Adaptation Tools and Research

Climate Impacts

California is already experiencing the impacts of climate change. The Office of Environmental Health Hazard Assessment (OEHHA) prepares a regular report  tracking indicators of climate change in California tracking indicators of climate change in California. This report documents the many changes that are already underway, including:

  •  Recorded increase in annual average temperatures, as well as increases in daily minimum and maximum temperatures
  •  An increase in the occurrence of extreme events, including wildfires and heat waves
  •  Reduction in spring runoff volumes, as a result of declining snowpack
  •  A decrease in winter chill hours, necessary for the production of high-value fruit and nut crops
  •  Changes in the timing and location of species sitings, including migration upslope of flora and fauna, and earlier appearance of Central Valley butterflies

In addition to these trends that have been documented over decades, the State’s current conditions point to a changing climate. California is in the middle of an historic drought. Recent scientific studies show that such extreme drought conditions are more likely to occur under a changing climate. And, in 2015 alone, California experienced nearly twice the acreage burned through wildfire as the five-year running average. These increases in the frequency and extent of wildfires in the Western United States have been attributed, in part, to a changing climate.

These impacts on physical and biological systems will affect all California residents, regardless of race or income. However evidence is emerging that some of the projected impacts of climate change on human health and well-being are already occurring, often disproportionately in our most vulnerable communities. Indicators such as exposure to urban heat, vulnerability to wildfires, farmworker exposure to extreme heat, and air conditioner ownership and cost show the impacts that climate change is already having on our communities, further exacerbating environmental justice issues.

California's Climate Change Research

California is continually investing in scientific assessments on the potential impacts of climate change in California and reports potential adaptation responses. The Third Climate Assessment, completed in 2012, developed estimates of climate change, downscaled from global models to a more planning-relevant scale, for California over the coming century. Uncertainty in these estimates arises from several sources, including the path that global emissions take over the coming century, and the sensitivity of the atmosphere to future and past GHG emissions. Looking ahead, the State’s Climate Change Assessment  points to a future with continued change. By using several emission scenarios and a suite of global climate models, the Assessment projects that annual average temperatures will increase between 1.8 and 5.4 degrees Fahrenheit by the middle of this century, and between 2.8 and 8.6 degrees Fahrenheit by the end of the century.