Date: 10/10/2022

Relevance: GS-3: Disaster and Disaster Management.

Key Phrases: Heatwave, Indian Meteorological Department (IMD), extreme Glacial Lake Outburst Flood, El Nino/Southern Oscillation (ENSO), National Monsoon Mission, National, and State disaster management authorities.

Why in News?

• A heatwave is a period of unusually hot weather with above-normal temperatures that typically last three or more days.
• Climate change is causing heat waves more frequently, and they are much stronger and can last for more days.

Heat waves in India:

• In India, heat waves are generally experienced during March-June. On average, two-three heatwave events are expected every season.
• Heatwaves are predominantly observed over two areas, central and northwest India and another over coastal Andhra Pradesh and Odisha, supported by favourable atmospheric conditions.
• Total duration of heatwaves has increased by about three days during the last 30 years and a further increase of 12-18 days is expected by 2060.
• In the future climate, heat waves will be spread to new areas including southern parts of India.

Caused fatalities:

• Heatwaves have multiple and cascading impacts on human health, ecosystems, agriculture, energy, water, and the economy.
• Heatwaves have posed severe challenges to human health and have created public health emergencies. Prolonged heat exposure causes heat strokes and heat exhaustion and causes various respiratory and cardiovascular diseases.
• The recent 2022 heatwave in India and Pakistan in March-April made devastating impacts. It is estimated to have led to at least 90 deaths across India and Pakistan.
• It also triggered an extreme Glacial Lake Outburst Flood in northern Pakistan.
• The extreme heat reduced India’s wheat crop yields from Punjab and Uttar Pradesh.
• There have been power outages due to a shortage of coal and a sudden rise in demand for electricity and irrigated water.

Cause of heat waves:

• Heatwaves are caused by large-scale atmospheric circulation anomalies like high-pressure areas, upper-tropospheric, jet streams, etc.
• The global forcing like the El Nino/Southern Oscillation (ENSO) and the Indian Ocean modulate the frequency and duration of Indian heatwaves.
• A heatwave can be further accentuated by local effects like depleted soil moisture and enhanced sensible heat flux.

Early Warning:

• Adaptation to heatwaves can be effective to minimize the negative impacts, by developing a comprehensive heat response plan that includes early warnings, awareness raising, and technology intervention.
• India has now a strong national framework for heat action plans involving the India Meteorological Department (IMD), the National and State disaster management authorities, and local bodies. Early warning systems are an integral part of this heat action plan.
• The research helped us to improve our understanding of the underlying mechanism of its genesis and intensity.
• Under the National Monsoon Mission, the Ministry of Earth Sciences (MoES) established an advanced prediction system for early warnings of heatwaves.
• IMD has the capability to predict the genesis, duration, and intensity of heatwave events with reasonable accuracy up to four-five days in advance. These predictions are widely disseminated to disaster management authorities.

Can we then predict heat waves two weeks in advance?

• A recent study published in the Scientific Reports by the scientists at the Indian Institute of Tropical Meteorology (IITM), Pune, has shown that heatwave genesis and duration in India can be predicted with good skill up to two weeks in advance.
• They have used the hindcasts from the MoES Extended Range Prediction System (ERPS) which uses an ensemble method combining four atmospheric general circulation models.

Improved prediction:

• In another recent study published in the International Journal of Climatology of the Royal Meteorological Society last month, scientists from IMD, IITM, and MoES have documented for the first time that Indian heatwaves can be predicted even one season in advance.
• They used 37 years (1981-2017) of hindcasts from the Monsoon Mission Coupled Climate Forecast Model (MMCFS) to document that seasonal predictions of the frequency and duration of Indian heatwaves during April-June are very useful.
• The model could reproduce the spatial distribution of heatwave frequency and duration very well.
• The model also showed useful skill in predicting the characteristics of heatwaves for different months (April to June) separately.

How better prediction will help?

• India has an end-to-end seamless prediction system to predict heatwaves in all time scales, from short-range to seasonal.
• The seasonal forecast will provide an outlook or probability of the frequency and duration of heat waves, one season in advance.
• This early outlook can be further strengthened using the extended-range (two weeks) and short-range (four-five days) forecasts for more focused region-wise response strategies. However, there is a scope for further improvement of this prediction system.

Conclusion:

• As climate change has become a reality, there will be a need for a much more advanced forecasting system for heatwaves in the near future for early warning.
• This will help us be better equipped and prepared for the severity of heat waves. This is just one example of how good science can help society.

Source: The Hindu

Mains Question:

Q. What are heat waves? Explain how better prediction technologies can help India be better equipped for the prevention and management of heat waves.