Climate change in California facts for kids

Animated map showing how the drought in California spread from 2013 to 2014. By December 2014, 75% of California was in a very serious drought.

Climate change in California means the state is getting warmer. This leads to more droughts and wildfires. Over the next few decades, climate change will likely cause less water to be available. It will also increase the risk of wildfires and make farming harder. Coastal areas and their plants and animals will also be in danger. California's economy will be affected too, as water becomes more expensive and farming jobs might be lost. California has taken many steps to reduce these problems.

Looking at Past Climates

Studies of Earth's past climate show that the last 150 years in California have been unusually wet. Before this, the state had much drier periods. Tree stumps found at the bottom of lakes and rivers show that these water bodies dried up in the past. This allowed trees to grow where water used to be. These dry times happened during warm periods in Earth's history. For example, during the Medieval Warm Period, California had at least two very long droughts, each lasting about 100 years. During these times, rainfall was only 60-70% of what it is today. Scientists believe that rising temperatures from global warming could cause California to enter another dry period. This would mean much less rain and snow than we have seen in the last 150 years.

Extreme Weather Changes

A study from 2011 predicted that both the highest and lowest temperatures would become more extreme due to global warming. The Fifth National Climate Assessment in 2023 also reported that coastal states like California are seeing "more significant storms and extreme swings in precipitation." This means weather can change very quickly from wet to dry, or from mild to very hot or cold.

Wildfires

Fire retardant (pink) and smoking plants during the Tumbleweed Fire. This fire burned 1,000 acres of land near Los Angeles in July 2021.

Warmer temperatures, frequent droughts, and past land management have made California more prone to wildfires. Also, more people are building homes in areas where fires are a risk. Wildfire activity is strongly linked to temperature and how dry the land is. Globally, the fire season has become almost 19% longer between 1979 and 2013. In the western United States, fire seasons are much longer. Since 1985, more than half of the land burned by wildfires in the western U.S. is due to human-caused climate change.

Also, because people have stopped many small fires in the past, a lot of dry plants and trees have built up. This "fuel" makes fires much bigger and more dangerous when they do start. Fires are now more likely to happen in dense, dry forests. In the past, fires usually happened in less dense areas. As more people move into high-risk areas, their homes are more likely to be damaged or destroyed by fires. Since 1990, the number of homes lost to wildfires each year has gone up by 300%. By 2017, almost 900,000 homes in the western U.S. were in high-risk wildfire zones. About 35% of California's wildfires start in these areas.

Many studies show that climate change is causing more frequent and larger wildfires in California. The cost of recent fire seasons, including health problems from smoke, has been very high. It is estimated to be as much as $148.5 billion. This is about 1.5% of California's yearly economy. As global warming continues, the risk of climate-driven wildfires is expected to keep increasing.

In 2019, after "red flag" warnings for wildfires, the electricity company Pacific Gas and Electric (PG&E) started turning off power. This was to prevent trees from touching power lines and starting fires. Millions of people were affected. The weather conditions that cause these warnings are happening more often because of climate change. If temperatures keep rising, these power outages could become common.

Recent wildfire seasons have broken many records. The 2018 season was the deadliest and most destructive in California's history. It killed 103 people and damaged or destroyed 24,226 buildings. The 2020 season was the largest ever recorded in terms of land burned. More than 4 million acres burned in 9,917 wildfires. Five of the six biggest fires ever recorded in California happened in 2020.

A 2017 study found that the biggest threat to Los Angeles County hospitals from climate change is the direct impact of more wildfires. In Los Angeles County, 34% of hospitals are within one mile of high fire risk zones. The study also noted that some hospitals are in danger of coastal flooding due to rising sea levels. This is another growing risk as global temperatures increase.

Drought

A dry lakebed in California. The state is facing its worst drought in 1,200 years, made worse by climate change. This has led to water rationing.

In February 2022, scientists reported that the drought in the southwestern U.S., including California, from 2000 to 2021 was the most severe in 1,200 years. Without climate change, the drought might have ended by 2005. About 42% of its seriousness is due to rising temperatures from climate change. During this time, 88% of the area was affected by drought. The flow of the Colorado River, which supplies water to 7 states, reached its lowest two-year average in over a century. If temperatures keep rising, the drought will get worse.

A 2014 report said that the drought was part of natural weather changes. However, the record-high temperatures during the drought might have been made worse by human-caused global warming. A 2015 study confirmed this, estimating that global warming caused 8–27% of the drought's severity from 2012–2014. While natural changes play a big role, human-caused warming has greatly increased the chance of extreme droughts in California.

In February 2014, the drought led the California Department of Water Resources to plan for cutting water to farms by up to 50%. At that time, California's 38 million residents had experienced 13 months of continuous drought. This is a big problem for the state's $44.7 billion farming industry. This industry produces almost half of all fruits, nuts, and vegetables grown in America. According to NASA, tests in January 2014 showed that the previous 12 months were the driest on record since 1885. Because of low snowpack (less snow in the mountains to melt into water), California's governor Jerry Brown ordered strict water limits on April 1, 2015.

This map shows the percentage of California's area affected by different levels of drought.

Megafloods

A study in 2022 said that climate change has already doubled the chance of "megafloods" in California since 1920. These floods can bring 100 inches (254 cm) of rain or melted snow in the mountains per month. They can also bring 25 to 34 feet (7.6 to 10.4 m) of snow in the Sierra Nevada mountains. In a future extreme storm, the amount of water flowing off the Sierra Nevada mountains is predicted to be 200 to 400% greater than historical amounts.

Forest Management

Between 2012 and 2016, 129 million trees in California died from drought and bark beetles. Among them were sugar pines around Lake Tahoe that survived the drought. Thousands of seedlings from these strong trees are now being planted on south-facing slopes near the lake. The hope is that these new trees have genes that make them more resistant to drought, less snow, and other effects of global warming in the Sierra Nevada forests.

A 2022 report on climate change suggests that California's land managers need to think about the changing climate when planning how to manage forests. This is especially true given the huge number of wildfires the region faces. The report suggests that controlled burning, a common practice, might not always be helpful. It can also release carbon into the air, making climate change and wildfires worse.

Agriculture

Longer periods of higher temperatures are expected to increase the number of navel orangeworms. These worms cause more damage to almond, walnut, and pistachio crops.

Conservation groups are working with farmers in Central California to flood fields for parts of the year. This helps create more habitat for animals affected by climate change, such as salmon and migratory birds.

Climate change's impact on rainfall can lead to severe droughts in California. During droughts, farmers leave some of their land unplanted. In the 2014 drought, 430,000 acres of farmland were left fallow. Farmers expect to leave a similar amount of land unplanted in 2022.

Fisheries Impact

Ocean heat waves since 2013 have caused delays in three Dungeness crab fishing seasons. This is because harmful algal blooms, which are linked to warmer waters, can contaminate crab meat.

Sea Level Rise

This map shows how many people live in different areas of the Western United States, and coastal zones that are low in elevation.

This map shows how many people live in different areas of the San Francisco Bay in 2010, and coastal zones that are low in elevation.

A 2017 study predicted that if sea levels rise by 1 to 2 meters (about 3 to 6.5 feet), between one-third and two-thirds of Southern California beaches will be underwater. Sea levels off the coast are expected to rise 20-55 inches (51-140 cm) over the next century. Rising sea levels can harm ocean life, cause permanent floods, and lead to coastal erosion. An economic study estimated that if greenhouse gas emissions continue at current rates, between $8 billion and $10 billion worth of property in California could be underwater by 2050. An additional $6 billion to $10 billion could be at risk during high tides.

Economic Impacts

Gross Domestic Product

The Natural Resources Defense Council (NRDC) estimates that if things continue as they are, the cost of providing water to the western U.S. could increase greatly. Between 2025 and 2100, it could rise from $200 billion to $950 billion per year. This is about 0.93–1 percent of the United States' total economic output (GDP). Four climate change impacts alone—hurricane damage, energy costs, real estate losses, and water costs—are expected to cost 1.8 percent of the U.S. GDP by 2100. This would be almost $1.9 trillion in 2008 dollars.

Job Opportunities

Solar panels being installed in Los Angeles.

A 2009 study showed that more frequent and intense extreme weather due to climate change will lead to less productive farming. This could mean less money for farmers and potential job losses. Changes in weather and rainfall patterns might require expensive changes, like moving where crops are grown or changing the types of crops. Farmers might also need to use more pesticides to adapt to changes in nature. These changes can hurt the economy and lead to job losses.

Climate change negatively affects farming in California, causing more workers to lose their jobs. For example, California's two most valuable farm products are dairy (milk and cream, worth $3.8 billion yearly) and grapes (worth $3.2 billion yearly). Climate change is also expected to harm the ripening of wine grapes, which could greatly reduce their market value.

Legislation

California has taken many legal steps and actions to prevent and reduce the risks of climate change. The state has put in place many incentives, measures, and plans for clean cars, renewable energy, and pollution controls on industries. California is known for its strong environmental laws, not just in the U.S. but globally.

In 2007, California passed AB 32, the Global Warming Solutions Act of 2006. This law required the state to reduce its greenhouse-gas emissions to 1990 levels by 2020. It gave the California Air Resources Board (CARB) the job of creating a plan to make this happen. AB 32 was in line with Governor Arnold Schwarzenegger's 2005 order, which also required California to cut its emissions to 80% below 1990 levels by 2050. CARB updated its plan in 2014.

In 2016, SB 32 was passed, setting California's climate goals beyond 2020. It requires a 40% reduction below 1990 levels by 2030 and an 80% reduction by 2050. CARB's 2017 plan explains how the state will meet SB 32's goals. It sets statewide goals for greenhouse gas emissions per person: they must be reduced to 6 metric tonnes of carbon-dioxide equivalent by 2030, and 2 metric tonnes by 2050. CARB's 2022 plan continues to work towards these goals.

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