Climate change already playing out in West, report says

Change 'more dramatic' in winter than previously thought, ecologist says

Published: Tuesday, Dec. 18 2012 6:10 p.m. MST

Trees to be harvested are marked in blue in Wolf Creek Campground in the Uinta National Forest, July 13, 2012.

Ravell Call, Deseret News

SALT LAKE CITY  — A new report says the effects of climate change are already being felt in bug-infested forests of the Intermountain West, in reduced flows of the Colorado River basin and in the amount of snow that falls in the Rocky Mountains.

What is key, the report stresses, is how state and federal governments are responding and what land and natural resource conservation strategies can be embraced or expanded to counter the impacts.

"I think the bottom line is that these impacts are not going to happen 50 or 100 years from now," said Bruce Stein, director of climate change adaption with the National Wildlife Federation. "Many of them are already here, and we are going to have to be rethinking what we do to protect our wildlife and how we build and protect our communities."

In addition to climate changes causing heat waves in the summer, the report highlights a surprise revelation that its biggest effect occurs in the winter months. Those warmer winters are enhancing pest outbreaks and accelerating the melting of snowpack each year, reducing the amount of water that's available later when needed.

The report, Impacts of Climate Change on Biodiversity, Ecoystems and Ecosystem Services, was peer-reviewed by the U.S. Geological Survey and drew on the expertise of 60 contributors from government agencies, universities and private, non-profit organizations such as The Nature Conservancy.

The report foreshadows the National Climate Assessment, a report done every four years for the U.S. president and Congress charting projections in global change for the next 25 to 100 years. Done by the U.S. Global Change Research Program, that report is anticipated to be released in draft form in January and available for public comment.

In a teleconference Tuesday highlighting key findings of the biodiversity report, moderator Mary Grimm said U.S. ecosystems are already undergoing "massive" transformations as the result of climate change.

"Ecological systems are already more stressed than at any comparable period in human history, said Grimm, a senior sustainability scientist at Arizona State University's Global Institute of Sustainability.

The report notes that forests are already responding to climate change, with longer growing seasons and warmer winters that enhance pest outbreaks such as rampant bark beetle infestations. Such attacks are leading to widespread die-offs of trees in forests, sparking increased risks for more severe and extensive fires.

"If trends continue," the report warned, "baseline tree mortality rates in western forests are projected to double every 17 to 29 years."

Peter Groffman, a microbial ecologist at the Cary Institute of Ecosystem Studies in Millibrook, N.Y., said their research turned up a significant surprise — that climate change's impacts are playing out more dramatically in the winter than in other seasons.

While assumptions and most research bemoans climate change with its potential for arid heat waves in the summer, those increasing temperatures during the winter months have substantial consequences as well, Groffman said.

"Climate change is more dramatic in the winter than we thought," he said. "Those changes have effects on biodiversity and ecoystems in the growing season," and accelerate snowmelt and even changes in peak runoff, which can come earlier.

"In the Colorado River basin, water shortages are expected as a consequence of changes in snowmelt timing," the report notes. "Acceleration of the annual melting of snowpack may reduce water availability later in the summer when it is most needed, particularly in the more arid regions such as the western United States."

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