Sakshi is a Climate Consultant at GeoHazards Society. She is a Post Graduate in Disaster Management from Tata Institute of Social Sciences (TISS), Mumbai.
Disha is reseracher in the field of geospatial technology and disaster management. She is a post graduate in Disaster Management from TISS, Mumbai
Longer more intense and frequent heat waves are one of the most common features of the worsening effects of Climate Crisis.
A Warming Planet
The average temperature of the earth has risen more than 1°C since the 1880s, primarily due to the rise in global Greenhouse Gas (GHG) Emissions, particularly through the burning of fossil fuels. Some areas of the world including the Arctic, are heating more rapidly, which is warming at least two times as fast as the rest of the planet. Moreover, more than one-fifth of the population of the globe now lives in regions that have already experienced warming greater than 1.5°C, an increase that almost all the nations have agreed to avoid to significantly reduce the risk of harmful impacts of climate change. Climate models project that, by the end of the century, heatwaves will routinely break records and increase heat stress on populations globally.
Recently, India and Brazil published research entitled “Large scale connection to deadly Indian Heatwaves” according to which Indian heatwaves occur due to a theoretical mechanism called “Quasi-Resonant Amplification” called QRA which can lead to deadly heatwaves caused by Arctic Warming, a result of Global Warming.
Genesis
Heatwaves occur when the air is trapped in a particular area for a long time, causing an increase in temperature, and having a harmful effects on the environment and human health. The main reason for this unusual pattern involves high-pressure air circulation systems that prevent the near-ground air to rise. Instead, it traps warm ground air which blocks any rain from occurring.
A heatwave in India is a period of abnormally high temperatures, more than the normal maximum temperature that occurs over the summer season in the northwestern and central parts of India. A heatwave is declared 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. April was the hottest month for central and northwestern India and the third hottest April, the country experienced since 1901.
Global warming is worsening heatwaves
According to Columbia University’s Earth Institute, global warming could kill as many as eighty-three million people over the next eight decades, a population equivalent to that of Germany.
In present times, the heatwave events arise three times more often than they did earlier in the 1960s. In addition to the heated air, raised humidity levels also cause a rise in heatwave incidents. This intensely heated air is the deadliest form of Extreme Weather event (EWE), causing more deaths than any other climate disaster. Scientists claim that 80% of heatwaves happen due to human activities, mainly through GHG emissions. This is evident through the number of heatwave days in India which has increased in a decade from 413 during 1981-90 to 575 in 2001-2010 and further to 600 in 2010-20(IMD, ICCS).
Cascading effects of Heatwaves
According to Intergovernmental Panel on Climate Change (IPCC), South Asia could be one of the hardest-hit regions in the world by heat stress, and “deadly” heat waves could push the limits of human survivability by the end of the century.
Extreme heat can increase the risk of several other disasters. Heat can exacerbate drought, and hot, dry conditions can in turn create wildfire conditions. Buildings, roads, and infrastructure absorb heat, leading to temperatures that can be 1-7 degrees F hotter in urban areas than in outlying areas – a phenomenon known as the urban heat island effect. This impact is most intense during the day, but the slow release of heat from the infrastructure (or an atmospheric heat island) overnight can keep cities much hotter than surrounding areas. Rising temperatures across the country pose a threat to people, ecosystems, and the economy.
Heatwaves are of tremendous significance in India due to it’s largely agrarian society, which depends on stable weather patterns. Heatwaves on land disrupt agricultural yields, which is a vital source of income for farmers living in central and northwestern India. Marine heatwaves, which cause bleaching of coral reefs and disrupt marine ecosystems, affect coastal communities which depend on fishing. It has cascading effects on several sectors such as:-
Human Health
Heatwaves are not just uncomfortable: they can also lead to illness and even death, particularly among older adults, the very young, and other vulnerable populations. Prolonged periods of severe heat can also lead to power outages as heavy demands for air conditioning strain the power grid. Heat stress occurs in humans when the body is unable to cool itself effectively. Normally, the body can cool itself through sweating, but sweat will not evaporate as quickly when humidity is high. This is known as a wet-bulb temperature of 35°C (95°F). This could potentially lead to heatstroke. High humidity and elevated nighttime temperatures are likely key factors in causing heat-related illness and mortality. When there’s no break from the heat at night, it can cause discomfort and lead to health problems, especially for those who lack access to cooling, which are often people who have low incomes. Hot days are also associated with increases in heat-related illnesses, including cardiovascular and respiratory complications and kidney disease.
In extreme temperatures, air quality is also affected. Hot and sunny days can increase the production of ground-level ozone, a harmful pollutant that is the main component of smog, which can damage the respiratory system and is particularly harmful to those with asthma. In addition, greater use of air conditioning requires more electricity which, depending on the electricity source, emits other types of pollution, including particulates that have an impact on air quality too. These increases in ozone and particulate matter can pose serious risks to humans.
Agriculture
High average temperatures can have disastrous implications on agricultural yield. Additionally, Heatwaves increase the chances of livestock experiencing heat stress, especially when nighttime temperatures remain high and animals are unable to cool off. Heat-stressed cattle can experience a decline in milk production, slower growth, and reduced conception rates. Hence, extreme heat threatens the food security of billions of people by hampering crop production, livestock viability, and fishing sustainability. Moreover, by mid-century, agriculture will have to produce nearly 50 percent more food to feed the world’s growing population. This can threaten Human survival.
Energy
Warmer temperatures affect many aspects of the energy system, including production, transmission, and demand. While higher summer temperatures increase electricity demand for cooling, at the same time, they can lower the ability of transmission lines to carry power, possibly leading to electricity reliability issues like rolling blackouts during heatwaves. Although warmer winters will reduce the need for heating, modeling suggests that total energy usage will increase in a warmer future. In addition, as rivers and lakes warm, their capacity for absorbing waste heat from power plants declines. This can reduce the thermal efficiency of power production. This can hamper economic and social development.
Transportation
The transportation sector suffers as well. Heat expands concrete, causing sections of road pavement to buckle. It causes steel-comprising drawbridges to expand, hindering their ability to open and close. Train tracks from “sun kinks” as the metal tracks bend under intense heat, increasing the risk of derailment. Planes can struggle to fly in high-heat conditions, and extreme temperatures can reduce the allowable weight of aircraft to take off. This increases the likelihood of disruptions to travel and shipping for passengers, manufacturers, and airlines alike. This can retard economic development.
Adaptation Measures
According to “Resilience Strategies for Extreme Heat”, some strategies are:
- Identifying vulnerable populations and creating heat preparedness plans with all residents in mind, may include steps like opening cooling centers during periods of extreme heat and adopting workplace heat stress standards.
- Installing cool and green roofs and cool pavement to reduce the urban heat island effect.
- Planting trees to provide shade and to cool the air through evapotranspiration.
- Pursuing energy efficiency to reduce demand on the electricity grid, especially during heatwaves.
Way Forward
Lower-income communities and developing nations are most vulnerable to heat-related illnesses and deaths due to their geographical location, deforestation, and lack of access to resources, such as air conditioning and cooling centers. Less than one-third of global households have access to air conditioning, according to the International Energy Agency(IEA), and only 8 percent of the 2.8 billion people living in the hottest parts of the world have air conditioners. Thus, there is an urgent need to mitigate the effects of extreme heatwaves by controlling the usage of fossil fuels and taking appropriate adaptation measures. Nature-based solutions to adaptation can act as a blessing in disguise.