Date: 12/05/2023

Relevance: GS-3: Biodiversity, and Environment.

Key Phrases: Ministry of Earth Sciences, albedo effect, Tropical Location, Land-Ocean Dynamics, Aerosol Concentration, Atmospheric Circulation, Intergovernmental Panel on Climate Change.

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.
• It varies in different regions and also at different times of the year.

Key Highlights:

• Temperature rise over land is much higher than over oceans.
• Overland, 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.
• 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.
• The polar regions, particularly the Arctic, have seen significantly greater 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.
• Another prominent cause 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.
• More recent research suggests that the higher warming in the polar region could be attributed to a host of factors, including the albedo effect, changes in clouds, water vapour and atmospheric temperatures.
• The warming in the polar regions accounts for a substantial part of the 1.1 degree Celsius temperature rise over the entire globe.

Why is Warming Over India Lower?

• Tropical Location:
  • 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.
• Land-Ocean Dynamics:
  • The distribution of land and oceans in India plays a role in its temperature rise.
  • Oceans have a higher heat capacity and can absorb and store more heat energy compared to land.
  • Therefore, land areas tend to heat up faster and to a greater extent than oceans.
  • As India has a predominantly oceanic landmass, the relatively lower temperature rise can be attributed to the moderating effect of the surrounding oceans.
• Atmospheric Circulation:
  • India's tropical location and proximity to the equator influence atmospheric circulation patterns.
  • The movement of air masses, such as the monsoon circulation, can contribute to regional temperature variations.
  • Monsoon winds bring moisture and rainfall to India, which helps regulate temperatures by providing a cooling effect.
  • Additionally, India's position in the Inter-Tropical Convergence Zone (ITCZ) affects its climate, with the ITCZ bringing moisture and cloud cover that can mitigate temperature.
• Impact Of Aerosols:
  • 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 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 in the Indian region.
  • A reduction in warming could be an unintended but positive side-effect.
  • Aerosols have the potential to avoid 0.1 to 0.2 degree Celsius of warming over the Indian region.

Factors Contributing to the Disparity in Temperature Rise Across Different Regions of The World:

• Heat Capacity:
  • Oceans have a higher heat capacity compared to land. They can absorb and store a larger amount of heat energy.
  • As a result, oceans warm up more slowly and to a lesser extent than land areas.
• Surface Albedo:
  • Albedo refers to the reflectivity of a surface. Land surfaces, especially those with darker colours such as forests and asphalt, have lower albedo and absorb more solar radiation, leading to faster warming.
  • In contrast, the reflective nature of water in oceans causes a higher percentage of solar radiation to be reflected back into the atmosphere, reducing the warming effect.
• Heat Transfer:
  • The movement of heat energy from the tropics towards the poles through atmospheric circulation patterns plays a role in temperature disparities.
  • Near the equator, warm air rises and moves towards the poles, redistributing heat.
  • This process results in greater warming at higher latitudes, particularly in polar regions.
• Atmospheric Dynamics:
  • Atmospheric circulation patterns, such as prevailing winds, jet streams, and global wind systems, influence temperature distribution.
  • These patterns can transport warm or cool air masses across different regions, affecting regional temperature variations.
• Land Use Changes:
  • Human activities, such as urbanization and deforestation, modify the land surface and can contribute to localized temperature increases.
  • Urban areas, with their concrete and asphalt surfaces, absorb and retain heat, creating "urban heat islands" with higher temperatures than surrounding rural are
• Ocean Currents:
  • Ocean currents can transport warm or cold water masses over long distances, affecting regional temperature patterns.
  • Variations in ocean currents, such as El Niño or La Niña events, can result in temporary temperature anomalies in specific regions.
• Geographical Features:
  • The presence of mountain ranges, large bodies of water, or proximity to coastal areas can influence regional temperature differences.
  • Mountains can create temperature gradients with cooler temperatures at higher elevations, while coastal areas are influenced by marine influences and breezes.

Conclusion:

• Temperature rise in India differs from the global average due to various factors.
• India's tropical location, land-ocean dynamics, and aerosol concentrations influence temperature trends.
• Understanding these complexities is essential for comprehending the impact of climate change in India.

Source: The Indian Express 

Mains Question:

Q. Analyze the reasons behind the relatively lower temperature rise in India compared to the global average. (150 Words).