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."
By 2050, climate change will triple the fraction of counties in the United States that are at high or extremely high risk of outstripping their water supplies, from 10 percent to 32 percent, the report notes, adding that the most at-risk areas in the United States are the West, Southwest and Great Plains regions.
Stein said water managers, particularly those in the Colorado River basin that includes Utah, are already responding to the threat of such shortages.
"'Water managers are planning their operations with climate in context, taking into account what is known as the 'new normal,'" he said. "Much of our water management was developed at a time when there was good supply of precipitation. Over the last 10 to 15 years, we can see that has changed. Along the Colorado, they are beginning to recalibrate their assumptions and accordingly recalibrate how they are managing the river and their allocations."
The study points to strides and real progress on the ground that demonstrates that government can be responsive and smart in the threat of climate change, and the public-private partnerships out there to curtail its range of potential consequences.
An example is a tree-thinning program instituted in Arizona, which experienced its largest wildfire on record in 2011. Still, the fire did not burn ridges where the thinning had happened. Such strategy invoked in advance of catastrophic wildfires can help reduce other threats, such as flash flooding that can imperil drinking water supplies, the report notes.
"The nexus of climate and forest fires is a flashpoint for several other degraded ecosystems such as water supply and water quality," the report said.
The report said that the federal government is beginning to take action by managing programs with climate change as a component.
Several states, too, have formal climate change adaptation programs on the books, and even those that don't are approaching the management of fish and wildlife with strategies that incorporate conservation in a broad sense, including habitat restoration and landscape connectivity.
