Al Gore has warned that there is now clear proof that climate change is directly responsible for the extreme and devastating floods, storms and droughts that displaced millions of people this year.
Speaking to an audience of business leaders, political leaders including Scotland's first minister Alex Salmond and green energy entrepreneurs in Edinburgh, Gore said the world was at a "fork in the road".
The former US vice-president and climate campaigner also argued that America has suffered a "breakdown in democratic governance", because members of Congress are obsessed with appeasing special interests in return for campaign funding, rather than confronting climate change.
The former vice president and climate campaigner said that US democracy had been undermined. "In the language of computer culture, our democracy has been hacked," he said.
In a near hour-long speech to the Scottish low-carbon investment conference, Gore said the evidence from the floods in Pakistan, China, South Korea and Columbia was so compelling that the case for urgent action by world leaders to combat carbon emissions was now overwhelming, Gore said.
"Observations in the real world make it clear that it's happening now, it's real, it's with us," he said. Failing to take action meant the world would face a catastrophe.
He added that nearly every climate scientist actively publishing on the subject now agreed there was a causal link between carbon emissions and the sharp increase in intense and extreme weather events seen across the globe.
"Every single national academy of science of every major country on earth agrees with the consensus and the one's that don't agree with it do not exist. This is what they say to governments: 'The need for urgent action is now indisputable'.
"The scientists have made a subtle but profound change in the way that they speak about the connection between the climate crisis and the extreme weather events. They used to say you can't connect any extreme weather event to climate because there are multiple factors. Now they've changed.
"The environment in which all storms are formed has changed. It's influence is now present according to the leading scientists in all storms, and they speak of relative causation."
Gore said there was now evidence that the globe's hydrological cycles were changing: as the atmosphere and oceans warmed, more water was evaporating and getting stored in the atmosphere. The amount of water vapour over the oceans had increased by 4% in 30 years, particularly around the tropics and sub-tropics.
In turn this fed even heavier and more violent storms and flooding incidents, which in Pakistan displaced 20 million people earlier this year, and which forced out 8.5 million from 13 provinces in China.
This destabilisation of global weather patterns then fed into a complex cycle of more intense and prolonged droughts in drought-prone regions, which in turn caused more frequent and more vicious wildfires, increased desertification of agricultural land, and was now affecting river levels in the Amazon.
There were 387 million people affected by droughts in the first six months of this year. China, Iraq and Iran also recorded their highest ever temperatures during this period. The city of Mohenjo-Daro in Pakistan recorded a temperature of 53.5C, while in the United States, 200 cities broke their highest temperature records this summer. In Texas, 252 out of the state's 254 counties had experienced major wildfires during 2011.
He continued: "They used to say we're changing the odds, we're loading the dice that make it more likely that we'll get extreme weather events. Now the change is we're not only loading the dice, we're painting more dots on the dice. We're not only rolling more 12s, we're rolling 13s and 14s and soon 15s and 16s."
Arguing that the younger generation would demand world leaders showed the "moral courage" to take action, he heaped praise on Salmond, applauding his "vision and leadership" for championing wave, tidal and offshore wind power in Scotland. He said the rapid growth in new renewable technologies gave hope that a successful shift from fossil fuels was possible.
Outside the conference venue, two women employed by the Kreate promotions agency in London handed out anonymously produced leaflets to delegates reproducing media reports of a high court judgment that heavily criticised the accuracy of Gore's 2007 climate documentary An Inconvenient Truth.
Barry Duncan, the manager of Kreate, said their staff had been hired by a client who wanted to remain anonymous, on behalf of another anonymous client, to hand out "leaflets on renewable energy". Duncan said: "This is a bit strange, I totally agree."
LONDON: Ice at the North Pole has melted to the lowest level since satellite observations began in 1972, meaning the Arctic is almost certainly the smallest it has been for 8000 years, polar scientists said.
If the trend continues, the Arctic will be largely ice-free in the northern summer 40 years earlier than anticipated in the last Intergovernmental Panel on Climate Change assessment report.
Daily satellite sea ice maps released by Bremen University physicists show that with a week's further melt expected this year, the floating ice in the Arctic covered 4.24 million square kilometres on September 8. The previous one-day minimum was 4.27 million square kilometres on September 17, 2007.
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The National Snow and Ice Data Centre in the US is expected to announce similar results in a few days.
The German researchers said the record melt was undoubtedly because of human-induced global warming. ''The sea ice retreat can no more be explained with the natural variability … caused by weather,'' the head of the Institute of Environmental Physics at Bremen, Georg Heygster, said.
''Climate models show that the reduction is related to the man-made global warming, which, due to the albedo effect, is particularly pronounced in the Arctic.''
The albedo effect is related to a surface's reflecting power - sea ice reflects more of the sun's heat back into space than darker seawater, which absorbs the sun's heat and gets warmer.
A senior researcher at the Australian Antarctic Division, Tony Worby, said the consensus view among polar scientists was that the Arctic melt was happening faster than the models used by the IPCC predicted.
''Some of the climate models showed that the ice would disappear in summer in about 70 years, but the observations are tracking well ahead of that,'' Dr Worby said.
Separate research suggests Arctic ice is in a downward spiral, declining in area and also thinning. Scientists at the Polar Science Centre of the University of Washington, Seattle, said last week that Arctic sea ice volume hit its lowest level in 2010 and was on course to set more records this year.
Their data suggests that the volume of sea ice last month was half the average and 62 per cent lower than the maximum covering the Arctic in 1979. The research will be published in the Journal of Geophysical Research.
''Ice volume is now plunging faster than it did at the same time last year when the record was set,'' the University of Washington senior oceanographer, Axel Schweiger, said.
The last time the Arctic was uncontestably free of summer-time ice was 125,000 years ago, at the height of the last major interglacial period.
Arctic ice plays a critical role in regulating Earth's climate. Retreating summer sea ice is described by scientists as a measure and a driver of global warming. This year, the Northwest and Northeast passages were mostly ice free, as they have been twice since 2008.
Last month, the 74,000-tonne STI Heritage tanker passed through the Northeast Passage in just eight days on its way from Houston, Texas, to Thailand. The north-east sea route, which links the Atlantic to the Pacific, is likely to become a ship operator's favourite.
Clouds could be made more reflective and oceans fertilised to increase carbon dioxide absorption under ideas to be discussed at Australia's first high-level climate engineering conference later this month.
International interest in climate engineering – also known as geoengineering – is increasing as efforts to curb the world's emissions of greenhouse gases continue to falter.
Scientists said the event was an important step for Australia into the controversial geoengineering debate but expressed grave concerns some proposed technologies could have dangerous and far-reaching side effects.
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The two-day science symposium, starting in Canberra on September 26, is being hosted by the Australian Academy of Science and the Australian Academy of Technological Sciences and Engineering.
Among the more controversial ideas being discussed is the injection of sulphur particles into the stratosphere to reflect sunlight and slow global warming.
Other technologies include fertilising oceans to increase uptake of carbon dioxide and spraying aerosols into the atmosphere to increase the reflectiveness of clouds.
But the meeting will also cover relatively benign ways to pull greenhouse gases from the atmosphere, including planting more trees and using climate-friendly agricultural techniques.
Speaker at the event Graeme Pearman, a respected climate scientist and former CSIRO chief of atmospheric research, told brisbanetimes.com.au it was a "very significant first step".
"It needs to be made clear that no one really wants to do this," Dr Pearman said.
"Some of the options are potentially dangerous, but we need to be prepared to act if we have to and we need to be assured that others will not act imprudently or in regional interest alone.
"It is my view we can only be assured of this by having these discussions out in the open."
Global emissions of greenhouse gases from burning fossil fuels hit an all-time high last year, according to the International Energy Agency.
Dr Pearman said the meeting was timely given slow global action to cut emissions and the observed changes in the climate. Also, private companies were already being set-up to "capitalise" on some geoengineering technologies.
In early 2009, German scientists dropped six tonnes of dissolved iron into the south-west Atlantic to fertilise a 300 square kilometre area. But scientists reported only a "modest" amount of CO2 had been soaked up.
Later this year, a team of academics in Britainare to test equipment that could spray particles 20 kilometres up into the atmosphere using a hose tethered to a balloon.
Geoengineering has gained prominence since Britain's Royal Society published a report in 2009 calling for more research into the area.
An international conference of 165 international scientists, including Dr Pearman, was also held in Asilomar in California last March and was part-funded by the Victorian Government.
The final report from the conference included a set of five principles to promote "responsible conduct of research on climate engineering".
Last November the UN Convention on Biological Diversity, to which Australia is a signatory, called a global moratorium on any geoengineering experiments that could affect biodiversity, but its effectiveness has been questioned.
Roger Gifford, chair of the AAS National Committee for Earth System Science, who will open the event, said Australia needed to be part of any global decisions, especially on how geoengineering was governed.
"Whether it is to squash some of these proposals or encourage certain aspects, Australia needs to be involved in the research and the global decision-making," he said.
Dr Gifford said it was "pretty much inevitable" that the globe would warm by 2 degrees above their pre-industrial levels.
"Everyone is aware that fiddling with the global energy balance directly could carry as many risks and potential unknowns as humanity's current collective fiddling with the greenhouse gas composition of the atmosphere has," he said.
In relation to geoengineering measures to block the sun's rays, Dr Gifford said: "Almost everyone in climate science is saying that if it comes to this then the world really is in a desperate shape climatically."
Also invited to speak at the Canberra meeting is author Clive Hamilton, professor of public ethics at Charles Sturt University, who is a strong critic of the principles and motivations behind many geoengineering technologies.
He fears some policy makers might see embracing geoengineering as an alternative to switching from fossil fuels to renewable energy.
"Anyone who has observed the politics of climate change knows that governments are keen to find alternatives to imposing deep emissions cuts,'' said Professor Hamilton, who is writing a book on geoengineering.
"If geoengineering appears to be an alternative to mitigation then governments will grab it if they can."
The Canberra conference, which costs $240 to attend, aims to "develop a southern hemisphere perspective" on geoengineering.
David Karoly, a leading atmospheric scientist at the University of Melbourne, said there was a perception the southern ocean was a preferred region to carry out ocean fertilization. This could have serious implications for marine biodiversity in the region, he said.
Professor Karoly warned cloud-whitening technologies and pumping sulphur particles high into the atmosphere could have global and regional impacts by changing rainfall patterns and damaging the ozone layer.
Falling sulphur particles and depleted ozone had additional human health impacts, he said.