(CBS News) WASHINGTON - The National Weather Service Thursday gave us its forecast for the rest of 2012. It's already been a volatile year for weather, and that's just the tip of the iceberg.
The ice that for millennia nearly covered the Arctic Ocean has been melting so quickly that the polar ice cap today is the smallest it's been since satellite record-keeping began more than 30 years ago.
Today, the polar ice cap is about half the size than it was in 1980. And the remaining ice is thinner than it used to be, making it more likely to melt next summer.
David Robinson, a climatologist with Rutgers University, said the record for melting sea ice was shattered in 2007.
"We thought that might be the record for quite a while," he said. "And here we are, just five years later, and we've shattered that record. We're seeing losses of sea ice I never thought I'd see in my career."
Robinson said the Arctic could be ice free well before the previous estimate of the year 2050. That's bad news for polar bears who live on sea ice, but it could also mean extreme weather for much of the northern hemisphere.
"We might change the pattern of the jet stream," he said, "might make it flow further to the north, and dip further to the south, be a more windy-twisty jet stream."
That could generate more storms and even greater extremes in temperature. Through the first eight months of 2012, 33 states set all-time records for average highs.
Government scientists said Thursday that trend is likely to continue at least through December, making this the warmest year on record, especially in the Midwest and northeast.
There's one possible piece of good news. If the jet stream does become more windy-twisty, that could mean more rain in the south and the Great Plains -- rain that's desperately needed after years of drought.