With nearly a month left in the summer melt season, researchers already know that 2015, on track to be the hottest year ever measured, will be awful for the world’s glaciers, which are likely to lose more ice than any year on record.
The latest evidence comes from the North Cascades in Washington state, where a team of scientists recently completed its 32nd annual survey of the mountain range’s major glaciers.
The North Cascades, home to more mountain ice than any state except Alaska, is expected to lose a record amount of its glacier mass this year: between five and seven percent, according to Mauri Pelto, professor of environmental science at Nichols College and director of the North Cascades Glacier Climate Project.
Smoke from the dozens of wildfires burning in Washington obscured the sky during the team’s three weeks of field work in the alpine basins between Snoqualmie Pass, east of Seattle, and the Canadian border. The catalysts for the fires — the severe heat and deep drought that wracked the Pacific Northwest this year — are also walloping the region’s glaciers.
Glaciers, in basic terms, shrink when more ice melts in the summer than accumulates in the winter. The imbalance in the North Cascades in 2015 is larger than ever. Pelto, who started monitoring the glaciers in 1983, called the scenario “disastrous.”
“It’s disastrous for the glaciers themselves,” Pelto told Circle of Blue. “It’s disastrous for water resources in the future. In watersheds fed by glaciers, there will be less runoff.”
Though an outlier in terms of severity, the 2015 melt follows the long-term trend line, which points downward. Less glacial runoff and less snowpack will eventually lead to a reordering of the mountain ecosystem. Pika, a cousin of the rabbit, are being driven toward extinction by the loss of snowy habitat. Salmon and other aquatic species will struggle in warm, depleted creeks without the pulse of summer meltwater.
Systems engineered by humans will also be altered. Hydropower production, a source of roughly 75 percent of Washington’s electricity generation, will decline. Drinking water reservoirs will require new operating procedures that reflect changes in the timing of water flows.
Most of the consequences are disruptive. However, the big melt is producing an ironic benefit this year. The Pacific Northwest winter was so warm that very little snow fell in the Cascades. The freezing level — the elevation at which air temperatures were cold enough for snow — climbed up the mountains, some 1,000 meters (3,280 feet) higher than normal in February. Without the slow release of water from melting snow, most Washington streams are running at historic lows and at temperatures warm enough to kill salmon. Streams fed by glaciers, on the other hand, are getting a boost.
“The near-term effects are not so bad,” Pelto explained, referring to the melt. “The only streams with water in them are those fed by the glaciers. The melting is helping to maintain streamflow.”