Understanding Multiple Environmental Stresses Report of a Workshop (2007) / Chapter Skim
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3 Atmosphere-Ecosystem Interactions
3 Atmosphere-Ecosystem Interactions
Pages 27-35
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From page 27... ...
of climate forcing from coal combustion identified key components in anthropogenic warming, and in the 19th century the claim that rain follows the plow was a powerful inducement for agricultural expansion in the western United States. Following the introduction of climate models, insights on bidirectional coupling began to emerge.
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From page 28... ...
. Also around this time a series of breakthroughs established the role of chemicals released from plants and from human processes in modulating the chemistry of the atmosphere (ozone hole, biogenic volatile organic components)
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From page 29... ...
Other important examples of threshold come from the response of temperate forest ecosystems to warming or the deposition of atmospheric nitrogen. In controlled ecosystem experiments nitrogen inputs produce little change over several years, but the nitrogen excess eventually reaches a point where the system collapses.1 In response to warming the initial response is a large increase in soil warming, followed by a sudden decline when the ecosystem runs out of easily decomposable material.2 Some of the important thresholds in earth system responses can operate in more than one direction.
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From page 30... ...
Modeling experiments show that carbon sink strengths vary with the rate of fossil fuel emissions, so carbon storage capacities of both land and oceans decrease and climate warming increases with faster emissions (Fung et al., 2005)
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From page 31... ...
While these are clearly simplifications, research teams simply did not have the breadth of expertise or the technical tools to tackle truly integrated approaches. A few teams have recently made bold attempts to integrate human actions and the natural sciences in an interactive framework.
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From page 32... ...
Several kinds of human factors can exaggerate vulnerability to the impacts modulated by atmosphere-ecosystem interactions. Poverty, lack of control over one's destiny, and an extremely unequal distribution of wealth all tend to decrease coping capacity, increase vulnerability, degrade ecosystem services, and increase the challenge of finding effective paths toward solutions.13 In contrast, human factors that stimulate technical innovation, distribute control, and encourage local decision making can decrease vulnerability while increasing ecosystem services.14 Atmosphere-ecosystem interactions introduce potentially important uncertainties into a large suite of future global changes.
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From page 33... ...
. Also, nitrogen fertilization leading to nitrogen saturation of terrestrial ecosystems results in the loss of nutrient cations, causing reduced productivity locally and eutrophication of aquatic systems downstream (Vitousek et al., 1997)
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From page 34... ...
For investigators not equipped to tackle the coupled system, collaborations are an essential tool, though interdisciplinary collaborations are often difficult and complex. Because some of the interactions unfold only on long timescales or large spatial scales, we need experimental, observational, and simulation techniques to explore the range of possibilities.
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From page 35... ...
What kinds of information are most useful to decision makers, resource managers, and others who could benefit? • How can we develop improved tools and strategies for addressing multiple environmental stresses, such as improved observational and modeling capabilities, integrated sensors, regional information systems, and predictive capabilities?
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