Understanding the response of Himalayan glaciers to global warming is vital because of their role as a water source for the Asian subcontinent. However, great uncertainties still exist on the climate drivers of past and present glacier changes across scales. Here, we analyse continuous hourly climate station data from a glacierized elevation (Pyramid station, Mount Everest) since 1994 together with other ground observations and climate reanalysis. We show that a decrease in maximum air temperature and precipitation occurred during the last three decades at Pyramid in response to global warming. Reanalysis data suggest a broader occurrence of this effect in the glacierized areas of the Himalaya. We hypothesize that the counterintuitive cooling is caused by enhanced sensible heat exchange and the associated increase in glacier katabatic wind, which draws cool air downward from higher elevations. The stronger katabatic winds have also lowered the elevation of local wind convergence, thereby diminishing precipitation in glacial areas and negatively affecting glacier mass balance. This local cooling may have partially preserved glaciers from melting and could help protect the periglacial environment.
Large amounts of new particles can form in the valleys of the Himalayas from naturally emitted gases and can be transported to high altitudes by the mountain winds and injected into the upper atmosphere.
The emitted particles may eventually affect climate by acting as nuclei for cloud condensation. These new findings about particles formation and sources will contribute to a better understanding of past and future climate.
“To understand how the climate has changed over the last century we need to know as reliably as possible the natural atmospheric conditions before the industrialization,” says Associate Professor Federico Bianchi from the University of Helsinki’s Institute for Atmospheric and Earth System Research (INAR).
In order to do that scientists are looking for pristine locations around the world where human influence is minimal. An international group of researchers has now completed a comprehensive study at the Nepal Climate Observatory at Pyramid station, located in the proximity of the Everest base camp at 5050 m above sea level. There, they were able to investigate the formation of atmospheric particles far from human activities. The results were published today in the prestigious journal Nature Geoscience.
Crazed environmentalists take note, the Himalayan mountain passes of Rohtang, Baralacha, Kunjum, Shikula are STILL blanketed in deep snow, in July!
Snow holding on until the end of July is incredibly rare on these passes, reports the The Statesman — in fact, it’s the first time in 20 years that it’s occurred, the packs are usually all-gone by the end of May.
Furthermore, heavy and record-breaking snow has been falling this week actually adding to the pack.
“The heavy accumulation of snow up to 4-5 feet on Rohtang, Baralacha, Kunjum, Shikula passes is certainly good for the environment in the Himalayas,” said Senior Scientific Officer at State Centre on Climate Change, Dr SS Randhawa.
A view of Solang Nullah from where the Rohtang tunnel connecting Kullu to Lahaul and Spiti is proposed photo by Birbal Sharma
La géologie, une science plus que passionnante … et diverse
