![[logo] US EPA](https://webarchive.library.unt.edu/eot2008/20081106182414im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Research Programs: Reducing Global Environmental Risks
Global Climate Change
NHEERL Research Programs
Problem: Ecosystems are dynamic and undergo change as a function of time in response to a variety of stressors, including climate. Climate change has the potential to influence the geographic location of ecosystems, species diversity, and ecosystem services. Human activity can exacerbate the impact of climate change through the build-up of greenhouse gases. While ecosystems are capable of adapting to change, global change may occur at a rate so rapid that ecosystems are unable to keep up, and thus are vulnerable.
Scientific Questions:
- What are the potential consequences of climate change and climate variability (in the context of other stressors) on human health, ecosystems, and social well-being in the United States?
- What are the indicators (sentinels) of climate change at population, community, and ecosystem levels of organization?
- How can one identify future ecological vulnerabilities on a range of spatial scales resulting from the joint effects of changes in climate, sea level, and other stressors such as pollutants and land use?
- How do climate-induced changes in temperature, moisture, and atmospheric composition affect the biology of ecosystems?
- How are human and ecosystem exposure to UVB radiation changing?
- What are the effects of these exposures?
Approach: NHEERL is studying the potential effects of global change on vulnerable ecosystems. Species or ecosystems whose natural habitat is within an ecotone are expected to exhibit the first signals of global change. Latitudinal migration of high altitude wild flowers, for example, may be such a signal. Identification of changes within these sentinel species would significantly decrease the uncertainty as to whether climate change is indeed occurring and provide information on the vulnerability of these sensitive ecosystems to climate change. Our research also focuses on coastal areas which are extremely vulnerable to sea-level rise and therefore considered high risk. The high population density, loss of coastal wetlands, the costs of defending sheltered shorelines and property, the loss of beaches and recreational facilities, as well as the impact on the infrastructure of coastal cities(i.e., sewers, drinking water supplies, etc.) establish the coastal regions as the most vulnerable region to climate change. The last component of our research focuses on the impacts of atmospheric stressors -- such as UV-B -- on ecosystem health, including potential linkages to amphibian decline.
- We have concluded a long-term collaborative effort with the International Rice Research Institute on the effects of climate change (specifically, increases in levels of ultraviolet-B, or UV-B, radiation) on rice production. Our studies of rice grown under realistic field conditions showed that UV-B does not pose a major risk to crop yield.
- We developed a technique for determining thermal requirements for freshwater fishes and used this technique to demonstrate that redistribution of fish species may represent a major impact of climate change.
- As one of the major accomplishments of the entire U.S. Global Change Research Program, we showed, in collaboration with extramural scientists, that the net loss of carbon from the terrestrial biosphere during the late 1980s was close to zero, indicating that carbon losses due to deforestation must be offset by carbon accretion elsewhere.
- Our researchers in Corvallis, OR, examined the effects of elevated CO2 and temperature on Douglas fir trees, an important species of Pacific Northwest forests valued for its timber. Tree seedlings were grown in specialized growth chambers that contained the components of a forested ecosystem in miniature. It was found that elevated temperatures altered bud growth and reduced shoot growth, resulting in deformed, shorter trees.
