This year’s spring LAGS lectures started off talking about fog, or it seems the growing lack of it.
Fog and Climate Change: Now You See It, Now You Don’t
In February, Dr. Steve LaDochy, professor of geosciences at CSULA, presented his research on how climate change is altering the amount of fog both locally and around the world.
To start, there are different types of fog: radiation fog, ground fog, high inversion fog, up slope fog, mt./valley fog, frontal fog, prefrontal fog (warm front), postfrontal fog (cold front), frontal passage, advection (mixing) fog, sea/tropical air fog and land/breeze fog.
Dr. LaDochy though talked about how dangerous fog can be and how it seems that fog is not as prevalent as it once was. Fog is among the worst weather-related accidents, concerning airplanes, cars and ships. Damages can cost billions of dollars and during some years, they caused more deaths via auto accidents in the US than tornadoes and hurricanes combined.
In London, the fog was so bad in December of 1952, that it caused an estimated 4,000 deaths. It’s known as the Great Smog of 1952 or Killer Fog. In Donora, Pennsylvania, there was another killer fog in 1948, which resulted in the deaths of 20 and the sickening of 7,000. Note that in both cases, these killer fogs were a combination of intense fog and polluted air. Thus these two incidents helped to create the clean air acts in both America and the UK.
On the other hand, fog can be a life saver. In one of the driest places on earth, Jorge, Chile there is a fog forest. The plants there take in moisture from fog rather than rain. There are also such things as fog collectors and collection projects where fog is a primary source of water for some villages in Chile, Nepal, etc. Without the fog, these places would be uninhabitable.
Fog though seems to be less frequent than in the past, possibly thanks to climate change. Dr. LaDochy stated that there was more fog in the 1940s and ’50s, about 200 hours a year. In the ’90s, there was only about 25 hours of fog a year. He also stated how there is less dense fog in coastal areas. California sits in a fog belt with its zones of upwelling, creating coastal fog. The ingredients for a Californian fog are cool temperatures, condensation nuclei, strong and low inversion and Santa Ana winds. But El Niños could be changing that.
Dr. LaDochy looked at average annual temperature changes between 1878-2008 and found an increase in the temperature. He also found that smog was decreasing and that when the sea surface temperature is warmer, there is less fog. A study done on the California redwoods warned that the lack of fog may dry them out and that the warming is to blame. Another reason for less or no dense fog can be attributed to the urban heat island effect. Dr. LaDochy said a better predictor of California’s temperatures would be the Pacific Decadal Oscillation (PDO), which has a cycle of 50 years.
In conclusion, Dr. LaDochy stated that Los Angeles seems to be a less favorable place for dense fog and that there is just less fog in general. You can read his paper for more detailed information. To learn more about climate change, oscillation, El Niños and fog check out the ESSEA Modules.