OTTAWA — Canada’s environment minister on Thursday heralded a possible continental climate change pact with the United States, saying US President Barack Obama has opened the door.

“At this point in history there is an enormous opportunity to work together as North Americans to achieve real focused and concerted progress on the environment,” Environment Minister Jim Prentice told reporters.

He pointed to the new US president’s willingness to tackle warming and his support of multilateralism, in contrast to the previous US administration.

Earlier, Prentice testified at a House Environment Committee that “Canadian and American governments need to work to ensure that respective policy and regulatory frameworks are coherent and mutually supportive, and that the road to reduced emissions travels straight through the heart of our two nations, towards one common target.

“Going forward, we can’t predict how talks with the US will play out, but we can say with certainty that the time is right for these discussions to take place,” he said.

“We must work together … with our continental partners, to find common ground that is good for Canada, good for the US, and good for the planet.”

Canada had agreed under the international Kyoto Protocol to reduce carbon dioxide emissions to 6.0 percent below 1990 levels by 2012, but emissions have instead increased by more than 35 percent.

In 2007, the Canadian government outlined a new plan to cut CO2 emissions 20 percent, based on 2006 levels, by 2020, saying the targets agreed to by the previous administration were unattainable.

Its reluctance to implement tougher measures stemmed in part from Washington’s refusal to ratify Kyoto.

There was a fear in Canada that since US companies would not be affected by the Kyoto Protocol — because the United States did not sign on to the accord — that Canadian companies would be at a trade disadvantage. The two nations are the world’s largest trading partners.

Prentice outlined for House committee his desire for a common North American target for reducing CO2 emissions, and a common North American cap and trade system.