Droughts, floods, surges in insect populations and threats to food supply may sound like a biblical apocalypse but according to Jonathan Patz, UW-Madison professor of environmental and population health sciences, these are likely future consequences of climate change.
When addressing a crowd of more than 100 members of the public last week as part of UW-Madison's Wednesday Nite @ the Lab"" series, Patz discussed the serious health issues that may arise as a result of a changing environment.
""The world's CO2 has been escalating, almost exponentially, since the industrial revolution,"" Patz said. ""And as CO2 rises, it traps heat. We've seen a rapid rise in average global temperature. Already it is warmer than any time in the last thousand years.""
Patz and a team of researchers from UW-Madison, Wisconsin Health and Family Services, the University of Illinois and the National Center for Atmospheric Research currently study the climate change health risks for the Wisconsin and Chicago areas. While the predicted temperature increase of a few degrees may not seem like much, Patz discussed the complex web of effects that rising temperature has on health.
Patz explained that climate change is more than just global warming. In the future, the Midwest and the planet can expect to experience more extremes in weather conditions such as an increase in floods and droughts. Though it may seem counterintuitive, Patz explained that warmer air temperatures allow water to evaporate from the soil more quickly, causing droughts. But warm air also holds more moisture and thus creates more thunderstorms.
Increased rainfall can serve as a health threat in multiple ways. For example, Milwaukee, like more than 900 cities in the United States, combines its sewage and storm-water into one system. When it rains hard the whole system overflows into the surface water contaminating drinking water and increasing exposure to waterborne diseases.
""Two-thirds of reported waterborne disease outbreaks were actually preceded by heavy rainfall,"" Patz said citing one of his recent studies. ""There seems to be a link between getting diarrhea and other types of diseases carried in water and heavy rainfall.""
In 1993, Milwaukee experienced an outbreak of Cryptosporidiosis, a chlorine-resistant parasitic disease that made 400,000 people sick and killed more than 100 people. This outbreak ""was preceded by the heaviest rainfall in a 50 year climate record we studied,"" Patz said.
Today, more than a trillion gallons of sewage and stormwater are overflowing into surface water in various communities, Patz said. The number of locations experiencing heavy rainfall, and thus risking an upsurge in waterborne diseases, is increasing rapidly in the United States. In addition to increased rainfall, rising temperatures can speed up the development of parasites making them infectious more quickly.
Globally and locally, climate change is already taking its toll.
""According to the World Health Organization, it's estimated that 160 people die every year because of the warming we've had and the effects of malaria, malnutrition and flooding '¦ mostly in poor countries right now, mostly in sub-Saharan Africa,"" Patz said. Yet, the United States remains the primary producers of climate change-inducing greenhouse gases.
""This problem is a local problem, a regional problem and it's a global problem,"" Patz said. ""How we behave and act locally can actually effect other people around the world.""
