BAR HARBOR – Students from all over Maine and the Northeast gathered this weekend at College of the Atlantic with a collective goal – to save the world.

At a time when the increasing threat of global warming has gathered momentum in discussions internationally, COA was host to the third annual Maine Climate Change Summit from Friday through Sunday.

Alison Drayton, a climate change negotiator for the United Nations and the summit’s keynote speaker, called global warming a major worldwide challenge in the same vein as poverty and violence.

“The most distressing thing about this debate is that 30 years after it’s been discovered, we’re still debating rather than implementing change,” Drayton said Friday before a crowd of about 75 students.

A report released last week by the Intergovernmental Panel on Climate Change concluded with 90 percent surety that global warming is caused by humans.

Drayton addressed the landmark report within the first five minutes of her speech and challenged the young audience to do its part to reverse what is happening.

“Addressing climate change is a daunting task because we’re so heavily reliant on fossil fuels,” she said. “But to say, ‘There’s nothing you can do,’ is just wrong.”

Drayton’s advice to the summit’s participants, many of whom were COA students, was simple and familiar: Think global, act local.

Simple changes such as taking warm showers rather than hot ones, using energy-efficient light bulbs and investing in “green” companies go a long way.

“Even minor changes in energy consumption can make a huge difference,” she said.

The weekend summit, though highlighted by Drayton’s speech, also featured several workshops exploring the many facets of climate change.

On Saturday, Sara Lovitz of the Natural Resources Council of Maine led a discussion about the Regional Greenhouse Gas Initiative, which aims to reduce emissions from major power plants.

Juan Pablo Hoffmaister, a COA student, member of the environmental youth group SustainUS and one of the summit’s organizers, led a workshop on the current international climate change policy.

“This is the unprecedented challenge of our time,” Hoffmaister said of global warming. “And we all share that challenge. As youth, we have the opportunity to shape our future.”

Drayton was part of a team that helped shape the current policy, something known as the Kyoto Protocol, an agreement to reduce greenhouse gas emissions.

More than 150 countries are participating in the Kyoto Protocol, but the United States is not among them.

Students listening to Drayton’s speech were more interested in what will happen when the protocol’s goals run out in 2012.

“It’s too difficult to predict,” she said. “And no one wants to go there. A lot of people are very entrenched in certain positions.”

She also said the United Nations can do little without the support of its member nations.

“Policy has to be set by governments,” she said.

COA, a liberal arts school of nearly 300 students, traditionally has been forward-thinking in its approach to environmental issues.

Last year, it’s new president, David Hales, who worked with Drayton years ago, introduced an initiative to make COA the nation’s only “net-zero” campus in terms of greenhouse gas emissions.