California is the most populous state in the United States. Its climate policies affect global climate change and federal climate policies. Following the advice of climate scientists, California has passed laws to reduce greenhouse gas emissions.

California has taken legislative steps to reduce the risks of climate change. These steps include incentives and plans for clean cars, renewable energy, and pollution controls in industry. Climate change policies in California are created by both the executive and legislative branches of the state government. Many policies focus on reducing greenhouse gas emissions, which increase global temperatures and disrupt natural patterns.

One important law in California is Assembly Bill 32, the Global Warming Solutions Act of 2006. This law required many parts of California’s economy to reduce greenhouse gas emissions to 1990 levels by 2020. The law also created the California Air Resources Board (CARB) to design policies and methods to meet the goal. CARB later started the state’s cap-and-trade program, the first of its kind in the United States. California met its emissions target four years earlier, in 2016.

California, the world’s fifth-largest economy, has long led the way in environmental policies related to global warming. In 2002, Governor Gray Davis approved AB 1493, a law that directed CARB to set standards for reducing greenhouse gases from vehicles. This law, now called the California Vehicle Global Warming law, requires automakers to reduce vehicle emissions by 30% by 2016. Although automakers challenged the law in court, support for it has grown as other states adopted similar rules. In 2002, Governor Davis also approved a law requiring the California Climate Action Registry to create procedures for reporting emissions and storing carbon in forests. A group at the California Energy Commission is working on these procedures.

In 2005, Governor Arnold Schwarzenegger signed an executive order to reduce greenhouse gas emissions in California. The goal was to cut emissions to 2000 levels by 2010, to 1990 levels by 2020, and to 80% below 1990 levels by 2050. Steps to meet these goals include stricter car emissions standards and requiring more electricity from renewable sources. Scientists estimate that if California’s car standards were used nationwide, drivers could save $26 billion each year by 2020.

On August 30, 2006, Governor Schwarzenegger and the California Legislature agreed on AB 32, the Global Warming Solutions Act. He signed the bill into law on September 27, 2006, stating, "We simply must do everything we can to slow down global warming before it is too late… The science is clear. The global warming debate is over." The Act limits California’s greenhouse gas emissions to 1990 levels by 2020 and creates a system to monitor compliance. This is the first program in the United States to set limits on all major industrial emissions and include penalties for not following the rules. The law requires CARB to create a program for reporting emissions and enforcing the rules. It also allows CARB to use market-based methods, such as cap-and-trade, to help meet goals. It permits a one-year extension of targets under special circumstances. So far, five types of projects have been suggested to create emissions reductions: manure management, forestry, building energy, SF6, and landfill gas capture.

On September 26, Governor Schwarzenegger signed SB 107, which requires California’s three largest utilities—Pacific Gas & Electric, Southern California Edison, and San Diego Gas & Electric—to produce at least 20% of their electricity from renewable sources by 2010. This shortens the time frame originally set by Governor Davis in 2002, which aimed to increase renewable energy use to 20% by 2017.

Governor Schwarzenegger also announced plans to work with Prime Minister Tony Blair of Great Britain and other international efforts to address global warming, independent of the federal government.

Legislation overview

To learn more about California's climate policies, see the California Climate Executive Orders. These documents describe the actions taken by California governors to address climate change.

California lawmakers have been leaders in the United States in creating laws to reduce climate change. Starting in the early 2000s, California governors signed several executive orders focused on climate change. The California State Legislature passed many laws to meet the goals set in these orders. These laws cover topics such as measuring emissions, transportation, waste, and energy use in California.

Climate change happens when human activities increase the amount of greenhouse gases in the atmosphere. Governments worldwide are working to control emissions. Setting goals to reduce emissions and using tools to measure progress are important steps. According to the 2022 IPCC report, the world must cut emissions in half by 2030 to limit warming to 1.5 degrees Celsius. California lawmakers have focused on reducing emissions since the 2000s.

A law created the California Climate Action Registry in 2001. However, this group closed in December 2010 and now asks members to report emissions to the Climate Registry instead.

In October 2001, SB 527 was passed. This law allowed the California Air Resources Board to use administrative penalties, not legal penalties, for breaking air pollution rules. The maximum penalty was $10,000 per day and $100,000 total. Before this law, the board had to rely on the Attorney General to enforce penalties. SB 527 also changed the Climate Action Registry’s responsibilities, such as focusing only on emissions within California and using specific reporting methods.

In September 2006, AB 32, the Global Warming Solutions Act of 2006, was passed. This law aimed to reduce human-caused greenhouse gas emissions in California to 1990 levels by 2020. The California Air Resources Board (CARB) was responsible for implementing and monitoring progress. Environmental justice groups influenced the law, so a cap-and-trade program was not required.

Environmental justice groups work to stop the unfair placement of pollution in communities of color, low-income areas, and Hispanic and Latino neighborhoods. These communities are more likely to live near major polluters, which release greenhouse gases and harmful air particles. Some groups believe cap-and-trade programs do not provide enough protection for these communities.

Because of these concerns, CARB was given the freedom to choose the best system to meet emission goals, with reviews every five years. This flexibility helped CARB achieve the 2020 emission target four years early.

To meet emission goals, CARB has used many strategies, including greener transportation, waste reduction, a cap-and-trade program, new energy-efficient technology, and expanding renewable energy.

AB 32 targets the following greenhouse gases:
– Carbon dioxide
– Methane
– Nitrous oxide
– Hydrofluorocarbons
– Perfluorocarbons
– Sulfur hexafluoride
– Nitrogen trifluoride (added later through legislation)

The emission goals in AB 32 were updated after Executive Orders B-16-12 and B-30-15. These updates added new measures to reduce emissions further.

Funding for AB 32 comes from fees paid by companies that produce greenhouse gases, such as power plants, oil refineries, and cement factories. Money from selling permits in the cap-and-trade program also supports AB 32 programs.

A key part of AB 32 is the Scoping Plan, which outlines how California will reduce emissions. The plan includes new and existing measures across all sectors of the economy.

The first AB 32 Scoping Plan included proposals that became law in 2008. These included a cap-and-trade program for carbon dioxide emissions, energy efficiency standards for buildings and appliances, cleaner fuels for oil companies, and a goal for utilities to use 30% of their energy from renewable sources like wind and solar. The Renewable Portfolio Standard, created in 2002, now requires electricity providers to use 44% renewable energy by 2024, 52% by 2027, and 60% by 2030. The plan also promotes walkable cities, high-speed rail, and hybrid vehicles.

California has also launched programs to reduce agricultural emissions, such as the Healthy Soils Program and the Alternative Manure Management Program. These programs aim to cut emissions from agriculture, which account for 8% of the state’s total emissions. The California Green Building Standards Code, introduced in 2009, helps reduce emissions from new or renovated buildings but does not apply to older buildings.

Other initiatives to meet AB 32 goals include:
– Completing the Million Solar Roofs initiative.
– A tire program that sets standards for tire pressure and replacement.
– Water-related energy efficiency measures.
– Regulations to reduce emissions from trucks.

Transportation

According to the EPA, transportation is the largest source of greenhouse gas emissions in the United States, producing 27% of the total emissions. Most vehicles use engines that burn fossil fuels, so California has passed laws to encourage people to buy cleaner vehicles powered by renewable energy.

This law is a follow-up to AB 1058, which was signed into law by Governor Gray Davis on July 22, 2002. It requires the California Air Resources Board (CARB) to create and enforce limits on greenhouse gas emissions from vehicles starting with the 2009 model year. Later, under AB 1493, CARB approved rules in September 2004 that set limits on greenhouse gas emissions from new passenger cars, SUVs, and pickup trucks sold in California in 2009. The automotive industry has challenged these rules, arguing they duplicate federal gas mileage standards. CARB staff has said the rules will save drivers money on fuel costs, which will outweigh the higher initial cost of new vehicles. Critics say the rules will only work if car and truck sizes are significantly reduced.

California’s standards use a measure called grams per mile of CO2-equivalent emissions. This method compares the climate impact of different greenhouse gases (for example, passenger cars must emit no more than 323 grams per mile in 2009 and 205 grams per mile in 2016).

In December 2007, a federal court ruled that California and federal laws can coexist. However, the EPA denied California’s request for a waiver to enforce its law in December 2007, stating that California’s emissions have little effect on global warming and that the state’s conditions were not “compelling and extraordinary” as required by law. California plans to sue the EPA, citing a previous court case (Massachusetts v. EPA) that said carbon dioxide is an air pollutant the EPA can regulate. Many other states, including Arizona, Colorado, Connecticut, and others, also want to adopt California’s vehicle emissions standards.

The Sustainable Communities and Climate Protection Act of 2008, also known as SB 375, requires urban planners to reduce urban sprawl. This law also created the California Clean Truck, Bus, and Off-Road Vehicle and Equipment Technology program to fund technologies that produce zero or near-zero emissions using money from the Greenhouse Gas Reduction Fund.

SB 375 also launched the Charge Ahead California Initiative, which aims to place at least 1 million zero-emission and near-zero-emission vehicles in service by January 1, 2023, with a focus on low-income communities to make these vehicles widely available.

The Alternative Fuel Vehicle Incentive Program (AFVIP), also called Fueling Alternatives, is funded by CARB and managed by the California Center for Sustainable Energy. It was created by AB 118 and received $25 million to support vehicles that use alternative fuels, such as compressed natural gas, electricity, and plug-in hybrid electric vehicles.

Vehicles that use alternative fuels include models like Global Electric Motorcars, Vectrix, and ZAP. The 2008 Tesla Roadster and 2008 ZENN neighborhood electric vehicle are also eligible for rebates under the Fueling Alternatives program.

The PHEV Research Center was created with funding from CARB. Fueling Alternatives includes vehicles such as Global Electric Motorcars, Vectrix, and ZAP. The 2008 Tesla Roadster and 2008 ZENN neighborhood electric vehicle are now eligible for rebates.

Since January 2009, all new vehicles sold in California must have a CARB window sticker showing a Smog Score and a Global Warming Score. Both scores range from 1 to 10, with 5 being average and 10 being the best (meaning the vehicle emits the least carbon dioxide). The scores are based on data from the U.S. Environmental Protection Agency.

Waste

SB 812 was passed in 2014. It required changes to the Department of Toxic Substance Controls’ process for approving permits at hazardous waste facilities. The law now requires owners of these facilities to submit both a Part A and Part B application for permit renewal at least two years before their current permit expires, instead of only six months before. It also requires owners to provide a written cost estimate for fixing problems related to hazardous waste under certain conditions.

SB 1383, officially named California's Short-Lived Climate Pollutant Reduction Law, was passed in 2016 by Governor Brown. The law aims to reduce methane emissions from decomposing organic waste. Methane is one of four short-lived climate pollutants. These are gases that stay in the atmosphere for a shorter time than carbon dioxide but trap much more heat. Methane is 28–34 times more powerful at trapping heat than carbon dioxide.

The new law controls how much organic waste is sent to landfills and how much edible food is rescued.
• By 2020, the law requires that organic waste sent to landfills be reduced by half compared to 2014 levels. By 2025, this must be reduced by 75%. Instead of being buried in landfills, this waste must be sent to composting or anaerobic digestion facilities, where methane can be captured.
• To reduce wasted food, the law requires that at least 20% of edible food from grocery stores and food service businesses be rescued and given to people in need by 2025.
• Starting in 2022, all counties must offer organic waste collection services to homes and businesses. These services will transport the waste to facilities that handle organic waste.

Renewable energy

Assembly Bill (AB) 1007 (Pavley, Chapter 371, Statutes of 2005) requires the California Energy Commission to create a plan to increase the use of alternative fuels in California, known as the Alternative Fuels Plan.

In 2012, Senate Bill (SB) 535 was passed. This law required that 25% of funding from the Greenhouse Gas Reduction Fund (GGRF) be used for projects that reduce greenhouse gas emissions and benefit disadvantaged communities. At least 10% of the funds had to be invested directly into these communities. CalEPA was responsible for identifying and locating disadvantaged communities. To help with this task, CalEPA developed a tool called CalEnviroScreen to map these communities and determine where funding should be focused. In 2016, AB 1550 was passed to expand SB 535, increasing the investment requirement from 25% to 35%.

Senate Bill (SB) 100, also known as the 100 Percent Clean Energy Act of 2018, shows California’s commitment to building renewable energy systems to replace energy from fossil fuels. The law has two main goals:
– By 2030, 60% of all energy generated will come from renewable sources.
– By 2045, 100% of energy used in the state will come from renewable sources.

The lower costs of wind and solar energy technologies have made these two sources the primary focus of California’s renewable energy systems.

Cap and trade

In 2018, California used $1.4 billion from its cap and trade program to reduce greenhouse gas emissions. This amount is part of a total of $3.4 billion spent since 2012. Important projects funded include the California High-Speed Rail and the Clean Vehicle Rebate for low-emission vehicles. Until 2021, the money was meant to be used only for reducing emissions. However, in the 2019-2020 budget, lawmakers decided to use some cap and trade funds for water quality projects. This decision raised questions about how these projects relate to reducing global warming.

California’s climate investments use money from cap and trade auctions to reduce greenhouse gas emissions, strengthen the economy, improve public health and the environment, and provide benefits to disadvantaged communities, low-income communities, and low-income households.

Resilience and adaptation

In 2020, the Ocean Protection Council created the Strategic Plan to Protect California's Oceans. This plan includes a five-year plan with four main goals and many specific targets: helping the ocean survive climate change, improving access to the ocean for everyone, protecting ocean life, and supporting jobs that depend on the ocean. Goals include preparing for 3.5 feet of sea level rise by 2050, restoring 10,000 acres of wetlands by 2025, and moving public buildings and infrastructure away from areas at risk. The plan uses existing money for the first two years and may use up to $500 million from a $4.75 billion bond proposed by Governor Gavin Newsom for the rest.

Even though California has taken many steps to reduce greenhouse gas emissions, the effects of climate change that already exist continue to affect the state. These effects include more frequent wildfires, droughts, and floods. To address these challenges, the state updated the Safeguarding California Plan in 2018. This plan includes over 300 steps taken by state agencies to reduce the harm caused by climate change to buildings, public safety, and the economy.

Some examples of the many projects the state has started to adapt to climate change include:

• Making energy use more efficient in public schools
• Replacing roofs to prevent damage from wildfires
• Supporting research to better understand how climate change affects the environment
• Making city electrical systems less likely to fail during heat waves
• Planting more trees and plants
• Adjusting highway routes that have been damaged by erosion along the coast
• Upgrading systems that provide water to farms

This is a timeline showing recent laws in California that aim to reduce greenhouse gas emissions.