Volunteers Help UB Scientist Gather Information On Freeze, Thaw Cycles of Hundreds of U.S. Lakes

BUFFALO, N.Y. -- Every winter and spring since the late 1960s, Kenton Stewart, professor of biological sciences at the University at Buffalo, has been making calls and sending postcards to scores of people who live on the shores of hundreds of lakes in the United States.

Lakes of all sizes, with names like Oneida, Cazenovia and Mooselookmeguntic.

Every year, he asks them to record and send to him the dates when their lake freezes in the fall or winter and when it opens or breaks up in the spring.

"Unlike those of us who live in relatively landlocked areas, lake residents are particularly attuned to the dates when their lakes freeze and thaw," Stewart notes. "Regardless of the calendar date for the start of spring, for residents around a lake, spring doesn't start until the lake ice is gone."

Stewart suspects that he monitors freeze/thaw cycles in more lakes than any other scientist in the world. He may have the largest scientific inventory of lake-ice dates in North America, covering more than 250 lakes in New York and several hundred in other states.

In September, data collected by Stewart with the help of his assembly of volunteer nonscientist assistants -- as well as data from 13 other scientists from around the world -- were published in a paper in the journal Science to draw the first global picture of trends in the formation and dissolution of ice on lakes and rivers in the Northern Hemisphere during the past 150 years.

The paper prompted newspaper headlines like "Chilling Evidence of Global Warming."

"Some of the lakes that I monitor in the states of New York, Maine, Minnesota and Wisconsin have been showing evidence of global warming for decades," says Stewart, who teaches limnology, the science of bodies of fresh water, at UB. "I thought that the same thing was probably happening at other lakes around the world, but wasn't sure until all of us brought our data together."

Since the late 1960s, Stewart has been studying lake-ice dates of an increasing number of lakes to see whether they can serve as proxy indicators of climate change.

Now that that point has been proven, he would like to focus his work on how these data compare within a specific region. Such an analysis would help determine how a particular region will fare as a result of climate change.

"Predicting future climate change is easier to do on a global scale than on a local or regional basis," according to Stewart. "We need a far more detailed look at the phenomenon."

Ironically, Stewart, like some of his co-authors on the Science paper, receives no funding to conduct his research; funding agencies have held that lake-ice dates do not demonstrate global climate change. He hopes the Science paper will prompt those agencies to reconsider that stance.

"People who live on the lakeshores notice ice events, but very few people record them," said Stewart, who notes that finding and maintaining contact with people who will record these events, especially in remote areas, is particularly challenging.

"People move, they go south for the winter and worst of all, they die," he added.

Stewart has never met most of those in the loyal ad hoc network of hundreds of lakeside observers with whom he makes contact every year to obtain lake-ice dates.

When trying to identify contacts for a new lake that he wants to add to his study, Stewart may contact a local sporting-goods store, the town hall or the local police station. He often is referred to a new participant by word-of-mouth.

Not long ago, a phone call to identify a new contact in the field appeared headed for a dead end: The man on the phone told Stewart that he didn't have any records on the lake, nor did he know of anybody who did.

"Then, while he was still on the phone with me, he turned to his wife and said, 'You don't know anyone who keeps lake-ice records, do you?' Well, it turned out she had been keeping that information in her diary for 18 years."

Stewart evaluates the general trustworthiness of the data he gets by comparing it with what he knows about the depth and surface area of a lake, as well as other data he has compiled on nearby lakes.

Some of his correspondents provide excellent detail, "as scientific as you can imagine," Stewart said, noting: "I ask a lot of questions, like 'What do you see out your window? Is there snow on the ice? Are there ice fishermen out there? Can you see any waves?'"

While some of the correspondence occurs by mail, Stewart says phoning is best.

"On the phone, I can ask a bunch of questions in a hurry and maintain the personal contact that helps keep people interested and wanting to remain part of the lake-ice network," he adds.