Global Warming Basics for the Bay Area

What is global warming?

When we burn wood, coal, oil, and gas, we release carbon dioxide (CO2). The increased CO2 forms a heat-trapping blanket around the earth. 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. Earth’s mean surface temperature has risen about 1.5º F in the last 130 years. About 2/3 of that increase came after 1980. The twelve warmest years on records have occurred since 1998.  Every year of the past 38 years has been warmer than the 20th century average.
  • The main reason is increasing concentrations of greenhouse gases -- carbon dioxide, methane, nitrous oxide, and ozone, and water vapor. These gases trap escaping heat and re-direct it back to Earth’s surface. CO2  levels today are about 25% higher than in 1957. They are higher than at any time since out ancestors began migrating out of Africa. They are now at 400 parts per million (ppm), and rising about 2 ppm each year.
  • 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:

  • Longer and more extreme summer hot spells; temperatures averaging about 2.7ºF higher by 2050. (There is no clear projection for rainfall.)
  • Rising wildfire frequency and cost, especially with growth in outlying areas.
  • Uncertain water supplies due to earlier and lessened snowmelt.
  • Changed plant and animal communities, including loss of species.
  • Changed marine life as (a) ocean waters absorb more carbon dioxide and become more acidic and (b) there are changes in upwelling of cold, nutrient-rich ocean water offshore.
  • Sea level rise may cause the most visible effects in the Bay Area!
What are the likely effects of sea-level rise in the Bay area?

Online interactive maps show details of how different amounts of warming and sea-level rise are likely to affect local areas. These all have limitations. Our Coast Our Future has a detailed set means for planners and land managers, showing how different levels of rise, and different storm and tide conditions, are likely to affect local communities. Maps from the National Oceanic and Atmospheric Agency also are carefully documented and detailed. The nonprofit Climate Central has simpler maps estimating "risk zones" and effects for different amounts of warming.

  • Worldwide, sea level rose about 7” in the 20th Century. The rate is increasing, mainly due to melting ice, but also because water expands as it warms. From 2010 levels, the Bay Area rise is projected at 2-12 inches by 2030, 5-24 inches by 2050, and 17-66 inches by 2100. Recent estimates tend toward the high end!
  • Most damage is be 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.
  • Coastal cliffs and beaches are retreating due to storms and rising seas. This retreat could be more than 100 feet by 2100 (highly uncertain).
  • 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 abundant sediments or room to move inland. But human development, especially dams, has greatly reduced replenishment of mud and sand. Because most of the Bay is ringed by development, marshes are unlikely to move inland. Wetland and marsh wildlife may have nowhere to go.
What we can do – and some challenges to doing it 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 in many ways: Generate energy with sun, wind, tides, or other methods that produce little or no greenhouse gases. Use transportation that emits less greenhouse gas. Build cities more compactly. Improve energy efficiency of buildings, industry, and farming. Reduce various kinds of waste. Increase 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 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 building 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.
  • Maintain and increase tidal marshes and “living shorelines” that can absorb waves and surges. (Coastal wetlands, such as salt marshes, also can capture and store 2-5 times as much carbon as 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 people are reluctant to relocate in this way.

What can you as an individual do?
  • Support candidates, laws, and policies that deal realistically with global warming. Climate action plans are required in all cities. Check with your city’s clerk or Sustainability Committee/Commission for information on what your city is doing and how you can help.
  • Support and volunteer with nonprofits working on climate initiatives. A beginning list of ideas is here
  • Reduce your carbon footprint. You can use a carbon-footprint calculator, like these from the  US EPA or UC Berkeley, to estimate your personal or family greenhouse-gas emissions and how you can reduce them (plus how much money you can save.) 
More information

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 the California Climate Commons. This web site has links to data, 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

Cal Adapt offers information on how climate change is likely to affect specific areas of California, as well as information and links to research.

What the Bay Area is doing 

Turning to local efforts, all cities are required to put together climate-action plans. Check with the clerk of your city or its Sustainability Committee or Commission for information on what your city is doing and how you can help. 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. 

The Bay Area Climate & Energy Resilience Project (Resilience Project),is led by the “big four” in regional planning: the Bay Conservation and Development Commission (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. 

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.