With only months to go before the White House is expected to make a decision on the Keystone XL pipeline, environmental groups are intensifying efforts to stop the energy project.

The American environmental group NextGen Climate Action is launching four new television ads this weekend.

The $1-million advertising buy will see the messages run during Sunday morning U.S. political shows for the next month.

This comes after a previous ad buy was pulled after an NBC affiliate said it violated its guidelines.

Billionaire Tom Steyer, who founded the environmental group, said it's important the environmental side of the debate is heard.

"From our point of view there's been a one-sided debate about the Keystone XL pipeline, and we've just tried to bring in the other side," he said on CBC News Network's Power & Politics this week.

As well, other environmental groups are planning rallies this fall in both the U.S. and Canada.

Green Party Leader Elizabeth May is hoping to meet with the next U.S. ambassador to Canada once that position is filled.

Canadian leaders make counter-arguments

Meanwhile, the federal government's push to support clearance for the pipeline project will continue this fall.

"Our job is to make sure that the facts are on the table, as opposed to the rhetoric and the noise and the hedge funds managers that are now engaged in this debate," said Gary Doer, Canada's ambassador to the United States.

For much of this year, cabinet ministers and premiers have travelled to Washington to push for the pipeline, some more than once.

The main argument has been that the pipeline would be good for jobs and the economy on both sides of the border.

But recently, U.S. President Barak Obama has questioned how many permanent American jobs the pipeline would create. He said it was possible that number could be as low as 50 to 100, after the initial pipeline construction phase.

In an interview Thursday, Doer emphasized that U.S. oil imports from Canada are increasing every year, so the pipeline proposal is just about how the product will be transported.

"I know people want to make it something it's not. But it's simply as the State Department reported: oil on trains or on pipelines," he said.

Doer said Canada has been making this argument long before the railway disaster in Lac-Megantic, Que.

He pointed out the delay in the Keystone XL pipeline has led to a 47 per cent increase in rail shipments of oil, which, according to the U.S. State Department, means more greenhouse gas emissions. Doer said that should not sit well with environmentalists.

"They're not stopping oil from coming from Canada. They're not stopping oil from being developed in the Bakken oilfields. It's just the way in which it gets here," he added.