OTTAWA — Climate-change activists have once again issued hoax news releases in the name of Canada's Environment minister in an apparent effort to embarrass the Conservative government.

And just as an elaborate ruse by the U.S.-based Yes Men in December 2009 involved a cascade of hoaxes intended to focus attention on Canada's environmental record, the latest effort drew in a respected advocacy group for progressive causes.

A release sent to media outlets used the Environment Canada news template to tout the "re-release" of what it claimed was a two-decade-old teaching tool on climate issues for Canadian students.

The teaching unit, called "What a Difference a Degree Makes," referred to the cultural influences of climate, including movies such as the "Big Chill" and musical groups Air Supply, Weather Report and Donna Summer.

A follow-up release, also phoney, had Environment Minister Peter Kent denouncing the hoax and calling the teaching unit out of date and no longer reflecting government priorities.

The advocacy group Council of Canadians issued a news release congratulating Environment Canada and stating that "proper climate-change education in Canadian schools has previously been neglected by our government" -- but a spokesman for the council says they were in on the joke.