Short-term effects include volcanic eruptions and the El Nino phenomenon, characterized by a warming in the tropical Pacific. Long-term effects include the release of "greenhouse gases" into the atmosphere and natural climatic cycles.

"There is no absolute definitive proof that the recent warming is an effect of greenhouse gases...but we expected warming and warming has occurred," McElroy says.

"I believe in the need to be cautious. The possibility for rapid climate change is real."

Even without definitive proof that human-produced gases are warming the earth, McElroy says we must take action to reduce toxic pollutants.

He cites the discovery of the ozone hole over Antarctica in the 1970s as evidence of the folly of delaying. "If we'd known about it in the 1960s then it wouldn't have happened," McElroy says. "Now we will feel its effects until the 2300s."

McElroy may worry about milder winters, but there are plenty of people who are glad to be free of snow and cold.

To the city's growing homeless population milder winters are something of a boon.

Sam S. Ellcock Jr., assistant director of the Cambridge Corps of the Salvation Army, says the number of those seeking shelter increases by as much as 50 percent during snow and cold.

Ellcock was homeless himself until four years ago and recalls sleeping in unlocked cars and on heat grates in order to escape the cold. "A couple of times I almost froze, got frostbite. It was real brutal, real hard."

Still, some shelters worry that milder winters keep homeless people on the streets and away from shelters and other services--such as substance abuse programs.

Although four distinct seasons were once a source of regional pride, many Cantabrigians now seem somewhat ambivalent about the recent tame winters.

Young has fond memories of the beauty and silence that carried across the city after the Blizzard of '78. "It made us feel very dependent on nature's willingness to keep us here," he says.

But even Young isn't sad to see the ground bare and students walking around without coats.

"My ideal winter would be roughly 67 degrees, a gentle breeze, early budding crocuses, and two beautiful sounds: the sound of a robin and the sound of a lacrosse ball landing in the cradle."