Report Indicates Big Changes For Nevada's Climate
More wildfires could be just the beginning of the problems Nevada and the Southwest could face if efforts aren't made immediately to reduce the rising temperatures brought about by greenhouse gas emissions.
That's one of the conclusions of the latest National Climate Assessment, which lays out how the drought and climate change are altering the landscape.
Dave Breshears is a professor at the University of Arizona. He contributed to the report, which was released the day after Thanksgiving. He said the modeling done by scientists show just how dramatic the changes have been.
“Due to the extra warming temperatures that we’ve had in the western United States between 1985 and 2015, the area burned by wildfires is about double what it would have been without warming,” he said.
Wildfires are not the only problem, he said. There is also the issue of tree die-off. Breshears said most years tree die-off is not noticeable and only a small percent of trees in a forest die.
But, rising temperatures are creating a huge die-off of trees in many southwest forests. He said it was particularly bad in the Four Corners area of the Southwest in 2002 and 2003 where several areas saw 20 percent or more die-off.
“What we are seeing with warming temperatures - even when we do get the same sort of snowfall amount - is that snow melts earlier, soils dry earlier," he said. "That puts trees in distress earlier in the growing season, and that stress is the driver for both the wildfires and the tree die-off whether it’s driven by climate or pests and pathogens," he said.
Breshears said if rising temperatures are not addressed, the future would be grim for forests around the West.
“If temperatures continue the way they are, we might be on a pathway where within a century we would be getting a tree die-off event every 20 years or so as opposed to getting one less than every 100 years," Breshears said.
That could be particularly troubling for slow-growing species like pinon and ponderosa pines that may struggle to get back to mature forests.
Southwest forests aren't the only concern. Professor Nancy Huntly said water supply could be dramatically impacted.
“We have already seen lower water availability, more droughts and that’s projected to increase sharply into the future,” she said.
Huntly is a professor at Utah State University and she also contributed to the report.
She said the problem isn't just the amount of precipitation that the western United States gets but the form of the precipitation. Currently, the Colorado River basin depends heavily on snowpack and snowmelt.
However, if the Rocky Mountains start to get more rain than snow the snowmelt that feeds the river later in the spring and summer won't be there.
In addition, the warmer air temperatures will draw more moisture out of the air making the southwest even more arid than it already is.
Huntly said adapting to the drier, hotter temperatures by conserving more water is one solution to the problem, but the other is mitigation.
“I think there is no long-term solution that doesn’t include both mitigation and adaption," she said.
Huntly said if something isn't done to stop greenhouse gas emissions then just adapting to the problem will become too expensive and impossible.
While the report sounds dire, Breshears said it also gives the world an understanding of what is causing temperatures to rise and what we can do to stop the increase.
“If we reduce emissions, we can prevent some of the worst effects that are coming,” he said. “Time is very, very short for us to start addressing this or things are going to get a lot worse very quickly.”
Huntly agrees that it may seem bleak but really the report is a path forward.
“It’s a warning but it also has information about things people are already doing to make things better,” she said.
Dave Breshears, professor, University of Arizona; Nancy Huntly, professor, Utah State University