Most of you will admit that few years back, Heat Waves were relatively tolerable than now. Heat waves are natural phenomenon of summers and human bodies adapt to heat by cooling the body through sweating. But the body’s cooling mechanism is unable to perform its best when heat is accompanied by humidity. Extreme heat (more than 350 C) combined with high humidity is termed as “Heat Stress.” Under such conditions, sweat does not evaporate quickly which makes the body vulnerable to heat stroke and other heat related illnesses.
What causes Heat Stress?
As per NASA’s Goddard Institute for Space Studies, global temperature has increased by around 10 C since the advent of Industrial Revolution. Laws of thermodynamics state that 10C rise in air temperature increases its water holding capacity by seven times. High air temperature and increased humidity gives rise to heat stress. Global Warming is real and heat stress is one of its many consequences.
Record smashing heat !
Year 2022 and 2023 saw record-breaking streaks of extreme heat. Europe witnessed hottest summer and more than 60,000 deaths due to heat-wave like conditions in 2022. World Meteorological Organisation has declared the first week of July 2023 as “The Hottest Week” ever. Not only this, global sea surface temperatures were record high for the month of May and June. Sea ice in Antarctica is 10% lower than usual in summer of 2023. Greece had hottest July weekend in 50 years and temperature reached 450C in some areas.
Economic impact
People working outdoors such as farmers, construction workers, and labourers are more vulnerable. Heat stress is not uniform; lower middle class people and low income countries which falls mainly in tropical regions are most affected. In 1995, economic loss due to heat stress was estimated to be $280 billion while the recent report of International Labour Organisation estimates that global GDP will decrease by $2400 billion by 2030. In 1995, heat stress was reason behind the loss of 1.4% of total working hours which is equivalent to 35 million full-time jobs. The projections for 2030 is 2.2% loss of working hours which is equivalent to 80 million full-time jobs.
An issue of Social Justice
Heat stress pops up the question of decent work conditions and occupational hazards. It will widen the already existing gender gaps in labour market. Extreme heat conditions are hurdle to achieve Sustainable Development Goals in terms of poverty, inequality, health, food security, decent work, and economic growth. Surprisingly, sub-regions with less emissions per person are worst affected by heat stress; examples are Southern Asia and Africa. Well, this attracts another domain for discussion and action and that is Climate Justice.
It is not merely about economic development or social justice; it is about every living being on the planet.Ideal temperature for most of the crops is between 200 C – 300 C. Exposure to extreme heat for longer durations decreases the crop production. Insects and birds have their breeding and spawning periods synchronised with seasons and heat stress negatively impacts the same.
Urban Heat Island Effect
Cities are 50C – 90C warmer than surrounding rural areas due to absorption of solar heat by buildings and concrete roads. This is termed as Urban Heat Island Effect. 55% of global population lives in cities and urbanisation is still sprawling, the heat effect is expected to worsen in the coming years. This is one of the main reasons for decreased labour productivity in cities. Cool roofs can be used to fend off heat as it uses sunlight reflecting materials. As per United Nations Environment Program, increasing urban canopy can bring down temperature by 10C. On a sunny day, a tree has cooling effect similar to a domestic air conditioner running for 24 hours.
Precautions and Prevention
We need practical solutions and one example is rescheduling the working hours. In 2023, Punjab Government (India) changed the timing of 52000 government offices during heat wave period. This provided favourable working conditions and saved 10,800 MW of electricity in 54 days. It is advised to stay indoors during heat waves which means staying in air-conditioned rooms.
Isn’t it ironic that greenhouse gas emitting air conditioners are used to beat the heat stress. We are escaping from heat and intensifying the global warming at the same time. We are trapped in a loop and situation worsens with every round. It’s time to look for another generation of cooling equipment or coolants.
