Earth Protect Blog

 Extended dry period in the West likely to continue, straining vital water supplies

By Conrad Swanson The Denver Post

Not only is the American West the driest it’s been in more than a millennia, but the megadrought is likely to continue for years, diminishing Colorado’s short water supply and increasing the risk of wildfires, climatologists say.

The current, 22-year megadrought plaguing the West has surpassed the megadrought in the late 1500s, previously considered the worst on record, according to a study published this week in the scientific journal Nature Climate Change. Plus, about 42% of this megadrought’s severity can be blamed on climate change caused by humans.

Soil moistures, increasing temperatures and climate modeling shows a 94% chance that the drought will continue for a 23rd year, Jason Smerdon, a climate scientist at the Lamont-Doherty Earth Observatory of Columbia University, said.

And there is a 75% chance that the megadrought will continue through its 30th year in 2029, Smerdon, also a co-author of the study, said.

The study focuses mostly conditions west of the Continental Divide, Russ Schumacher, director of the Colorado Climate Center, said. But those conditions affect life on the Front Range as well.

Snow and rainfall can fluctuate through wet and dry months or years, Schumacher said, and because temperatures are increasing, more moisture than normal is lost because of evaporation.

“The situation gets very concerning if you have lots of years of dryness and similarly the precipitation and snowpack that we do get doesn’t go as far as it used to,” Schumacher said.

The likely continuing dry period comes at a time when the Colorado River, which supplies water to about 35 million people, and reservoirs along the waterway are hitting record low levels, Smerdon said.

Currently no part of Colorado is untouched by the water shortage, according to data published Thursday by the National Drought Mitigation Center. The vast majority of the state is considered “abnormally dry” or in varying stages of “moderate” or “severe” drought. About 9% of the state’s land is considered in “extreme” drought, the data shows.

In addition, snowpack levels for the majority of the state are below normal levels for this time of the year, according to data published Wednesday by the U.S. Department of Agriculture’s Natural Resources Conservation Service. Continuous, above-average snowfall and precipitation is needed well into the spring to recharge the state’s parched soils and waterways, experts repeatedly have told The Denver Post.

Schumacher said some more snowfall is projected for western Colorado next week, but likely not enough.

“February and March are key times for building that snow accumulation,” he said. “And unless they’re those really big storms like we had in December, things are certainly not in as good a shape as they were a month ago.”

The ongoing lack of water moving forward would also mean an increased risk of dying forests, wildfires, insect outbreaks and other environmental consequences, Smerdon said. Agriculture, tourism and other portions of the economy also would suffer, although the societal implications are difficult to predict, he said.

“We know what happens when we warm the climate,” Smerdon said. “What we don’t know is what happens when we warm people.”

The Nature Climate Change study, which examined soil moisture and data collected in tree rings, showed that severe megadroughts have occurred throughout the Earth’s history, Smerdon said, but human development and the outpouring of greenhouse gas emissions worsened the effects of these naturally occurring droughts.

“This would have been a dry period, absent human influence, but it wouldn’t have been as severe, as long or as uniformly widespread in the Southwest,” Smerdon said.

Unless humans take steps to stop dumping greenhouse gasses into the atmosphere, the effects of climate change are likely to compound, he said.

“If you’re in a hole, stop digging,” Smerdon said. “We absolutely have to reverse course.”