Sea Level Rise Might Be Worse Than We Thought

Water from melting flows off the Greenland
Ice Sheet. Recent research suggests ice
sheet melting in Greenland and
Antarctica might be worse than first thought. 

The science shifts a little from time to time as to how bad sea level rise is going to get with global warming. The latest study is mostly bad news on this front.

The latest salvo in this discussion is a new study that says melting ice sheets in Antarctica and Greenland are now speeding up the process.

Global warming causes sea levels to rise in two ways: Warmer water expands. When the water heats up, it gets "bigger" meaning it has nowhere to go but up.

The other way sea levels rise is more obvious: Land based ice sheets melt, and the meltwater eventually makes its way to the oceans. Hence, higher water.

The latest research says the pace of sea level rise has picked up over the past 25 years mostly because of the melting ice sheets.

According to The Weather Channel:

"Of the 3 inches of sea level rise in the past quarter century, about 55 percent is from warmer water expanding, and the rest is from leting ice. But the process is accelerating, and more than three quarters of that acceleration since 1993 is due to melting ice sheets in Greenland an Antartica, the study shows."

The bottom line is that by the year 2100, sea levels could rise by two feet, instead of the one foot projections we've commonly heard are due by the end of the century.

One big wild card in all this is probably Antarctica. Will big parts of it keep melting faster and faster? Or will increased snowfall over that continent at the bottom of the Earth offset some of the melt. It tends to snow more when it's warmer, as long as it's not above freezing. A warmer Antarctic climate could increase snowfall. On top of that, some sort of natural cycle has increased snowfall in Antarctica over the past 10,000 years.

A NASA study, using satellite analysis, says the Antarctic ice sheet showed a net gain of 112 billion tons of ice per year from 1992 to 2001. That rate slowed to 82 billion tons of ice per year between 2003 and 2008.

It's possible this net gain trend will reverse itself in coming decades. Plus, everybody knows that parts of Antarctica are indeed showing a melting trend. And other research, including the new work I described above, contradicts the NASA findings.

As you can see, scientists really need to continue figuring out Antarctica and how it relates to climate change.

Meanwhile, things are worse in some areas than others. Changing sea currents and sinking land in some parts of the U.S. East Coast are making things worse. After sinking land amid rising sea levels can never be a good thing.

The combined land sinking and sea level rise means that the sea level in the past 100 years has shown a net gain of 11 inches in New York and Boston, 16 inches in Atlantic City, 18 inches in Norfolk, Virginia and 25 inches in Galveston, Texas.

While some of the research is still a little murky, one thing is clear: It's only going to get worse.