Scientists say the Arctic will remain on thin ice and climate warming will begin affecting the Antarctic as well.

Oceanographer James Overland says the North and South Poles have responded differently to similar levels of solar radiation and greenhouse gases. Sea ice in the North shrank to a record low last summer. But there's been little change at the bottom of the Earth.

Researchers have concluded that global warming and climate variability reinforced one another in the North, taking away sea ice. But the ozone hole over Antarctica masked conditions there, keeping temperatures low over most of the continent. But federal oceanographer James Overland says global warming will begin to affect the South Pole as the Ozone hole fills in.

As for the Arctic, he says it's likely last summer's record low levels of sea ice will be matched this year.

Overland says he used to be a global-warming skeptic but he says what's happening now is "startling."