Climate change in California has resulted in higher than average temperatures, leading to increased occurrences of drought and wildfires. During 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] California has taken a number of steps to mitigate impacts of climate change in the state. [6]
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. [7]
A 2011 study projected that the frequency and magnitude of both maximum and minimum temperatures would increase significantly as a result of global warming. [8] The same study further projected that the frequency and magnitude of both maximum and minimum temperatures would likely increase as a result of global warming. [8] 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". [9]
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. [10] 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.
Numerous studies have also found that climate change is increasing the frequency of large and explosive wildfires in California in particular. [11] [12] [13] 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. [14] 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. [15] 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. [16] 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. [17]
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. [18] If the temperatures keep rising, such power outages could become common. [19]
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. [20] 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. [21] Out of six of the biggest fires ever recorded in the state of California, five took place in 2020. [22]
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. [23]
In February 2022 researchers described the drought in the southwest of the USA, 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. [25] 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. [26]
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. [27] 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." [28] 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." [29]
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. [30] 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. [31] 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. [32]
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. [33]
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. [34]
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. [35] [ 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. [36]
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. [37] [38]
The impact of climate change on precipitation in California can lead to the occurrence of severe drought. [39] During droughts in California, farmers leave land fallow. In 2014 drought season, 430,000 acres of farmland were left to fallow. [40] Farmers anticipate they will fallow a similar number of acres of farmland in 2022. [41]
Ocean heat waves since 2013 have delayed three Dungeness crab seasons, due to harmful algal blooms that contaminate crab meat. [42]
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. [43] Sea levels off the coast are projected to rise 20-55 inches over the next century. [44] 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." [45]
Expected increases in extreme weather could lead to increased risk of illnesses and death. [46] 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." [47]
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. [48]
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. [49]
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. [50]
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. [51]
Five of the ten most ozone-polluted metropolitan areas in the United States (Los Angeles, Bakersfield, Visalia, Fresno, and Sacramento) are in California. [52] [53] 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. [54]
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. [55] 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. [56]
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. [52] 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). [57] It is also expected to adversely affect the ripening of wine grapes, substantially reducing their market value. [58]
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 [59] [60] 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. [61] [62] [63] California is internationally known for its leading role in the realm of ecoconscious legislature not just on a national level but also globally. [64] [59] [65]
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. [66] It tasked the California Air Resources Board (CARB) with developing a Scoping Plan to implement the statute. [67] 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. [68] CARB updated the Scoping Plan in 2014. [69] 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. [70] 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. [71] CARB's 2022 Scoping Plan continues the implementation of SB 32. [72]
In physical geography, tundra is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term comes from the Finnish word tunturia, meaning "treeless plain". There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra.
A wildfire, forest fire, bushfire, wildland fire or rural fire 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 distinct from beneficial human usage of wildland fire, called controlled or prescribed burning, although controlled burns can turn into wildfires. Modern forest management often engages in prescribed burns to mitigate risk and promote natural forest cycles.
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.
Global dimming is a decline in the amount of sunlight reaching the Earth's surface, a measure also known as global direct solar irradiance. It was observed soon after the first systematic measurements of solar irradiance began in the 1950s, and continued until 1980s, with an observed reduction of 4–5% per decade, even though solar activity did not vary more than the usual at the time. Instead, global dimming had been attributed to an increase in atmospheric particulate matter, predominantly sulfate aerosols, as the result of rapidly growing air pollution due to post-war industrialization. After 1980s, reductions in particulate emissions have also caused a "partial" reversal of the dimming trend, which has sometimes been described as a global brightening. This reversal is not yet complete, and it has also been globally uneven, as some of the brightening over the developed countries in the 1980s and 1990s had been counteracted by the increased dimming from the industrialization of the developing countries and the expansion of the global shipping industry, although they have also been making rapid progress in cleaning up air pollution in the recent years.
Climate change affects the physical environment, ecosystems and human societies. Changes in the climate system include an overall warming trend, more extreme weather and rising sea levels. These in turn impact nature and wildlife, as well as human settlements and societies. The effects of human-caused climate change are broad and far-reaching. This is especially so if there is no significant climate action. Experts sometimes describe the projected and observed negative impacts of climate change as the climate crisis.
Climate change in South Asia is having significant impacts already which are expected to intensify as global temperatures rise due to climate change. The South Asia region consists of the eight countries: Afghanistan, Pakistan, India, Nepal, Bhutan, Bangladesh, the Maldives and Sri Lanka. In the 2017 edition of Germanwatch's Climate Risk Index, Bangladesh and Pakistan ranked sixth and seventh respectively as the countries most affected by climate change in the period from 1996 to 2015, while India ranked fourth among the list of countries most affected by climate change in 2015. The Indian subcontinent is one of the most vulnerable regions globally to a number of direct and indirect effects of climate change, including sea level rise, cyclonic activity, and changes in ambient temperature and precipitation patterns. Ongoing sea level rise has already submerged several low-lying islands in the Sundarbans region, displacing thousands of people.
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 affects regions of the country.
Climate change has serious effects on Russia's climate, including average temperatures and precipitation, as well as permafrost melting, more frequent wildfires, flooding and heatwaves. Changes may affect inland flash floods, more frequent coastal flooding and increased erosion reduced snow cover and glacier melting, and may ultimately lead to species losses and changes in ecosystem functioning.
Pollution in California relates to the degree of pollution in the air, water, and land of the U.S. state of California. Pollution is defined as the addition of any substance or any form of energy to the environment at a faster rate than it can be dispersed, diluted, decomposed, recycled, or stored in some harmless form. The combination of three main factors is the cause of notable unhealthy levels of air pollution in California: the activities of over 39 million people, a mountainous terrain that traps pollution, and a warm climate that helps form ozone and other pollutants. Eight of the ten cities in the US with the highest year-round concentration of particulate matter between 2013 and 2015 were in California, and seven out of the ten cities in the US with the worst ozone pollution were also in California. Studies show that pollutants prevalent in California are linked to several health issues, including asthma, lung cancer, birth complications, and premature death. In 2016, Bakersfield, California recorded the highest level of airborne pollutants of any city in the United States.
The environmental impact of the energy industry is significant, as energy and natural resource consumption are closely related. Producing, transporting, or consuming energy all have an environmental impact. Energy has been harnessed by human beings for millennia. Initially it was with the use of fire for light, heat, cooking and for safety, and its use can be traced back at least 1.9 million years. In recent years there has been a trend towards the increased commercialization of various renewable energy sources. Scientific consensus on some of the main human activities that contribute to global warming are considered to be increasing concentrations of greenhouse gases, causing a warming effect, global changes to land surface, such as deforestation, for a warming effect, increasing concentrations of aerosols, mainly for a cooling effect.
Climate change is impacting the environment and human population of the United Kingdom (UK). The country's climate is becoming warmer, with drier summers and wetter winters. The frequency and intensity of storms, floods, droughts and heatwaves is increasing, and sea level rise is impacting coastal areas. The UK is also a contributor to climate change, having emitted more greenhouse gas per person than the world average. Climate change is having economic impacts on the UK and presents risks to human health and ecosystems.
The effects of climate change on human health are increasingly well studied and quantified. Rising temperatures and changes in weather patterns are increasing the frequency and severity of heat waves, wildfires, droughts, floods, landslides, hurricanes, and other causes of injury and illness. Heat waves and extreme weather events have a big impact on health both directly and indirectly. Direct effects of exposure to high and extended temperatures include illness, reduced labour capacity for outdoor workers, and heat-related mortality.
Deforestation is a primary contributor to climate change, and climate change affects forests. Land use changes, especially in the form of deforestation, are the second largest anthropogenic source of atmospheric carbon dioxide emissions, after fossil fuel combustion. Greenhouse gases are emitted during combustion of forest biomass and decomposition of remaining plant material and soil carbon. Global models and national greenhouse gas inventories give similar results for deforestation emissions. As of 2019, deforestation is responsible for about 11% of global greenhouse gas emissions. Carbon emissions from tropical deforestation are accelerating. Growing forests are a carbon sink with additional potential to mitigate the effects of climate change. Some of the effects of climate change, such as more wildfires, insect outbreaks, invasive species, and storms are factors that increase deforestation.
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.
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.
As the most populous state in the United States, California's climate policies influence both global climate change and federal climate policy. In line with the views of climate scientists, the state of California has progressively passed emission-reduction legislation.
In Italy, widespread impacts of climate change are currently being felt. With an increase in extreme events such as heatwaves, droughts and more frequent flooding, Italy faces many challenges adapting to 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.
This article documents events, research findings, scientific and technological advances, and human actions to measure, predict, mitigate, and adapt to the effects of global warming and climate change—during the year 2022.