Susan Schwartz, F5C president, wrote this outline for a walk on the King Tide day of Feb. 9, 2013. It is a work in progress. Please email comments, corrections, and suggested additions to f5creeks@aol.com.
What is global warming? Our globe’s mean surface temperature has increased about 1.4º F since the early 20th Century. About 2/3 of that rise came after 1980. Scientists broadly agree on three points:
· Earth’s rise in temperature is accelerating and will accelerate more in this century
· The main reason is increasing concentrations of greenhouse gases -- carbon dioxide, methane, nitrous oxide, and ozone, and water vapor. These gases trap escaping heat escaping and re-direct it back to Earth’s surface.
· The increase in greenhouse-gas concentrations is overwhelmingly due to human activity, mainly burning of carbon-based fuels -- wood, coal, oil, and natural gas.
What does global warming mean for the Bay area? For the Bay Area, global warming’s expected effects include the following:
· Longer and more extreme summer hot spells; temperatures averaging about 2.7ºF higher by 2050. No clear projection for rainfall.
· Rising wildfire frequency and cost, especially with greater growth in outlying areas.
· Uncertain water supplies due to lessened and earlier snowmelt.
· Changes in plant and animal communities, including loss of species.
· Changes to marine life due to weakening of the nutrient-rich coastal upwelling that nourishes coastal and Bay fisheries.
· Changes to marine life as ocean waters absorb more carbon dioxide and become more acidic. There already is evidence that coastal upwelling is bringing increasingly acidic water to the surface and into the Bay. The most obvious effect probably would be on shell-building creatures, from tiny animals basic to the food chain to mollusks such as oysters, mussels, clams, and snails. But fish and other creatures could be affected, e.g. by effects on blood oxygen or development.
Sea level rise may cause the most visible effects in the Bay Area
Here are some basic projections for the Bay, from two 2012 reports of scientific consensus, from the National Academies Board on Earth Sciences and Resources and a state-sponsored coalition of scientists from UC Berkeley, Stanford, and others.
· Worldwide and in the Bay, sea level rose about 7” during the 20th Century. That rate is increasing, mainly due to melting ice, but also because water expands as it warms.
· Sea level rise affects different areas in different ways, due to plate tectonics, rebound from melt of Ice Age glaciers, and long-term climate patterns. For the Bay Area, sea level rise from 2010 is projected at 2-12 inches by 2030 (with reasonable certainly), 5-24 inches by 2050, and 17-66 inches by 2100 (highly uncertain).
· Coastal cliffs and beaches are retreating due to storms and sea-level rise. This retreat could be more than 100 feet by 2100 (again, highly uncertain in both directions).
· Bay Area wetlands, such as tidal marshes, are likely to keep up with sea level until about 2050. After that, their survival will depend on high sedimentation, room to move inland, or uplift. Other research makes clear that San Francisco Bay’s coastal wetlands are threatened by lack of sediment. Human development, especially dams on the Sacramento and San Joaquin Rivers, has greatly reduced the Bay’s supply of replenishing mud and sand. Because most of the Bay is ringed by development, sea-level rise could mean that creatures that need marshes or mudflats have nowhere to go.
· Sea-level rise is not best thought of as water rising in a bathtub. Most damage is caused by storm tides: simultaneous high tides, storms, large waves, and heavy freshwater runoff. Sea-level rise increases these effects. Waves, for example, become more powerful as they move across longer stretches of deeper water.
" title="" href="">The King Tides project aims to make people aware of these changes and challenges by documenting them through photography. The goal is photographs taken during the highest winter tides, when conditions resemble what may be normal in future.
What can we do?
We will need to deal with sea-level rise with some mixture of all of the following:
· Slow climate change by reducing emissions of greenhouse gases: We can do this generating energy with sun, wind, tides, or other methods that burn less or no greenhouse gas; using forms of transportation that emit less greenhouse gas; building cities more compactly; improving energy efficiency of buildings, industry, and farming; reducing various kinds of waste; and increasing carbon storage (sequestration). Many on-line carbon calculators will help you calculate your own global-warming footprint and how to reduce it. But significant effects require collective and political action.
· Harden and build higher and drier: Build, raise, or strengthen levees. Build dams, gates, or locks to control tidal flows. Strengthen bridges, docks, and seawalls against higher waves and storm surge. Strengthen and protect tunnels and pipes that are below high-tide levels. Elevate bulding pads or other surfaces. This will cost billions of dollars and require unprecedented planning and cooperation.
· Accommodate: Build floating buildings, docks, and bridges. Build to accommodate floods, from building on piers to using ponds and permeable surfaces to manage floodwaters. Accept that some roads, parks, etc. will be temporarily inaccessible.
Looking to the natural world, maintain and increase tidal marshes and “living shorelines” that can absorb waves and storm surges. (The latest research from the National Oceanic and Atmospheric Administration, NOAA, shows that coastal wetlands, such as salt marshes, also can capture and store 2-5 times as much carbon than tropical forests.). Provide corridors so that plants and animals can move to areas where they can survive, or move them deliberately. These efforts can ease but not solve the problem.
· Move: Move houses, roads, and critical infrastructure such as pipelines, railroads, and airports away from the Bay shore, low-lying areas subject to flood, and areas that have subsided below sea level (mainly parts of the South Bay and large areas in the Delta). History suggests that this is difficult to achieve.
More information and Bay Area efforts
Most of the information in this outline came from two 2012 reports synthesizing recent research:Scientific consensus from the National Academies Board on Earth Sciences and Resources and Climate Chance Impacts, Vulnerabilities, and Adaptation in the San Francisco Bay Area, a synthesis put together by scientists from UC Berkeley, Stanford, and others, sponsored by the California Energy Commission, part of the state Natural Resources Agency.
The California Landscape Conservation Cooperative, basically conservation groups working with government agencies and researchers, hosts Climate Commons. This web site has links to datasets, research articles, and web resources. Many and varied collaborative research efforts are listed on the web site of the closely affiliated Bay Area Ecosystems Climate Change Consortium. These two groups hosted a November, 2012, meeting on “climate-smart” actions for managers of natural areas. Proceedings are here.
San Francisco Estuary Project includes a wide variety of short, easy-to-read, and informative articles in its January 31 newsletter.
Turning to local efforts, all cities are required to put together climate-action plans, which when complete should be updated regularly. Check with the clerk of your city or its Sustainability Committee or Commission for information on status. In many cities, these efforts are carried on in partnership with nonprofits. Berkeley, for example, works with the Climate Action Coalition, put together by the Ecology Center. Transition Albany is very active in Albany.
Almost all environmental nonprofits are active in some way in climate change. Check with local chapters of the Sierra Club, Audubon Society, and various transportation-related groups, as well as local chapters of the League of Women Voters. Kyoto USA, based in Berkeley, works particularly with schools to encourage installation of solar power. The Bay Area's Greenbelt Alliance works to encourage dense building and discourage sprawl, a critical element in controlling greenhouse-gas emissions.
Regionally, Adapting to Rising Tides (ART), a partnership formed in 2010 between the San Francisco Bay Conservation and Development Commission (BCDC) and the National Oceanic and Atmospheric Administration (NOAA), is trying to assess how sea-level rise is likely to affect Bay Area coastal areas. Its ongoing pilot project is assessing likely effects of sea-level rise, and what can be done to lessen them, along the East Bay shore between Emeryville and Union City.
The broader, newer Bay Area Climate & Energy Resilience Project (Resilience Project),is led by the “big four” in regional planning: BCDC plus Association of Bay Area Governments (ABAG), Metropolitan Transportation Commission) (MTC), Bay Area Air Quality Management District (BAAQMC). The aim is to induce the Bay Area’s myriad stakeholders – cities, counties, special districts, utlities, nonprofits, more than 100 public, private, and nonprofit entities to collaborate in responding to climate change. Look for reports beginning this year.
The big four resolved late in 2012 to develop Regional Sea Level Rise Adaptation Strategy, perhaps over 10 years and costing some $20 million – plus decades and billions of dollars to carry it out. implement it. A first step would expand the ART project, above, to other parts of the Bay.
Several other initiatives are seeking cooperative solutions for more local areas, e.g. for the Hayward Shoreline, the North Bay, and Corte Madera Creek in Marin. Many of these are listed here.
National, state, and regional parks as well as conservation agencies are increasingly incorporating sea-level rise into planning for coastal projects. Examples range from Redwood Creek on the Pacific to Breuner Marsh in Richmond.
Sea-level rise is inching into permitting decisions. BCDC now requires consideration of sea-level rise for permits for development in the narrow coastal strip where it has authority. The state-required 25-year transportation plan for the Bay Area is set to require that climate change effects, including sea-level rise, be considered in land-use and transportation decisions.
A variety of projects, ongoing and new, seek to use sediment dredged from Bay ports and elsewhere to restore wetlands. These include the North Bay Hamilton Field and Bel Marin Keyes restorations and three creek restoration projects envisioned in Flood Control 2.0,