A new U.S. Geological Survey study finds, “Warmer spring temperatures since 1980 are causing an estimated 20 percent loss of snow cover across the Rocky Mountains of western North America.”
The USGS explains, “The new study builds upon a previous USGS snowpack investigation which showed that, until the 1980s, the northern Rocky Mountains experienced large snowpacks when the central and southern Rockies experienced meager ones, and vice versa. Yet, since the 1980s, there have been simultaneous snowpack declines along the entire length of the Rocky Mountains, and unusually severe declines in the north.”
We reported on that previous work in 2011 — see “USGS: Global Warming Drives Rockies Snowpack Loss Unrivaled in 800 Years, Threatens Western Water Supply.” The USGS explained back then:
The warming and snowpack decline are projected to worsen through the 21st century, foreshadowing a strain on water supplies. Runoff from winter snowpack – layers of snow that accumulate at high altitude – accounts for 60 to 80 percent of the annual water supply for more than 70 million people living in the western United States.
What’s most worrisome is that we now have three major trends driven by human emissions of greenhouse gases that threaten to significantly worsen drought and water problems in the West and Southwest:
- Less precipitation in many areas (see here)
- Less snowpack, as the USGS studies have found
- Hotter temperatures (see “We’re Already Topping Dust Bowl Temperatures — Imagine What’ll Happen If We Fail To Stop 10°F Warming“).
Assuming the anti-science crowd continue to block any serious action, these catastrophic changes will last a long, long time (see NOAA: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe).
For the record, it was the possibility of losing the Sierra snowpack in the second half of the century that led then Energy Secretary Chu to warn in 2009, “Wake up,” America, “we’re looking at a scenario where there’s no more agriculture in California.”
Geophysical Research Letters published the new research, “Regional patterns and proximal causes of the recent snowpack decline in the Rocky Mountains” (subs. req’d). Here are the key points from the USGS news release: