Kathmandu [Nepal], September 9 – An analysis of weather data has found unusually high temperatures in the Himalayan region before a glacier collapse triggered the deadly floods in Nepal and China on August 26.
Researchers estimated that average temperatures in the area located at an elevation of about 5,200 metres reached nearly 5 degrees Celsius between August 21 and 26. Such temperatures are considered exceptionally high.
More than 55 years of weather records show that temperatures during the same period had never previously exceeded 4 degrees Celsius. However, researchers have cautioned that a direct link between the extreme heat and the glacier collapse has not yet been established.
Robert Rohde, lead scientist at Berkeley Earth reconstructed the unusual temperatures by analysing multiple weather datasets. He found that average temperatures in the area during August 21-26 have risen by about 1.8 degree Celsius since the mid-20th century.
Rohde said that after accounting for warming caused by climate change temperatures of this magnitude could be expected only once in several thousand years.
An analysis of data from the European Union’s Copernicus Climate Change Service also showed that the event coincided with the fourth-hottest summer on record in the Langtang region since 1970.
French climate scientist Valerie Masson-Delmotte said the exceptional heat may have accelerated permafrost thawing and contributed to the combined collapse of rocky slopes and glaciers.
Satellite images showed significant snowmelt in the days before the disaster. Glaciologist Etienne Berthier said meltwater may have entered cracks in the mountain potentially weakening slopes.
Experts, however warned against drawing a direct causal link between rising temperatures and the collapse. Researchers are continuing to study changes in temperature and mountain activity preceding the event.
