Fog isn’t unique to California but it is associated with San Francisco, keeping the city chilly.
Strangely, the Bay Area had a warm summer this year, with a daily average high lingering below 70 degrees Fahrenheit during June, July and August, per The New York Times.
This visible absence may have been celebrated by many who were able to walk without clinging to their jackets. But this fog plays many important roles in the local ecosystem.
It's a water source for the redwood forest and provides coolness for agricultural areas around the Bay Area. Changes in this weather pattern could be life-altering for humans as scientists try their best to understand a tricky phenomenon that is nature’s ghost.
“It’s an incredibly sensitive point between water being vapor, and water being liquid,” said Alicia Torregrosa, a project scientist at the U.S. Geological Survey and director of the Pacific Coastal Fog Project, told Inside Climate News. “And that transformation, that transition, (is) driven by more things than you can even count.”
As the level of fog lowers, it indicates that the power balance of the ecosystem is in turmoil. Climate change may have something to do with it. Other coastal California cities are also struggling.
Todd Dawson, an integrative biology professor at the University of California, Berkeley, told the news outlet that in the 1950s, Santa Cruz got at least 12 hours of fog every season. Now, it’s down to nine hours, with the fog season being shorter, too.
“Of about 1,000 stations, 600 or 700 show a statistically significant decrease. All over Europe, all over North America, South America — everywhere,” he said, per the Times.
“Fog has decreased, more or less everywhere,” said Otto Klemm, a professor of climatology at the University of Münster in Germany. The decrease was because of two main reasons — climate change and lower levels of air pollution.
But that’s the tricky thing with fog — its form is ever changing.
The Times report summarized the problem perfectly: “To say that fog is increasing or decreasing depends on so many variables. Is this valley, this hill, this beach, this city as foggy as it used to be? How can you really tell?”
When Santa Cruz tried looking for an answer in its 2019 integrated regional water management plan, the city acknowledged that “the future of coastal fog under climate change remains uncertain” as temperatures rise.
What the report did find was that a decrease in coastal fog can create water scarcity.