In recent years, climate change is said to have caused more frequent and more violent natural disasters, such as Hurricanes Irma and Harvey, according to a December 2017 BBC report. Closer to home, climate change created the conditions that exacerbated 2017’s destructive California wildfires.
What people may not realize is that between the more impactful natural disasters, many smaller problems can affect the environment in significant ways. One such problem is land subsidence. According to a report published by Science Magazine on March 7, written by Manoochehr Shirzaei and Roland Bürgmann (professors of Earth science at Arizona State University and UC Berkeley respectively), up to 260 square miles of coastal land around the San Francisco Bay could be at an increased vulnerability of flooding by the year 2100 due to sea level rise and land subsidence. According to the report, land subsidence (the gradual sinking of Earth’s crust) is currently less than two millimeters per year, but it could one day reach and exceed 10 millimeters per year in some areas.
While that is less than one inch of land, it could cause major problems in the future, such as an increased likelihood of flooding for coastal communities. According to the United States Geological Survey, it could also affect water flow in the California Aqueduct, which brings water from the Sierra Nevada Mountains to Southern California. Fine-grained sediments, which break off from landmasses during subsidence, could contaminate the interior of the aqueduct. Minor changes in the inside structure of the aqueduct could slow down water flow within the aqueduct, limiting the amount of water that travels through it.
Even more significant than land subsidence is the process of sea level rise, a direct result of global warming. Enough sea level rise can lead to increasingly damaging storm surges. During a storm this April, the parking lot at Stinson Beach collapsed. Events like this have show that sea level rise is a real environmental problem and must be addressed. Many different people and organizations such as The Surfrider Foundation have gone to great lengths to address these problems. Others, such as Redwood AP Environmental Science teacher Mitch Cohen, have studied these problems.
“You can see it just driving around here on a super high tide; it doesn’t necessarily have to be a big storm event, but when you have king tides, you go through low-lying areas. Even right out front here [on Doherty Drive by Redwood] you can see that the roads flood,” Cohen said.
Combined with a large storm with lots of rain runoff, higher tides created by sea level rise can create dangerous flood conditions.
“[High tides create] a one-two punch [with large storms], where the water doesn’t have anywhere to go and then you get flooding,” Cohen said.
According to Cohen, while humans are the most significant cause of climate change, we can still help to limit the damage it creates.
“The question of what we can do falls into two major categories. There’s mitigation, and that’s stuff that individuals and communities and companies can do to try to prevent climate change,” Cohen said. “The other thing that gets probably not as much attention is what we call adaptation strategies. And as sea levels rise communities are going to need to think about adapting.”
As stated by Cohen, mitigation strategies attempt to reduce the amount of greenhouse gases in the atmosphere, such as using renewable energy like solar or wind power. Adaptation strategies can include building sea walls to keep water from damaging communities, as well as moving inland to avoid potential water damage altogether.
According to Cohen, water expands as it gets warmer. Along with the melting of polar ice caps adding freshwater to the oceans, this causes sea levels to rise. According to satellite data collected by NASA since 1993, sea levels have risen by an average of 3.2 millimeters per year. That is an increase in the rate of sea level rise according to NASA and Australian scientific research agency CSIRO (the rate of sea level rise between 1870 and 2000 was approximately 0.65 millimeters per year). According to those statistics, the rate of sea level rise in the past two decades is nearly five times what it was in the previous 130 years.
According to Scott Tye, chairman of the Marin chapter of the Surfrider Foundation, many people are dedicated to solving this problem.
“Our chapter for the last two or three years has determined that [sea level rise has] to be our number one priority. So we do beach cleanups, we do water testing, we do all of these other things, but they really are impacted by climate change. [It] makes the problem much worse,” Tye said.
The Surfrider Foundation was founded in 1975 by surfers in Southern California who were concerned with the pollution of the ocean. They were able to stop coastal developments to protect public beach use and the environment. For example, in 1989 the Surfrider Foundation was able to stop the development of a marina at Bolsa Chica beach in Huntington Beach, CA that would have limited public use of the beach and put the local environment at risk. Since then the Surfrider Foundation has grown to become an internationally-known stewardship conservation organization, dedicated to the ocean in the same way that the Sierra Club is dedicated to the land and forest.