Global Sea Levels to Rise About 2.3 Meters with Each Degree of Warming

Global warming has resulted in a major shift in climate patterns and another consequence of this change has been the rising sea levels. A latest  research indicates that sea levels could rise to about 2.3 meters or more than seven feet for every degree the planet warms over several thousand years.

The latest study published in the Proceedings of the National Academy of Sciences is one of the first to collectively analyze the four major contributors to potential sea level rise. The result was then compared with past sea level responses to accelerating global temperatures.

"The study did not seek to estimate how much the planet will warm, or how rapidly sea levels will rise," noted Peter Clark, an Oregon State University paleoclimatologist and author on the PNAS article. "Instead, we were trying to pin down the 'sea-level commitment' of global warming on a multi-millennial time scale. In other words, how much would sea levels rise over long periods of time for each degree the planet warms and holds that warmth?"

Clark continued to say that the simulation of the future scenarios were consistent with the evidence of the rise in sea levels from the past.  "We saw that around 120,000 years ago, the sea levels rose five to nine meters higher when it was 1-2 degrees warmer. We found this to be consistent with what the models suggest will happen in the years to come."  

According to the scientists, on a global scale the four major contributors to the rising sea levels will be the melting of glaciers and Greenland ice sheets, expansion of the oceans in response to warmer climate and the melting of the Antarctic ice sheet. In the past, several studies have analyzed each of the components separately but this is the first study that combines different analysis into a single one.

In order to calculate how the four areas respond to the warming, the researchers ran more than hundred simulations through their model.  The results were linear. They found that the response of sea level and the amount of melting corresponded.

Greenland was the only exception where it seems the response to warming can be higher.  Clark predicts that the temperature in Greenland will eventually increase due to the elevation loss. The temperature warms to about six degrees for every 1000 meters elevation loss. This loss will accelerate the melting of the Greenland ice sheets.  On the other hand, Antarctic ice sheets are so cold that they are not affected by it.  The ice sheets melt as a result of calving of icebergs that drift and melt in warmer waters.

Clark concludes, "Keep in mind that the sea level rise projected by these models of 2.3 meters per degree of warming is over thousands of years. If it warms a degree in the next two years, sea levels won't necessarily rise immediately. The Earth has to warm and hold that increased temperature over time. However, carbon dioxide has a very long time scale and the amounts we've emitted into the atmosphere will stay up there for thousands of years. Even if we were to reduce emissions, the sea-level commitment of global warming will be significant."

Rising sea levels will lead to frequent coastal flooding. Some islands will be totally submerged. This is a serious threat as nearly 10 percent of the world's population resides in vulnerable areas that are just 30 feet above the sea level. Reports  from NASA satellite reveal that since 1993 sea levels are rising at the rate of 3 millimeters per year.