Ottawa is under fire from Quebec and Ontario for its modest greenhouse gas emission reduction targets at the Copenhagen climate talks.

In Denmark on Sunday for the United Nations climate convention, Quebec Premier Jean Charest condemned the federal government for the potential economic consequences of its anemic fight against climate change.

"Commercial sanctions are a real danger for countries refusing to put in place tough targets," he said. "We could be vulnerable."

The premier said Quebec's export-based economy could be an early victim should the European Union act on its threat to impose a carbon tax on products coming from delinquent countries.

Further, the World Trade Organization declared last summer it would be acceptable to impose taxes on imports coming from countries that fail to address climate change or renege on international engagements.

"We have to be on the lookout because we're so dependent on foreign markets," said Charest. "We should have stricter targets in Canada. They're too low."

Charest was backed by Ontario Environment Minister John Gerretsen, who says he doesn't want his province's efforts to allow the rest of Canada to get a free ride.

"We are obviously concerned that the good work we have done may in affect be used by the federal government to allow others not to have such strong targets as we have," he said.

"We want fairness."

Gerretsen said Ottawa's stance "can be an embarrassment," and singled out the ongoing tar sands development in Alberta and Saskatchewan as a specific problem.

"If they are developed there may have to be larger greenhouse gas emission (cuts) elsewhere in the country in order to meet our overall targets," he said.

Both provinces have adopted aggressive reduction targets and are looking to implement cap-and-trade programs.

Quebec, following the EU's example, announced plans to reduce its greenhouse gas emissions by 2020 to 20 per cent below 1990 levels.

The Conservative government has a modest reduction goal of three per cent below 1990 levels. So far, it has no clear plan on how it is going to achieve that target.

And it's unlikely that Canada will meet its obligations under the Kyoto accord, which set its emission reduction target at six per cent below 1990 levels by 2012.

By 2007, Canada's emissions had jumped 26 per cent over 1990 levels, mainly due to tar sands development.

Climate experts suggest countries commit to a drop of 25 to 40 per cent in emissions to avoid a potential two degree rise in global temperatures by 2020.