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Climate change worsens heatwaves

Worldwide, low-income countries hit harder

Badwater Basin in Death Valley National Park, California. Photo by Eric Hunt, used with permission.

Since the 1980s, climate change has increased the impact of heatwaves. They arrive earlier, last longer, have higher temperatures, and cover wider areas.

Their effects across the globe, however, vary by location and income level. USDA Forest Service scientist Jeffrey Prestemon contributed to a study, led by Mohammad Reza Alizadeh at McGill University, that shows people living in low-income countries are exposed to more heat than people in high-income countries.

Low-income regions had 30% more heatwave days in the 2010s than high-income regions. The size of a decadal heatwave in some low-income regions was up to 150% larger in area than heatwaves experienced in the 1980s.

Low-income countries experienced 24 additional heatwave days per year in the 2010s than in the 1980s, compared to an increase of 14 days in high-income countries. Thus, more residents of low-income countries are exposed to excessive heat for longer periods of time, and their exposures are increasing fastest. These trends are projected to continue with a warming planet.

Many low-income countries are hot and tropical. When these countries are affected by heatwaves, they may not have the capacity to adapt. For example, not everyone has electricity for air cooling or access to running water. As a result, the cost to human health and life in these countries is higher. Most high-income countries are located in cooler climates and tend to have more adaptive capacity to deal with heatwaves.

Low-income countries will need help dealing with heatwaves. The study discusses ways to deal with climate stress through:

  • Developing early warning systems and awareness,
  • Promoting access to water, electricity, and cooling systems,
  • Improving infrastructure, and
  • Building institutional capacity and coordination.

Forest Service researchers and their partners use their economics and modeling expertise to explain when, where, and how climate stresses will affect individuals and communities. This knowledge will help regions better prepare by knowing where resources are critically needed.

Read the article in Earth’s Future. For more information, email Jeffrey Prestemon at jeff.prestemon@usda.gov.

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