Days of extreme heat are increasing in intensity and frequency due to the effects of climate change, an analysis of data from 103 countries showed in a recent Lancet report.
The recently published report called Lancet Countdown on health and climate change: health at the mercy of fossil fuels has stated that due to rapidly increasing temperatures, vulnerable populations such as people over the age 65 and infants under the age of one were exposed to 3.7 billion more person-days of heatwave in 2021 than annually in 1986-2005. Person-days of heatwave exposure refers to the number of days or hours per year that exceed a heat exposure threshold multiplied by the total urban population exposed.
Serious ailments such as acute kidney injury, heatstroke, adverse pregnancy outcomes, and worsening cardiovascular and respiratory diseases can be caused due to exposure to extreme heat.
Children below the age of one experienced 600 million more person-days of heatwaves every year than the average in 1986 to 2005 while adults above the age of 65 experienced 3.1 billion more days.
During 2021-22, extreme weather conditions such as floods, wildfire, drought and heatwaves has affected almost every continent in the world. Higher than usual temperatures were recorded in India, Pakistan, Oman, Turkey, Italy and the UK.
In 2021 alone, people older than 65 in Canada experienced 47 million more person-days of heatwaves. This was due to a heatwave in North America that was at least 150 times more likely to have happened due to climate change. The heatwave was a direct cause of death of at least 569 people in British Columbia and more than 100 deaths in Washington, USA.
In the past two decades, the human population has been experiencing temperatures which are 0.6°C higher in summers than the average summers from 1986 to 2005.
As recently as April 2022, India experienced a heatwave that was 30 times more likely to have happened owing to climate change. At least 90 deaths were attributed to the heatwave.
According to the report, heat-related deaths have increased by 68% for people over the age of 65 between 2000-04 and 2017-21. The death toll was further exacerbated by the confluence of the COVID-19 pandemic.
While death and disease are direct effects of climate change-induced heatwaves, it has widespread implications that effect humans indirectly also.
For instance, over the past decade, extreme heat has stopped people from exercising and increased the risk of falling ill while doing light exercise. The rise in risk has been greatest for countries ranking medium on the Human Development Index (HDI) with an increased risk of heat stress during light outdoor physical activity.
Intense heat also affects labour productivity and puts workers’ health in danger. A worker has lost 139 work hours on an average in 2021. In total, 470 billion work hours, an increase of 37% since 1990-99, were lost last year due to high temperatures. Among these, two thirds of all labour hours lost globally in 2021 were in the agricultural sector. This proportion was highest in low HDI countries at 87%.
The report suggests “modification in the landscapes and built environment” can provide relief from heat risks. Water bodies and heavy vegetation will also help the temperatures to dip as they act as heat sinks and absorb heat through evapotranspiration. Measures as simple as reflective roofing, better building insulation, closing windows blinds to block solar radiation and reducing core body temperature can help in adapting to extremely high temperatures.
“As the planet heats, climate risks are increasingly complex, frequent, and unpredictable, compounding existing vulnerabilities and inequities within populations and causing emergencies that cascade across different systems and sectors. Humanitarian agencies are now seeing how these problems are putting millions of people across the world at immediate risk of famine and death,” said Médecins Sans Frontières’s Louisa Baxter, in a recent Lancet report.
Apart from heat-related problems, increasing deaths and deterioration of health in vulnerable populations due to extreme weather events such as wildfires, drought and floods have also been noted in the report.