To assist with this issue, in 2014 RCPA teamed with scientists to develop a local assessment of climate risks and produce the Climate Ready Sonoma County: Climate Hazards and Vulnerabilities report.
The risks, uncertainties, and volatility associated with climate change pose potentially high costs to communities in terms of public health, safety, economic vitality, security, and quality of life. While some uncertainty remains in the timing of changes – especially due to uncertainty regarding future global greenhouse gas (GHG) emissions scenarios – there is enough confidence in projected trends to begin the work of preparing for climate hazards now. Preparing now will yield more cost-effective and flexible strategies than delaying action until responding to unprecedented conditions.
The first step to respond to climate change locally is to assess our exposure to climate hazards. Across all four of the representative climate futures Sonoma County can expect to experience:
Hotter, drier weather with longer summers
More variable rain
Sea level rise
Projected future changes in air temperatures vary across the county. In Figure 6, the map shows the geographic distribution of changing temperatures using the “hot/dry” future scenario, which is a conservative scenario to use when planning for heat-related hazards. Inland valleys and mountain ridges are most affected, and some regions experience no change.
Whether the North Bay region experiences more or less rainfall over the year, our land and watersheds will be hotter and drier overall due to rising temperatures and increased evapotranspiration (the process of transferring moisture from the earth to the atmosphere by evaporation of water and transpiration from plants.) Climatic water deficit (CWD) is a numeric measure of drought stress which quantifies plants’ need for water that exceeds moisture available in the soil. CWD is projected to increase over this century, producing 10-20% drier conditions in the Summer months, leaving less water available for recharge and runoff.
