arizona professor who also worked on the climate assessment.

After one New Mexico fire, a refuge manager predicted that it would take more than a generation for ponderosa pines to re-establish themselves. “That’s the kind of forest that had been there for centuries,” Garfin said.