-
Ten years ago, climate scientists observed a strange cooling trend in Himalayan glaciers.
-
They now think this trend may be the result of an intensification of winds that can reach speeds of over 100 miles per hour.
-
As climate change makes mountains increasingly dangerous, climbers can’t take a break.
As climate change increases global average temperaturesGlaciers around the world’s highest mountains get slightly colder during the warm season, according to new research published in the peer-reviewed journal Natural Geology.
Located on the south face Mount Everest Along the Khumbu Valley, approximately 3.1 miles above sea level, lies one of the world’s few high-altitude science laboratories called the Pyramid International Observatory.
Since the early 90s, it has been collecting hourly data on measurements such as mountain air temperature, total precipitation, humidity and wind speed. With nearly four decades of data at their disposal, scientists saw a strange pattern.
They found: maximum daytime temperature Temperatures in the warm months from May to October have decreased by approximately 0.040 °C over the last 15 years.
Was this a mistake? The researchers cross-checked the data with other weather stations around the southernmost stations of the Tibetan plateau. They realized that the cooling trend was not limited to the glaciers around Mount Everest; it was like that the whole time Himalayas.
So how can this happen? Finally, report Himalaya, published last year glaciers melted faster This shows that between 2010 and 2019, compared to the previous decade, glaciers are warming along with the rest of the world.
blame the wind
Researchers think this cooling trend is the result of a well-understood phenomenon. katabatic winds.
On hot days, as sunlight warms the glaciers, the air just above the glacier surface warms and rises. This creates a vacuum that causes cold air to form around it. snowy peaks descending rapidly due to gravity.
As this event intensifies, local katabatic winds are formed that typically peak in the afternoon and can reach speeds of over 1000 metres. 100 mph.
As average global temperatures increase worldwide, climate changeKatabatic winds become more intense because the more heat that warms and rises from the mountain surface, the further down it forces the cold air. This is the reason for the cooling trend over the last 15 years, researchers reported.
Moreover, researchers think that cold winds may partially help. slow down melting The condition of these glaciers could otherwise be even worse.
But there is a problem.
The study also found that the lowest night temperature also increased during the colder months (November to April). As the coldest nights become less cold and the warm lunar days become slightly colder, the average temperature tends to level off, giving a deceptive impression of the temperature trend.
However, in the face of climate change, glaciers will continue to melt because the melting of glaciers does not depend only on air temperature close to the ice.
Glaciers will continue to melt as global temperatures increase
Ice can act as a buffer by absorbing some heat before its temperature increases.
During warm daylight hours, glacier ice absorbs heat from the surrounding air. Then at night, the ice releases some of the stored heat energy, preventing the air temperature from dropping too much.
The ice thus suppresses daily heat peaks and cold dips in the region immediately surrounding the glacier.
Temperatures away from the glacier therefore better reflect actual daily peaks and nighttime cooling, which in turn affects melting processes.
“It was a great relief to understand this whole process,” said Franco Salerno, lead author of the paper and an environmental scientist at the National Research Council at the Institute of Polar Sciences in Milan.
His team noticed a trend of decreasing temperatures in the warmer months about 10 years ago, but could not pinpoint the phenomenon. More studies can now focus on this local weather phenomenon.
Most importantly, the finding demonstrates the role of glaciers in shaping local mountain climate. This had a huge impact on climbers.
Increasing risks for businesses
Cold, intense, high-speed katabatic winds can easily intensify, even reaching hurricane speeds. As a result, these winds have a huge impact on the local weather of the mountain.
As a result, “climbing has become much more challenging as our guides have to evaluate the route to the summit on each trip,” said Gordon Janow, director of the Alpine Ascents mountaineering guide service, which has been in the mountaineering industry for nearly four decades. .
The terrain also became more technical as melting glaciers opened large crevasses.
“We need to go 100 meters to the right, then cut left, then cut right,” he said.
What was once a 10-hour journey to the summit can take up to 12 or even 14 hours. “Then suddenly we might encounter a glacier that we can’t cross,” Janow added. As a result, many mountains can no longer even be climbed.
The melting of glaciers triggered by such local weather events has caused trouble not only in the Himalayas but also in mountains all over the world.
For example, Mount Rainier has traditionally served as a training area for many climbers. “I’ve seen people come up and say things like, ‘My grandfather climbed Mount Rainier by himself in 1957. We’re going to do that.'” said.
“But people don’t understand that this isn’t your grandfather’s mountain anymore,” he said.
Read the original article on Business Insider