ORONO – Maine residents and policymakers must simultaneously join the international effort to slash greenhouse gas emissions and prepare for the inevitable yet unpredictable changes wrought by a warming global climate, scientists said Thursday.

“We’re not necessarily going from a good place to a bad place. We are going to a different place and we’re going to need to adapt,” Ivan Fernandez, a University of Maine professor of soil science, told about 450 people attending a two-day climate change conference at the university.

Fernandez and about a dozen other scientists said there have been countless changes in Earth’s climate over history, including several since modern man emerged.

What makes the current climate shift unique – and therefore difficult to predict – is the fact that humankind appears to be playing such a pivotal role.

Paul Mayewski, director of UM’s Climate Change Institute, said carbon dioxide levels in the atmosphere today are at their highest point and are rising 100 times faster than ever before, according to scientific analyses of ice and sediment cores.

Mayewski said exactly what this means to Maine or the Earth is hard to predict. Emissions from natural sources, such as volcanoes, and even humanmade air pollution that blocks some of the sun’s rays, may have actually helped offset global warming.

But Mayewski and others said there are ample examples of abrupt changes in global temperatures and even sea level. And these sudden changes, which sometimes happened over just a few years rather than millennia, were the result of natural factors alone.

That makes the current human-driven climate changes so alarming, researchers said.

George Denton, professor of earth sciences involved with the Climate Change Institute and a member of the National Academy of Sciences, said he doesn’t believe humans should be tinkering with a climate system capable of such dramatic changes on its own.

“It’s in my view something that we should not be fooling with,” Denton said.

But the reality is humans have been “fooling with” the composition of the Earth’s atmosphere for centuries, and particularly since the Industrial Revolution. The amount of carbon dioxide and other heat-trapping gases pumped into the air by the burning of fossil fuels continues to surge.

A warming global climate would present both challenges and opportunities to Maine, the researchers said.

Sea levels would likely rise, inundating some low-lying parts of Maine. Oceans would also likely become both warmer and more acidic, which can harm fish species as well as impede lobsters and other hard-shelled critters from forming exoskeletons.

Warmer temperatures would mean less snow, which would affect Maine’s winter economy, and would change the composition of Maine’s vast forests, starting with sugar maples. But farmers could benefit from a longer growing season and a climate closer to Maine’s southern neighbors, researchers said.

Then again, there’s also the chance of the exact opposite.

A disruption of the global currents and wind patterns through, say, a massive influx of fresh water from the melting Greenland ice sheet could dramatically change global weather patterns. One scenario discussed Thursday is that some areas could experience much higher temperatures while the North Atlantic could be plunged into a cold spell.

“We are taking the Earth into unchartered territory, for sure,” said George Jacobson, a professor of biology, ecology and climate change at UMaine.

Not all of Thursday’s discussion was gloom and doom, however.

State officials discussed steps Maine and other states are taking to reduce greenhouse gas emissions, such as the recently launched regional cap-and-trade program for carbon dioxide from power plants.

Stephen Norton, a professor of earth science involved with the Climate Change Institute, pointed out that atmospheric levels of lead, mercury and other industrial pollutants appear to be declining in Maine and elsewhere across the U.S.

Those reductions appear tied to the implementation of the Clean Air Act, which resulted in much stricter emissions standards for factories.

“If we recognize the problem, we can deal with it,” Norton said. “It’s not going to be easy and some serious decisions have to be made, but I think we have to get on with it.”

UM’s Climate Change 21 conference continues today with several panels of international experts discussing the topics of climate change mitigation and adaptation.

Audio from the conference is being streamed online through climatechange.umaine.edu.

kmiller@bangordailynews.net

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