OTTAWA — The federal Conservatives are cancelling a $1.5 million pledge by the previous Liberal government to help developing countries cut greenhouse emissions under the rules of the Kyoto Protocol.

Abandoning the pledge made at a United Nations conference in Montreal last December is another blow to the teetering climate treaty which the Conservative government still claims to support.

The money would have gone to the treaty's clean development mechanism (CDM), which allows industrialized countries to earn credits by investing in emissions-cutting projects in the Third World.

"Taxpayers' dollars will not be spent on international credits,'' said Ryan Sparrow, spokesman for Environment Minister Rona Ambrose, in an interview.

"That's what our government's position has been since taking office.''

Canada was among 20 industrialized countries which collectively pledged more than $8 million for the CDM. Canada's pledge, the biggest of any country, was seen as a big boost for the Kyoto process.

Environmentalists were dismayed to hear the commitment won't be honoured.

"The CDM is so important and it's doing such good work,'' said Green Party Leader Elizabeth May.

"It's economically rational (and) it makes sense because it's a way of outreach to developing countries to get them involved in binding targets.''

One of the Conservative government's main objections to Kyoto is that it does not set emissions-cutting targets for developing countries such as China and India.

In theory, the CDM would provide an incentive for developing countries to participate in the Kyoto process by giving them access to the clean technology.

The mechanism is intended to promote technology transfer from north to south, while ensuring that emissions are cut at the lowest possible cost.

As of June the CDM had about 800 projects in the pipeline, and the UN Climate Change Secretariat estimates it will generate more than one billion tonnes of emissions reductions by the end of 2012.

"The CDM is an excellent, positive feature of the Kyoto Protocol that is channelling billions of dollars to developing countries to fund projects that reduce greenhouse gas emissions,'' said Matthew Bramley of the Pembina Institute.

Cancellation of the pledge highlights Prime Minister Stephen Harper's ambivalence toward the protocol.

Harper has rejected the Kyoto emissions-cutting targets as unachievable but has not pulled out of the treaty. In July he told a British news conference that Canada remains "fully engaged'' in the Kyoto process.

Days later at the G-8 summit in Moscow, Harper endorsed a G-8 communique supporting the Kyoto Protocol and noting the importance of the CDM for the protocol's success.

Some critics claim the prime minister is using Canada's position within the treaty to undermine it, acting on behalf of Washington which has little influence in Kyoto negotiations because the United States is not part of the protocol.

"This exposes the real agenda of the Harper government,'' said Dave Martin of Greenpeace. "This is deliberate sabotage of one of the fundamental Kyoto mechanisms.''

May said she fears that other countries will be influenced by Canada's decision and also withhold promised funding for the clean development mechanism.