Canada is the only country in the world outside the agreement. Prime Minister Stephen Harper's government has been vilified an as outlier on climate change policy in past international meetings.
Harper said Thursday that the U.N. Convention to Combat Desertification is too bureaucratic. Foreign Affairs Minister John Baird called it a "talkfest" that does a disservice to taxpayers. The federal cabinet last week ordered the withdrawal on Baird's recommendation.
Former Canadian ambassador to the U.N. Robert Fowler said the move is a "departure from global citizenship."
The U.N. body has a research committee dedicated to finding ways to stop the spread of droughts that lay waste to farmland across the planet.
Canada's pullout has stoked more criticism of the Harper government's record on the environment. Canada, along with Japan, Russia and New Zealand, joined the United States in opting out of the Kyoto Protocol to reduce greenhouse gas emissions.
Maude Barlow, head of the Council of Canadians and the author of a forthcoming book on global droughts, said the Harper government is "anti-environment" and is more interested in exploiting Canada's mineral and energy wealth as an "energy superpower.
"Anything that they're involved in that can lead to more evidence that we're a planet in crisis environmentally, they don't want to be part of," Barlow said.