Mains Paper 1: Geography | changes in critical geographical features (including waterbodies and ice-caps) and in flora and fauna and the effects of such changes.
From UPSC perspective, following things are important:
Prelims level: Read B2B about Heat waves.
Mains level: Important topic of Geography and Environment for Mains paper 1
• What: According to a study, 74% of the world’s population will face deadly heatwaves by 2100, if carbon dioxide emissions continue to rise at current rates
• What if we try to control carbon emissions: According to researchers, even if emissions are effectively reduced, the percentage of the world’s human population affected is expected to reach 48%
• Risks from Heatwaves: Heatwaves pose a considerable risk to human life because hot weather, aggravated with high humidity, can raise body temperature, leading to life-threatening conditions
• Threshold limit identified: Researchers have identified a threshold beyond which temperatures and humidities become deadly for humans
• Currently, about 30% of the world’s human population is exposed to such deadly conditions each year.
B2B Heat waves
A Heat Wave is a period of abnormally high temperatures, more than the normal maximum temperature that occurs during the summer season in the North-Western parts of India. Heat Waves typically occur between March and June, and in some rare cases even extend till July.
The extreme temperatures and resultant atmospheric conditions adversely affect people living in these regions as they cause physiological stress, sometimes resulting in death.
The Indian Meteorological Department (IMD) has given the following criteria for Heat Waves :
• Heat Wave need not be considered till maximum temperature of a station reaches atleast 40*C for Plains and atleast 30*C for Hilly regions.
• When normal maximum temperature of a station is less than or equal to 40*C Heat Wave Departure from normal is 5*C to 6*C Severe Heat Wave Departure from normal is 7*C or more.
• When normal maximum temperature of a station is more than 40*C Heat Wave Departure from normal is 4*C to 5*C Severe Heat Wave Departure from normal is 6*C or more.
• When actual maximum temperature remains 45*C or more irrespective of normal maximum temperature, heat waves should be declared.