Researcher says sea level rising faster

PORTLAND, Maine -- Sea level has risen between 12 and 20 inches along Maine's coast and as much as two feet in Nova Scotia during the past 250 years, according to a team of international researchers.

It's the biggest rise in the past millennium and global warming is to blame, said Roland Gehrels of the University of Plymouth in England.

"Sea level today is rising faster than at any time in the past when it was subject to natural climate change," the lead researcher said.

He said sea level rose at the end of the 18th century as a result of natural warming. The rate of increase slowed, but then increased in the 20th century as industrialization swept the globe.

The findings were presented at the Geological Society of America's annual meeting last week in Boston.

Gehrels and researchers from the University of Maine, the University of Plymouth and Reading University in England studied sites at Machiasport and Wells in Maine, and at Chezzetcook in Nova Scotia.

Gehrels and his team reconstructed sea levels by using new dating techniques on salt marsh sediments.

Gehrels drilled into the three locations and sampled sediments from the core. He was able to reconstruct the sea level by focusing on a fossilized microorganisms called foraminifera.

He determined how often the marshes were flooded by comparing the levels of foraminifera in the core with those typically found on the surface. That helped him to determine the sea levels.

The reconstructed data for most of the 20th century was verified by tide-gauge records, which date from 1912 in Maine, giving greater confidence of the accuracy of the data going back in time.

"It's a wonderful result. It's really exciting," said Orson van de Plassche of the Free University in Amsterdam, Netherlands, who has conducted similar research at salt marshes in Connecticut.

Gehrels' researchers were able to determine sea levels 1,200 years back at the Maine locations and 300 years back in Nova Scotia.