US struggling to respond to climate shift

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Climate change is leaving its mark on US ecosystems sooner and more emphatically than biologists had expected.

And because the US is not adequately prepared to measure those changes as they occur, land managers may have a harder time mounting an effective response to climate change.

These unsettling conclusions come from a report released yesterday by the US Climate Change Science Program, a government body set up to coordinate climate change research.

The program assembled 38 scientists from government, academia and conservation organisations, who spent nearly two years combing the scientific literature to assess what is known about the effects of climate change on US ecosystems.

Their conclusion adds new urgency to the response to climate change.

Bigger and faster

“The fact is, we’re seeing lots of effects and impacts right now. These effects appear to be happening faster than expected, and the magnitude is bigger than expected.

That’s a surprise,” says Anthony Janetos, an ecologist who directs the Joint Global Change Research Institute in College Park, Maryland, and one of the lead authors on the report.

For example, climate change has already brought forward the start of spring growing seasons by as much as two weeks, and similar changes have occurred in the timing of bird migrations, says Janetos.

Warmer conditions have also resulted in many plants and animals extending their geographic range further northward and higher up mountains.

As climate change alters precipitation patterns, much of the eastern US has already become moister, while the west has become more arid.

This means less winter snowpack in western mountains, and thus less snowmelt to keep rivers running cold and full in summertime. The higher stream temperatures are likely to put added stress on aquatic ecosystems, the report predicts.

Close to the edge

Warmer, dryer conditions in the arid west increase stress on plants and animals that are already living close to their physiological limits.

This is likely to increase the harm caused by grazing and off-road vehicle use. More prevalent wildfires