Catastrophic Weather Imminent with 21st Century Climate Change
A future California may experience droughts, floods, and rising seas, according to researchers from the University of California at San Diego’s Scripps Institution of Oceanography.
During a January webinar, Dan Cayan and Julie Kalansky presented key research findings from their report on climate, drought, and sea level rise. The California Energy Commission funded the work as part of California’s Fourth Climate Change Assessment.
Cayan and Kalansky emphasized the potential to use their findings to manage California’s resources. Their report drew from models that tailored global climate data to California. The study focused on two scenarios: one in which greenhouse gas emissions taper off midcentury, and one in which emissions continue to rise at the current rate.
Both scenarios project an increase in average temperature intensity and frequency of heat waves. In the low emissions scenario, the temperature rise is expected to subside by midcentury, but not before what Cayan described as “the consequence of an additional 2.5 degrees Celsius warming.” A high emissions scenario would produce more severe consequences by the end of the 21st century.
Temperature affects other aspects of climate. Northern California is projected to have shorter, wetter winters and shorter, drier springs. Southern California will be drier year-round. High rain variability and more intense precipitation events would affect the entire state, Cayan said.
“On the other side of the coin, dryness is a really important part of our climate,” he said. “Our future is not only one which sees heavier individual precipitation events, but also more droughts.”
The research found crucial water sources such as lakes, rivers, and snowpacks will drain due to prolonged dry spells, intensifying California’s chronic water shortage. The threat to state water supply will not be a lack of water, but warmer temperatures causing sudden and rapid snowmelt in high elevations.
Without sustained snowmelt over the summer months, California will be less equipped to meet water storage needs. Major water sources for Southern California, such as Lake Mead, are drying rapidly, Cayan said.
Drier land will lead to wildfires, which are projected to spike in the latter half of the 21st century. The fires will occur in bursts and become a more significant problem that California will have to confront in the future, he said.
Cayan said sea levels were also projected to swell by the end of the century, creating risk for essential infrastructure, such as sewage lines or hospitals.
