Overall temperatures are expected to rise substantially throughout this century. During the next few decades, scenarios project average temperature to rise between 1 and 2.3°F; however, the projected temperature increases begin to diverge at mid-century so that, by the end of the century, the temperature increases projected in the higher emissions scenario (A2) are approximately twice as high as those projected in the lower emissions scenario (B1).
These projections also differ depending on the time of year and the type of measurement (high's vs. lows), all of which have different potential effects to the state's ecosystem health, agricultural production, water use and availability, and energy demand.
There are several available models that project temperature, and this tool allows you to view the results of four of these models throughout different months and scenarios. Data lines represent historic temperature, followed by the four different climate projection models, and an average of these models. Adjust the options above to view different scenarios, models, and months.
This information is being made available for informational purposes only. Users of this information agree by their use to hold blameless the State of California, and its respective officers, employees, agents, contractors, and subcontractors for any liability associated with its use in any form. This work shall not be used to assess actual coastal hazards, insurance requirements, or property values and specifically shall not be used in lieu of Flood Insurance Studies and Flood Insurance Rate Maps issued by the Federal Emergency Management Agency (FEMA).
The data presented in this tool are projections of future climate. They are not weather predictions and should not be treated as such. Climate projections tell us how weather conditions are likely to change on average, but they cannot predict the weather at a particular day and time. Learn more about what climate models can and cannot tell us.
Although climate models are powerful and effective tools for simulating the climate system, there is some uncertainty inherent in any projection of the future, and climate model projections are no exception. For example, climate model projections illustrate how the climate system is expected to behave under specific scenarios of greenhouse gas emissions. Since our emissions of greenhouse gases depend on a variety of different social, political, and economic factors, we cannot be certain how they will change. Therefore, projected climate data may not prove to be accurate if the actual emissions pathway we follow differs from the scenarios used to make the projections.
Another source of uncertainty in climate projections is the fact that different climate models—the tools used to simulate the climate system and produce future climate data—may produce different outcomes. There are more than 30 global climate models developed by climate modeling centers around the world, and they have different ways of representing aspects of the climate system. In addition, some aspects of the climate system are less well understood than others. Climate scientists are constantly working to improve our theories of the climate system and its representation in climate models. In the meantime, one way to account for model differences is to look at projections from many different models to get a range of possible outcomes. You can then take the average of the values across the different models, and this average value is a more likely outcome than the value from any single model. The default visualizations in this Cal-Adapt are based on the average values from a variety of models. Find out more about climate change data.