Mickaël Lalande et al.

The study of climate change in the High Moutain Asia and the Tibetan Plateau is crucial, particularly because this region is partly covered by glaciers and snow, which constitute a significant water resource for nearly 1.4 billion people. In addition to its impact on snow cover, climate change in the High Moutain Asia is also affecting permafrost and glaciers, intensifying desertification, and affecting the hydrological cycle, consequences that could have a major impact on agriculture, drinking water supply, and hydropower production.

Figure 1 : Image satellite composite de la chaîne de l’Himalaya et du plateau tibétain. (Crédit : NASA)

To anticipate the changes in climate and water resources in the region over the next century, modeling is a valuable tool. In this study, we used the latest generation of general circulation models (GCMs). These models have a resolution of the order of 100 km, which is too coarse to describe climate changes on a local scale, but they are particularly interesting for simulating the global response of the climate system to greenhouse gas emissions, and they still provide a vision of climate changes on a regional scale.

Our study shows that climate change in the High Moutain Asia could result in a temperature increase of between +1.9°C and +6.5°C by the end of the century relative to the 1995-2014 average depending on greenhouse gas emission scenarios. This warming is associated with a relative decrease in snow cover extent estimated between -9.4% and -32.2%, and an increase in precipitation between 8.5% and 24.9%. This warming is 11% faster in this region of the world compared to other continental surfaces in the Northern Hemisphere (excluding the Arctic region, which is also characterized by exacerbated warming).

In a scenario of drastic limitation of greenhouse gas emissions, limiting the global temperature increase to +2°C compared to the pre-industrial period, the warming is stopped around the years 2060-2080, with temperature, precipitation, and snow cover trends reversing by the end of the 21st century.

Figure 2: Climate change in the High Mountain Asia in CMIP6 (Lalande et al. 2021) - CC BY 4.0

Our study also points out the weaknesses of current models in this region of the world, explained in particular by the difficulty of simulating the climate in regions with rugged terrain and peaks reaching more than 8000 meters in altitude. There is still work to be done to improve the general circulation models in this region of the world! This work is particularly delicate because of the symptomatic lack of observations in this region of the world. In this sense, our current work aims to contribute to the improvement of climate models in mountain regions.

Updated on 3 November 2021