Global Climate Change
Adapting the Army Corps of Engineers' mission
In 2007, the United Nations’ Intergovernmental Panel on Climate Change reported: “Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases.” It was a simple statement, validating the concerns of American scientists, the public, and policymakers about the future of the nation’s natural and man-made systems.
The fact that the Earth is getting warmer raises two questions for the U.S. Army Corps of Engineers (USACE) and its partners in the federal government: How will climate change affect our systems? And what are we going to do about it?
The federal government’s U.S. Global Change Research Program (USGCRP), begun as a presidential initiative in 1989, represents the world’s largest investment in global climate change research. The Department of Defense (DoD) is one of USGCRP’s 13 member departments and agencies. USACE, with its civil works and military construction missions, has been involved in the study of climate change longer than most people have been discussing it: In the early 1950s, as the Army began to study the suitability of Greenland’s ice sheet as a foundation for the Cold War’s distant early warning radar stations, scientists with the precursors to the USACE Cold Regions Research and Engineering Laboratory (CRREL) helped to perfect many of the ice drilling techniques that supported early climate science.
USACE also – as one of the four agencies in the federal Climate Change and Water Working Group (CCAWWG), formed in 2008 – helped to produce the document that anchors the government’s effort to anticipate and adapt to climate change in the management of its water resources – “Climate Change and Water Resources Management: A Federal Perspective.” That document, released in 2009, identifies ongoing changes that have the potential to affect the nation’s water resources and infrastructure. Temperature increases are generally expected to result in more rain and less snow. Some areas will receive more precipitation, while some will receive less. And sea-level changes, both at the mean and at the extreme high, will increase shoreline erosion and change salinity in coastal and estuarine environments where land is also subsiding.
These changes have the potential to alter several aspects of the nation’s water resources, including:
- the nationwide availability, demand, and quality of water;
- infrastructure for stormwater, wastewater, and flood and storm protection;
- wildland fire intensity and frequency;
- ecosystem and coastal zone function; and
- energy production and demand.
Together and separately, these potential changes have profound implications for USACE’s civil works and military support missions.
Water Resources Management: A Holistic Approach
In 2009, President Barack Obama convened the Interagency Climate Change Adaptation Task Force and issued Executive Order 13514, requiring federal agencies, among other things, to identify climate change adaptation strategies in conjunction with this task force.
Adapting the way USACE plans and implements its civil works mission with climate change is a complicated task, with multiple variables. Water resources planning involves assumptions about future hydro-climatic conditions – temperature, precipitation, and river flows – but these are only part of the equation. People are involved, too: Over time, water resource locations experience changes in population size and distribution; land use and economic decisions; aging infrastructure; ground-water development; and social values. This complex web of variables is discussed and analyzed in the CCAWWG’s “Addressing Climate Change in Long-Term Water Resources Planning and Management: User Needs for Improving Tools and Information” document, released by USACE and the Department of the Interior in January 2011.
Devising a policy that embraced all these variables meant that USACE – which released its first sea-level change policy in 1987 – would have to combine many elements of its civil works mission. When Jo-Ellen Darcy, assistant secretary of the Army for Civil Works, submitted the “USACE Climate Change Adaptation Plan and Report 2011” to the White House in June 2011, she called for integrating climate change adaptation into all that the organization does, based on the best available – and actionable – science. Furthermore, she directed USACE to consider climate change impacts when undertaking long-term planning and decision-making.
“Actionable” is a key word. Climate change science is a new field, relatively speaking, and according to Kathleen White, Ph.D., senior lead for global and climate change at the USACE Institute for Water Resources (IWR), USACE isn’t about to break out the heavy equipment right away. “We need to develop policy and guidance before we can actually put a shovel in the ground and implement,” she said. Before USACE modifies a coastal project, for example, it needs an actionable model of sea-level change in that facility’s specific location.
With USACE leadership, actionable science is getting closer to reality. USACE has worked together with other agencies to address practical alternatives for “nonstationary” hydrology, for example. While current science is based on older hydrologic models that assume the frequency of hydrologic events to be unchanging, or stationary, over time, nonstationary hydrology takes into account the new reality introduced by global climate change. In a nonstationary world, future availability, quality, and demand for water will vary regionally and could be much different than in the past.
The nation’s water resources affect everyone, and USACE plans cannot be developed in a vacuum, warned White. Policies and plans need to be developed in concert with other agencies to achieve a nationwide approach. In addition to its partners in the CCAWWG – the Department of the Interior Bureau of Reclamation and the U.S. Geological Survey, the National Oceanic and Atmospheric Administration, the Federal Emergency Management Agency, and the Environmental Protection Agency (EPA) – USACE works with other federal partners, including the National Aeronautics and Space Administration (NASA) and the Department of Energy (DoE) on the science that will underpin the way the nation’s water resources are managed.