Protesters in Environment Minister Jim Prentice's Calgary office on Monday called for a stronger Canadian policy on climate change. (CBC)

A sit-in at federal Environment Minister Jim Prentice's constituency office in Calgary ended after eight hours Monday with the arrest of seven protesters.

They were charged with criminal mischief and are to appear in court Dec. 31.

Calling themselves Citizens for Climate Justice, the protesters are mostly constituents of Calgary-Centre North. They had crowded into the small reception office at 10 a.m. MT, saying they wouldn't leave unless Prentice agreed to improve the country's policy on climate change.

The group wants Prentice to commit to reducing greenhouse gas emissions by 2020 to 25 per cent of 1990 levels.

Prentice was not in Calgary but held a teleconference with the group late Monday afternoon in an attempt to defuse the situation. His spokesman, David Wilson, said the group was not satisfied with Prentice's response to their demands.

"We, like 75 per cent of Canadians recently polled, are embarrassed by our environment minister's position on climate change," the protesters said in a statement issued after their arrest. "We have talked with Minister Prentice, but the minister still refuses to act to stem the human costs of climate change or turn Canada from a climate laggard into a climate leader.

"After decades of talking, we see only more inaction. We must step up the pressure. So, today we engaged in peaceful civil disobedience, like those before us, to ensure we do our part to solve the greatest environmental and economic threat of our time."