Context:
The India Meteorological Department (IMD) declared higher-than-average heat wave conditions for various regions of India on Monday. These conditions are affecting the southern, central, eastern, and northwestern parts of the country. This announcement coincides with India’s ongoing struggle to meet its electricity demand.
Relevance:
- GS-1- Important Geophysical Phenomena
- GS-3- Climate Change
Mains Question:
What defines a heat wave and how does the IMD forecast heat wave days across different regions of India? Discuss the factors behind the rise in heatwave occurrences in India. (15 Marks, 250 Words).
More on the Electricity Demand:
- According to a Reuters analysis, India experienced the sharpest decline in hydroelectric power generation in at least 38 years.
- Consequently, hydroelectric output is expected to remain low in the upcoming months, leading to increased reliance on coal.
- This shift comes at a time when India has committed, under its Nationally Determined Contributions as part of the Paris Agreement, to reducing the emissions intensity of its GDP by 45% by 2030 compared to the 2005 level.
What’s the forecast according to the IMD?
- The IMD’s forecast indicates that most of India will encounter above-average maximum and minimum temperatures. While the El Niño event, known for causing reduced rainfall and heightened temperatures in India, has weakened since the start of the year, moderate El Niño conditions persist in the equatorial Pacific, resulting in increased sea surface temperatures.
- This alteration in heat distribution affects air currents above the ocean. Given that the Pacific Ocean covers nearly a third of the Earth’s surface, fluctuations in its temperature and wind patterns can disrupt global weather systems.
- January 2024 was recorded as the warmest in 175 years, as noted by the U.S. National Oceanic and Atmospheric Administration, with an overall elevation in the average global land and ocean surface temperatures.
- However, the El Niño event is expected to diminish in the upcoming season. Some models even suggest the potential emergence of La Niña conditions during the monsoon period, which could amplify rainfall across South Asia.
What defines a heat wave?
- A heat wave is characterized by a period of exceptionally high temperatures. The India Meteorological Department (IMD) identifies a heat wave when the maximum temperature at a weather station reaches a minimum of 40 degrees Celsius in plains areas and at least 30 degrees Celsius in hilly regions, with a deviation of approximately 4.5-6.4 degrees Celsius from the normal maximum temperature.
- Additionally, the IMD may declare a heat wave if the actual maximum temperature surpasses 45 degrees Celsius, and a ‘severe heat wave’ if it exceeds 47 degrees Celsius.
- Beyond these numerical thresholds, a heat wave can be described qualitatively when the air temperature becomes dangerously high for human health. Heat waves in India typically occur between March and June, with the peak often observed in May.
What’s behind the rise in heat wave occurrences?
- According to a study published in the journal PLOS Climate in April 2023, heat waves worldwide are becoming more frequent, severe, and deadly due to the effects of climate change.
- Utilizing data from April 2022, the study highlighted that abnormal temperatures resulting from climate change could significantly impact over 90% of India.
- This escalation in both the frequency and intensity of heat wave days can impose substantial costs on various aspects such as livelihoods, food production, and the spread of diseases, as emphasized by the study.
- The World Health Organization warns that higher temperatures can lead to heat stress and even fatalities among humans.
- Additionally, the ongoing El Niño weather phenomenon contributes to elevated temperatures, further fueling the increased incidence of heat waves.
What steps has the EC recommended to mitigate the impact of heat waves?
- As India prepares for general elections spanning from April 19 to June 1, coinciding with the summer season and the potential occurrence of heat waves, the Election Commission (EC) has issued guidelines to address the impact of high temperatures during the voting process.
- These guidelines include carrying water bottles and taking measures to shield oneself from direct sunlight. It’s important to note that heat can pose a significant risk even outside of formally declared heat wave conditions if the wet bulb temperature exceeds 30-35 degrees Celsius.
- The wet bulb temperature represents the lowest temperature at which a surface can be cooled by water evaporation, or in simpler terms, the lowest temperature at which sweating can effectively cool the skin.
- Crossing this threshold can lead to severe health consequences, even during brief periods of inactivity in normal environmental conditions.
Conclusion:
Preventive measures such as ensuring access to water, providing oral rehydration solutions (ORS), offering shaded areas, particularly in public spaces, and implementing flexible working hours in workplaces, along with making special provisions for outdoor workers, can help reduce heat-related deaths. It is essential for local administrations to proactively enforce these measures, with oversight from higher authorities, to ensure their effectiveness.
