Climate Disruption & Adaptation

Climate Disruption & Adaptation

Greenhouse Gas Emissions  Temperature  Sea Level Rise and Flooding Projections

Sustainability Goals

Greenhouse gas (GHG) emissions are reduced to a level that is in balance with nature’s ability to absorb them. Mileage standards for automobiles continue to rise, and multi-modal transportation options reduce total vehicle miles of travel. Energy is produced from renewable and greenhouse gas-neutral sources and is used efficiently. New buildings are constructed to the highest green standards, and older buildings are retrofitted to ensure efficient energy use. While working to mitigate GHG emissions, communities simultaneously implement adaptation measures, such as building levees or restricting development in floodplain areas.

Greenhouse Gas Emissions

California’s Global Warming Solutions Act, AB32, requires the state to reduce GHG emissions to 1990 levels by 2020 and then reach an 80% reduction from 1990 levels by 2050. Recent passage of SB32 added an interim goal requiring reducing carbon emissions to 40 percent below 1990 levels by 2030. Local governments and businesses will play a key role in meeting these goals.

ssmc_2016_juneupdate_LOW Greenhouse Gas Emissions, San Mateo County, 2013 ssmc_2016_marchupdate-01 California Greenhouse Gas Emissions, 2013
  • Emissions in most sectors have gone down since 2000. Sectors that have seen an increase in GHG emissions are Commercial, Residential, and Agriculture.
  • In 2013, total GHG emissions decreased by 1.5 million metric tons of CO2 equivalents (MMTCO2e) compared to 2012.
  • Annual per capita GHG emissions in California have continued to drop from a peak in 2001 of 14.0 metric tons per person to 12.0 metric tons per person in 2013; a 14% decrease.
  • The transportation sector is the largest source of GHG emissions in California, responsible for over three times the emissions of electricity generation.
  • Note: the above chart measures include emissions only and does not include “Excluded” or “Biogenic emissions”. To see the complete inventory of CA emissions, click here.

Climate Action Plans

Local governments have a key role in helping the state meet its greenhouse gas (GHG) emissions reductions targets for AB32. Adopting a Climate Action Plan (CAP) is the first step. Cities are encouraged to start by creating a baseline inventory of municipal and community GHG emissions and then to identify target reductions. Emissions reductions strategies unique to the community are then evaluated, and after public meetings and an environmental review process, the most promising strategies are put into the CAP and/or General Plan. As of May 2016, 71% of cities/unincorporated county had a completed CAP (Brisbrane, Burlingame, Colma, Daly City, East Palo Alto, Foster City, Hillsborough, Menlo Park, Pacifica, Redwood City, San Carlos, City of San Mateo, County of San Mateo, South San Francisco, and Woodside), and 29% were in the process of completing one (Atherton, Belmont, Millbrae, Portola Valley, and San Bruno).

The National Climate Assessment, released in May 2014, paints a sobering picture of the impacts of climate change in the U.S. According to the Report, climate change is not distant issue but is something being felt now, with varying effects throughout the country. In California and the Southwestern United States the main threats are:

  • Reduced snowpack and stream flows which will lead to decreased water supply for cities, agriculture, and ecosystems.
  • Declining agriculture yields resulting from increased temperatures and droughts.
  • Increased and more severe wildfires due to rising temperatures, droughts, and insect outbreaks.
  • Sea level rise for coastal communities.

Climate change, once considered an issue for a distant future, has moved firmly into the present.” -2014 National Climate Change Assessment Report

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Global weather measurements indicate that 2016 was the hottest year on record, while 2015 was the second hottest year. This gradual warming trend was recorded in several locations in San Mateo County. Earth’s average temperature has increased 1.4º Fahrenheit over the last century and is projected to rise another 2–11º over the next 100 years if we do not curb emissions.

Updated June 2017 Average Annual Temperature San Mateo County, 2006-2016

The increase in average temperature is a measureable indication of climate change with serious impacts:

  • Causes changes in weather patterns and increases the intensity and likelihood of storms.
  • Contributes to drought and wildfires.
  • Stimulates insect outbreaks.
  • Causes precipitation to fall as rain rather than snow, compromising the Sierra snow pack, the state’s largest water storage system.
  • Complicates indoor temperature regulation, which requires more power generation for cooling.

Climate is a major factor in agricultural crop production. Plant growth is determined by atmospheric temperature, humidity, moisture, and nutrients (carbon, nitrogen, etc.). Crops are selected for compatibility with the local climate, and fluctuations may require a shift in production if temperatures change. Shown below are examples of how climate affects agriculture, drought, and other resources.

  • Increased heat compromises the health of farmworkers and others who work outdoors.
  • Though a slight temperature increase will result in higher crop output, a change beyond 3 degrees Celsius will decrease production (TIMM, 2015).
  • Higher temperatures extend growing seasons, which increases the demand for water to maintain crops. Competition for water resources will heighten demand for energy, while hydropower generation will become less reliable (CalCAN, 2015).
  • Chill time is another climate factor affected by temperature. Minimum hours of chill are needed for apples, cherries, grapes, pears, nuts, avocados, stone fruit, tomatoes, rice, corn, sunflower, and wheat.
  • Higher concentrations of atmospheric carbon dioxide stimulate crop growth, as well as weeds, and pests. Warmer weather may cause weeds and pests to migrate north. To combat these threats, growers may increase their use of herbicides and pesticides resulting in air and water pollution.
  • Heavy rainfall is another potential side effect of climate change that may damage crops and cause soil erosion.
  • Climate change poses threats to pollinators as flowers may bloom at different times of the season out of sync with pollinator’s migration patterns.

Sea Level Rise and Flooding Projections

The impacts of climate change—altered rainfall patterns, rising sea levels, and more extreme weather events—can already be observed, and Bay lands and coastal areas in San Mateo County are vulnerable to these threats.

Updated June 2017 Average Sea Level Redwood City and San Francisco, 1986-2016

Sea level rise is the result of thermal expansion (water temperature increase) and the melting of vast bodies of ice. These phenomena, as well as high intensity storms, are a result of climate change. The combination of sea level rise, high tide, and wind caused by storms pose a major threat of flooding in low lying areas on the bay side of the county and erosion along the coast. According to the San Francisco Bay Area Planning and Urban Research Association (SPUR), 40 percent of the state’s land drains its water into the San Francisco Bay.

The National Oceanic and Atmospheric Administration (NOAA) reports that sea level remained stagnant until the 20th Century. However, since 1900, sea level has risen 0.04 to 0.1 inches per year, a cumulative 8 inches in the Bay Area by 2015. Projections indicate a 55-inch sea level rise in San Mateo County by 2100. An estimated 10% of San Mateo County’s population will be directly affected by a sea level rise of 36 inches.

The Bay Institute reports that flooding from storm surges is the greatest threat to developed areas along the bay’s shoreline. Intense wind and waves from a 1% annual chance storm* and sea level rise will result in erosion of the county’s coastal bluffs and beaches and saltwater intrusion in watersheds. According to the San Mateo County Sea Level Rise Vulnerability Assessment Draft, sea level rise of 3.3 feet and a 1% annual chance storm poses a threat to 7,000 acres of wetland, $34 billion in assessed property value, 380 miles of roads, 7 of 9 wastewater treatment plants and over 100,000 people.

*1% annual chance storm describes an incident of extremely heavy rainfall that only has a 1% probability of occurrence within a 1-year period. Though this level of storm has been referred to as a 100-year storm because the recurrence interval is about 100 years, it implies that such a storm could not occur two years in a row, which is a possibility.

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Evaluation and Preparation Projects

  • The San Mateo County Office of Sustainability in collaboration with the Coastal Conservancy is conducting a Sea Level Rise Vulnerability Assessment to be completed in 2017. The project utilizes sea level rise projections combined with storm scenarios to evaluate the risk to assets including infrastructure, wetlands, and wild life habitat. Learn more at the Sea Change San Mateo County
  • In November, Foster City residents will vote to enhance the 8-mile levee that protects the city from bay tides. The current structure was deemed insufficient to prevent flooding during a 1% annual chance storm by the Federal Emergency Management Agency (FEMA). Though Foster City now resides in a flood zone, FEMA has placed a temporary hold on flood insurance requirements to allow the city to make improvements. The $90 million project requires approval from the federal government as well as several state and regional entities (Daily Journal).
  • SFO’s Airport Shoreline Protection Feasibility Study led to the adoption of the 2015 Shoreline Protection Program (SPP), guiding preparation for sea level rise and a 1% annual chance storm.
  • The San Francisquito Creek Joint Powers Authority (SFJPA) is conducting a feasibility study to restore marshlands, create recreation trails, and protect against flooding and three feet of sea level rise. The project has secured funding from three city governments, a local business, and the US Fish and Wildlife Service. Learn more about the SFJPA’s projects on their website.
  • In 2014, FEMA revised its flood and wave data for the San Mateo County Flood Insurance Study report and Flood Insurance Rate Map, which are used to determine flood insurance rates. The new floodplain projections are illustrated in the maps below.

Flood Risks from Sea Level Rise in San Mateo County

Flood Risks from Storms in San Mateo County

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Cattle and Methane

Over half of California’s methane emissions are from cattle and dairy farms (CalCAN, 2015). To decrease the carbon footprint of cattle products, ranchers and dairy producers are developing a suite of best practices.

Co-digestion of manure and other waste streams is a method to reduce methane emissions, extract reusable water, and create fertilizer. This method is practiced at Straus Family Creamery in Petaluma, CA. Research has shown that dry manure management has the potential to reduce methane emissions and reduce contamination of food and soil compared to wet management practices; however, dry manure management requires more labor.

Local ranches, such as LeftCoast Grass-fed at TomKat Ranch and Markegard Family Grass-fed, implement Holistic Management systems that preserve grassland and contribute to carbon storage. In this system, cattle eat grass and trim the top to stimulate new growth, while fertilizing the land with manure. The cows are then moved to a new swath of grass or pasture to begin the process again. This practice is also beneficial for habitat conservation where riparian areas are maintained; and carbon sequestration is enhanced where perennial grasses exist.

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Gasoline and Diesel Consumption.California Air Resources Board EMFAC Database. Retrieved from:

Climate Action Plans comes from the San Mateo County Climate Energy Watch, retrieved from

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From the 2017 Indicators Report

Between 2010 and 2015, the average rental cost rose by 49% and the median house sale price rose by 52% in San Mateo County.

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‟The nation behaves well if it treats the natural resources as assets which it must turn over to the next generation increased, and not impaired in value.”—Theodore Roosevelt