Having lived in the Midwest for a few years, Woods Hole Research Center scientist Dr. Michael T. Coe knows that global warming sounds good to some ears - it implies shorter winters and higher temperatures.
"But the devil is in the details," Mr. Coe told the full house in attendance for Rising Tide: A Global Warming Forum, held Saturday night upstairs at the Grange Hall in West Tisbury. Three scientists sat on the panel, each with his own method for measuring and predicting the effects of global warming: plant flowering and bird migration, weather trends and sea level change.
The Intergovernmental Panel on Climate Change (IPCC) estimates that the sea level will rise a half meter (almost 20 inches) by the year 2100, but during the forum, which was co-hosted by Polly Hill Arboretum and Martha's Vineyard Museum, Mr. Coe said the estimate is probably low. "It's going to be very hard to keep sea level change to only one meter in this century," he said.
He said ice melting is a process that feeds off itself - the rate of melting increases dramatically as more ice melts. It is not certain how rapidly ice loss could occur in places like Greenland and Antarctica, he said.
"Greenland is already rapidly responding to a 0.7 degree global change in temperature," Mr. Coe said.
He showed maps of Martha's Vineyard with its current shoreline and the shoreline it would have with one meter to three meters of sea level rise. There was a ripple of murmurs as audience members saw the places they know disappear beneath the blue sea.
"That's when I start worrying less about my insurance premiums and more about other issues," Mr. Coe said.
He ended his 15-minute talk on a hopeful note.
"There is a huge difference between a future in which we do nothing and a future if we act now," he said. "Pass on the message that climate change is real. The debate really is over."
Dr. Richard A. Houghton, an ecologist and deputy director of Woods Hole Research Center, gave a slide show overview of global warming. "All I can say about climate change in 15 minutes," he said. Slides full of detailed research showed trends in temperature, carbon dioxide, floods, heat waves and other extreme weather.
One slide showed that the earth's current levels of carbon dioxide are the highest they've been in at least 650,000 years. Climate change is caused in part by burning fossil fuels, which releases carbon dioxide into the air, and deforestation - particularly tropical deforestation - which removes plants that would absorb carbon dioxide, Mr. Houghton said.
Another slide showed that 2005 was the hottest year on record. Mr. Houghton said temperature increases are most marked at high latitudes. The southern hemisphere shows a slower response to climate change because there is less land and more ocean.
Major floods have increased on every continent and extreme heat waves are already twice as frequent as they once were, Mr. Houghton said. Glaciers are disappearing, sea ice is shrinking, permafrost is melting, Greenland is shrinking and sea level is rising, he also said.
Society has three options, he said: mitigation (reducing climate change by controlling its causes), adaptation (dealing with climate change by growing different kinds of crops, for example) or suffering. "Global warming is a misleading term because it implies gradual and uniform - but it's not," Mr. Houghton said. "It's rapid and damaging."
Examining the effects of global warming on a more local level, Boston University biologist Dr. Richard B. Primack told the audience what he discovered when he repeated Henry David Thoreau's research of Concord's flowering plants in the 1850s.
Mr. Primack found that plants are flowering anywhere from four days to one month earlier than in Thoreau's time because of temperature increases. He also found that 20 per cent of the plant species Thoreau documented are now extinct and 32 per cent are now rare. While there were 21 species of orchids in Concord in Thoreau's time, there are now only seven.
Mr. Primack's research determined that most of those plants were lost in the last 40 to 50 years. This is despite the fact that about 30 per cent of Concord is undeveloped and 30 per cent is protected.
For endangered plants, global warming will be the final knockout blow, Mr. Primack said.
"Cities are good places to study climate change because they show us what the rest of the country will be like in the future," he said, noting that temperatures increase from urban development as well as global warming. "Eastern Massachusetts is a great place to study climate change because the temperature has already risen two degrees in the last 100 years," he said.
Mr. Primack also studied wood duck migration by using the notebooks of self-taught naturalist Kathleen Anderson, who documented the happenings around her home in Middleborough for decades. Her notes show that between 1970 and 2000, the wood duck's migration changed from mid-April to late February or early March.
Many birds use day length instead of temperature to determine when to migrate, Mr. Primack said. This has led to what he calls mismatches - ecological balances and food chains that have been thrown off kilter.
For example, the English oak blooms two weeks earlier than it used to, so the winter moth larvae hatch two weeks earlier to feed on the leaves. The pied flycatcher, a bird, would normally arrive when the larvae hatched and feed on them. But when the pied flycatchers continued to arrive at the same time of year, the larvae population was already dwindling. The flycatcher numbers have decreased as a result.
Mr. Primack also showed photographs of a Concord cemetery in May 30, 1868 and May 30, 2005. In 1868, there were no leaves on the trees and the people were clad in heavy winter clothing. In 2005, the trees were in full bloom with lush leaves.
"Eventually, the temperature is going to reach a point that these plants and animals can't survive," he said.
He cited pollution, an increase in deer populations that eat plants, invasive plant species and too many trees that shade the plants from light as other problems. He concluded that it's not enough to buy land for conservation, and said land must also be managed to ensure there are not too many deer or too many trees. He recommended the use of controlled burns.
He also encouraged audience members to do their own version of his Thoreau experiment on the Vineyard - find historical records of plant flowerings and bird migrations and compare them to today.
On the bright side, after many year of trying, Mr. Primack's wife has finally been able to grow a fig tree at their Boston home.