"Study Splits Urban Warming into Urbanisation and Climate Change"
Urban Heat Island (UHI)
phenomenon where built-up cities stay hotter than nearby rural areas, especially at night.
Wet-bulb temperature
a heat-humidity measure showing how well the human body can cool itself by sweating.
Indian cities are warming faster than the country as a whole. Two separate forces are driving this: local urbanisation and wider climate change. Urbanisation replaces soil and vegetation with concrete, asphalt, and buildings. These materials absorb heat during the day and release it slowly at night. This is called the urban heat island (UHI) effect. It makes cities hotter than nearby villages, especially after dark. Climate change works differently. It raises the baseline temperature of the whole region. It does this by trapping heat through greenhouse gases like carbon dioxide and methane. When both forces act on the same city at the same time, the warming becomes harder to separate. It also becomes harder to manage.
India has built policy tools to respond to this rising heat. The World Meteorological Organization (WMO) defines a heat wave as five or more consecutive days where the highest temperature is at least 5°C above the historical average. India's updated Nationally Determined Contribution (NDC), its climate pledge under the global climate framework, commits the country to shifting toward non-fossil fuel energy. It also commits to working toward climate justice. State governments have also rolled out heat action plans and early warning systems. These cut heat-related deaths. They build on models like Ahmedabad's plan.
Extreme heat is dangerous not just because of high temperature readings. It is also dangerous because of wet-bulb temperature. This is a measure that combines heat and humidity. The human body cools itself by sweating. But this only works if sweat can evaporate. When humidity is very high, sweat cannot evaporate well. So the body cannot release heat even if it keeps producing more sweat. Some global assessments warn that parts of India could increasingly see wet-bulb temperatures near levels where safe outdoor activity becomes difficult. This is exactly why UHI-driven heat and climate-driven heat together are a bigger health threat than either alone.
To manage city heat properly, planners first need to know how much warming is caused by local urban growth. They also need to know how much is caused by regional climate. Separating these two signals is scientifically difficult. Both act at the same time and place. A detailed method would require tracking every building, road, park, water body, and air conditioner in a city. This takes enormous time and resources.
A simpler method uses satellite data. Researchers used high-resolution night-time land surface temperature readings from MODIS. This is a sensor aboard NASA's Aqua satellite. They assumed that temperature change in rural areas near a city, over the period 2003 to 2020, reflects only regional climate change. …
The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report?
I.Peninsular India will most likely suffer from flooding, tropical cyclones and droughts.
II.The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult.
Select the correct answer using the code given below.
Consider the following statements regarding the Urban Heat Island (UHI) effect:
1.The temperature differential between urban and rural areas is most pronounced during the daytime.
2.Impervious surfaces like concrete and asphalt absorb and re-radiate solar heat, intensifying urban warming.
Which of the statements given above is/are correct?
According to the World Meteorological Organization (WMO), a heat wave is officially recognised when:
Match the following terms with their correct descriptions:
List I
A.Urban Heat Island
B.Wet-bulb temperature
C.Nationally Determined Contribution
D.MODIS
List II
1.India's official climate action pledge
2.Satellite sensor measuring land surface temperature
3.Phenomenon of cities being warmer than surrounding rural areas
4.Combined heat-humidity measure of body cooling limits
Select the correct answer using the code given below.
With reference to a recent 141-city study on urban warming in India, consider the following statements:
1.Cities were found to be warming at nearly twice the rate of the rest of the country.
2.Local-scale urbanisation was found to be the dominant driver of warming in all large megacities, more so than in tier-II cities.
Which of the statements given above is/are correct?
The MODIS sensor, used in a recent study to measure night-time land surface temperature across Indian cities, is aboard which of the following satellites?
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