Canada’s Wildfires are a Warning to India: Here is how we must shore up our cities against heatwaves

SourceTimes of India

Relevance: With the increasing frequency of Heatwaves in India, it needs adequate attention for mitigation.

Synopsis: The frequency of Heatwaves is increasing in India. The existing measures are not enough for mitigating it.

For decades, scientists have warned that the climate crisis will increase the frequency and intensity of heat waves. However, Canada is not one of the countries predicted to be severely impacted. But the recent Wildfires, caused by the extreme heat, have reduced Canada’s tiny town of Lytton to ash.

Global Heat Wave projections:
  • Lethal heatwaves are projected to bring death and destruction across the Middle East, South Asia, and portions of Africa and China.
  • Deadly heatwaves will become commonplace across South Asia even if global warming is contained to 1.5 °C; The consequences would be far worse if 1.5 °C is breached.
  • Heat waves in India:
    • Researchers from IIT-Gandhinagar published a study in Environmental Research Letters in 2017 that convincingly proved a considerable rise in the frequency and severity of heatwaves from 1951 to 2015. It also revealed that the five most severe heatwaves occurred after 1990.
    • IIT-Gandhinagar’s projections suggest that the frequency of severe heatwaves will increase 30-fold by 2100 if the global temperature increases by 2°C.
    • Another study reveals that the mortality rate due to heatwaves has increased by 62.2% in the last 50 years.
How Heatwaves are declared in India?

Only in 2015 did the Indian government declare the heatwave a natural disaster under the National Disaster Management Act of 2005.

IMD declares a heatwave based on temperature. A heatwave is proclaimed when the highest temperature at a station surpasses 45°C; if it exceeds 47°C, it is referred to as a severe heatwave. Heatwaves in coastal and hilly locations are declared using similar criteria.

How human body react to heatwaves?

The human body reacts to a combination of heat and humidity known as the ‘wet-bulb temperature’. Wet-bulb temperature can be high even when the temperature is relatively low. Only a few humans can tolerate a wet-bulb temperature exceeding 35°C because their bodies can no longer cool themselves.

  • For example, if the temperature is 35°C and the relative humidity is 80%, the wet-bulb temperature will be 32°C, which is considered dangerous for manual labour. Similarly, if the temperature is 40°C and the relative humidity is 75%, the wet-bulb temperature is about 36°C.
  • Many regions of India now experience wet-bulb temperatures exceeding 32°C during certain parts of the year. However, we are not declaring such days to be heatwaves, endangering the lives of people engaged in manual labour.

Development of Heat Action Plans in India:

Many cities and states have acknowledged the threat and developed Heat Action Plans. For example, in 2013, Ahmedabad became the first city to implement a HAP to raise public awareness, identify high-risk groups, issue heatwave alerts, and improve inter-agency collaboration. So far, 30-odd cities have adopted similar HAPs.

State-wide HAPs have also been introduced in Tamil Nadu, Kerala, Maharashtra and Odisha.

Suggestions to mitigate Heatwaves in India:
  • Prepare a national heat code: A heat code will outline the criteria for declaring heatwaves and will develop SOPs to be used during heatwaves. Further, It will also give the district administration the authority to declare an emergency, halt outdoor activities, and allocate resources for heat relief.
  • Plan to cool our cities: Our existing building codes and urban planning are worsening heatwaves by magnifying the heat island effect. To reduce heatwaves, India needs to modify urban planning standards and building bylaws to enhance green areas and water bodies and promote cool roofs and green buildings, among other things.
  • Recognise the Emergency: The central government has to acknowledge heatwaves as a real threat and assists states and districts in implementing heat codes and HAPs. Moreover, scientists and planners will also have to update the definition of a heat emergency and the guidelines for dealing with it
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