Greenhouse Gases, Climate Change, & the California Coast

California’s coastal environments and communities are impacted by rising greenhouse gases in many ways.

By the California Coastal Commission

Greenhouse Gases and Climate Change

Solar energy is absorbed at the Earth’s surface and radiated back into the atmosphere as heat. Greenhouse gases (GHGs) are specific gases in the Earth’s atmosphere that trap heat and help to maintain a warmer temperature on the planet. This process of trapping heat in the Earth’s atmosphere is known as the ‘greenhouse effect.’  

GHGs consist of carbon dioxide, methane, ozone, nitrous oxide, chlorofluorocarbons, and water vapor. GHGs are a natural component of the Earth’s atmosphere and are responsible for maintaining a ‘Goldilocks’ planet – where conditions are just right, not too hot or too cold, for life as we know it to thrive.  

 The Greenhouse Effect,  United States Environmental Protection Agency (US EPA).

However, in the last century, human activities are responsible for significant increases in GHGs that have disrupted the Earth’s energy balance. The largest source of GHG emissions from human activities is burning fossil fuels for electricity, heat, and transportation. Other human activities that contribute to the increase of global GHG emissions include clearing forests, fertilizing crops, storing waste in landfills, raising livestock, and the production of industrial products. The increase in GHGs is causing Earth's greenhouse effect to grow more intense, increasing global temperatures, and changing the planet as we know it.

 What Is the Greenhouse Effect ?, National Aeronautics and Space Administration (NASA), 2020.

Climate change refers to shifts in temperatures and weather patterns. Such shifts can be natural, due to changes in the sun’s activity or large volcanic eruptions. Anthropogenic climate change refers to human activities as the main driver of a changing planet due primarily to the burning of fossil fuels, including coal, oil, and gas. Rising temperatures, rising sea levels, and increased extreme weather events are all examples of climate change impacts on Earth. Today, anthropogenic climate change has caused widespread changes on regional and local scales across the planet.

 The Keeling Curve  refers to the longest-running measurement of the concentration of carbon dioxide in the atmosphere made atop  Hawaii’s Mauna Loa  since 1958. The data collection and program are run by the Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA).

Scientific observations and climate models help to monitor and study evidence of past, present, and future climate change, including global land and ocean temperature increases, rising sea levels, glacier loss, and indications of extreme weather events such as hurricanes, heatwaves, wildfires, droughts, and floods.

According to the  Intergovernmental Panel on Climate Change ’s (IPCC’s) Sixth Assessment Report, researchers have concluded with a high level of confidence that human-driven GHG emissions have resulted in a global temperature increase of 1.1 degrees Celsius (~ 2 degrees Fahrenheit) from 1850 to 1900.  

To help curb GHG emissions and the related impacts, the IPCC recommends a suite of mitigation and adaptation measures focused on nature-based solutions, safeguarding biodiversity, and enhancing carbon sequestration. To learn more, check out the IPCC’s Sixth Assessment Report on Impacts, Adaptation, and Vulnerabilities  here . 

Greenhouse Gas Emissions in California

Transportation is the single largest source of GHG emissions in California, accounting for 38% of total statewide emissions in 2021. This includes emissions from on- and off-road vehicles, intrastate flights, trains, and water-borne vessels. Electricity production, industrial, and residential sources also make notable contributions to GHG emissions in California.

 2022 California GHG Emissions by Main Economic Sector . MMT CO2e = Million metric tons of carbon dioxide equivalent. California Air Resources Board (CARB).

It is imperative to reduce our current GHG emissions across the state to limit the widespread effects of climate change. California has passed landmark bills to help support the push towards GHG emission reductions, including the  Global Warming Solutions Act of 2006  (AB 32, later amended by SB 32). In 2022, California set an ambitious goal to achieve  carbon neutrality  by 2045 and to maintain net negative emissions thereafter with  Assembly Bill 1279 . 

 California’s Climate Plan Lays the Roadmap to 2045 , California Air Resources Board (CARB) Scoping Plan, November 2022.

The  California Air Resources Board  (CARB) is responsible for laying out a path to achieve these ambitious GHG reduction goals through regular updates to its  AB 32 Climate Change Scoping Plan . The latest Scoping Plan highlights that achieving state goals will require significant reductions in the state’s GHG emissions in conjunction with the removal of carbon dioxide from the atmosphere.

Key strategies include expansion of renewable energy and zero-emission vehicle infrastructure, reducing reliance on fossil fuels and gas-powered vehicles, preserving and enhancing carbon sinks such as forests and wetlands, and working towards carbon-neutral buildings and industrial facilities.

The California Coastal Commission advances these statewide GHG initiatives through guidance, resources, and tools to help local governments and other stakeholders reduce GHG emissions in California’s coastal zone.  The Commission also permits and coordinates with other agencies on projects that reduce GHG emissions, such as offshore wind and infrastructure for electric vehicles, and reviews and approves Local Coastal Program policies that can reduce GHG emissions such as those relating to sustainable development.

Climate Change Impacts in the California Coastal Zone

Approximately 26.8 million people live in California’s coastal counties and rely on coastal and ocean related industries, services, and recreation. Unfortunately, California’s coast is becoming increasingly vulnerable to climate change impacts like sea level rise, wildfires, frequent and intense storm events, ocean acidification, reductions in species diversity and distribution, and coastal flooding.

 California King Tides Project , Highway 101, Sausalito, CA.

The increase of global temperatures associated with climate change has contributed to the net loss of ice sheets and glaciers, which contributes to sea levels rising across the globe. Elevated rates of sea level rise have already impacted environmental, social, and economic systems in coastal areas, including damage to coastal infrastructure, freshwater resources, terrestrial and marine ecosystems, and general public access.

According to the most recent best available science, by the year 2100, sea levels in California may rise by 1 to 6.6 feet (0.3 to 2.0 meters) depending on GHG emissions levels. The California Coastal Commission recommends using the best available science to predict and plan for sea level rise. More information on sea level rise science and planning can be found on the Commission’s  Sea Level Rise  website. 

Climate Change and Environmental Justice Impacts

Climate change is happening today on a global scale, but the effects can differ locally. It is essential to remember that certain sectors, regions, habitats, and human populations are more vulnerable or are subject to unique risks due to climate change. These disproportionate effects are caused by physical, social, political, and/or economic factors, which are exacerbated by climate impacts. These factors include, but are not limited to, race, socioeconomic status, age, national origin, and income inequality.

Environmental justice, tribal, elderly, and linguistically isolated communities are examples of communities who often have less capacity and fewer resources to cope with, adapt to, or recover from climate change impacts.

For example, farmworkers and elderly populations are particularly vulnerable to heat-related adverse health effects. As another example, low-income and elderly residents who reside in low-lying industrial communities in the coastal zone have fewer financial resources to protect against and recover from flood damage, property loss, and/or exposure to contaminants. This is a particular concern in a  study  conducted in the San Francisco Bay Area where sea level rise threatens to expose over 400 industrial facilities and contaminated sites in California, including power plants, refineries, and hazardous waste sites. To learn more about climate change and environmental justice, see the Commission's  Environmental Justice  website.

“Disadvantaged communities in California are more than five times more likely to live less than one kilometer from one or more industrial facility or contaminated site at risk of flooding in 2050, and six times more likely in 2100.”

Toxic Tides and Environmental Injustice: Social Vulnerability to Sea Level Rise and Flooding of Hazardous Sites in Coastal California, Cushing et al., 2023.

Toxic Tides Sea Level Rise, Hazardous Sites, and Environmental Justice in California. Dr. Rachel Morello-Frosch’s research team in collaboration with community partners characterized the threats posed by sea level rise and the flooding of hazardous sites to socially disadvantaged populations as well as creating an online mapping tool that visually depicts toxic facilities at risk of flooding due to sea-level rise and associated socioeconomic conditions.

Addressing GHG Emissions in the Coastal Zone

In August 2023, the Commission adopted the  Sustainability Principles: A Framework for Reducing Greenhouse Gas Emissions in the Coastal Zone , which describes how GHG emission reduction efforts interface with the Coastal Act and relate to the Coastal Commission’s work on coastal resiliency. As a regulatory and planning agency, the Commission is in a unique position to implement the Coastal Act to mitigate the impacts of climate change and bolster statewide mandates for GHG emission reductions in the coastal zone.

In particular:

  • Section 30250 generally requires new development to be concentrated in existing developed areas;
  • Section 30252 facilitates the provision of public transit services and non-automobile circulation in new development projects;
  • Section 30253 requires new development to minimize energy consumption and vehicle miles traveled (VMT) and to meet air pollution control requirements;
  • Section 30604 (h) provides the Commission with the ability to consider environmental justice issues when making decisions regarding development on the California coast;
  • Other policies protecting the marine environment, sensitive habitat areas, coastal waters, agricultural lands, and timberlands not only protect coastal ecosystems, but also help preserve the carbon sequestration benefits that those ecosystems provide (e.g., Sections 30230, 30231, 30233, 30240, 30241, 30243); and
  • Section 30270 requires the Commission to “take into account the effects of sea level rise in coastal resources planning and management policies and activities in order to identify, assess, and, to the extent feasible, avoid and mitigate the adverse effects of sea level rise.”

Together, these Coastal Act sections provide the Commission with the authority and the duty to address the climate-related impacts of coastal land use policy and development decisions.

The Sustainability Principles recommend multiple strategies for the Commission and local governments to achieve these goals, including conducting meaningful tribal consultation and environmental justice community engagement; streamlining permit processes for climate resiliency projects; protecting and restoring natural lands for their carbon sequestration values; employing innovative sea level rise adaptation strategies; enhancing non-automobile transit alternatives; and encouraging policies and practices that lead to new carbon-neutral development.

Example GHG Mitigation Strategy: Greenhouse Gas Life Cycle Analysis

Given that excess GHG emissions lead to and perpetuate climate change, reducing the GHG emissions associated with goods and services in all industries and sectors can mitigate climate impacts. The Commission, local governments, applicants, and organizations can use a variety of tools to measure and reduce GHG emissions.

One tool is a GHG life cycle analysis, which government agencies and organizations can use to track, analyze, and conceptualize the GHG emissions and related environmental impacts over the course of the entire life cycle of a product, material, process, or other measurable activity. The term “life cycle” encompasses starting this analysis from the raw materials sourcing through the production, transportation, use, and end of life stages. The Commission and local governments can use this tool to understand GHG emission implications and potential alternatives or mitigation needs associated with a coastal development project or land use change.

 Greenhouse Gas Life Cycle Analysis Schematic , United States Environmental Protection Agency (US EPA).

A common goal of a life cycle analysis is to reduce the environmental impacts like GHG emissions, energy usage, water consumption, and air and water quality impacts of the activity or product; to communicate those impacts; and to discuss how the impacts compare to alternatives.

For example, a life cycle analysis focusing on GHG emissions identifies and communicates all of the GHG emissions generated from all stages of a product, and can be used to identify stages with high GHG emissions and evaluate alternatives to reduce GHG emissions.

Ultimately, effective life cycle analyses can provide valuable information that can be used to support sustainability initiatives and to help the Commission and local governments better understand the GHG emissions associated with coastal development projects and land use plans.

Conclusion

California's coastal environments and communities are affected by rising GHG emissions and associated climate change impacts in many ways. Reducing GHG emissions through sustainable land use planning and development practices is necessary for building more resilient coastal communities and protecting coastal resources over the long term. There are a myriad of tools and resources to help measure and reduce GHG emissions. Conducting a GHG life cycle analysis is one tool in the permit analysis toolbox within the coastal zone regulatory space for both the Commission and local governments to employ.

References

  • Cushing, L., Yang, J., Kulp S., Depsky, N., Karasaki, S., Jaeger, J., Raval, A., Strauss, B., and Morello-Frosch, R. Toxic Tides and Environmental Injustice: Social Vulnerability to Sea Level Rise and Flooding of Hazardous Sites in Coastal California, Environmental Science & Technology 2023 57 (19), 7370-7381, DOI: 10.1021/acs.est.2c07481. 

 The Greenhouse Effect,  United States Environmental Protection Agency (US EPA).

 The Keeling Curve  refers to the longest-running measurement of the concentration of carbon dioxide in the atmosphere made atop  Hawaii’s Mauna Loa  since 1958. The data collection and program are run by the Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA).

 2022 California GHG Emissions by Main Economic Sector . MMT CO2e = Million metric tons of carbon dioxide equivalent. California Air Resources Board (CARB).

 California’s Climate Plan Lays the Roadmap to 2045 , California Air Resources Board (CARB) Scoping Plan, November 2022.

 California King Tides Project , Highway 101, Sausalito, CA.

 Sustainability Principles: A Framework for Reducing Greenhouse Gas Emissions in the Coastal Zone , California Coastal Commission, 2023.

 Greenhouse Gas Life Cycle Analysis Schematic , United States Environmental Protection Agency (US EPA).