Mountains as water towers: New research highlights warming differences between high and low elevations

BOZEMAN – In new research published this week, work by a Montana State University scientist aims to explore the gradations in elevation-dependent changes in climate, including in mountainous ecosystems like those in Montana and the Rockies.

John Knowles, an assistant professor in MSU’s Department of Land Resources and Environmental Sciences in the College of Agriculture, is one of nearly two dozen authors from around the world on the new paper, titled “Elevation-dependent climate change in mountain environments.” The work was published Nov. 25 in the journal Nature Reviews Earth & Environment.

Because they are difficult places to collect consistent data, mountain ecosystems around the world have been understudied in terms of changes in climate or long-term weather trends, Knowles said. That idea led to the research collaboration, which was led by British scientist Nick Pepin.

The new paper is a follow-up to a 2015 publication, also led by Pepin, that identified the concept of elevation-dependent warming, or EDW: the observation that changes in temperature happen fastest at higher elevations.

“Mountains are important for so many reasons,” Knowles said. “They’re sentinels of change, meaning we often detect changes first in mountain environments before lowlands.”

Mountains provide many “services,” he said, from offering ecological resources like wildlife habitat and recreation opportunities that feed mountain economies to the holding and gradual dispersion of water as snowpack melts to fill rivers and lakes.

“These research findings are important,” said Bob Peterson, head of MSU’s Department of Land Resources and Environmental Sciences. “They have direct implications for Montana towns, farms, ranches and industries, all of which need to make challenging decisions about water availability and use."

The researchers on the new paper focused on elevation-dependent variations in precipitation and surface albedo — the brightness of the landscape — in addition to updating air temperature trends over time for mountain ranges across the globe. The authors also highlight humidity, wind, aerosols and radiation as understudied components of the mountain climate system.

The brighter an environment, the more sunlight is reflected, Knowles said. The darker an environment, the more heat energy is absorbed. Snow is the brightest environmental element in the natural world, and as snowpack melts, the albedo of an area decreases, intensifying warming.

This work is particularly relevant in Montana, Knowles said, where mountain region recreation and wildlife habitat are intertwined with agricultural production and other economic engines, like the region’s ski areas.

“I like to think of mountains as nature's water towers. They accumulate and store precipitation as snow all winter long and then dispense it in nature's drip irrigation system all summer long,” he said. “In Montana, mountains are emblematic of our state. They provide the water for rivers that represent the lifeblood of our agricultural and recreation economies.”

Knowles said MSU is an ideal place to be doing his type of research. As a land-grant institution, the university’s historic and continuing contributions to agriculture and the natural sciences allow him to explore mountain ecosystems in a more comprehensive way than he could elsewhere, providing knowledge and information on the sustainability of natural and managed systems that matter to citizens of Montana. 

-end-

This story is available on the Web at: http://www.montana.edu/news/24950