Some words just don't seem to go together, and a recent headline caught my eye for that reason. "Can Global Warming Cause an 'Ice Age'?" The research was presented by Dr. Robert Gagosian, president and director of Woods Hole Oceanographic Institution.

He contends that global warming could actually lead to a big chill in some parts of the world, and could soon produce a dramatic cooling throughout the North Atlantic region. This region is home to approximately 60 percent of the world's economy.

Gagosian defines "dramatic" cooling as a winter that would average 5 degrees Fahrenheit colder over most of the United States, and 10 degrees colder in the northeast U.S. as well as Europe. He contends this would freeze rivers and harbors and clog up the North Atlantic shipping lanes, as well as create a rapid growth in glaciers in the Alps.

Farming and fisheries would change dramatically and energy needs would soar. The researcher also believes these changes could happen within a decade and last for centuries.

How could this rapid and worldwide change take place? The Earth-Atmosphere system attempts to maintain a sense of balance by transporting heat towards the equator and moving cold toward the poles.

The atmosphere only distributes about half of the energy that the Earth receives from the Sun. The other half is transported globally by the ocean. It's this ocean circulation system that is not well understood. And while the atmosphere transports weather disturbances rapidly from one part of the globe to another, the ocean moves slowly. When the ocean begins to change its circulation, the resulting climate change can last for centuries.

The Woods Hole research focuses on the Great Ocean Conveyor, a major heat circulation system that keeps our planet from overheating. Heat in the ocean is transported from the equator north and south to each pole. As a warm ocean current moves into higher latitudes, it loses heat into the air. This cools the water, causing it to become denser and sink. The cold water sinks deep into the ocean and returns toward the equator. There it warms, rises to the surface, and begins its journey to the polar region once again.

What if this conveyor system ceased operation? By looking at deep ocean sediments, climatologists can look back in time and estimate the state of the world's oceans. It is estimated that about 12,000 years ago the North Atlantic Ocean waters cooled dramatically. So did the land masses.

It was a cold spell that lasted 1,300 years. Regular changes in the ocean conveyor have occurred, with a change from warming to cooling ocean currents taking place in less than a decade and lasting for up to a thousand years.

Is there evidence the Great Ocean Conveyor is approaching another changing point? Dr. Gagosian says yes. He says the change may come because of too much fresh water in the North Atlantic Ocean. If too much fresh water is added to the salty ocean, the ocean becomes less salty and therefore less dense.

The ocean currents will stop sinking as warm water moves from the equator to northern latitudes. That would cause the warm ocean currents like the Gulf Stream from penetrating into the cold waters of the northern Atlantic. Without warmer water moving into the northern latitudes, the U.S., Canada and Europe get colder.

Oceanographers who measure water conditions in the ocean find that the North Atlantic Ocean is getting fresher, less salty. Where is this fresh water coming from? Global warming may be melting glaciers and Arctic sea ice and this adds fresh water to the oceans. Over the past several decades, there has been a 40 percent decrease in the volume of Arctic sea ice.

Fresh water won't sink like salty water. In fact, the surface waters in the Greenland Sea are sinking at a rate that is 20 percent slower than in the 1970s. Could this be signaling a slowing of the Great Ocean Conveyor?

Dr. Gagosian's research adds another wrinkle to our climate landscape. We know the global temperatures have been warming, whether due to increasing pollutants like carbon dioxide, natural Earth climate cycles, or both. Not as much attention has been focused on the ocean's role in climate change. From what the Woods Hole researchers tell us, the waters of our planet may play a larger role than any of us thought possible.