POZNAN, Poland - Al Gore has called for world governments to significantly strengthen their carbon emission reduction targets in the face of growing evidence that global warming will strike harder and sooner than scientists realised.
Gore, a former US vice president, told UN climate talks in Poznan, Poland that even the most ambitious existing targets would be unable to hold world temperature rise to safe levels.
He called for a new global goal of limiting carbon dioxide levels in the atmosphere to 350 parts per million (ppm) - current levels are already over 380ppm, up from 280ppm before the industrial revolution.
"I call on the people of the world to speak up more forcefully," he said. "We need to focus clearly and unblinkingly on this crisis rather than spending so much time on OJ Simpson, Paris Hilton and Anna Nicole Smith."
He called for world leaders to meet several times over the next few months, to ensure a new global deal on climate change is agreed at a UN meeting in Copenhagen next year.
Gore spoke of ending the "old divide" between rich and poor countries and said the developed world needed to combine efforts to fight poverty and reduce climate emissions.
He said people across the world faced with the threat of global warming deserve better than "politicians who sit on their hands and do nothing".
His speech was a rare show of ambition at the Poznan talks, which are edging towards the low-level achievements predicted at the start by negotiators. The talks aim to set the stage for a global agreement in Copenhagen in 2009. British officials said the only likely process would be to formally launch a new negotiating phase when they conclude tonight.
Campaigners have criticised rich countries for failing to commit to new carbon reduction targets at Poznan. Insiders say no progress on that is expected until Barack Obama makes his intentions clear as new US president in the spring.
Gore admitted that progress at Poznan appeared to be "painfully slow" but said he was optimistic that Copenhagen would reach the required deal. "I say that it can be done and that it must be done."
And he described the EU effort in Brussels this week to reach a compromise between environmental and economic priorities as a "struggle between hope and fear".
Gore's call for a new global carbon target of 350ppm echoes warnings by Jim Hansen, a climate expert with Nasa, who argues that carbon levels must be brought down to prevent catastrophic warming and sea level rise over the next century.
At present, most scentists and politicians in the developed world focus on a target of 450-550ppm, which could raise temperatures at least 2C-3C.
Earlier this year, Kevin Anderson, a climate expert at the Tyndall Centre for Climate Change Research at Manchester University, said it was "improbable" that levels could be stabilised below 650ppm, because of booming carbon emissions since 2000.