(Beyond Pesticides, January 6, 2009) According to a new study published December 10, 2008 in the online edition of Environmental Health Perspectives, climate change is likely to increase human exposure to agricultural contaminants, including pesticides. Risks of many pathogens, particulate and particle-associated contaminants could increase significantly. The study, “Impacts of Climate Change on Indirect Human Exposure to Pathogens and Chemicals from Agriculture,” examines pathogens and chemicals in the environment and their fate and transport.
The researchers determined the potential implication of climate change on chemical and pathogen inputs in agricultural systems and explored the effects of climate change on environmental transport and fate of different contaminants. These data were combined to assess the implications of climate change in terms of indirect human exposure to pathogens and chemicals in agricultural systems.
The study concludes that climate change will result in an increase in risks of pathogens and chemicals from agriculture to human health. It will fuel increased use of pesticides and biocides as farming practices intensify. Increased use will lead to increased exposure through food air and water, as well as increased occupational exposure for farmworkers. Extreme weather events will mobilize contaminants from soils and fecal matter, potentially increasing their bioavailability.
According to the researchers, climate change will also affect the fate and transport of pathogens and chemical contaminants in agricultural systems. While increases in temperature and changes in moisture content are likely to reduce the persistence of chemicals and pathogens while changes in hydrological characteristics are likely to increase the potential for contaminants to be transported to water supplies.
This study follows new U.S. Department of Agriculture (USDA) research shows weeds flourishing from increasing levels of carbon dioxide in the atmosphere. Lewis Ziska, PhD, and his team of researchers, have found “noxious” weeds to be more adaptable to changing conditions than crops, predicting further growth of their productivity and range in urban and rural areas. Previous research by Dr. Ziska shows that common pollen allergens – including the troublesome ragweed pollen – may be getting worse as a result of global climate change.
While solving climate change will require action on many fronts, including carbon-free energy, reduced energy consumption and increased efficiency, organic agriculture is also part of the solution. The adoption of organic methods, particularly no-till organic, is an opportunity for farming both to mitigate agriculture’s contributions to climate change and to cope with the effects climate change has had and will have on agriculture. Good organic practices can both reduce fossil fuel use and provide carbon sequestration in the soil through increased soil organic carbon (SOC). Higher SOC levels then increase fertility and the soil’s ability to endure extreme weather years. Organic agriculture relies on non-chemical ways of maintaining fertility, managing pests and controlling weeds, thus eliminating the need for synthetic fertilizers and toxic pesticides. The Rodale Institute estimates that converting one 320-acre farm to organic methods is equivalent to removing 117 cars from the road.