Rise.......

Ocean’s rise takes a surprising turn

By ARIANNA SKIBELL 

Sea levels across the Southeastern United States are rising three times faster than the global average.

That’s according to a new study from the journal Nature Communications, writes POLITICO’s E&E News reporter Chelsea Harvey. Another study published earlier this month in the Journal of Climate found a similar pattern.

The findings suggest that communities along the U.S. Gulf and Southeastern coastlines, from Houston to New Orleans and Miami to Cape Hatteras, N.C., could be at even greater risk from rising tides than scientists had predicted.

In recent years, the already vulnerable landscape has seen increased flooding, more severe hurricanes and eroding shorelines that once provided protection from storm surges. Millions of Americans are watching their shorelines not-so-gradually slip into the ocean as flood damages rise and insurance costs spike.

The science: Human-caused global warming — primarily from burning fossil fuels — is driving sea-level rise worldwide. But the disproportionate rate in the southeastern U.S. is somewhat of a mystery. Scientists agree that physical ocean dynamics are likely to blame, but the nature of those dynamics is less clear.

Researchers thought perhaps the tidal rises were exacerbated by sinking land, a notable problem in parts of Texas and Louisiana. But they found no real connection between sea-level rise and sinking land in the region.

Meltwater from the world’s shrinking glaciers and ice sheets has contributed to a global acceleration in sea-level rise — but it doesn’t fully explain the pattern happening on U.S. coastlines.

Some researchers suggest that warming waters and changing wind patterns have altered the ocean’s circulation in parts of the North Atlantic and the Caribbean, changing the way masses of water flow up to U.S. coastlines. Others say perhaps the increase is being driven by changes in a warm-water current passing through the Gulf of Mexico.

The upshot: Researchers say the accelerated sea-level rise could slow back down eventually, but no one knows if that’s probable or how long it might take — adding another uncertainty to the consequences of a warming planet.