One quarter of humans vulnerable to sea surge

Just to put a rough number on the portion of humanity that might decide to move to higher ground (or build some pretty damn impressive sea walls), a new report from a team at the U.S. Geological Survey reveals that

More than 1 billion people live in low-lying areas where a sudden surge in sea level could prove as disastrous as the 2004 Asian tsunami

Add to that the number of people living less than 100 feet above current sea levels and you get a quarter of the world's population.

But just to provide some perspective to Americans, the article ends with this tidbit from Usery:

A 30-meter surge in Florida would leave the whole state covered except for a little plateau area.

Does this mean that we can expect sea surges and/or tsunamis that rise up to 100 feet? Well, sort of...

The team also found that a 100-foot (30-meter) rise in sea level would cover 3.7 million square miles of land worldwide. A rise of just 16 feet would affect 669 million people and 2 million square miles of land would be lost.

Sea levels are currently rising about 0.04 to 0.08 inches (1 to 2 millimeters) each year, making it unlikely such a scenario would suddenly occur across the globe, Usery [E. Lynn Usery, who led the team] said.

But he said 10,000 years ago sea levels rose 20 meters in 500 years -- a relatively short span -- after the collapse of the continental ice sheets.

"It can happen in a short period of time if we look at the historical data," Usery said.

Using a 500-year example is probably not going to motivate many people at the 50-plus elevation to move. But that billion who are within range of a good-sized tsunami (admittedly not a climate-related event, but becoming more of one as sea levels rise) should seriously be considering a change of scene. The problem for the vast majority of these people is that their livelihoods depend on being at sea level.