OTTAWA — The federal government says it sees no need to change its greenhouse gas strategy despite a new, hard-hitting report -- commissioned by Ottawa -- that shows Canada falling far short of its climate change objectives.

The report by the National Round Table on the Environment and the Economy added up every provincial and federal measure -- existing and proposed -- to reduce greenhouse gases.

It found that Canada is on track to achieve only half of its 2020 target to reduce greenhouse gases by 17 per cent below 2005 levels.

"Canada will not achieve its 2020 GHG emissions reduction target unless significant new, additional measures are taken," the report said.

"More will have to be done. No other conclusion is possible."

In order to actually meet the target, Ottawa would have to take the lead, collaborate closely with provinces and introduce significant new measures to curtail emissions, especially in Alberta, the report concluded.

A spokesman for Environment Minister Peter Kent said the report validates the federal government's approach.

"Our approach is the way to go. It's working," said press secretary Adam Sweet.

He said Kent is in constant contact with the provinces so that regulations at all levels of government complement each other.

"The fact that we're 50 per cent of the way, that's supportive of what we've been saying the whole time," Sweet said. "We are making significant progress.... We recognize that more has to be done. We've always stated this."

The federal government is busy right now developing regulations to curtail emissions in the oil and gas sector, he added. He would not give a timeline for when the rules would be in place or what impact they would have on emissions.

But the opposition NDP says the federal Conservatives' unwillingness to acknowledge the findings of the report, coupled with their scaling back of environmental regulations, prove they have no intention of meeting their emissions targets.

"If you're going to be approving projects without considering greenhouse gases -- and that's going to be the case -- then it will be impossible to meet targets of any kind," said NDP Leader Tom Mulcair.

"They have no intention of meeting those commitments. They can't do it."

The round table's findings that Canada is not on track to meet its emissions targets echoed the conclusions reached by many analysts, as well as the federal environment commissioner. The advisory panel's report, however, is the first full accounting to add every initiative on the books and project emissions out to 2020 and 2030.

The federal government, after several false starts, has decided to regulate each carbon-producing sector one by one, implementing the rules gradually over the coming years.

Provinces have taken their own paths, with British Columbia implementing a carbon tax and Quebec heading toward a cap-and-trade system.

"The history of this file has been fragmented, uneven, uncertain and therefore uncontrollable in terms of saying here's what the outcomes are going to be," the round table's president, David McLaughlin, said in an interview.

So far, provinces are more effective than the federal government in reducing emissions. They are collectively responsible for 75 per cent of the reductions so far -- although that may change as the federal regulations fall into place.

Even so, the report warned that since each province is acting alone and the federal government rarely acts in concert with provincial provisions, overlap and policy gaps are a certainty.

"Governments have talked, have acted to some degree, but sustained progress that Canadians can count on is not yet taking place," McLaughlin said in an introduction to the report.

"We need to move beyond current approaches and have a truly pan-Canadian dialogue on how to do this better. If not, Canada's 2020 target will remain a hope, not a reality."

It is possible to catch up and meet the emissions reduction target -- but only at a high cost and with unprecedented federal-provincial co-operation, McLaughlin said.

The provinces have all told him they want more certainty in federal policy, and they also want Ottawa to at least consider additional measures that would put a price on carbon, he added.

Kent's spokesman, however, said the sector-by-sector approach will prove to be sufficient.

The report pointed out that Alberta is key to making progress.

Since most of Canada's future emissions will come from the oil and gas sector, emission reductions from Alberta will need to make up at least half of the country's total, if the target is to be met.

All other provinces will need to increase their efforts too, even though Nova Scotia and Saskatchewan are on track to achieve their internal targets, and Ontario is close.

"Put succinctly, Canada's target cannot be achieved without emissions reductions in Alberta, but Alberta alone cannot achieve Canada's target," the report said.

The federal government needs to take the lead, and collaborate with provinces in a formal forum that allows all jurisdictions to make serious commitments, McLaughlin said.

The federal government has made an effort to move out of areas of shared jurisdiction. When it comes to the environment, Ottawa is scaling back its role in environmental assessment, allowing the provinces more scope.

And when it comes to tackling greenhouse gas emissions in particular, the federal government has consistently ignored the round table's advice to put a price on carbon and act quickly, in order to spare the country from an expensive panic later.

Now, the federal government is shutting down the round table itself, saying its research can be found elsewhere.

The round table's report contradicted that claim, pointing out that Environment Minister Peter Kent actually commissioned the emissions tally, saying the round table was in "a unique position to advise the federal government on sustainable development solutions."