A group of environmental activists are cutting back on protests in Waterville against a proposed pipeline they say could put the nation on a path toward unavoidable, catastrophic climate change.

The weekly demonstrations were begun in January, when it seemed as though a national decision on the Keystone XL Pipeline, which would carry oil from the tar sands of western Canada to refineries on the Texas Gulf Coast, was imminent.

In the wake of a recent announcement by President Barack Obama that he intended to delay that decision indefinitely, the protesters, part of an environmental group called 350 Central Maine, said they will reduce their demonstration schedule to one Sunday each month.

The controversy surrounding the pipeline has become a significant national issue and is likely to be a topic of debate in the 2014 midterm elections.

Iver Lofving, of Skowhegan, was one of about a dozen people displaying signs to traffic passing their position outside the Unitarian Universalist Church.

Lofving said he was happy about the delay, announced by the White House in mid-April, because he thinks Obama is more likely to scuttle the pipeline after the midterm elections in November.

“The good thing is, the pressure will be off after November,” he said.

Many Republican candidates, including Maine’s 2nd Congressional District hopefuls Kevin Raye and Bruce Poliquin, have touted the $5.4 billion pipeline project as a means of boosting domestic energy production while creating thousands of jobs.

The project’s developer, TransCanada, which saw its stock prices drop in the wake of Obama’s announcement, says the pipeline would support the creation of 40,000 American jobs.

The company also has tried to blunt environmental concerns by citing a series of new safety regulations that it says would make Keystone XL the safest pipeline in the world.

Most crude oil lies in pools beneath the earth’s surface and can be pumped out of the ground using drills and wells.

By contrast, low-grade tar sands oil is mixed with clay and sand in pockets beneath the ground. Before it is refined, it is a thick sludge with a consistency sometimes compared to peanut butter; it cannot flow through a pipeline without being thinned first.

Among the many environmental concerns about tar sands, the tapping of which new technologies have made profitable only in recent years, is that burning the substance produces 5 percent to 15 percent more carbon dioxide than burning traditional oil, according to an analysis by the Cambridge Energy Research Associates.

It is the potential effect on global warming that has moved the pipeline to the top of the agenda for 350 Central Maine.

The group’s name is a reference to the level of carbon dioxide in the atmosphere that it says would be needed to avoid the extreme weather events associated with climate change — 350 parts per million.

Historical levels of carbon dioxide have been 277 parts per million, but current levels are 392 parts per million and expected to increase, not decrease.

The name is used most broadly by the website 350.org, which was founded by author and environmentalist Bill McKibben, and which has spawned many local activist groups, such as 350 Maine and 350 Central Maine.

The larger, international group, which took up the pipeline as a cause in August 2011, has a membership of 530,000 people.

Environmental groups say tar sands are also dirtier to refine, dangerous to ship and more difficult to clean up in the event of spills, while oil companies say it is no more dangerous than traditional crude.

MAINE MAKING NOISE

Maine has played an active role in the ongoing national debate.

In February 2013, 1,400 protesters from across New England and eastern Canada came together in Portland to protest the pipeline reversal.

A 350 Maine rally against the pipeline reversal drew 200 protesters to Sebago Lake State Park last summer.

Area activists made headlines in June 2013 when six of a larger group of 30 protesters from 350 Maine were arrested after they erected a wooden barrier on Pan Am railroad tracks in Fairfield. At the time, a representative for the group said the action was taken to prevent about 70,000 barrels of crude oil from reaching New Brunswick. The district attorney’s office declined to press trespassing charges against the demonstrators at the time.

Two months later, three more protesters affiliated with the group were arrested after staging a mock oil spill on Pan Am railroad tracks used to ship oil through Auburn.

In March, Canada’s National Energy Board approved the reversal of a pipeline that would bring tar sands from western Canada to Montreal, setting the stage for a possible flow of oil through Maine, New Hampshire and Vermont.

The boosting of oil production in Canada has caused Portland Pipe Line Corp, which is owned by Montreal Pipeline Ltd., to consider reversing the flow of a 236-mile pipeline that carries crude oil from tankers in South Portland to Montreal.

On Wednesday, the National Wildlife Federation filed a federal lawsuit to try to force the U.S. Department of State to release documents about the possible reversal in Maine.

Throughout those developments, the weekly protests in front of the Waterville church have been a reminder to the public that the issue still is being decided, according to Richard Thomas, a psychologist at MaineGeneral who also has participated each week.

The activists said public awareness is key to building grass-roots opposition to the pipeline. They said it has become a priority because it could have such a significant effect and because stopping it is an attainable goal.

“This is the big issue in my life,” Thomas said.

Matt Hongoltz-Hetling — 861-9287 mhhetling@centralmaine.com Twitter: @hh_matt