The Other Changing Sea Level

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In his final State of the Union address, President Obama put more emphasis on climate change than ever before [1]. Scientists no longer dispute the fact that humans are having an impact on the earth, and global leaders have come to an agreement that involves taking actions to fight climate change and mitigate its negative effects [2].

The impacts of climate change are already visible around the world, from extreme storms and fluctuating temperatures, to long droughts and threatened agricultural productivity. These changes are difficult to predict because modern civilization has never experienced any periods of such extreme warming. However, polar ice is indisputably melting faster than it can be replenished by snowfall accumulation [4], and governments all over the world are already preparing for and combating sea level rise.

So, how will climate change and sea level rise impact the drying Salton Sea?

Prehistorically, we know that the Salton basin was occupied by Lake Cahuilla, which was part of the greater Colorado River basin. However, the Colorado River delta silted up over time, eventually leaving ancient lakebeds, such as the Salton Sink and Laguna Salada, sitting far below sea level without any connection to or from the ocean[3].

Delta
Map of the ancient Colorado River delta region, including the Salton basin. Image obtained from San Diego State University Center for Inland Waters [9]
Over the last century, annual sea level rise has doubled and still continues to accelerate [4]. Sea level rise is the result of a combination of:

  1. Thermal expansion: As ocean water gets warmer, it is able to store more heat energy and thus take up more volume.
  2. Glacial melt: As temperatures in polar regions increase, glaciers that are currently solid ice on land will eventually melt, and increase the liquid volume in the ocean.

Unfortunately, variables like ocean salinity and local temperature differences make it difficult to estimate the rates and extent that each of these changes will occur [4].

In 2013, the National Climate Assessment, conducted by NASA, released models of predicted global temperature change by 2100 [5]. In their best-case scenario (B1, in the video below), in which actions are taken to globally reduce environmental impacts, different parts of the world will experience between 2° and 5°F of warming. In the worst-case scenario (A2, in the video below), in which global development continues while ignoring environmental impacts, some parts of the world could see nearly 15°F increases by 2100. At that point, the Salton Sea would be well on its way to connecting with the Sea of Cortez.


NASA visualization of predicted changes in annual and summer temperature, based on the best- and worst-case carbon emission scenarios [5].

While the rate of change is difficult to accurately predict for the relatively short-term future, what we do know is that our actions during this century will essentially lock in the increased sea levels at some point in the future[6]. Carbon persists in the atmosphere and continues to affect the earth long after it is emitted. This means that even if we stopped burning fossil fuels today, the sea level will continue to rise for hundreds and thousands of years[7].

It would take about 30 feet of sea level rise to connect the Salton Sink to the ocean and permanently fill it again. Realistically, climatologists expect at most 2 meters (about 6.5 feet) of sea level rise by 2100[8]. But, you can play with sea level change models like this one and see that without significant reductions to our carbon emissions and/or physical intervention to block sea level rise, the Salton Sink (as well as all of the area reaching from Imperial Valley to the Sea of Cortez) will eventually be permanently under water.

Salton Sea
These maps from Climate Centrals Surging Seas project show that even with current carbon emissions, Mexico’s Laguna Salada is guaranteed to eventually be permanently connected to the Sea of Cortez. If we don’t reduce our future carbon emissions, the earth could potentially warm as much as 4 degrees Celsius, and the sea level would eventually rise enough to reach and fill the Salton basin. You can check out the impacts of sea level rise around the would under various climate scenarios at choices.climatecentral.org

What will be the repercussions of increasing temperatures and sea levels as it pertains to the Salton Sea? Let us know what you think in the comments, and we’ll be back with another post on the various potential consequences soon!


 

[1] Dokoupil, T., Obama goes big on climate change. MSNBC, January 12, 2016. Available at http://www.msnbc.com/msnbc/obama-goes-big-climate-change

[2] United Nations Conference on Climate Change, More details about the agreement. Available at http://www.cop21.gouv.fr/en/more-details-about-the-agreement/

[3] Schoenherr, Allan A., A Natural History of California. University of California Press, New York, NY, 1995.

[4] Intergovernmental Panel on Climate Change, WMO, UNEP. Climate Change 2013: The Physical Science Basis, Chapter 13: Sea Level Change. Available at http://www.ipcc.ch/report/ar5/wg1/

[5] National Climate Assessment: 21st Century Temperature Scenarios. Visualizations by Greg Shirah. March 7, 2013. Available at http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4029

[6] Strauss, B.H., Kulp, S., Lenermann, A. (2015) Carbon choices determine U.S. cities committeed to futures below sea level. Proceedings of the National Academy of Sciences, 112, 44 (13508-13513). Available at http://www.pnas.org/content/112/44/13508

[7] Climate Central’s Surging Sea: Mapping Choices. Available at choices.climatecentral.org

[8] Pfeffer, W.T., Harper, J.T., O’Neel, S. (2008) Kinematic contraints on glacier contributions to 21st-century sea-level rise. Science, 321, 5894 (1340-1343). Available at http://science.sciencemag.org/content/321/5894/1340

[9] San Diego State University Center for Inland Waters. Salton Basin-Colorado Delta Mothersite. Available at http://www.sci.sdsu.edu/salton/SaltonBasinHomePage.html

5 comments on “The Other Changing Sea Level”

  1. Thank you for rediscovering this map.

    It provides additional evidence the Imperial/Coachella Valley is the northern arm of the Colorado River delta.

    The Colorado River was a navigable river at the time of California’s Statehood. Steamboats started using it as early as 1948.

    The California State Lands Commission says a river extends laterally over its entire flood plain and longitudinally from headwaters to the sea, lake or sink.

    As the delta of the river, the doctrine of public trust applies to all areas of the Salton Sea and especially to the activities associated with the Quantification Settlement Agreement, which is ruining the lake.

    The California State Water Resources Control Board has an affirmative duty to take the public trust into account in the planning and allocation of water resources, and to protect public trust uses whenever feasible, according to the decision by the State Supreme Court concerning Mono Lake more than twenty years ago.

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  2. Aside from the sea levels rising due to warming, what are the chances of the San Andreas taking one big slip and bringing in the Sea of Cortez? It is a known fact that the western side of the fault is moving northward little by little…does it not stand to reason then that ocean water from the Sea of Cortez will find it’s way northward along that fault line and eventually flood the Imperial Valley, reclaiming the land?

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    1. Hi Art,

      Thanks for this interesting inquiry. My geologic engineering background is quite limited, but I will look into this more and perhaps we’ll publish a full blog post on the topic in a few weeks. Stay tuned!

      Holly Mayton

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  3. The Sea of Cortez has extremely high (and low) tides resulting from the long narrow funnel shape of the Sea. High tides are up to 15′ above sea level. The Sea of Cortez will breach the hill into the Salton Sink long before some scientific “sea level” average gets that high. Once “sea level” rises about 10′ it will only take one well timed hurricane coming up from the south during a full or new moon. The ocean waves will wash over the sandy hill and rush into the Salton Sink. The hurricane will pass and the tide will fall, but the breach will get bigger/lower with every high tide. The good news is that if the oceans rise ten feet we’ll have a lot bigger problems to worry about all over the world and the Salton Sea refilling will be the least of our problems.

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