More than 100 Canadian and U.S. researchers are calling on Canada to end expansion of its oilsands, for 10 reasons that they describe as "grounded in science."

"Based on evidence raised across our many disciplines, we offer a unified voice calling for a moratorium on new oilsands projects," said a statement issued Wednesday by the group, led by academics at the University of Waterloo, Simon Fraser University and the University of Arizona.

The statement, signed by a range of researchers including biologists, political scientists, physicists, economists and geographers, including a Nobel Prize winner and several Order of Canada recipients, is being sent to Prime Minister Stephen Harper, MPs and the Canadian media.

The group says it has requested meetings with federal politicians to discuss the science behind their reasons in favour of the moratorium. Those include concerns about carbon emissions making climate change worse, hampering the shift to clean energy, environmental contamination, aboriginal rights, and potential effects on international policy. The researchers also cited evidence that stopping oilsands expansion won't hurt the economy.

Marc Jaccard, a professor in the School of Resource and Environmental Management at Simon Fraser University who co-authored the statement, said the group is targeting the oilsands primarily because most of them are Canadian.

"So of course you try to clean up your own backyard before you start pointing your finger at others," Jaccard said.

Carbon deal signed

He added that the scientists are not calling for existing oilsands projects to shut down — they just don't want new ones to start up.

"No new oilsands or related infrastructure projects should proceed unless consistent with an implemented plan to rapidly reduce carbon pollution, safeguard biodiversity, protect human health and respect treaty rights," the letter says.

That makes good sense, he added, given that G7 leaders, including Prime Minister Stephen Harper, have just agreed to end the use of fossil fuels by 2100.

"Would you really want to start new investment and expansion on something you want to shut down in next few decades?"

The statement is a follow-up to a commentary published in the scientific journal Nature last year that also called for a moratorium and was signed by just eight researchers.

Scientists want wider debate

Jaccard said that since then, other researchers from many different fields have approached him wanting to become more engaged in public debate about the issue.

Jaccard remembers one scientist who studied British Columbia's pine trees, decimated by a pine beetle expansion made worse by warming temperatures.

"This little scientist studying pine beetles and the foot of Godzilla called climate change comes down on top of it," Jaccard recalled.

"He said, 'I feel silly. Why am I just studying this thing and not trying to help humanity do something?"'

David Schindler, a University of Alberta ecologist, agreed.

"Everyone in this group really sees what climate change is starting to do to our ecosystems and the potential for harming society in major ways."

The harm will be more than environmental, suggested David Keith, who teaches both physics and public policy at Harvard.

"The world is going to gradually decarbonize and the decisions will not be driven from Alberta," he said.

"The deeper we get into a commitment to these large projects, the better off we are in the very short term, but the worse off we are in the long term. We'll be worse off economically when there are real restrictions on carbon emissions."

The scientists are urging action now, no matter what the price of oil.

Greg Stringham of the Canadian Association of Petroleum Producers said science will make the industry sustainable.

"There are thousands of other scientists working across the world on behalf of industry and government to ensure that these oilsands are developed responsibly," he said.

The answer isn't a moratorium, but even more spending on research to mitigate the industry's impacts, he said.

"It's applying technology in an accelerated fashion that's going to be the answer to the future of where oilsands goes."