Environmental Change and Human Health The effects of humans on the global environment are increasingly well chronicled. We are also beginning to understand that many of the ecosystem level changes that are occurring not only have widespread environmental consequences, they can directly affect human health in a range of ways. These can range from well publicized effects on air and water pollution, to less well known feedbacks to the ecology of important human diseases. These connections between changes in the environment and our own health are essential to understand, and an opportunity for environmental and earth scientists to collaborate more closely with public health professionals to manage a growing risk to human welfare. Our group is concentrating on one aspect of such links: those involved with the changing global nitrogen cycle. This work is in close coordination with the goals and activities of the North American Nitrogen Center Extraordinary increases in the fixation of atmospheric N2 into reactive forms is the basis for some major public health benefits; for example, the ability to produce large amounts of N fertilizers fuels much of our current world food production. However, as human creation and use of reactive N becomes increasingly large, a wide range of negative consequences for health are also becoming common. These range from effects on air and water pollution, to suboptimal nutrition in both rich and poor nations that is related to the use and distribution of fertilizers, to effects of increased N availability on the ecology of parasitic and infectious diseases. A review of these topics can be found here. More recently, we are concentrating on the links between N and disease, both in a review paper (see publications page), and in the development of a mutli-disciplinary research project to study the effects of eutrophication on schistosomiasis. For more information on these recent projects, please contact Alan Townsend by email.

Graph above : Figure from an in review paper (McKenzie and Townsend, see publications page) showing that the largest future increases in N deposition (blue line) will occur in tropical regions, where species richnes of human parasitic and infectious diseases (red lines) is at it's highest global levels. Below: Picture of the trematode that causes schistosomiasis, a disease which affects millions worldwide. Snails that serve as intermediate hosts for schistosomiasis and many other trematode diseases often appear to respond positively to eutrophic conditions, potentially increasing the risk of disease as nutrient loading to disease-carrying water bodies increases.