Global warming: Why India is heating up slower than the world average

Source: The post is based on the article “Global warming: Why India is heating up slower than the world average” published in Indian Express on 10th May 2023

What is the News?

The annual mean temperature of the world is known to have increased by 1.1 degree Celsius from the average of the 1850-1900 period. But this increase is not uniform. It varies in different regions and also at different times of the year.

About the Temperature rises over lands and Oceans

Temperature rise over land is much higher than over oceans. 

According to the latest report of the Intergovernmental Panel on Climate Change, over land, the annual mean temperatures have risen by as much as 1.59 degree Celsius since preindustrial times. Oceans, in contrast, have warmed by about 0.88 degree Celsius.

The warming trends over the Indian region are very different. An assessment of climate change over the Indian subcontinent, published by the Ministry of Earth Sciences in 2020, said annual mean temperatures had risen by 0.7 degree Celsius from 1900. 

This is significantly lower than the 1.59 degree Celsius rise for land temperatures across the world.

Why is warming over India lower? 

The relatively lower rise in temperatures over India is not a surprise.

This is because the increase in temperatures is known to be more prominent in the higher altitudes, near the polar regions, than near the equator. This is attributable to a complex set of atmospheric phenomena, including heat transfers from the tropics to the poles through prevailing systems of air circulation. India happens to be in the tropical region, quite close to the equator.

How much is the Arctic region warming?

The IPCC report says the Arctic region has warmed at least twice as much as the world average. Its current annual mean temperatures are about 2 degrees Celsius higher than pre-industrial times. Some other studies suggest the Arctic could be warming even faster.

The prominent reason for this is what is known as the albedo effect, or how much sunlight a surface reflects. The ice cover in the Arctic is melting, because of which more land or water is getting exposed to the Sun. Ice traps the least amount of heat and reflects most of the solar radiation when compared with land or water. 

The warming in the polar regions accounts for a substantial part of the 1.1-degree Celsius temperature rise over the entire globe.

What is the impact of Aerosols on Global warming in India?

Aerosols refer to all kinds of particles suspended in the atmosphere. These particles have the potential to affect the local temperature in multiple ways. 

Many of these aerosols scatter sunlight back so that lesser heat is absorbed by the land. Aerosols also affect cloud formation. Clouds, in turn, have an impact on how much sunlight is reflected or absorbed.

Aerosol concentration over the Indian region is quite high, due to natural as well as man-made reasons. Due to its location in the tropics and the arid climate, India is no stranger to dust. But it also happens to be experiencing heavy pollution right now. Emissions from vehicles, industries, construction, and other activities add a lot of aerosols to the Indian region.

Hence, a reduction in warming could be an unintended but positive side-effect of aerosols.