A UN-led climate change report released Friday says keeping greenhouse gas emissions near current levels would cost only a tiny fraction of world economic output, but that more drastic reductions are needed by 2050 in order to keep global warming in check.

The summary of the Intergovernmental Panel on Climate Change's third report this year said keeping greenhouse gas emissions between 445 and 710 parts per million by 2030 would cost three per cent of global GDP — or 0.12 per cent annually — or less.

A Skytrain moves along elevated tracks Friday in Bangkok, Thailand, where delegates to a conference hailed a policy statement as a key advance toward battling global warming.
(Sakchai Lalit/Associated Press)

Greenhouse gas concentrations are now at about 430 ppm, but the report warns that, if current trends continue, emissions are expected to rise between 45 and 110 per cent by 2030.

Two earlier reports this year said the continued rise in greenhouse gas emissions could be disastrous for the planet's health, saying that rising temperatures and sea levels could lead to extinction of species, coastal flooding and water shortages in arid regions.

"If we continue doing what we are doing now, we are in deep trouble," cautioned Ogunlade Davidson, the chair of one of the working groups at the weeklong conference in Bangkok, Thailand, where the report was unveiled.

The report suggests a number of strategies for reducing emissions, including:

• Improving energy efficiency in buildings.
• Switching from coal to sources of renewable energy like solar power.
• Increasing fuel efficiency in vehicles.
• Improving crop and land management.
• Introducing economic measures, such as energy incentives or carbon trading initiatives.

University of Toronto climate change expert Danny Harvey, one of the lead authors of the report the summary was based on, said the findings are a wake-up call for those who think climate change policies are economically unachievable.

"There are a lot of people who say that if you start reducing emissions you'll ruin the economy," Harvey told CBC News Online. "But these are just scare tactics."

But to keep global temperatures from rising more than two degrees Celsius above pre-industrial levels, emissions would have to stabilize by 2015 and be reduced by between 50 to 85 per cent by 2050, the report said.

Must reduce fossil fuel dependence

Achieving these drastic reductions may be difficult to manage given our current reliance on fossil fuels, said Bob Evans, the director of the University of British Columbia's Clean Energy Research Centre.

"Worldwide we depend on fossil fuels for 80 per cent of our total energy consumption so it will take a long time to completely eliminate our use of fossil fuels," he told CBC News.

But while the task seems daunting, Evans said the only way to deal with the problem is quickly.

"We need to start working on things now to get to as good a position as possible by mid-century, I think," he said.

Contributors to the report were pleasantly surprised by how much of it stayed in Friday's document after delegates from over 120 countries spent a week of wrangling over the wording.

Almost no changes were made, said John Drexhage, the director of the International Institute for Sustainable Development's climate change and energy program, and one of the lead authors of the report.

Almost no changes were made, said John Drexhage, one of the lead authors of the report.
(CBC)

"It unexpectedly went the way I expected," Drexhage told CBC News Online.

Drexhage said now that the scientists have spoken it's time for the politicians to establish the regulatory framework needed to make these goals achievable.

The report is the third of four to be produced by the Intergovernmental Panel on Climate Change this year. The first report laid down the scientific foundations for the next three, stating that global warming was "unequivocal" and very likely caused by man-made greenhouse gases produced from the burning of fossil fuels.

The second report — which so far has only come out as a summary for policy-makers — looked at the consequences of global warming, predicting widespread extinction of species and water shortages in the developing world if temperatures were to rise by even two degrees.

A fourth report, summarizing the finding of the previous three, is expected in the fall.

With files from the Associated Press