Cooling Amid Warming

In his address to the 28th Conference of Parties on Climate Change (COP28) Dubai early this month, Prime Minister Pushpa Kamal Dahal Prachanda had successfully drawn the attention of the international community to the devastating impact of climate change on Himalayas. In his opening lines, he had struck the right chord: mountains are tortured by rising temperatures. The PM’s remark has been substantiated by a number of scientific research. A recent Intergovernmental Panel on Climate Change (IPCC) report states that the climate-induced disasters are breaking records in the Himalayas. One-third of our glaciers have disappeared and another one-third is feared to be lost by the end of this century. The loss of snow-capped mountains at an alarming rate is a wake-up call to not only Nepal but also all of global community.

Nepal is known for her numerous shiny mountains. It is Sagarmatha (Mt. Everest), the world’s highest peak, which gives an identity to Nepal and Nepalis. Mountaineers from around the world have a dream to conquer the tallest peak but not all succeed to make it to the highest point of the earth. Amidst the growing apprehension that the world’s tallest peak will become the victim of rising temperature, a new scientific study has brought new fact about it. It has revealed unexpectedly cool temperatures on the slopes of the highest peak due to the impact of glaciers. The findings, published in Nature Geoscience, present unique climate dynamics of Mt. Everest, which contradicts the notion that the temperature rise is warming the Himalayan mountains in the rates that exceed the global average.

A team of around 19 scientists from different countries, including Dr. Sudeep Thakuri, Associate Professor at Tribhuvan University, and led by Dr. Franco Salerno from Italy's National Research Council in Milan were involved in the research that reveals a unique glacier effect on local temperature. They have employed hourly temperature data since 1994 at the Lobuche Pyramid International Laboratory– Observatory (Pyramid Lab) on Mt. Everest's slopes, which is situated at an altitude of 5,035 metres above sea level, according to news report of this daily. The laboratory has the longest weather dataset in the Himalayas. The team has recorded changing weather patterns in the last 15 years, with maximum summer temperatures decreasing at a rate of about 0.04 degrees Celsius per year. This trend also matched with observations from other nearby weather stations at higher elevations.

Experts have explained the reason of local cooling traced on Everest's glacial slope. They say that glaciers exchange heat with the atmosphere at higher elevations, causing the warmer cooling effect. This exchange triggers instability, making the air above glaciers to cool and flow downhill. This results in a cooling effect around the Pyramid Lab and its surroundings. Although the air higher up is getting warmer, the air right above the glacier surface is getting cooler that increases downhill winds and affects lower glacier areas and the surrounding land where the glacier melts. The local cooling protects lower glacier areas from warming and scales down the point where winds from different directions meet. It causes less rainfall at higher elevations and negatively impacts the balance of glacier mass. This new revelation calls for further study about the climate dynamics of the Himalayas and other mountains around the world in relation to climate change impacts.