India is heating up slower than the world average

Published
11th May, 2023

Context

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, as can be expected, is not uniform.

Warming trend over the Indian region

The warming trends over the Indian region are very different.

Temperature rise (land vs oceans)

Temperature rise over land is much higher than over oceans.
Over land, the annual mean temperatures have risen by as much as 1.59 degree Celsius since preindustrial times, according to the latest report of the Intergovernmental Panel on Climate Change.
Oceans, in contrast, have warmed by about 0.88 degree Celsius.

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 7 degree Celsius from 1900.
This is significantly lower than the 59 degree Celsius rise for land temperatures across the world.
It could give the impression that the problem of climate change over India was not as acute as other parts of the world. But that is not entirely accurate.

Why is warming over India lower?

The relatively lower rise in temperatures over India is not a surprise. Also, India is not a special case.
The increase in temperatures is known to be more prominent in the higher altitudes, near the polar-regions, than near the equator.
Location: India happens to be in the tropical region, quite close to the equator.
Impact of aerosols: Aerosol concentration over the Indian region is quite high, due to natural as well as man-made reasons. Emissions from vehicles, industries, construction, and other activities add a lot of aerosols in the Indian region.

Aerosols refer to all kinds of particles suspended in the atmosphere. These particles have the potential to affect the local temperature in multiple ways. Aerosols also affect cloud formation. Clouds, in turn, have an impact on how much sunlight is reflected or absorbed.

Which region is warming faster?

The planet as a whole has warmed by 1.1 degree Celsius compared with preindustrial times.

The IPCC report says the Arctic region has warmed at least twice as much as the world average.

But, this is just the average. Different regions have seen very different levels of warming.
The polar-regions, particularly the Arctic, have seen significantly greater warming.
This is attributable to a complex set of atmospheric phenomena, including
- Heat Transfer: Heat transfers from the tropics to the poles through prevailing systems of air circulation.
- Albedo effect: 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.
- Changes in clouds, water vapour and atmospheric temperatures
The warming in the polar-regions account for a substantial part of the 1.1 degree Celsius temperature rise over the entire globe.