The Health Effects of Global Warming

Infectious Diseases and Death Rates Rise Along With Global Temperatures

Global Health
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Global warming is not only a threat to our future health, it already contributes to more than 150,000 deaths and 5 million illnesses annually, according to a team of health and climate scientists at the World Health Organization and the University of Wisconsin at Madison -- and those numbers could double by 2030.

Research data published in the journal Nature show that global warming may affect human health in a surprising number of ways: speeding the spread of infectious diseases such as malaria and dengue fever; creating conditions that lead to potentially fatal malnutrition and diarrhea, and increasing the likelihood of heat waves and floods.

Health Effects of Global Warming Hardest on Poor Nations

According to the scientists, who have mapped the growing health impacts of global warming, the data show that global warming affects different regions in very different ways. Global warming is particularly hard on people in poor countries, which is ironic because the places that have contributed the least to global warming are most vulnerable to the death and disease higher temperatures can bring.

"Those least able to cope and least responsible for the greenhouse gases that cause global warming are most affected," said lead author Jonathan Patz, a professor at UW-Madison's Gaylord Nelson Institute for Environmental Studies. "Herein lies an enormous global ethical challenge."

Global Regions at Highest Risk from Global Warming

According to the Nature report, regions at highest risk for enduring the health effects of climate change include coastlines along the Pacific and Indian oceans and sub-Saharan Africa. Large sprawling cities, with their urban "heat island" effect, are also prone to temperature-related health problems. Africa has some of the lowest per-capita emissions of greenhouse gases. Yet, regions of the continent are gravely at risk for diseases related to global warming.

"Many of the most important diseases in poor countries, from malaria to diarrhea and malnutrition, are highly sensitive to climate," said co-author Diarmid Campbell-Lendrum of WHO. "The health sector is already struggling to control these diseases and climate change threatens to undermine these efforts."

"Recent extreme climatic events have underscored the risks to human health and survival," added Tony McMichael, director of the National Centre for Epidemiology and Population Health at the Australian National University. "This synthesizing paper points the way to strategic research that better assesses the risks to health from global climate change."

Global Responsibilities of Developed and Developing Nations

The United States, which currently emits more greenhouse gases than any other nation, has refused to ratify the Kyoto Protocol, choosing instead to initiate a separate multinational effort with less ambitious goals. Patz and his colleagues say their work demonstrates the moral obligation of countries with high per-capita emissions, such as the United States and European nations, to take the lead in reducing the health threats of global warming. Their work also highlights the need for large, fast-growing economies, such as China and India, to develop sustainable energy policies.

"The political resolve of policymakers will play a big role in harnessing the man-made forces of climate change," said Patz, who also holds a joint appointment with the UW-Madison department of Population Health Sciences.

Global Warming is Getting Worse

Scientists believe that greenhouse gases will increase the global average temperature by approximately 6 degrees Fahrenheit by the end of the century. Extreme floods, droughts and heat waves are likely to strike with increasing frequency. Other factors such as irrigation and deforestation can also affect local temperatures and humidity.

According to the UW-Madison and WHO team, other model-based forecasts of health risks from global climate change project that:

  • Climate-related disease risks of the various health outcomes assessed by WHO will more than double by 2030.
  • Flooding as a result of coastal storm surges will affect the lives of up to 200 million people by the 2080s.
  • Heat related deaths in California could more than double by 2100.
  • Hazardous ozone pollution days in the Eastern U.S. could increase 60 percent by 2050.

Individual People Can Make a Difference

Aside from research and the needed support of policymakers worldwide, Patz says individuals can also play an important role in curbing the health consequences of global warming.

"Our consumptive lifestyles are having lethal impacts on other people around the world, especially the poor," Patz said. "There are options now for leading more energy-efficient lives that should enable people to make better personal choices."