Is the Rise in Sea Level Reversible?

November 23, 2013

With one side portraying climate change as doomsday for the earth and the other side calling it a load of hodgepodge, the science can sometimes get lost in the political debate.  Both factions can quote statistics and facts that will back up each of their arguments, which coupled with the media pressure to report both sides evenly causes confusion within the non-science population.  One thing that could help slightly clear the befuddlement is for the people to educate themselves on global warming science with primary sources (i.e. science papers).  However, this is much easier said than done. It would be extremely difficult, for every person to read, much less comprehend, all scientific literature. For the average person, the style of writing and terminology can convolute the conclusions the reader was meant to grasp. The IPCC summary that was recently released provides a good summary of much of the scientific literature.  Here, I present a summary of a paper not submitted in time for inclusion into the report.

This paper has to do with the rise in sea level, a consequence of increased emission of greenhouse gases (mainly CO2) in the atmosphere. While this is a miniscule part of the body of climate change research, hey, I’m only one person.

The EPA has a good explanation of why rising sea levels is detrimental to the earth.  The IPCC has a more detailed explanation of the causes and effects of sea level rising.  The figure below is from the IPCCC website . 

This figure shows that sea levels have risen in the past and are projecting to dramatically increase over the next 100 years.

Because of these dramatic predictions, scientists are looking into whether sea level rise can be slowed or even reversed.  The paper I am going to summarize is The Reversibility of Sea Level Rise by N. Bouttes, J. M. Gregory, and J.A. Lowe.  To start off, here is the abstract.

This study explores the correlation between CO2 increase and sea level rise.  They use a 3D atmosphere-ocean general circulation model (AOGCM) to see how emissions of CO2 affect peak sea level.  Below are the results from several models that these and other scientists have used to describe and predict sea level and surface temperature changes. 

The conclusions from this study are as follows:

 

·      Sea level changes depend not only on the cumulative emission of CO2 but also the time profile of emission.  This means that the longer CO2 has been emitted the larger the sea level change.  It is not just the total amount of CO2 that matters but the time period in which it was been released.  These scientists recommend that future policy should focus not only on reducing the cumulative CO2 emission, but also the rate of emission as well.

·      Theoretically, sea level rise is reversible.  Reducing and stabilizing emissions would halt and maybe reverse the sea level rise, but removing CO2 from the atmosphere would reverse it more quickly.  This would require geoengineering technology, which may have negative side effects and has its own controversy. 
 

There are a few implications that these conclusions have on future negotiations.  Countries should not only focus on their total CO2 emissions but also on their rate of emissions.  Lowering the total level CO2 emitted, may not be enough to halt sea level rise.  It also suggests that geoengineering techniques should be explored more.  According to the models, removing CO2 from the atmosphere will be an effective way in reversing sea level rise.

For the entire research paper, click this link.

Hopefully, this summary of a single recent publication will clarify the science on one aspect of global warming.  Rising sea levels are a problem directly linked to increased CO2 emissions.  The goal is that clear conclusions will allow the political debate to be more on the solution rather on the severity of the problem.

--Vanya Britto