International Energy Agency chief economist Fatih Birol said Sunday that the pollution caused by Canada's oil sands was not enough to warrant not tapping the resource. The news was a blow to environmental activists opposed to the Keystone XL pipeline project, which would transport oil from the sands.

The Paris-based IEA is one of the major international organizations promoting the use of renewable fuels. In a report last week, it warned that the rise in global temperatures caused by global warming would result in more extreme weather conditions, causing an increase in droughts and floods.

But Birol said building the pipeline, which would go from Canada to the Gulf of Mexico, would actually alleviate that because it would cut dependence on other resources like coal that release more greenhouse gasses into the atmosphere.

"The oil sands definitely makes a contribution to the increase in CO2 emissions. But the difference in getting oil from oil sands when compared to conventional oil, it is such a small contribution that it will be definitely wrong to highlight this as a major source of carbon dioxide emissions worldwide," he said, according to Toronto's Globe and Mail newspaper.