Changes in ecosystem biogeochemical processes (including GHG emissions) and biodiversity (including changes in reflectance characteristics) have the potential to exacerbate or offset certain aspects of climate change (i.e., act as feedbacks). Models and experiments that integrate knowledge about ecosystem processes, plant physiol-
Ocean ecosystems face growing threats globally from overfishing, habitat damage, pollution, and especially acidification (Halpern et al., 2008). As a result, the persistence of several marine species is at risk, and ecosystem services provided by intact coastal ecosystems could be compromised. Compared to the land, a minute fraction of the sea is set aside for protection. In response to growing threats, a number of nations, including the United States, are establishing networks of new marine protected areas (MPAs) with special protections (Airame et al., 2003; Fernandes et al., 2005). In the United States, the largest network of MPAs is being established along the coast of California, where dozens of new protected areas are currently being designed and implemented.
Although MPAs can be dramatically successful at restoring depleted ocean ecosystems (Lester et al., 2009), many questions remain:
• Will the effectiveness of MPAs be compromised by climate change, ocean acidification and/or the migration of marine species outside the boundaries of protected areas?
• MPA network design is based on where species occur today, not where they will be driven by future climate shifts—will the expected conservation gains from MPA networks go unrealized as the seascape shifts?
• Alternatively, could large networks of MPAs along entire coastlines provide protected havens to aid species driven poleward by shifting climate?
• Does uncertainty about future climate change increase the need for MPAs as a hedging strategy?
ogy, vegetation dynamics, and disturbances such as fire need to be further developed and included in advanced Earth systems models.
Assess the potential of land and ocean ecosystems to limit or buffer impacts of climate change. How can specific land uses (including managed and unmanaged forests and grasslands, agricultural systems, fisheries, urban systems, and aquatic systems) be managed for provisioning services as well as for their effects on GHG emissions, carbon storage, reflectivity, and evapotranspiration? What ecosystem management strategies can provide co-benefits that meet multiple goals, including carbon storage, biodiversity conservation, and watershed protection? To address these questions, new tools and approaches need to be developed for evaluating different land and ocean uses for their potential in helping to limit the magnitude of climate change. Such research needs to address the trade-offs between alternative land management options, including economic costs and impacts on ecosystem services that are difficult to quantify in economic terms. The efficiency and efficacy of overlapping systems of governance and management structures to address trade-offs and determine management strategies is also a critical area of research.
Assess vulnerabilities of ecosystems and the benefits society derives from them to climate change. Ecosystems on land and in the ocean, and the services they provide, are key components of the maintenance of environmental functions and human well-being. Climate change affects this maintenance, with potentially significant societal consequences. Identifying critical linkages and feedbacks among changing ecosystems, their services, and human outcomes (e.g., crop yields, water supply) is essential. To do this requires analytical frameworks and methods for assessing vulnerability of coupled human-environment systems, and the ability of the social and environmental components of such systems to adapt to change. Complicating these assessments is the need to address climate change in the context of other changes, such as land use, acid rain, and nitrogen deposition.
Improve observations and modeling. There is a great need for global-scale, long-term, and continuous observations of land and ocean ecosystems and ongoing changes within them. Such observations will enable measures of ecological processes at relatively fine spatial and temporal scales, which are needed both to provide critical inputs to Earth system models and to track gradual and abrupt change in Earth system processes. The development of indicators of ecosystem health and ecosystem vulnerability is also needed as part of an early warning system (see NRC, 2009i). As mentioned earlier, new Earth system models that address multiple drivers and feedbacks from climate-ecosystem interactions are needed, and they will be most effective if linked to climate models that function at regional scales.
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