Editorial: Shift from climate change debate to action

We've reached an important moment in the conversation about climate change. A moment that requires us to pivot from debating whether it's real to deciding what we're going to do about it.

A new report on climate change released last week demands such action. The U.S. National Climate Assessment -- written by scientists overseen by the federal government -- is thorough and definitive. It marshals scads of scientific evidence and draws conclusions that do not overreach. And its bottom line is worrisome: The effects of global warming seen so far are nothing compared with what lies ahead.

On Long Island, climate change is a water issue, and the scientists describe major consequences:

More than half of the nation's population lives in coastal communities that are "increasingly vulnerable" to climate change. That's us.

Sea levels in the Northeast have risen 1 foot since 1900, and the rise through 2100 is projected to be greater than the global average of 1 to 4 feet, which will increase storm surges. That's our shoreline in peril.

Warmer seas in the North Atlantic fuel more intense and longer-lasting storms. That was Sandy.

The politics underscoring the release of the report cannot be ignored. President Barack Obama, stymied on environmental initiatives by conservatives in Congress, plans June 2 to issue new regulations to reduce carbon dioxide emissions from power plants. The White House hopes the report builds support for Obama's move by creating urgency among Americans that action must be taken.

But the politics doesn't mean the report's findings can be ignored. And they are striking.

Average temperatures in the Northeast have risen nearly 2 degrees since 1895, and will rise another 3 to 6 degrees by the 2080s -- if global emissions of heat-trapping gases like carbon dioxide are reduced substantially. If they aren't, the rise could be as much as 10 degrees.

The troubling effects of those temperature changes have been seen all over the country. Summers are longer and hotter, winters shorter and warmer. Rainstorms are becoming more severe, heat waves longer and more extreme. Water shortages are becoming more common in dry areas and wildfires are getting more intense.

For a hint of what we'll face, check out Alaska, which has warmed more rapidly than the rest of the United States. Its average temperatures are up by 3 degrees (6 degrees in the winter). Glaciers and frozen ground called permafrost are melting and Arctic sea ice is receding, leaving the coastline vulnerable to battering storm surges and erosion. Entire villages are facing relocation.

The report makes clear: It's silly and irresponsible to deny that the world is getting warmer, that the trend will continue, and that major problems will face the children of today's children.

The good news is there still is time to act. But the window of opportunity -- both for this country and other major polluters such as China -- is closing.

The best ways to reduce climate change are known: reduce emissions from power plants and use less energy from fossil fuels. There has been limited progress on both fronts in the United States, but much more is needed. The Supreme Court's decision last month upholding the right of the Environmental Protection Agency to regulate pollution from coal-fired power plants that blows from the Midwest to the East Coast was critically important to clearing hurdles for the next set of rules.

Other sensible and well-understood steps: invest in mass transit and renewable energy sources, build energy efficiency into new construction, encourage retrofitting programs for homes, and plan for resiliency to better withstand the effects of climate change.

Slowing what has been an inexorable rise in temperature won't be easy. But we have to start trying -- really trying. It's time to act.