Decline in Snow Cover – Impacts and Trends in the Northern Hemisphere – A Climate Study

GS Paper III Environment

Context:

The study, published in the journal Nature, highlights decline in Snow Cover is expected to accelerate with further warming.

Decline in Northern Hemisphere Snowpacks: Snowpacks have shrunk in size in the past 40 years due to human-induced climate change.
Sample Size: The study analyzed 169 river basins and found declining trends of snow in 82 of them.
Relationship Between Global Temperature Increase and Snow Sensitivity: The relationship between snow and increase in global temperatures was highly non-linear in nature.
- For Example: It has been found that when winter temperatures exceed -8 degrees Celsius (°C), snow becomes marginally more sensitive to 1°C of warming.
Warming Trends in the Northern Hemisphere: The warming is much higher in those regions of the northern hemisphere which get significant amounts of snowfall (such as Europe).
Declining Snow Water Equivalent (SWE) in a Decadal Analysis (1981-2020) due to Decline in Snow Cover

The amount of accumulated snow is measured in snow water equivalent (SWE), which is the amount of water a snowpack contains.

- In much of western, central and northern Europe, the SWE in March (which is the end of the snowfall season for the northern hemisphere) has decreased by 10-20 per cent per decade between 1981 and 2020.
- In the Ganga and Indus River basins, the SWE has decreased by 1-3 per cent in the last 40 years.
Rate of warming in the Hindu Kush Himalayan (HKH) region: The rate of warming is also much faster in the Hindu Kush Himalayan (HKH) region, which is home to around 54,000 glaciers and needs to be replenished to an extent by snowfall every winter

News Source: Down to Earth