NATURAL RESOURCES AND THE ENVIRONMENT
Climate Change Reports Urge Prompt Action
Building on decades of climate change science, the National Research Council completed its most comprehensive review of the subject to date, a congressionally requested suite of studies known as America's Climate Choices. Four panel reports declare that climate change is occurring and that the United States should act now to reduce greenhouse gas emissions, develop a national strategy to adapt to the inevitable impacts of climate change, and coordinate reliable information systems to guide decision making.
Climate change is caused largely by human activities and poses significant risks for a broad range of human and natural systems, says Advancing the Science of Climate Change. A new, interdisciplinary era of climate change science is needed, emphasizing "fundamental, use-inspired" research that improves understanding of climate change and the actions needed to respond.
The United States should establish a greenhouse gas emissions "budget" that sets a limit on total domestic emissions over a fixed period of time, says Limiting the Magnitude of Future Climate Change, and pursue a major departure from business as usual in how we produce and use energy. A comprehensive carbon-pricing system, together with a collection of strategically targeted complementary policies such as regulations and incentives, is the most cost-effective way to proceed. The report warns, however, that the longer the nation waits to begin reducing emissions, the harder and more expensive it will likely be to reach any given emissions target.
While limiting emissions can lessen future climate change impacts, some are already being observed -- such as rising sea levels, disappearing sea ice, and increasingly extreme weather events -- and others in the future may be unavoidable, says Adapting to the Impacts of Climate Change. Adaptation to climate change calls for a new paradigm -- one that identifies risk reduction measures for a range of possible future climate conditions and associated impacts, some outside the realm of past experience. Boosting U.S. adaptive capacity now can be viewed as "an insurance policy against an uncertain future," while inaction could increase the risks. Although much of the response to climate change will occur at local and regional levels, a national strategy and federal resources are needed to support adaptation and facilitate coordination across all levels of government and the private sector.
To help guide decision makers on how they should limit and adapt to climate change, the federal government needs to establish reliable and timely information and reporting systems, such as climate services and a greenhouse gas accounting system, says Informing an Effective Response to Climate Change. It also recommends mechanisms for improving communication and education about climate science and response options and calls for a systematic and iterative framework that allows for ongoing evaluation of responses to climate risks.
The America's Climate Choices project was funded by the National Oceanic and Atmospheric Administration.
Easing Ecosystem Damage in California Bay-Delta
A system of pumping stations that diverts fresh water from the California Bay-Delta region has met the state's diverse water needs for decades. It has also affected the Bay-Delta ecosystem, and declines of several species of fish are of particular concern.
In response to proposed changes in water system operations, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service issued biological opinions under the Endangered Species Act requiring restrictions on diverting water during certain periods, depending on environmental conditions. The agencies' proposed actions are intended to reduce adverse effects on delta smelt, Chinook salmon, Central Valley steelhead, and green sturgeon.
A Scientific Assessment of Alternatives for Reducing Water Management Effects on Threatened and Endangered Fishes in California's Bay-Delta, the first of at least two reports addressing sustainable water supplies and the environment in California, says that most of these proposed actions are scientifically justified, but the choice of some specific environmental conditions to trigger reductions in water diversions is not well-supported by scientific analyses. The report's recommendations include careful monitoring of the proposed actions, adaptive management, and additional analyses.
The Research Council study is being funded by the U.S. Department of the Interior's Fish and Wildlife Service.
Everglades Restoration Advances Slowly
The Florida Everglades was once a diverse aquatic ecosystem covering millions of acres. But agricultural and urban development have dramatically reduced and altered its landscapes. In 2000 the Comprehensive Everglades Restoration Plan (CERP) was initiated, a multidecadal federal and state effort to reverse the ecosystem's decline while continuing to meet growing demands for clean water and flood control.
CERP has made tangible albeit slow progress toward its goals, including improvements in the pace of restoration and in the relationship between the federal and state partners over the last two years, says Progress Toward Restoring the Everglades: The Third Biennial Review, 2010. Although important scientific advances have been made, continued decline of some aspects of the ecosystem, such as water quality and endangered bird populations, makes more rapid improvements critical.
Attaining water quality goals throughout the system is likely to be very costly and take several decades of continued commitment, the report says. To help officials decide on future restoration priorities, the report calls for rigorous analysis of potential trade-offs -- including water quality versus quantity -- from a whole ecosystem perspective. Additionally, a comprehensive cost-effectiveness analysis should be conducted to optimize water quality outcomes given state and federal financial constraints.
The Research Council study was funded by the U.S. Army Corps of Engineers, South Florida Water Management District, and U.S. Department of the Interior.
Sediment Management in the Missouri River
A network of dams and other control structures built along the Missouri River has successfully controlled flooding, provided water, and supported commercial navigation for many years. However, the projects have also significantly reduced the amount of sediment traveling toward the Mississippi River and the Gulf of Mexico and contributed to the decline of certain fish and bird species.
To address these issues, the U.S. Army Corps of Engineers has for the past 10 years been restoring sandbar and shallow water habitats along the lower river. Some have voiced concerns that sediments being discharged at these sites carry levels of contaminants that are degrading water quality and increasing the size of the oxygen-depleted dead zone in the Gulf.
Missouri River Planning: Recognizing and Incorporating Sediment Management finds the Corps' projects to restore habitats along the river will not significantly change the size of the Gulf's dead zone, nor will options for reintroducing sediment be able to substantially re-establish historic levels of sediment transported downstream to the Louisiana delta. To improve decisions and better manage the river's sediment and related resources, the report calls for more organized and systematic procedures to gather and evaluate Missouri River sediment data. The Corps and the U.S. Geological Survey should develop a "sediment budget" for the river that could be revised and updated as new data become available.
This Research Council study was funded by the U.S. Army Corps of Engineers.
Linking Emissions Levels to Climate Impacts
Carbon dioxide in the Earth's atmosphere is now at its highest level in 800,000 years. Depending on emission rates, this level could double or nearly triple by the end of the century. Choices made now about reducing carbon dioxide emissions will affect climate change impacts experienced not just over the next few decades but also over the coming centuries and millennia, says Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia.
Policy choices can be informed by recent advances in climate research that quantify the relationships between atmospheric CO2 and warming levels, and between warming levels and future impacts, the report says. It estimates changes in precipitation, streamflow, wildfires, crop yields, and sea-level rise that can be expected with different degrees of warming. For each degree Celsius (or 1.8 degrees Fahrenheit) of global warming, for example, there could be 5 percent to 10 percent less total rain in the U.S. southwest and 5 percent to 15 percent lower yields of some crops, including U.S. and African corn and Indian wheat.
The report also estimates the average temperature increases that would be likely if CO2 were stabilized in the atmosphere at various target levels. It does not recommend any particular stabilization target, noting that choosing among different targets is a policy decision rather than strictly a scientific one.
The Research Council study was funded by the Energy Foundation and the U.S. Environmental Protection Agency.
Acidification of the Ocean
The ocean helps regulate climate by absorbing, storing, and releasing heat and moisture. Excess carbon dioxide in the atmosphere -- a major contributor to climate change -- is also absorbed by the ocean, making sea water more acidic. The resulting acidification may have serious consequences for sea life, many fear.
Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean concludes that man-made carbon dioxide emissions are changing ocean chemistry at an unprecedented rate. Even if there were to be no further emissions, the ocean will continue to absorb excess carbon dioxide currently in the atmosphere. To date, carbon dioxide emissions from fossil fuels and changes in land use have increased ocean acidity by 30 percent.
The long-term effects of ocean acidification on marine ecosystems are uncertain, but scientists expect that many types of marine life will be affected, the report notes. These organisms include reef-building corals, commercially important mollusks such as oysters and mussels, and several types of plankton at the base of marine food webs.
The federal National Ocean Acidification Program currently in development is a positive move toward coordinating efforts to understand and respond to the problem. The report calls for international collaboration on a global monitoring network for ocean chemical and biological observations as well.
The Research Council study was funded by the National Oceanic and Atmospheric Administration, NASA, the U.S. Geological Survey, and the National Science Foundation.
