A Blue View: Rising Seas
Published June 26, 2013
A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.
From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.
Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.
June 26, 2013: Rising Seas
Click here to listen to John discuss the impact
climate change is having on rising sea levels.
On these hot summer days, our thoughts tend toward ice cream cones and tall glasses of ice water on a sweltering afternoon rather than the melting of ice sheets around the world. But just as the ice melting in your glass causes the water level to rise, so too does the melting of the world’s ice shelves.
Perhaps you've seen the incredible videos of massive chunks of ice breaking away from a glacier, causing crashing impressively into the sea. Until recently, it was thought that this was the primary cause of ice loss in Antarctica. But in fact, a study by NASA and university researchers indicates that warming oceans are also dissolving the ice from underneath the ice shelf at unprecedented rates, causing the greatest loss of Antarctic ice shelf mass. Scientists plan to use these data to help determine how ice shelves melt, improving projections of how the ice sheet might respond to a warming ocean and contribute to sea level rise.
Ice loss is not just occurring at the poles: NASA researchers have discovered that glaciers outside of the ice sheets of Greenland and Antarctica lost an average of 571 trillion pounds of mass each year during the six-year study period, causing sea levels to rise almost two-tenths of an inch during that time. This actually matches the sea level rise attributed to the combined ice loss of the Greenland and Antarctica ice sheets.
Ice melting isn’t the only contributor to sea level rise. Warming temperatures cause waters to warm and expand. In turn, warming waters take up more volume. This phenomenon is called thermal expansion. The combination of ice melting and thermal expansion means that sea level rise is not just a possibility…it is happening now, and the only question is how fast it’s going to rise.
Many scientists now believe that sea levels will rise by no less than one to two feet by 2100. And without dramatic reductions of greenhouse gas emissions, the threat could be much more substantial.
The East Coast in particular is at greater risk from sea level than other areas of the world, mainly due to ocean currents and differences in seawater temperature and ocean salinity, according to climate scientists. The U.S. Geological Survey found that sea levels from North Carolina to Boston climbed by about 2 to 4 millimeters a year between 1950 and 2009 as compared to a global average of one-half to 1 millimeter.
These amounts may seem small and unimportant, but the repercussions from these rising levels are anything but. Imagine increased coastal flooding, shoreline erosion, loss of wetlands, and destroyed homes and businesses on the order of superstorm Sandy. Sea level rise does affect us all.
We need to take steps to control warming, as sea surface temperature and sea level rise are inextricably linked. According to the EPA, sea surface temperatures have risen at an average rate of 13 one-hundredths of a degree per decade since 1901. As small as that may sound, over 112 years, that’s an increase of one and a half degrees, which is already impacting not only sea level, but also coral reefs and other essential ocean habitats, migration and breeding patterns, the intensity of storms, and the spread of invasive species and marine diseases.