One of NASA's top scientists will appear at hearings into a proposed oilsands project to warn about the climate change consequences of approving Total E&P Canada's $2-billion plan to build the Joslyn North mine.

James Hansen, head of the Goddard Institute for Space Studies, is slated to testify at public hearings into the proposal, which begin Tuesday in Fort McMurray, Alta.

Hansen, sometimes dubbed the godfather of climate change science and who has spoken out against the oilsands before, will appear for the Pembina Institute, an environmental think-tank that is intervening in the hearing.

"He's a star witness," said institute spokesman Simon Dyer, who suggested Hansen might be appearing at the end of September, about the same time as Hollywood director James Cameron is slated to make his own high-profile trip to the controversial developments.

Total, which received regulatory approval this week for an upgrader to process the bitumen it hopes to mine, is planning to develop a 5,400-hectare site adjacent to the community of Fort McKay along the Athabasca River north of Fort McMurray.

While the company is involved with renewable energy projects, oilsands are an important part of the company's future, said spokeswoman Elizabeth Cordeau-Chatelain.

"There needs to be room for all kinds of energy to be able to supply the energy needs of the people on the globe."

The mine is expected to eventually produce 100,000 barrels of bitumen a day. Total said it would employ 1,650 workers during construction and 600 during operation.

Over the course of the mine's 27-year life, the company projects it would pay $7.5 billion in taxes and royalties to Alberta and Ottawa.

Documents filed with the company's application promise the site will be reclaimed.

"The reclamation program will result in lands that are maintenance-free, with self-sustaining ecosystems," says the project introduction.

The application says air and water emissions are not expected to result in "significant" increases to those are already entering the environment from industry. It also proposes a tailings pond that would be in use for the first 15-20 years of the mine's operation.

But the application faces a host of concerns from local aboriginal groups, environmentalists and even the Regional Municipality of Wood Buffalo, which includes Fort McMurray.

"The (municipality) recognizes the benefit of oil sands development to the economy as a whole but remains concerned about the pace of growth within the region and its ability to manage that growth," says the municipality's submission.

It says the Total project could be the start of another wave of oilsands expansion that would put the community into another round of overwhelming growth.

Aboriginal groups in the area are opposing the development outright, saying it violates their constitutional rights to use traditional lands for subsistence harvesting.

And environmental groups say Total's proposal doesn't represent any significant advance over the last major oilsands project, Imperial's Kearl mine, approved in 2007.

"This is a status-quo oilsands development," said Dyer.

The Kearl panel recommended that Alberta put land-use and wetlands policies in place before any new developments were approved. Those policies are both still in development, with a land-use plan for the region now out for public comment.

Total says mine tailings will be used to gradually reclaim the pit as mining occurs, removing the need to store them permanently in a pond at the end of the project's life. The company says its plan meets new regulatory requirements on tailings ponds, but Dyer said it's not clear Joslyn will live up to them.

Nor has Total made any specific commitments in its proposal on greenhouse gas-reducing technology.

"The project will continue to monitor technology developments that will improve energy efficiency and, where economically viable, will implement process changes to improve energy efficiency and reduce greenhouse gas emissions," its documents say.

Environmentalists calculate that the 1.5 million tonnes of greenhouse gases the project will emit are the equivalent of putting 270,000 cars on the road.

Cordeau-Chatelain said the plan does include environmental advances.

She points out it will be able to store enough water on site for 90 days of operations, which will reduce the need to draw water from the Athabasca River during winter's low flows. As well, it plans to have 60 per cent of the site restored by the end of mine operations, with complete reclamation within another six or seven years.

Still, federal scientists remain concerned about contaminant leakage into the Athabasca River and the gradually increasing cumulative effects of yet another massive industrial development in the region.

"(Environment Canada) remains concerned with the long term cumulative effects of the oilsands developments, especially when the proposed future mines are accounted for," says the department's submission.

The Joslyn North proposal will be studied by a joint federal-provincial review panel.

No proposal for an oilsands mine has ever been turned down.