Great Lakes ice declining despite cold

CLEVELAND, March 23 (UPI) -- U.S. researchers say ice cover on the Great Lakes has declined 30 percent since the 1970s, despite weather cycles that temper the overall warming.

Scientists at the Great Lakes Environmental Research Laboratory in Ann Arbor, Mich., say the heavy ice cover this year shows natural weather systems play a role in the Great Lakes system, The (Cleveland) Plain Dealer reported Monday.

"We are seeing the impact of global warming here in the Great Lakes -- but the natural variability is at least as large a factor," Jia Wang, an ice research climatologist at the laboratory, told the newspaper.

Researchers said ice on the Great Lakes is forming later in the fall and dissipating earlier in spring, even when taking into account annual fluctuation.