January 26, 2010
Managing Ecosystems During Periods of Climate Change
Ecologists outline necessary actions for mitigating and adapting to a changing climate
Global warming may impair the ability of ecosystems to perform vital services -- such as providing food, clean water and carbon sequestration -- says the nation's largest organization of ecological scientists. In a statement released today, the Ecological Society of America (ESA) outlines strategies that focus on restoring and maintaining natural ecosystem functions to mitigate and adapt to climate change."Decision-makers cannot overlook the critical services ecosystems provide," says ESA President Mary Power. "If we are going to reduce the possibility of irreversible damage to the environment under climate change, we need to take swift but measured action to protect and manage our ecosystems."
ESA recommends four approaches to limiting adverse effects of climate change through ecosystem management:
Prioritize low-alteration strategies. Many ecosystems sequester a sizable amount of carbon -- simply allowing them to function naturally can significantly help mitigation efforts. Deforestation, for example, has a two-fold impact: removing agents of carbon sequestration -- trees in this instance -- while simultaneously releasing stored carbon. Therefore, preserving forests is a straightforward way to both reduce and offset emissions.
Critically evaluate management-intensive strategies. Management strategies that seek to increase carbon sequestration above natural levels should undergo thorough life-cycle analysis and evaluation prior to implementation. For example, increasing carbon uptake on agricultural lands -- one approach to enhancing the sequestration potential of ecosystems -- typically requires more fertilizer than standard processes; the tradeoff, therefore, is higher emissions and pollution associated with fertilizer production.
Acknowledge the ecological implications of geoengineering. Understand the potential risks associated with engineering the environment, called geoengineering, and the unintended negative impacts that could emerge from long-term or widespread use. For example, injecting sulfur particles into the atmosphere to reflect solar rays would have a cooling effect but could also increase acid rain and destabilize weather patterns.
Address long-term risks. Assess the far-reaching consequences of ecosystem alterations. Monitor carbon stores sequestered under given management practices and develop or apply models to forecast ecosystem responses several decades into the future.
In addition to mitigating climate change, steps should be taken to prepare ecosystems to withstand climate change impacts. Human activity has impaired the natural resilience of many ecosystems. ESA outlines four adaptation strategies to safeguard ecosystem services in the face of climate change:
Take additional steps to protect water quality and quantity. Freshwater resources are at particular risk from the interaction of climate change and intensification of human use. Rising temperatures have already lowered river flows, warmed surface waters and dried out wetlands. Sustaining freshwater resources is critical to both environmental and public health.
Enable natural species migration across human dominated landscapes. Create and maintain wildlife corridors across jurisdictions and private lands to help species relocate and adapt as habitats shift with climate change. Steps should be taken to restore the ability of native species to migrate across landscapes severely fragmented by human land use.
Improve capacity to predict extreme events. Monitoring and modeling natural disturbance and recovery processes at regional scales will help state and federal agencies understand and respond to novel rates and intensities of environmental change.
Manage collaboratively at the ecosystem level. Many natural resources and services, such as fresh water, clean air and crop pollination, are not contained within jurisdictional boundaries; resource management should reflect this and operate at the ecosystem level.
"Even conservative warming projections show that natural systems will experience unprecedented stresses, including shifting habitats and ecological processes and more frequent and severe natural disturbances, such as fires, floods and droughts," ESA says in the statement. "These unavoidable changes will require management that addresses ecological thresholds, tipping points and other sources of uncertainty."
According to the Intergovernmental Panel on Climate Change, global temperatures could rise 1-6 degrees C by the end of the 21st Century.
"The sooner such strategies are deployed, the more effective they will be in mitigating the extent of change and helping us to adapt to inevitable changes." ESA says in its statement.
The Ecological Society of America's statement is available at http://www.esa.org/pao/policyStatements/pdfDocuments/Ecosystem%20Management%20in%20a%20Changing%20Climate.pdf in a Changing Climate.pdf.
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