A new report commissioned by Environment Canada says the government has little time to waste in putting a price tag on greenhouse-gas emissions before the country experiences severe economic repercussions.

The report by National Round Table on the Environment and the Economy (NRTEE) suggests if Ottawa puts a tax on emissions the long-term economic effects will be manageable.

"Deep, fast early action by the government, strong price signals and a proper price on carbon leaves inconsequential restraint to GDP growth," Glen Murray, chairman of NRTEE told reporters Wednesday. "Any delay in action would have greater and more negative impacts on the economy."

Environment Minister John Baird asked the roundtable to give advice on how to cut emissions by 60 and 70 per cent by mid-century.

The interim report provides cost estimates of emissions reductions of 45 per cent and 65 per cent below 2003 levels by 2050 -- expressed as dollars per tonne of CO2 equivalent.

To attain a 45 per cent reduction target, the price is estimated at $160 and $200/tCO2e in 2050. To attain a 65 per cent reduction target, price estimates are $270 and $350/ tCO2e in 2050. The difference in prices is attributed to the GHG price path scenarios -- 'fast' versus 'slow'.

The higher prices are associated with a 'slow' start, which the paper shows will be extremely costly.

"The findings show that an economy-wide price is required if long-term carbon emission reductions are to be achieved," Alexander Wood, CEO of the NRTEE, told reporters Wednesday.

"It also reminds us that delay is costly, both economically and environmentally and that an emissions price is required sooner rather than later."

If the federal government sets clear emissions prices in the near future, Canadian businesses and investors will be able to make smart, environmentally sound investment choices, says the report.

If provinces know what kind of environmental rules and penalties Ottawa will impose, they can invest in appropriate energy infrastructure.

Don Drummond, chief economist of Toronto-Dominion Bank, says the cost to rectify the damage of inappropriate billion-dollar investments will be staggering.

"On the basis of current technologies, it requires quite a price shock to lower greenhouse gas emissions," Drummond, who has been doing similar research himself, told The Globe and Mail.

"The sooner we get going, the better."

Under Baird's recently released climate plan a tonne of carbon dioxide will be valued at $15 beginning in 2010, rising to $20 in 2013 and annually after that at the rate of growth of nominal gross domestic product.