Sea Level Rise: How bad is it really going to be?

by Gabi Goodrich, RJD Intern

For years scientists have been discussing the effects of global warming, carbon emissions and those effects on the oceans. But how bad is it really? Currently the rate of sea-level rise is about 3.2 millimeters per year (about .13 inches per year) ^[1].  However, with our current output of carbon emissions, scientists say that rate will increase tenfold. This means we have “locked in” a fate of sea levels rising 1.3 – 1.9 meters (4.27 – 6.23 feet) higher than today. Anders Levermann and his team of scientists have found that the sea levels are hyper sensitive to global warming. In fact, for every degree Celsius increase in global temperature, sea levels will rise about 2.3 meters (7.55 feet).

Based on our current carbon pollution emissions and using physical models with support of ancient sea level responses to temperature change, Levermann and his team dispute the widely accepted 2 ºC increase as a “safe level.” Instead, they say with the 2 ºC increase, global sea levels would rise a mean of 4.8 meters (15.75 ft.).  To put that in perspective, that rise is twice the height of hurricane Sandy’s peak storm surge at The Battery in New York City and surpasses average elevations of major coastal cites worldwide ^[2].

If sea level rises according to current projections, it will be devastating for areas like the Florida Keys. Photo by Gabi Goodrich

So what then does this mean for American coastal cities? Nearly 18 million people and 1,400 municipalities would be submerged at high tide by the end of the century. Even if there were cuts to lower emissions, around 500 municipalities would be affected. Regardless places like Miami, Florida, Virginia Beach, Virginia, Jacksonville, Florida, and Sacramento, California have “locked in” a watery fate. So what do we do? Can we cut emissions completely? Levermann says having an annual average reduction of carbon emissions lower than 5% is impossible. Trying to achieve such low emissions could put strains on the economy. Furthermore, political inertia also creates strains.  Although reaching that 5% is futile, reductions in carbon emissions could lessen the impacts of sea level rising.

The point Levermann is trying to make is not when sea levels will rise, but by how much and why. He and his team are trying to warn us of the impending danger and leaving us to find a feasible solution to the irreversible damage that has already been done. With all the bad news and what seems like a dark future, although we cannot fix what has been done, we can take steps to reduce the implications of our actions. The window is quickly closing, however. If we do not take steps towards a change, our watery future will not be thousands of years away but hundreds.

REFERENCES

1. “Sea Level Rise.” National Geographic. National Geographic Society, n.d. Web. 01 Sept. 2013. <http://ocean.nationalgeographic.com/ocean/critical-issues-sea-level-rise/>.
2. Strauss, Benjamin H. “Rapid Accumulation of Committed Sea-level Rise from Global Warming.” Rapid Accumulation of Committed Sea-level Rise from Global Warming. PNAS, 20 Aug. 2013. Web. 21 Aug. 2013. <http://www.pnas.org/cgi/doi/10.1073/pnas.1312464110>.