PARIS — The bleak outlook of a major new report on climate change shifted the onus onto governments, even mankind, to take action, with dire warnings Friday from around the world that drastic, rapid change is needed, not least from the United States.

Officials in Indonesia and the Maldives, two archipelagos threatened by rising sea levels, said they feared for the future of their lands. Others said the threat was not simply to the environment, but to international peace, prosperity and development.

South Africa's Environmental Affairs Minister Marthinus van Schalkwyk said failure to act would be "indefensible."

"We are now beyond a critical turning point in the debate: those who continue to ignore the threat and its causes, or invoke half-baked arguments to confuse and obstruct, will be doing the greatest disservice imaginable to current and future generations," said van Schalkwyk. The South African minister said the report "is a wake-up call to the world's largest emitter, the United States."

In Ottawa, Prime Minister Stephen Harper said his government needs to "stabilize emissions" before tackling the more difficult, long-term task of reducing Canada's contribution to global warming.

He said those who propose immediate reductions in Canada's carbon dioxide emissions are dreaming and "we have to talk about facts, not about fantasy."

In Paris, Environment Minister John Baird promised to regulate industry, which accounts for about half of Canada's emissions. He also said Ottawa is working to strengthen the proposed Clean Air Act.

Meanwhile, campaigners and governments pressed industrialized countries to significantly cut greenhouse-gas emissions.

"The more we know, the more precarious the future looks," said Stephanie Tunmore, of Greenpeace. "There's a clear message to governments here, and the window for action is narrowing fast."

There were calls for urgent talks for a new worldwide agreement to stop global warming. Italy's environment minister, Alfonso Pecoraro Scanio, called for a global tax on carbon emissions and a "strong" United Nations organization for the environment.

The long-awaited report from the Intergovernmental Panel on Climate Change said global warming is "unequivocal," "very likely" man-made and will "continue for centuries," findings bleaker than its last report in 2001.

India, which along with China is developing rapidly with a quickly expanding population, faces the challenge of how to develop economically without ruining its environment. A senior ecology official noted that the climate change panel is "a network of scientists" that cannot set policy.

"This is a group of climate experts attempting to reach a scientific consensus. It doesn't commit governments to any course of action," said the official, Pradipto Ghosh, of India's Ministry of Environment and Forests.

The Indonesian environment minister, Rachmat Witoelar, has predicted that some 2,000 of Indonesia's estimated 18,000 islands would be swallowed by the sea within three decades because of man-made climate change. He called on developing countries to commit to cutting emissions by 40 to 60 per cent.

"We want to see our grandchildren enjoy the earth too, don't we?" Witoelar.

Ahmed Saeed, foreign minister of the Maldives, an archipelago of 1,190 low-lying coral islands off southern India, expressed similar fears.

"If the sea level rises permanently it will submerge the whole country forever," Saeed said.

On a cold morning in Madrid, Spain, one mother had a simpler solution.

"I am worried for him more than anything," said Maite Leon, gesturing toward her six-month-old. "By myself I cannot do anything, but if we each do our little bit, maybe we can change things. We have to do it all together."