Climate change in California has resulted in higher than average temperatures, leading to increased occurrences of droughts and wildfires. Over the next few decades in California, climate change is likely to further reduce water availability, increase wildfire risk, decrease agricultural productivity, and threaten coastal ecosystems. [3] The state will also be impacted economically due to the rising cost of providing water to its residents along with revenue and job loss in the agricultural sector. [4] [5] Economic impacts also include inflation from rising insurance premiums, [6] [7] energy costs and food prices. [8] [9] [10] California has taken a number of steps to mitigate impacts of climate change in the state. [11]
Paleoclimatological studies indicate that the last 150 years of California's history have been unusually wet compared to the previous 2000 years. Tree stumps found at the bottom of lakes and rivers in California indicate that many water features dried up during historical dry periods, allowing trees to grow there while the water was absent. These dry periods were associated with warm periods in Earth's history. During the Medieval Warm Period, there were at least two century-long megadroughts with only 60-70% of modern precipitation levels. Paleoclimatologists believe that higher temperatures due to global warming may cause California to enter another dry period, with significantly lower precipitation and snowpack levels than observed over the last 150 years. [12]
A 2011 study projected that the frequency and magnitude of both maximum and minimum temperatures would increase significantly as a result of global warming. [13] According to the Fifth National Climate Assessment published in 2023, coastal states including California, Florida, Louisiana, and Texas are experiencing "more significant storms and extreme swings in precipitation". [14]
Because of warming, frequent droughts, and the legacy of past land management and expansion of residential areas, both people and the ecology are more vulnerable to wildfires. Wildfire activity is closely tied to temperature and drought over time. Globally, the length of the fire season increased by nearly 19% from 1979 to 2013, with significantly longer seasons in the western states. Since 1985, more than 50% of the wildfire area burned in the western United States can be attributed to anthropogenic climate change. [15] In addition, due to human fire suppression methods, there is a build up of fuels in some ecosystems. This makes them more vulnerable to wildfires. Currently, there is a greater risk of fires occurring in denser, dryer forests, whereas historically these fires have occurred in low-density areas. Lastly, with increases in human population, communities have expanded into areas that are at higher risk to wildfire threat, making these same populations more vulnerable to structural damage and death due to wildfires. Since 1990, the average annual number of homes lost to wildfires has increased by 300%. Almost 900,000 of western US residences were in high risk wildfire areas as of 2017 with nearly 35% of wildfires in California starting within these high risk areas.
Numerous studies have also found that climate change is increasing the frequency of large and explosive wildfires in California in particular. [16] [17] [18] And the economic and human health damages (mostly from smoke-related air pollution) of recent fire seasons has been estimated to be as high as $148.5 billion, or roughly 1.5% of California's annual GDP. [19] As a consequence of further global warming, it is projected that there will be an increase in risk due to climate-driven wildfires in the coming decades. [16] Because of warming, frequent droughts, and the legacy of past land management and expansion of residential areas, both people and the ecology are more vulnerable to wildfires. Wildfire activity is closely tied to temperature and drought over time. Globally, the length of the fire season increased by nearly 19% from 1979 to 2013, with significantly longer seasons in the western states. Since 1985, more than 50% of the wildfire area burned in the western United States can be attributed to anthropogenic climate change. [15] In addition, due to human fire suppression methods, there is a build of fuels in some ecosystems, making them more vulnerable to wildfires. There is greater risk of fires occurring in denser, dryer forests, where historically these fires have occurred in low-density areas. Lastly, with increases in human population, communities have expanded into areas that are at higher risk to wildfire threat, making these same populations more vulnerable to structural damage and death due to wildfires. Since 1990, the average annual number of homes lost to wildfires has increased by 300%. Almost 900,000 of western US residences were in high risk wildfire areas as of 2017 with nearly 35% of wildfires in California starting within these high risk areas. [20]
In 2019, after "red flag" warning about the possibility of wildfires was declared in some areas of California, the electricity company "Pacific Gas and Electric (PG&E)" begun to shut down power, for preventing inflammation of trees that touch the electricity lines. Millions can be impacted. The climatic conditions that cause this warning became more frequent because of climate change. [21] If the temperatures keep rising, such power outages could become common. [22]
Recent wildfire seasons have broken number of records. The 2018 season became the deadliest and most destructive in the state's history, with 103 people killed and 24,226 buildings damaged or destroyed. [23] The 2020 season became the largest in the state's recorded history in terms of area burned, with more than 4 million acres burned across the state in 9,917 wildfires. [24] Out of six of the biggest fires ever recorded in the state of California, five took place in 2020. [25]
In 2017, a study projected that the single largest threat to Los Angeles County hospitals related to climate change is the direct impact of the expected increase in wildfires. In Los Angeles County, 34% of hospitals are located within one mile of fire hazard severity zones. Additionally, one of these hospitals was also deemed in danger of coastal flooding due to the effects of climate change as concluded by the study. This latter issue was also included and focused on, as the study likewise concluded that this would become a greater hazard as sea level rise due to increase annual temperatures. [26]
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In February 2022, researchers described the drought in the southwest of the US, including California, in the years 2000–2021 as the most severe in 1,200 years, "which is as far back as the data goes." Without climate change, the drought was probably finished already in 2005. [28] 42% of its severity is due to temperature rise as a result of climate change. 88% of the area was drought-stricken. The flow of the Colorado river supplying water to 7 states had "shrank to the lowest two-year average in more than a century of record keeping." If the temperature rise will continue the drought will become worse. [29]
According to the NOAA Drought Task Force report of 2014, the drought is not part of a long-term change in precipitation and was a symptom of the natural variability, although the record-high temperature that accompanied the recent drought may have been amplified due to human-induced global warming. [30] This was confirmed by a 2015 scientific study which estimated that global warming "accounted for 8–27% of the observed drought anomaly in 2012–2014... Although natural variability dominates, anthropogenic warming has substantially increased the overall likelihood of extreme California droughts." [31] A study published in 2016 found that the net effect of climate change has made agricultural droughts less likely, with the authors stating that "Our results indicate that the current severe impacts of drought on California's agricultural sector, its forests, and other plant ecosystems have not been substantially caused by long-term climate change." [32]
In February 2014, the Californian drought effects caused the California Department of Water Resources to develop plans for a temporary reduction of water allocations to farmland by up to 50% at the time. During that period California's 38 million residents experienced 13 consecutive months of drought. This is particularly an issue for the state's 44.7 billion dollar agricultural industry, which produces nearly half of all American-grown fruits, nuts, and vegetables. [33] According to NASA, tests published in January 2014 have shown that the twelve months prior to January 2014 were the driest on record, since record-keeping began in 1885. [34] Lack of water due to low snowpack prompted Californian governor Jerry Brown to order a series of stringent mandatory water restrictions on April 1, 2015. [35]
A study published in Science Advances in 2022 stated that climate-caused changes in atmospheric rivers affecting California had already doubled the likelihood of megafloods since 1920—which can involve 100 inches (250 cm) of rain and/or melted snow in the mountains per month, or 25 to 34 feet (7.6 to 10.4 m) of snow in the Sierra Nevada—and runoff in a future extreme storm scenario is predicted to be 200 to 400% greater than historical values in the Sierra Nevada. [36]
Drought-surviving sugar pines around Lake Tahoe have been found among 129 million trees in California killed between 2012 and 2016 by drought and bark beetles. Thousands of seedlings descended from these trees are being planted south-facing slopes on the lake basin's north side with the hope that they carry genes that make them more resilient to drought, waning snowpack and other effects of global warming in the forests of Sierra Nevada. [37]
2022 IPCC report on climate change and mitigation suggests that California land management needs to consider the changing climate when updating their forest management practices especially when considering the massive amounts of wildfires the region endures. The report suggests that prescribed burning, a popular practice in land and fire management, may not have as beneficial results and often ties adds carbon into the air furthering the problem of climate change and wildfires. [38] [ better source needed ]
Extended periods of higher temperatures are expected to increase navel orangeworm reproduction, resulting in increased insect damage to almond, walnut, and pistachio crops. [39]
Conservation groups are partnering with farmers in Central California to flood fields for portions of the year, in order to increase habitat for species impacted by climate change, such as salmon and migratory birds. [40] [41]
The impact of climate change on precipitation in California can lead to the occurrence of severe drought. [42] During droughts in California, farmers leave land fallow. In 2014 drought season, 430,000 acres of farmland were left to fallow. [43] Farmers anticipate they will fallow a similar number of acres of farmland in 2022. [44]
Ocean heat waves since 2013 have delayed three Dungeness crab seasons, due to harmful algal blooms that contaminate crab meat. [45]
A 2017 study published in the Journal of Geophysical Research projected that a sea level rise of between 1 and 2 m will swallow between one-third and two-thirds of Southern California beaches. [46] Sea levels off the coast are projected to rise 20-55 inches over the next century. [47] The rise of sea levels leads to the destruction of sea life, permanent floods, and coastal erosion. According to an economic assessment done by Risky Business Project, "if current global greenhouse gas emission trends continue, between $8 billion and $10 billion of existing property in California is likely to be underwater by 2050, with an additional $6 billion to $10 billion at risk during high tide." [48]
Expected increases in extreme weather could lead to increased risk of illnesses and death. [49] There are various diseases that will impact Californians as a result to climate change. "Exposure to wildfire smoke has been linked to health problems such as respiratory infections, cardiac arrests, low birth weight, mental health conditions, and exacerbated asthma and chronic obstructive pulmonary disease.17 Longterm exposure to wildfire smoke generated an estimated $76 billion to $136 billion per year in health costs across the continuous United States from 2008 to 2012, with some of the most significant impacts in northern California." [50]
From May to September 1999 – 2003, a study was conducted in nine Californian counties that found that for every 10 °F (5.6 °C) increase in temperature, there is a 2.6 percent increase in cardiovascular deaths. [51]
A study of the 2006 Californian heat wave showed an increase of 16,166 emergency room visits, and 1,182 hospitalizations. There was also a dramatic increase in heat related illnesses; a six-fold increase in heat-related emergency room visits, and 10-fold increase in hospitalizations. [52]
A study of seven counties impacted by the 2006 heat wave found a 9 percent increase in daily mortality per 10 degrees Fahrenheit change in apparent temperature for all counties combined. This estimate is 3 times greater than the effect estimated for the rest of the warm season. The estimates indicate that actual mortality during the 2006 heat wave was two or three times greater than the initial coroner estimate of 147 deaths. [53]
Research suggests that the majority of air pollution related health effects are caused by ozone (O3) and particulate matter (PM). Many other pollutants that are associated with climate change, such as nitrogen dioxide, sulfur dioxide, and carbon monoxide, also have health consequences. [54]
Five of the ten most ozone-polluted metropolitan areas in the United States (Los Angeles, Bakersfield, Visalia, Fresno, and Sacramento) are in California. [55] [56] Californians suffer from a variety of health consequences due to air pollution – including 18,000 premature deaths attributed to various causes such as respiratory diseases as well as a number of other illnesses. [57]
Climate change may lead to exacerbated air pollution problems. Higher temperatures catalyze chemical interactions between nitrogen oxide, volatile organic gases and sunlight that lead to increases in ambient ozone concentrations in urban areas. A study found that for each 1 degree Celsius (1 °C) rise in temperature in the United States, there are an estimated 20–30 excess cancer cases, as well as approximately 1000 (CI: 350–1800) excess air-pollution-associated deaths. [58] About 40 percent of the additional deaths may be due to ozone and the rest to particulate matter annually. Three hundred of these annual deaths are thought to occur in California. [59]
Economic impacts also include inflation from rising insurance premiums, [60] [61] energy costs and food prices. [62] [63] [64]
The Natural Resources Defense Council (NRDC) estimates that under a business-as-usual scenario, between the years 2025 and 2100, the cost of providing water to the western states in the United States will increase from $200 billion to $950 billion per year, an estimated 0.93–1 percent of the United States' gross domestic product (GDP). Four climate change impacts—hurricane damage, energy costs, real estate losses, and water costs—alone are projected to cost 1.8 percent of the GDP of the United States, or, just under $1.9 trillion in 2008 U.S. dollars by the year 2100. [4]
A study conducted in 2009 showed that increases in frequency and intensity of extreme weather due to climate change will lead to a decreased productivity of agriculture, revenue losses, and the potential for lay offs. [5] Changing weather and precipitation patterns could require expensive adaptation measures, such as relocating crop cultivation, changing the composition or type of crops, and increasing inputs such as pesticides to adapt to changes in ecological composition, that lead to economic degradation and job loss. [55] Climate change has adverse effects on agricultural productivity in California that cause laborers to be increasingly affected by job loss. For example, the two highest-value agricultural products in California's $30 billion agriculture sector are dairy products (milk and cream, valued at $3.8 billion annually) and grapes ($3.2 billion annually). [65] It is also expected to adversely affect the ripening of wine grapes, substantially reducing their market value. [66]
California has taken a number of legislative steps and extensive measures and initiatives targeted at the broader issue of climate effects seeking to prevent and minimize the risks of possible effects of climate change [67] [68] by a wide variety of incentives, measures and comprehensive plans for clean cars, renewable energy, and pollution controls on industry with overall high environmental standards. [69] [70] [71] California is known for its leading role in the realm of ecoconscious legislature not just on a national level but also globally. [72] [67] [73]
In 2007, the California Legislature enacted AB 32, the Global Warming Solutions Act of 2006, which required the state to reduce greenhouse-gas emissions to 1990 levels by 2020. [74] It tasked the California Air Resources Board (CARB) with developing a Scoping Plan to implement the statute. [75] AB 32 was consistent with Governor Arnold Schwartznegger's 2005 Executive Order S-03-05, which, in addition, required California to reduce its emissions to 80% below 1990 levels by 2050. [76] CARB updated the Scoping Plan in 2014. [77] SB 32, enacted in 2016, set the State's climate goals beyond 2020, requiring a 40% reduction below 1990 levels by 2030 and an 80% reduction by 2050. [78] The CARB 2017 Scoping Plan, detailing how the State will implement SB 32, sets statewide goals for per-capita GHG emissions: they must be reduced to 6 MTCO2e (metric tonnes of carbon-dioxide equivalent) by 2030, and 2 MTCO2e by 2050. [79] CARB's 2022 Scoping Plan continues the implementation of SB 32. [80]
Climate change is having profound impacts on wildlife in California, altering habitats, species distributions, and ecological relationships. As temperatures rise, many species are shifting their ranges to higher elevations or northward, while some southern bird species are now nesting regularly in the state. These shifts are causing significant habitat loss, with projections suggesting that between 21-56% of California's natural areas may become unsuitable for current ecosystems by 2100. [81] Some ecosystems, such as pinyon-juniper woodland and freshwater marshes, could lose up to 97% of their suitable habitat. [82] Some species that could be affected include the California Spotted Owl. This species relies on stable forest environments with large, old trees. Climate change-induced droughts and extreme weather events disrupt these habitats, affecting their ability to reproduce and survive. [83] The effects also extend to the Central California Coast Coho Salmon: These salmon are vulnerable to habitat changes due to increased droughts and floods. Climate change can degrade their spawning grounds, affecting egg and juvenile survival. [84] Sacramento River Winter-Run Chinook Salmon are also impacted by the worsening of climate change in California. Rising temperatures and reduced water availability due to climate change threaten their spawning success, as they require cold water conditions. [85] The Desert Slender Salamander is an example of an amphibian affected by California’s climate change. This species depends on moist habitats that are increasingly drying out due to higher temperatures and reduced precipitation associated with climate change. [86]
A drought is a period of drier-than-normal conditions. A drought can last for days, months or years. Drought often has large impacts on the ecosystems and agriculture of affected regions, and causes harm to the local economy. Annual dry seasons in the tropics significantly increase the chances of a drought developing, with subsequent increased wildfire risks. Heat waves can significantly worsen drought conditions by increasing evapotranspiration. This dries out forests and other vegetation, and increases the amount of fuel for wildfires.
A wildfire, forest fire, or a bushfire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a bushfire, desert fire, grass fire, hill fire, peat fire, prairie fire, vegetation fire, or veld fire. Some natural forest ecosystems depend on wildfire. Wildfires are different from controlled or prescribed burning, which are carried out to provide a benefit for people. Modern forest management often engages in prescribed burns to mitigate fire risk and promote natural forest cycles. However, controlled burns can turn into wildfires by mistake.
A natural disaster is the very harmful impact on a society or community after a natural hazard event. Some examples of natural hazard events include avalanches, droughts, earthquakes, floods, heat waves, landslides, tropical cyclones, volcanic activity and wildfires. Additional natural hazards include blizzards, dust storms, firestorms, hails, ice storms, sinkholes, thunderstorms, tornadoes and tsunamis. A natural disaster can cause loss of life or damage property. It typically causes economic damage. How bad the damage is depends on how well people are prepared for disasters and how strong the buildings, roads, and other structures are. Scholars have been saying that the term natural disaster is unsuitable and should be abandoned. Instead, the simpler term disaster could be used. At the same time the type of hazard would be specified. A disaster happens when a natural or human-made hazard impacts a vulnerable community. It results from the combination of the hazard and the exposure of a vulnerable society.
Extreme weather includes unexpected, unusual, severe, or unseasonal weather; weather at the extremes of the historical distribution—the range that has been seen in the past. Extreme events are based on a location's recorded weather history. They are defined as lying in the most unusual ten percent. The main types of extreme weather include heat waves, cold waves and heavy precipitation or storm events, such as tropical cyclones. The effects of extreme weather events are economic costs, loss of human lives, droughts, floods, landslides. Severe weather is a particular type of extreme weather which poses risks to life and property.
Effects of climate change are well documented and growing for Earth's natural environment and human societies. Changes to the climate system include an overall warming trend, changes to precipitation patterns, and more extreme weather. As the climate changes it impacts the natural environment with effects such as more intense forest fires, thawing permafrost, and desertification. These changes impact ecosystems and societies, and can become irreversible once tipping points are crossed. Climate activists are engaged in a range of activities around the world that seek to ameliorate these issues or prevent them from happening.
Climate change has been a critical issue in Australia since the beginning of the 21st century. Australia is becoming hotter and more prone to extreme heat, bushfires, droughts, floods, and longer fire seasons because of climate change. Climate issues include wildfires, heatwaves, cyclones, rising sea levels, and erosion.
Climate change has led to the United States warming by 2.6 °F since 1970. The climate of the United States is shifting in ways that are widespread and varied between regions. From 2010 to 2019, the United States experienced its hottest decade on record. Extreme weather events, invasive species, floods and droughts are increasing. Climate change's impacts on tropical cyclones and sea level rise also affect regions of the country.
The 1988–1990 North American drought ranks among the worst episodes of drought in the United States. This multi-year drought began in most areas in 1988 and continued into 1989 and 1990. The drought caused $60 billion in damage in United States dollars, adjusting for inflation. The drought occasioned some of the worst blowing-dust events since 1977 or the 1930s in many locations in the Midwestern United States, including a protracted dust storm, which closed schools in South Dakota in late February 1988. During the spring, several weather stations set records for the lowest monthly total precipitation and the longest interval between measurable precipitation, for example, 55 days in a row without precipitation in Milwaukee. During the summer, two record-setting heatwaves developed, similar to those of 1934 and 1936. The concurrent heat waves killed 4,800 to 17,000 people in the United States. During the summer of 1988, the drought led to many wildfires in forested western North America, including the Yellowstone fires of 1988.
Climate change in Africa is an increasingly serious threat as Africa is among the most vulnerable continents to the effects of climate change. Some sources even classify Africa as "the most vulnerable continent on Earth". Climate change and climate variability will likely reduce agricultural production, food security and water security. As a result, there will be negative consequences on people's lives and sustainable development in Africa.
The effects of climate change on human health are profound and increase the likelihood of many diseases and conditions. There is widespread agreement among researchers, health professionals and organizations that climate change is the biggest global health threat of the 21st century.
Droughts and heatwaves are the main hazards due to the climate of Turkey getting hotter. The temperature has risen by more than 1.5 °C (2.7 °F), and there is more extreme weather.
Climate change in Arizona encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Arizona.
Climate change in Colorado encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Colorado.
Wildfires can happen in many places in the United States, especially during droughts, but are most common in the Western United States and Florida. They may be triggered naturally, most commonly by lightning, or by human activity like unextinguished smoking materials, faulty electrical equipment, overheating automobiles, or arson.
In 2018, several heat waves with temperatures far above the long-time average and droughts were recorded in the Northern Hemisphere: The earth's average surface temperature in 2018 was the fourth highest in the 140 years of record keeping. It is assumed that the jet stream is slowing down, trapping cloudless, windless and extremely hot regions of high pressure. The jet stream anomalies could be caused by polar amplification, one of the observed effects of global warming.
In Afghanistan, climate change has led to a temperature increase of 1.8 °C since 1950. This has caused far-reaching impacts on Afghanistan, culminating from overlapping interactions of natural disasters, conflict, agricultural dependency, and severe socio-economic hardship.
Italy is experiencing widespread impacts of climate change, with an increase in extreme events such as heatwaves, droughts and more frequent flooding; for example, Venice is facing increasing issues due to sea level rise. Italy faces many challenges adapting to climate change including the economic, social, and environmental impacts that climate change creates, and an increasingly problematic death toll from the health risks that come with climate change.
The climate in Texas is changing partially due to global warming and rising trends in greenhouse gas emissions. As of 2016, most area of Texas had already warmed by 1.5 °F (0.83 °C) since the previous century because of greenhouse gas emissions by the United States and other countries. Texas is expected to experience a wide range of environmental impacts from climate change in the United States, including rising sea levels, more frequent extreme weather events, and increasing pressure on water resources.
Climate migration is a subset of climate-related mobility that refers to movement driven by the impact of sudden or gradual climate-exacerbated disasters, such as "abnormally heavy rainfalls, prolonged droughts, desertification, environmental degradation, or sea-level rise and cyclones". Gradual shifts in the environment tend to impact more people than sudden disasters. The majority of climate migrants move internally within their own countries, though a smaller number of climate-displaced people also move across national borders.
The 2022 California wildfire season was a series of wildfires throughout the U.S. state of California. By the end of the year, a total of 7,667 fires had been recorded, totaling approximately 363,939 acres across the state. Wildfires killed nine people in California in 2022, destroyed 772 structures, and damaged another 104. The 2022 season followed the 2020 and 2021 California wildfire seasons, which had the highest and second-highest (respectively) numbers of acres burned in the historical record, with a sharp drop in acreage burned.