Heatwaves

• Context (TH): Parts of Odisha, West Bengal, Telangana, Andhra Pradesh and others are expected to face heatwave conditions.
• A Heatwave is defined based on the temperature thresholds over a region in terms of actual temperature or its departure from normal.
• In certain countries, it is defined in terms of the heat index based on temperature and humidity or based on the extreme percentile of the temperatures.

Criterion for Declaring Heatwave

• Heatwave is considered if the maximum temperature of a station reaches at least 40˚C or more for Plains and at least 30˚C or more for Hilly regions.

Based on Departure from Normal

• Heat Wave: Departure from normal is 4.5˚C to 6.4˚C.
• Severe Heat Wave: Departure from normal is >6.4˚C.

Based on Actual Maximum Temperature

• Heat Wave: When actual maximum temperature ≥ 45˚C.
• Severe Heat Wave: When actual maximum temperature ≥47˚C.

Criteria for Heatwave for Coastal Conditions

• When the maximum temperature departure is 4.5˚C or more from normal, a Heatwave may be described, provided the actual maximum temperature is 37˚C or more.

Favourable conditions for Heatwave

• Transportation/Prevalence of hot dry air over a region (There should be a region of warm dry air and appropriate flow pattern for transporting hot air over the region).
• Absence of moisture in the upper atmosphere (As the presence of moisture restricts the temperature rise).
• The sky should be practically cloudless (To allow maximum insulation over the region).
• Large amplitude anti-cyclonic flow over the area.

IMD colour-coded warnings for Heatwave

Also, read > Indian Meteorological Department.

Causes of Heatwave

• Heatwaves are caused due to shifting of Jet Streams (Rossby Waves; cause Heat Domes), hot local winds like loo (affects Gangetic Plains Region), and anthropogenic causes like global warming.
• Urbanisation aggravates heat waves in the form of Urban Heat Islands.

Global Warming and Heatwave

• The global average temperature increase since 1900 is around 1.3°C, in India, it has crossed 2°C.
• IMD and the Indian Institute of Tropical Meteorology (Pune) have established that the frequency and severity of heatwaves have risen significantly in India over the last three decades.

Effects of Heatwave

• Sunstroke (results in body temperature >40°C) and vital organ failure: In 2015, 2,300 people died in India due to heat waves. A record heatwave in July 2021 killed 500 people in western Canada.
• Reduced human output: This happens due to adverse effects on mental health (the body works best in a narrow range of body temperature — 36-37.5°C).
• Economic cost: Increased expenditure on cooling appliances like ACs and refrigerators (this creates a positive feedback mechanism and enhances global warming. More cooling appliances more emissions severe heat waves, and the cycle repeats).
• Impact on the energy sector: Heatwave can cause grid stability issues and power outages. It can also lead to increased demand for electricity, transmission and distribution issues, and reduced power generation due to inefficient power plants.
• Ecological damage: Reduced biological activity and carbon sequestration.
• Forest fires: One of the worst consequence of heat waves in temperate regions are wildfires. This is evident in the 2019-2020 Australian Bushfires and July 2021 Western Canada Wildfires.
• Impact on Agriculture: Heatwaves can cause crops to wilt and die, leading to reduced yields or even total crop failure. It can also create ideal conditions for pests and insects to thrive.
• Water Scarcity: Heatwaves can exacerbate existing water scarcity issues by causing water sources to dry up faster and increasing demand for irrigation.

Heatwave is not notified disaster in India: Reasons

Finance Commission Reluctance

• States have put the demand of including heatwaves as a notified disaster before the last three Finance Commissions. However, the Finance Commissions have not entirely been convinced.
• As per the 15th Finance Commission, the existing list of notified disasters “covers the needs of the states to a large extent” and did not find merit in the request to include heatwaves.
• It, however, endorsed an enabling provision created by the preceding Commission that allowed states to utilise a part of the SDRF money, i.e., up to 10%, for “local disasters” such as lightning or heatwaves, which states could notify on their own.
• Using this new enabling provision, at least four states, Haryana, Uttar Pradesh, Odisha, and Kerala, have added heatwaves as local disasters.

Practical Difficulties

• The government has to provide monetary compensation, i.e., Rs 4 lakh, for every life lost because of a disaster that is in the notified list. Grievous injuries also have to be compensated. This would place an extra burden on the state exchequer.
• Problem in attributing deaths to heatwaves. In most cases, heat itself does not claim lives but aggravates the pre-existing conditions, leading to difficulty in ascertaining if heat was the real cause behind death.

Heat Action Plan

• HAPs are India’s primary policy response to economically damaging and life-threatening heatwaves.
• They prescribe a variety of preparatory activities, disaster responses, and post-heatwave response measures across state, district, and city government departments to increase preparedness and lower the adverse impacts of extreme heatwaves.
• Odisha first developed a Heat Action Plan in 1999 following more than 2,000 Heat Wave deaths in 1998.
• Followed by this, the first city level Action Plan was developed by Ahmedabad in 2013 following severe Heat Wave in 2010.
• The National Disaster Management Authority and IMD are reported to be working with 23 States to develop HAPs.
• There is no centralised database on HAPs, but at least 23 HAPs exist at the State and city level, with a few States, such as Odisha and Maharashtra, laying out district-level HAPs.

What do HAPs recommend?

1. Establish Early Warning System and Inter-Agency Coordination
   • Early Warning and Indicators of heat-wave
   • Forecast and Issuance of Heat Alert or Heat Warning
   • Identification of Color Signals for Heat Alert
2. Capacity building/training programme for health care professionals at local level to recognize and respond to heat-related illnesses, particularly during extreme heat events.
3. Public Awareness and community outreach on how to protect against the extreme heat-wave through print, electronic and social media and Information.
4. Collaboration with non-government and civil society to improve bus stands, build temporary shelters, improve water delivery systems in public areas, etc to tackle Heat wave conditions.

What debilitates HAPs from addressing the problem effectively?

Ignoring the local context

• The HAPs (except Odisha and Rajkot HAPs) lack climate analysis of the city or state where it will be implemented.
• A national threshold is what determines a heatwave today. Many cities have been reeling under extreme temperatures, although no heatwave has been declared.

Failure to include assessment of Socio-economic differences in Heat Stress Prone Areas

• The lack or presence of cooling solutions, the ability to afford them, the ratio of size to inhabitants, and the community infrastructure all play a key role in understanding the residents’ ability to respond to heat waves.
• It also can help inform priority areas for implementing adaptation and mitigation infrastructure.

Not Climate-Vulnerability Based

• Ignoring historical climate trends and ground-level assessments of hotspots and socio-economic status has made the HAPs static in nature.
• Thus, the HAP framework is not equipped to develop pre-emptive strategies for key vulnerable areas and those most at risk from heat waves.

Understanding Climate Change Projection

• Very few Action Plan Strategies (like the Telangana Heat Action Plan) have given due consideration to climate change projections and the cumulative impact of the growing urban population.
• The impact of urbanisation and climate change on Heat Waves needs to be studied in detail and considered while framing Action Plans.

Inconsistent methods

• While most HAPs have conducted vulnerability assessments during the development of the plans, the methods adopted are inconsistent.
• It is time to transition to a robust, full-fledged climate risk assessment that can identify the likelihood of heat waves in different areas and estimate the exposure of people and important assets to heat waves.
• Hotspot mapping is needed to prioritise and formulate targeted interventions, which is now possible with easy-to-access geospatial data.

Vulnerable populations

• All HAPs prioritise the protection of vulnerable populations such as low-income communities, children, and the elderly.
• However, what is missing are targeted interventions that account for the varying needs of populations based on local social and demographic factors, in addition to infrastructure elements that could exacerbate heat.

Way Forward

Factoring in Regional Variations

• The scope of a heatwave needs to be expanded to accommodate humid heat, warmer nights, and extreme dry heat. This requires the development of a heat index that accounts for multiple factors beyond temperature.
• Regional variations also need to be considered, as HAPs that are tailored to specific climatic conditions, demography, and a region’s infrastructure can lead to the formulation of strategies and interventions suited to the local context.

Understanding Heat Hotspots

• External factors that influence the heat profile of the areas should also be included.
• Factors like urban heat Islands and how they interact with the existing heat hotspots must be studied and included to help authorities understand the actual changes in temperatures during, before, and after the heatwave occurrences. However, most HAPs lack this analysis.

Resource allocation

• The implementation of HAPs can vary significantly depending on the priorities of local governments and the capacities available. Allocating dedicated budgets for HAPs is necessary.
• Further, dialogues between the state, civil society organisations, and worker unions are essential to co-plan a financial mechanism that allows informal workers to stay indoors during a heatwave without losing their income.

Breaking down silos

• HAPs currently are stand-alone plans with limited finance. Pooling in resources would be possible if they are integrated with broader action plans promoting urban resilience and climate adaptation.
• Such integration will likely affect the overall effectiveness of HAPs and their implementation, prompting improvements in data collection and monitoring systems, which are essential to helping assess their effectiveness over time.

Focus on building infrastructure

• Finally, while HAPs mention long-term measures, they are limited to building infrastructure (especially cool roofs), with a cursory mention of green and blue spaces.
• For HAPs to be effective, focused planning on including nature-based solutions to address extreme heat in hotspots is a must.

Increase the use of Renewable Energy

• Incentivising individuals and businesses to invest in renewable energy, such as solar panels. This would help reduce the impact of rising temperatures, create new jobs, and stimulate economic growth.