In the wake of the July 6 explosion of a train carrying crude oil from North Dakota through Maine to Lac-Megantic, Quebec, opponents of so-called tar sands crude oil gathered Saturday at Sebago Lake State Park to protest transportation of the bituminous oil across Maine and call attention to the threat to the lake from the pipeline.

Bill McKibben — one of the country’s foremost experts on climate change and founder of 350.org — told about 200 people gathered near the beach that their organized action against tar sands oil is working, but that the threat to the state, the country and the world from climate change is still very real.

“The whole world is just coming apart,” McKibben said. “When I first wrote about this 25 years ago … it was pretty abstract. There is nothing abstract about it now. Someplace around the world, every single day, people are dying [from climate change].”

The event was organized by 350 Maine, a statewide group whose stated goal is addressing the climate crisis. Sass Linnekin of 350 Maine said the group is working to ensure that the owners of the Portland Pipeline, the 63-year-old, 236-mile-long pipeline that transports crude oil from tankers off the coast to South Portland to Montreal — and which passes by a cove of Sebago Lake — do not reverse the flow on the pipeline, and that they don’t use it to transport tar sands oil, which is considered more corrosive to aging pipes.

“Our lakes are freezing later in the fall and thawing sooner in the spring,” said Connie Cross, who worked to pass a resolution in the town of Naples opposing transporting tar sands oil through the pipeline. “Sometimes this big lake doesn’t freeze at all. That never happened 30 years ago. I think we all have reason to be concerned.”

Bill Palmer, who owns a home in Raymond, said he worries about the lake where he grew up. His house, on Jordan Bay, is “a couple tenths of a mile from the pipeline. I don’t trust a 63-year-old pipeline at all. I don’t want tar sands. Go with solar and windpower and stop messing around with coal and all of this nasty stuff. Science is telling us our planet is in trouble.”

Read Brugger, who along with five others was arrested June 27 for protesting the transportation of crude oil through the state, said their message that day was simple: “Stop sneaking dirty fracked oil through Maine. Nine days later, the world woke up to the horror of Lac-Megantic. The rail disaster in Lac-Megantic is emblematic of a system that has lost its moral compass.”

McKibben said Saturday’s protest, like larger-scale action around the country — in particular, those against TransCanada’s proposed Keystone XL pipeline, which would carry the controversial oil sands bitumen from Alberta, Canada to the Gulf of Mexico — are having an impact.

“Two years ago when they started building the Keystone XL pipeline, everybody said it was a done deal,” McKibben said. “They haven’t built it yet.”

McKibben said he’s confident tar sands oil will not be transported by pipeline through New England.

“Your governor is not a paragon of environmentalism — at least that’s how it looks from a distance,” McKibben said prior to the rally. ‘But I think the people of Maine are. They’re standing up in town after town after town. I imagine it won’t be long before Augusta is following the people on this one.”