Why is it in the news?

• A recent study has linked the heatwaves observed in India during the month of April to climate change, which is not surprising given the rising global temperatures. The frequency and intensity of heatwaves in the country have significantly increased.

More about the news

• The extreme heat experienced in parts of eastern and southern India in April has been specifically attributed to climate change. The study indicates that climate change has made such abnormally high temperatures around 45 times more likely to occur. Without climate change, recording temperatures at this level would be highly unlikely at this time.
• The research was conducted by World Weather Attribution, an international group of researchers dedicated to determining whether extreme weather events are caused by climate change. This is the third consecutive year that early summer heatwaves in India have been linked to climate change. Previous studies by the same researchers also suggested that the excessive heat in March-April of 2022 and April of 2023 was most likely a result of climate change.
• Attribution science, a relatively new field of study, plays a crucial role in understanding the impacts of climate change. While scientists are cautious about directly attributing any individual weather event to climate change, advancements in tools and methodologies have made it possible to determine whether climate change has influenced the likelihood of specific events.

Heatwaves in India

• Heatwaves are not solely defined by high temperatures but rather by temperature anomalies. For instance, a region that normally experiences a summer temperature of 40 degrees Celsius would not be considered in a heatwave if the temperature rises to 42 or 43 degrees. In contrast, a location with a normal temperature of 27 or 28 degrees during that time would be classified as undergoing a heatwave even at 35 degrees.
• Heatwaves have become increasingly frequent, intense, and prolonged in northern, central, and eastern India due to the impacts of climate change.
• Last year, several parts of India experienced heatwave conditions in February, a typically colder month. Maximum temperatures were 5 to 11 degrees higher than usual, meeting the criteria for heatwaves. This posed a challenge for the India Meteorological Department (IMD) since heatwaves are typically declared between April and July. Overall, February 2023 was the second hottest February ever recorded in India, with the mean temperature for that month being 1.36 degrees Celsius higher than normal. In addition, 2023 was the second warmest year for India.
• The heatwave outlook for this year indicated even more significant challenges. Heatwaves at the beginning of summer were predicted to last for 10 to 20 days consecutively in some areas, compared to the usual 4 to 8 days. These predictions were confirmed when an 18-day heatwave was recorded in Odisha, marking the state’s second-longest spell on record. Gangetic West Bengal also experienced the highest number of heatwave days in the last 15 years, making April the warmest on record for eastern India.

Impact of Heatwaves

• Prolonged exposure to extreme heat can lead to dehydration, cardiovascular and respiratory diseases, and can exacerbate existing health conditions, sometimes resulting in sudden deaths.
• Although the implementation of heat action plans by state governments and district administrations has contributed to a decline in the number of heat-related deaths, recent trends have shown a reversal, likely due to better reporting or increased severity of heatwaves.

Mitigation of Heatwaves

• Each of the 23 states vulnerable to heatwaves in India now has heat action plans in place to manage the adverse impacts. These plans include measures such as providing cool drinking water at public places, distributing free oral rehydration solutions, adjusting school and college hours during peak heat, and providing access to parks and shaded areas.
• These efforts have brought relief to many people, preventing illnesses and deaths in several cities.