Some types of crude oil are much worse than others when it comes to their role in climate change, and that from Alberta's oilsands is among the worst offenders.

That was the conclusion of a report that compares the greenhouse gas emissions of 30 varieties of crude worldwide — from the oilfield to the refinery to the tailpipe.

The University of Calgary's Joule Bergerson contributed to the report, along with researchers from Stanford University and the Carnegie Endowment for International Peace.

Using publicly available data, the researchers found there was more than an 80 per cent difference between the highest and lowest carbon-emitting fuels on a per-barrel basis.

The total greenhouse gas emissions range for "extra heavy oil" — which includes Alberta's oilsands — were the highest of the bunch, along with "high flare" ones that require excess natural gas to be burned off.

Bergerson says Alberta's oilsands industry was one of the most open with its information, compared with other global players.