Coastal California is a special place. Living here we are well aware of the beauty and opportunity it offers. This ecosystem is incredibly dynamic and changes day-to-day and more drastically over the years. Those living near the coast surely have witnessed the rise and fall of the tides, seasonal storms and accompanying increased wave heights. Walking along the shore during these events we bare witness to the incredible power of the ocean.
For billions of years these processes have been occurring. The moon’s orbit pulls on the ocean creating the predictable high and low tides we see. The wobbling tilt of the earth creates the seasons and effects atmospheric pressure systems creating storms that batter the coast causing erosion. These natural cycles are nothing new. Global sea level has been fluctuating for millions of years through ice ages and interglacial periods.
As you must know, we are currently in a warming trend. Sea levels have been rising for the past 18,000 years and will continue for the foreseeable future. This reality is already starting to create problems for the nearly 100 million people living within three feet of sea level. Though we know the earth is warming and that we will see a drastic increase in sea levels over the next century, scientists are unsure exactly how high and how fast levels will rise. Understanding the answers to these questions will provide us a clearer picture and will inform a more effective response to the issue.
Though we are unsure about some of the specifics regarding the rates of sea level change, we are certain of its cause. Global warming, influenced by both natural processes and the addition of tremendous amounts of greenhouse gases from human activities have contributed to sea level rise by melting ice caps and glaciers and have also caused thermal expansion of our oceans as it slowly warms. Thermal expansion is the increase in waters volume associated with its increase in temperature and has accounted for around ¼ of total sea level rise over the past several thousand years.
As sea level rises, waves break closer to shore causing increased erosion rates thusly creating problems for coastal development. Low lying coastal areas are at increased risks for tidal flooding with some even predicted to be completely underwater by the turn of the next century. Many communities are responding to these issues and planning projects by taking into account predicted increases as well as implementing managed retreats of developments to higher ground.
The ocean is often an unpredictable environment. However, understanding past effects of climate change and predicting and planning for future sea levels will reduce the threat posed by rising tides and will greatly increase our ability to live and interact closely with the marine environment.
Sources:
- Data Points: Griggs, Gary. Introduction to California’s Beaches and Coast. Berkeley and Los Angeles: University of California Press, 2012. Print
- Image: Renda, Dominic, Oceanseed Project – Pleasure Point Sunset, March 2011