India is currently experiencing intense heatwaves across several states. The India Meteorological Department (IMD) has issued warnings for various regions, including Odisha, Jharkhand, and Gangetic West Bengal. These alerts highlight the significance of understanding heatwaves, their definitions, and the criteria used to declare them.
What Is a Heatwave?
A heatwave is a prolonged period of excessively high temperatures. The definition varies by region, reflecting local climate norms. For instance, what constitutes a heatwave in Kerala is different from that in Odisha.
IMD’s Heatwave Declaration Criteria
The IMD declares a heatwave when certain temperature thresholds are met. For plains, a maximum temperature of 40 degrees Celsius or more is required. In hilly areas, the threshold is 30 degrees Celsius. A heatwave is identified if the temperature exceeds normal levels by 4.5 to 6.4 degrees Celsius. Severe heatwaves occur with a temperature departure above 6.4 degrees Celsius.
Temperature Measurement and Reporting
The IMD utilises a comprehensive network of observatories to monitor meteorological parameters. This includes daily maximum temperatures, relative humidity, and other factors. The climatology for maximum temperatures is established based on data from 1991 to 2020. Heatwaves are declared when criteria are met at multiple stations for consecutive days.
Regional Variations in Heatwave Conditions
Heatwaves are not uniform across India. Coastal areas may experience heatwaves with a maximum temperature of 37 degrees Celsius and a departure of 4.5 degrees Celsius from normal. The IMD considers local climate when issuing warnings to ensure accuracy.
Impacts of Heatwaves on Health
High temperatures can lead to severe discomfort. Increased humidity exacerbates the situation as sweat evaporation is hindered. High night-time temperatures prevent the body from cooling down, leading to health risks. Vulnerable populations, such as the elderly and children, are particularly at risk.
Heatwave Season in India
In India, heatwaves primarily occur from March to June. In some cases, they may extend into July. Awareness of this seasonal pattern is crucial for preparedness and response measures.
Importance of Heatwave Alerts
Heatwave warnings are essential for public safety. They inform citizens about potential dangers and encourage precautionary measures. Staying indoors during peak heat hours and hydrating adequately are vital recommendations.
Future Considerations
As climate change progresses, the frequency and intensity of heatwaves may increase. Ongoing research is needed to understand these changes and develop effective adaptation strategies.
Questions for UPSC:
- Critically analyse the impact of climate change on the frequency of heatwaves in India.
- What are the physiological effects of extreme heat on human health? Explain with suitable examples.
- Comment on the role of meteorological departments in disaster management during heatwaves.
- What are the socio-economic implications of prolonged heatwaves in agricultural regions? Discuss.
Answer Hints:
1. Critically analyse the impact of climate change on the frequency of heatwaves in India.
- Climate change leads to rising global temperatures, increasing the likelihood of extreme heat events.
- India has experienced rise in average temperatures, correlating with more frequent and intense heatwaves.
- Changes in precipitation patterns due to climate change can exacerbate heatwave effects, leading to droughts.
- Vulnerable regions, particularly in northern and central India, are seeing a higher frequency of heatwaves.
- Long-term climate models predict an increase in the duration and severity of heatwaves, impacting ecosystems and human health.
2. What are the physiological effects of extreme heat on human health? Explain with suitable examples.
- Extreme heat can lead to heat exhaustion and heat stroke, conditions that can be life-threatening.
- High temperatures can exacerbate pre-existing health conditions, particularly cardiovascular and respiratory diseases.
- Dehydration is a common effect, leading to increased hospitalizations during heatwaves.
- Vulnerable populations, such as the elderly and children, are at higher risk of heat-related illnesses.
- Prolonged exposure to extreme heat can also affect mental health, increasing anxiety and stress levels.
3. Comment on the role of meteorological departments in disaster management during heatwaves.
- Meteorological departments provide timely warnings about heatwaves, enabling proactive public safety measures.
- They utilize extensive data collection networks to monitor temperature and humidity, informing heatwave predictions.
- Collaboration with government and health agencies is crucial for effective response strategies during heat events.
- They educate the public on heat safety, including hydration and avoiding outdoor activities during peak heat.
- Post-heatwave assessments help refine future warning systems and disaster management protocols.
4. What are the socio-economic implications of prolonged heatwaves in agricultural regions? Discuss.
- Heatwaves can lead to crop failures, reducing agricultural productivity and food security.
- Livestock health can decline due to heat stress, impacting meat and dairy production.
- Prolonged heat can increase water scarcity, leading to conflicts over water resources in agricultural areas.
- Economic losses in agriculture can result in higher food prices, affecting low-income households disproportionately.
- Farmers may face increased debt and financial instability due to crop losses, impacting rural economies.
