Poorest people will face the greatest burden of heatwaves

Heatwaves are becoming more frequent and intense around the world. Heatwaves, defined as prolonged periods of excessive heat, cause many devastating ecological, economic and human health impacts. The number of extreme heat days has increased 60 percent over the past four decades globally. Extreme heat is one of the deadliest and costliest natural hazards, claiming more than 166,000 lives between 1998 and 2017 worldwide. 
To reduce the impacts of rising temperatures, adaptation measures such as infrastructure improvement, access to water, cooling systems, early warning systems, and increased awareness are relied upon. These mechanisms are costly to implement, and are more widely available in wealthier countries.

Lower income countries often lack access to adaptation measures, and are exposed to heat waves for longer periods of time. This inequality will only continue to rise as climate change persists, as demonstrated by new research. 

The authors of the study, which is published by the American Geophysical Union, theorizes that “vulnerability to risk, and degrees of suffering, are determined by levels of economic development, rather than simple exposure to natural hazards.”

The researchers analyzed historical income data, climate records and heat adaptations to quantify the level of heat wave exposure that people in different income levels face around the world. Observations were paired with climate models to predict how exposure will change over time. 

The experts found that heatwaves have intensified more in low-income areas as opposed to high-income regions. When compared to people with higher incomes, lower income populations currently face a 40 percent higher exposure to heatwaves.

The study revealed that this disproportionate exposure to heatwaves will only increase in the world’s lowest-income population by 2100, even if access to adaptation measures such as air conditioning, cool air shelters, and safety regulations are implemented. By the end of this century, people in the lowest-income population will face 23 more days of heat waves than those in the highest income quarters every year. 

At the same time, the highest-income regions in the world with resources and capacity to adapt will experience little change. The richest two regions are expected to experience stable heatwave metrics by the end of the century. This is because high-income countries have greater capacity to adapt to climate change. 

Many low-income regions are geographically located in already-warm tropics, and their populations are expected to grow, contributing to additional heat wave exposure. At the same time, higher-income countries have historically contributed to the majority of global greenhouse gasses. 

The findings reinforce the fact that populations who have contributed the least to climate change often bear the brunt of climate change impacts, said lead study author Mojtaba Sadegh, a climatologist at Boise State University. 

The global inequalities of climate change can be addressed over time through innovative and affordable solutions, such as energy-efficient cooling solutions. “We need to raise awareness of dangers and heat safety, and to improve early warning systems – and access to those early warning systems,” said Sadegh.

The study is published in the AGU journal Earth’s Future.

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By Katherine Bucko, Earth.com Staff Writer