In speeches greeted with occasional ripples of applause, the long-term critics of Western policy lashed out at what they called the hypocrisy of the world’s wealthy elite.
Mr Chavez, the President of Venezuela, was one of the first world leaders to take the podium at the venue of the Copenhagen talks.
He seized the occasion to characterise newly-minted Nobel Peace laureate US President Barack Obama as a warmonger.
"I don’t think Obama is here yet," said Mr Chavez.
"He got the Nobel Peace Prize almost the same day as he sent 30,000 soldiers to kill innocent people in Afghanistan."
Mr Obama, who picked up his Nobel last Thursday, is expected to arrive in Copenhagen on Friday for the climax of the 12-day world conference on climate change, according to the US delegation.
Mr Chavez, paraphrasing Karl Marx, said "a ghost is stalking the streets of Copenhagen… it’s capitalism, capitalism is that ghost."
"The destructive model of capitalism is the eradication of life," he said.
Recalling how rich nations last year swiftly pumped hundreds of billions of dollars into their faltering banking systems, he added: "If the climate was a bank, they would have already saved it."
Bolivian President Evo Morales, the Andean nation’s first indigenous leader, said that the capitalist system itself bore blame for climate change.
"Climate change isn’t a problem of technology or financing," he said at a press conference, referring to key demands of developing nations from leaders of wealthy states.
"It’s an issue of way of life and a result of the capitalist system and if we don’t understand that then we’re never going to resolve these problems," he said.
The anti-capitalist theme was picked up on by Mr Mugabe, Zimbabwe’s veteran President, who is the target of Western sanctions over alleged human rights abuses.
"When these capitalist gods of carbon burp and belch their dangerous emissions, it’s we, the lesser mortals of the developing sphere who gasp and sink and eventually die."
The 85-year-old said industrialised countries in the northern hemisphere which bore historical responsibility for global warming showed none of the zeal for punishing ‘eco-offenders’ that they did for abusers of human rights.
"Why is the guilty north not showing the same fundamentalist spirit it exhibits in our developing countries on human rights matters on this more menacing threat of climate change?" he said.
"Where are its sanctions for eco-offenders? When a country spits on the Kyoto Protocol by seeking to shrink from its diktats, or by simply refusing to accede to it, is it not violating the global rule of law," he added in reference to the core emissions treaty which the US has refused to sign.