As the Copenhagen climate change summit opens, Canadian environmental activists are urging the government to go much further than they are planning to cut greenhouse gas emissions.

“Our demand is clear: Base Canada’s climate change plan on what the science tells us is necessary,” John Bennett, executive director of Sierra Club Canada, told reporters in Ottawa on Monday.

Bennett said Canada must commit to reducing emissions by at least 25 per cent below 1990 levels by 2020.

“We make this demand knowing full well that it won’t be an easy target and that it will have a cost. But we owe it to our children to act and to act now," he said.

Prime Minister Stephen Harper has said Canada’s target is for a 20-per-cent reduction from 2006 levels of greenhouse gases by 2020. The proposal also includes a cap-and-trade system with the United States.

Robert Fox, executive director of Oxfam Canada, said climate change is claiming lives in the global south through drought and violent weather.

“Canada has a critical role to play in terms of leadership at Copenhagen in putting serious money on the table because, in fact, billions of dollars are required this year and every year into the future in order to ensure that we can protect lives and protect livelihoods.”

He said there needs to be additional funding for adaptation to climate change, but stressed that it "isn’t about robbing development funding in order to pay for climate change.”

The conference — which is expected to draw about 15,000 people — is aimed at reaching a new agreement on controlling greenhouse gas emissions

Climate negotiators and political leaders from 192 countries, including Canada, are attending the summit