The US Global Change Research Program just released Volume II of the Fourth National Climate Assessment (NCA4-II). News stories on this report have focused on the report’s “dire” and “grim” predictions. Problem is, NCA4-II did not predict anything, except in the most general terms. What the report did was present “scenarios”, which it defines as “a set of assumptions used to help understand potential future conditions such as population growth, land use, and sea level rise. Scenarios are never predictions nor forecasts. Scenarios are commonly used for planning purposes.” (my emphasis). Note that the projected effects of climate change would be hugely different depending on which scenario one uses. For instance, compared to pre-industrial times, global sea level could rise anywhere from one foot to eight feet by 2100- depending on the scenario being used. Consistent with its purpose as a planning tool, NCA4-II focused most on a worst-case scenario (RCP8.5), the better to capture “a range of uncertainties and plausible futures but also [to provide] information about the potential benefits of mitigation.”
Ok - enough about nonexistent predictions. The remainder of this series will consist of brief excerpts from NCA4-II on existing or proposed adaptations to the effects of climate change. Without further ado…
Chapter 7: Ecosystems, Ecosystem Services, and Biodiversity
Climate-driven changes are most effectively managed through highly adaptive and proactive approaches that are continually refined to reflect emerging and anticipated impacts of climate change. Decision support tools, including scenario planning and structured decision-making, can help decision-makers explore broad scenarios of risk and develop actions that account for uncertainty, optimize trade-offs, and reflect institutional capacity.
Identifying and conserving climate change refugia (that is, areas relatively buffered from climate change that enable persistence) in ecological corridors can help species stay connected. For example, areas of particularly cold water have been identified in the Pacific Northwest that, if well-connected and protected from other stressors, could act as critical habitat for temperature-sensitive salmon and trout populations.
Federal agencies with responsibilities for natural resource management are increasingly considering climate change impacts in their management plans, and many have formulated climate-smart adaptation plans for future resource management… For example, USFWS [U.S. Fish and Wildlife Service] has considered climate change in listing decisions, biological opinions, and proposed alternative actions under the Endangered Species Act.
Understanding these realities, coastal cities such as Boston, New York City, Miami, San Francisco, New Orleans, and Los Angeles are beginning to make investments to adapt to SLR [Sea Level Rise]… From these efforts, and others like them, examples of successful adaptation planning are being collected to provide guidance to other communities facing similar challenges.
The city [Norfolk, VA] has begun to invest in mitigation and adaptation actions, but recent estimates indicate it will cost hundreds of millions of dollars to improve storm water pipes, flood walls, tide gates, and pumping stations. Natural and nature-based infrastructure projects such as the Colley Bay living shoreline have improved water quality, mitigated erosion, and restored habitats. Additional planned projects include constructing berms, reclaiming filled waterways and wetlands, and raising roads and structures.
Next: Chapter 9/Oceans and Marine Resources