An international environmental organization has ranked Canada and the U.S. last among the G8 nations when it comes to tackling climate change.

With the G8 Summit set to begin on Wednesday, the World Wildlife Fund (WWF) released its semi-annual climate-change "scorecard" today.

The group says Canada is "definitely and firmly in the red" when ranked on its scale of environmental bad guys.

Canada's policies and practices are "sharply at odds" with Kyoto commitments and rank at "the bottom of the heap" when it comes to energy efficiency, says the WWF.

The "climate change litmus test" will be whether Prime Minister Stephen Harper agrees to an ambitious energy efficiency target proposed by Germany, says the WWF.

German Chancellor Angela Merkel wants to see a resolution holding the rise in global temperature to two degrees Celsius, the level at which scientists say damage to the planet can be contained.

Doing so will require a cut in greenhouse gas emissions of at least 50 per cent below 1990 levels by 2050, say the Germans and most other European nations.

The U.S. rejects the initiative and Harper has indicated that he'd like to act as a 'broker' between the two countries.

"By presenting climate promises without action, the Bush administration undermines German Chancellor Merkel's effort to secure a meaningful agreement at G8," said Hans Verolme, director of WWF's Global Climate Change Programme, in a press release. "Canada must break ranks with the U.S. to restore its former reputation as a leader on climate change."

Russia is also ranked among the worst performers in the Group of Eight. Italy and Japan ranked as low-medium when it comes to emissions control.

France, Germany, and the U.K. were all ranked "in the yellow" as they are the only elite countries where greenhouse gas emissions are declining.

On Monday, Harper told a conference in Germany that Canada will not meet its Kyoto targets but that it can still be held up as an example for the rest of the world.

He touted intensity-based greenhouse-gas reduction targets as the solution.

The intensity system calls for less pollution per unit of production but has been widely blasted by environmentalists who say it offers no absolute guarantees that emissions will ever go down.

With files from The Canadian Press