Climate change to boost spread of waterborne disease in China

A coal barge navigates the Yangtze River in China. Creative Commons: Marshall Segal, 2008

A coal barge navigates the Yangtze River in China. Creative Commons: Marshall Segal, 2008

A new study released this week has found that by the year 2030 climate change will have set back China’s attempts to prevent waterborne illnesses by seven years, creating a serious risk for the world’s largest population.

The research used estimates to predict how far China would progress in reducing these diseases by 2020 and 2030 in a moderate climate, and then compared with scenarios where the temperatures had risen due to climate change.

The results predicted that progress would be greatly slowed, especially if China failed to adequately implement sanitation and provide clean water to the 401 million people without access to clean water in their homes.

This is despite the fact that the country has made significant progress in preventing serious waterborne diseases, meeting its Millenium Development goal of halving the numbers of those without access to clean water and adequate sanitation.

Between 1990 and 2010, the mortality rates from diarrheal diseases dropped by 94%. Malaria and Japanese encephalitis—diseases which both rely on water in order to develop—have also dropped by 60% and 80%, respectively.

Yet climate change could hamper the progress China has made, as warmer temperatures provide favorable circumstances for waterborne disease organisms to grow and spread. Extreme rainfall, which increases the likelihood of clean water mixing with sewage, is one critical way these diseases are spread.

In addition, warmer temperatures and changing weather patterns are likely to increase the range of disease vectors. One recent study found that for every degree the air temperature increased in Lima during an El Nino event, admissions to hospital for diarrhea increased by 8%.

Similar extreme weather activity and rising temperatures in China could mean that many will find themselves at greater risk of contracting diseases found more commonly in warmer climates, such as malaria, or dengue fever.

Elsewhere in the world, there is already evidence that public health is at risk from diseases that are spreading due to climate change. For instance, cases of Valley Fever have surged in arid regions of North America and Mexico over the last few years. In Ohio, climate change was implicated in a toxic algae bloom that affected approximately 400,000 people’s access to water.

Anthony Costello, a pediatrician and director of the UCL Institute for Global Health, said:

The health impacts [of climate change] will be felt all around the world—and not just in some distant future but in our lifetimes and those of our children.

Already, climate change is contributing to huge storms, floods, and droughts—all of which come with very real human costs. Meanwhile, climate change’s contributions to the spread of disease gives world leaders yet another reason to cut emissions and protect the communities that are being hit hardest by global warming.


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Quick Facts on Public Health

  • Heat is already the leading cause of weather-related deaths in the United States, with more than 6,300 deaths resulting from exposure to extremely hot weather between 1979 and 2006.  >> EPA, 2010

  • High temperatures raise the levels of ozone and other pollutants in the air, exacerbating cardiovascular and respiratory disease. Urban air pollution causes about 1.2 million deaths each year.  >> World Health Organization, 2010