Global warming
- May 11, 2023
- Posted by: OptimizeIAS Team
- Category: DPN Topics
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Global warming
Subject :Environment
Section: Climate Change
More on 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, as can be expected, is not uniform.
- It varies in different regions and also at different times of the year. This single number denoting global temperature increase, very effective for communicating the dangers of climate change, is built on top of several layers of averages.
- 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 0.7 degree Celsius from 1900. This is significantly lower than the 1.59 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.
Factors affecting mean temperature:
- Altitude: The increase in temperatures is known to be more prominent in the higher altitudes, near the Polar Regions, than near the equator.
- 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.
- Albedo effect: Ice traps the least amount of heat and reflects most of the solar radiation when compared with land or water. The ice cover in the Arctic is melting, because of which more land or water is getting exposed to the Sun.
- 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.
- Higher warming over land than oceans: Land areas have a tendency to get heated faster, and by a larger amount, than oceans. Daily and seasonal variations in heating over land and oceans are usually explained in terms of their different heat capacities. Oceans have a higher capacity to cool themselves down through the process of evaporation. The warmer water evaporates, leaving the rest of the ocean relatively cooler.
- Tropical location key: A majority of the global landmass is concentrated in the northern latitude In the tropics and along the equator, it is mostly oceans. Land areas are also prone to faster, and greater heating.
Why is warming over India lower?
- A major part of India’s relatively lesser warming can be attributed to its location in the lower latitudes. India, located in the tropics, the deviation in temperature rise from the global average is not surprising.
- 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.
Arctic Amplification: https://optimizeias.com/combined-antarctic-arctic-sea-ice-extent-lowest/