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EMMA ALBERICI, PRESENTER: A landmark report by the United Nations climate panel says that scientists are now 95 per cent sure humans are responsible for global warming.
The Intergovernmental Panel on Climate Change released its report in Stockholm tonight urging countries around the world to reduce greenhouse gas emissions to prevent further changes to the climate.
The panel of scientists also stated that a recent pause in global warming during the past 15 years is too short to reflect longer term trends.
John Stewart reports.
JOHN STEWART, REPORTER: Six years in the making the UN's climate panel report was produced by more than 800 scientists.
Within the mass of detail was one clear statement, scientists are now 95 per cent sure that humans are responsible for global warming.
RAJENDRA PACHAURI, PROFESSOR, IPCC CHAIRMAN: Since the 1950's, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen and the concentration of greenhouses gases have increased.
JOHN STEWART: The report summary shows the concentration of Co2 in the atmosphere has risen by 40 per cent since the pre-industrial era.
Almost all climate modelling shows temperatures are likely to rise by two degrees by the end of the 21st century. And the worst case scenario includes a sea level rise of almost one metre by the end of the century.
The report found that heat waves will be more frequent and last longer and wetter regions will receive more rain.
The UN's climate panel called for governments around the world to take action.
RAJENDRA PACHAURI: There is a need for us to reduce emissions of greenhouse gases substantially if we really want to stabilise the earth's climate and I hope this is a message that the world will receive and accept.
JOHN STEWART: Professor Andy Pitman at the University of New South Wales says that keeping global temperature rises below two degrees will not be easy.
ANDY PITMAN, PROFESSOR, UNSW: I don't want your listeners to think that two degrees is safe. We've seen a dramatic increase in global temperature extremes with a global warming of 0.8 or 0.9 degrees.
So if we see dramatic changes with 0.8 degrees or 0.9 degrees, it's hard to imagine that two degrees is safe. If you do accept the two degree limit cuts of about three per cent per year is required globally and I really don't see a lot of hope in the global community making those sorts of cuts in the next 10 to 15 years.
JOHN STEWART: The UN climate panel found that a recent pause in global warming during the past 15 years is too short to reflect longer term trends. Australia has recently experienced a wetter, La Nina season, usually associated with lower temperatures.
ANDY PITMAN: We've been through a long double dip La Nina event which is traditionally, statistically related to above normal rainfall and below normal temperatures. It is extremely surprising that we have been breaking summer and winter temperature records to the degree that we have, through a period of sustained La Nina, it is something that truly surprises many of us.
JOHN STEWART: Australia is currently in a neutral period and it's unclear when the drier El Nino phase will begin.
The UN's climate report is more than 3,000 pages long, so big that it will be released in three parts over the next year.
John Stewart, Lateline.