Context: According to the latest report of the Intergovernmental Panel on Climate Change (IPCC), the temperature rise over the Indian subcontinent is lower as compared to the global average.
Relevance of the Topic: Prelims: Key trends related to climate change (global as well as India-specific).
Key trends regarding Global Temperature Rise
- 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.
- Over land, the annual mean temperatures have risen by as much as 1.59 degree Celsius since preindustrial times.
- Oceans have warmed by about 0.88 degree Celsius.
Warming trends over Indian Subcontinent
- As per the assessment of climate change over the Indian subcontinent, published by the Ministry of Earth Sciences in 2020 - 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.
Reasons for lower warming over India
- Location of India:
- India is located in the tropical area, quite close to the equator.
- The increase in temperatures is known to be more prominent in the higher altitudes, near the polar regions, than near the equator, because:
- heat transfers take place from the tropics to the poles
- melting of ice has led to reduced albedo and increased absorption of solar radiation
- release of greenhouse gasses from the melted ice further increasing the temperatures.
- Higher Aerosol concentration:
- Aerosol concentration over the Indian region is quite high, due to natural (tropical location, arid climate, greater amount of dust) as well as man-made reasons (heavy pollution).
- Aerosols have a cooling effect because they scatter sunlight back into space, such 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.
Conclusion: Incidentally, while the maximum temperatures over India have shown a significant increase since 1900, the rise in minimum temperatures has not been much. Expanding the weather observation network and strengthening of computing and analysis capabilities is a pre-requisite.