Global warming continues but rate slows
Human-generated heat-trapping gases like carbon dioxide are surging to unprecedented levels in the atmosphere and causing global temperatures to continue to climb, however the rate of temperature rise has slowed and scientists are attempting to discover why.
Transcript
EMMA ALBERICI, PRESENTER: Last week the Government sacked the Climate Commission, but Lateline can reveal tonight that the Commission will defy the Government's wishes and continue to operate on a voluntary basis with the same commissioners, including Professor Tim Flannery.The move comes ahead of the release this Friday of the latest Intergovernmental Panel on Climate Change report, updating the science on global warming for the first time in seven years.
Leaked drafts confirm that global warming is continuing and is largely due to human-generated greenhouse gases. In a moment we'll hear from Australia's new Environment minister, Greg Hunt, but first this report from Margot O'Neill.
MARGOT O'NEILL, REPORTER: Here's what climate scientists say they're sure of: that human-generated heat-trapping gases like carbon dioxide are surging to unprecedented levels in the atmosphere and that this is causing global temperatures to continue to climb with records tumbling, including in Australia.
ANDY PITMAN, CLIMATE CHANGE RESEARCH CENTRE, UNSW: We had more days in a row at excessively high temperatures, we broke the all-time continental record for extreme temperature. It's what you would expect to happen as a result of more energy in the system and the more energy in the system is because of CO2.
MARGOT O'NEILL: But over the last 15 years, the rate of global warming has slowed and more recently, almost stalled. Scientists admit they're not sure why. Various theories are being tested. First of all, good old-fashioned variability. There've been decade-long hiatus periods before. Scientists are also modelling whether a prolonged cyclical dip in the sun's energy called a solar minimum has played a role and whether aerosols from increased industrial pollution and volcanic ash have reflected heat away from the Earth's surface.
Some scientists also believe the climate's sensitivity to increased levels of carbon dioxide may have been overestimated.
Still, they wonder what's happened to the extra heat generated by accelerating greenhouse gases. If it's not going into surface temperatures, where is the heat going?
The deep oceans; in particular, the Pacific Ocean.
MATTHEW ENGLAND, CLIMATE CHANGE RESEARCH CENTRE, UNSW: So the oceans are accelerating their uptake of heat, and so as a result, the atmosphere has warmed slightly less over those coupla years. The oceans have already taken up 90 plus per cent, so more than 90 per cent of the heat we've trapped from greenhouse gases has gone into the oceans already.
MARGOT O'NEILL: But even with slower rates of warming recently, the pace of some physical impacts has surprised scientists.
ANDY PITMAN: We've seen a dramatic decrease in Arctic Sea ice. We've seen rapid reductions in snow cover. We've seen permafrost melt. We've seen a rapid increase in ocean heat content. We have seen temperature extremes globally. A lot of these records have been broken during La Ninas, which should be cool periods, particularly over Australia. So, last January, during a la Nina, it should have been an enormously cool summer. The fact it was an enormously warm summer during a La Nina makes those of us in this game very nervous about what's going to happen at the next El Nino.
MARGOT O'NEILL: Scientists stress that a single weather event can't be wholly attributed to climate change, but they believe its signal is increasingly detected in the frequency and intensity of floods and heatwaves.
So where does this inexact timetable for global warming leave policymakers?
Tim Wilson of the conservative think tank the Institute for Public Affairs believes the Federal Government should now refuse to ratify the second part of the Kyoto treaty committing Australia to more ambitious emission reduction targets.
TIM WILSON, INSTITUTE OF PUBLIC AFFAIRS: The Parliament shouldn't ratify the Kyoto extension because it just doesn't put the equivalent action on other countries to cut their emissions in the way that Australia has promised to do so. There'll be no environmental dividend at all, but it will continue to increase the costs on Australia.
MARGOT O'NEILL: New Environment Minister Greg Hunt has previously given in-principle support to the Kyoto treaty extension. But the battle over climate policy is just getting started.
Last week, the minister abolished the Climate Commission headed by Tim Flannery set up to offer independent assessments to the public.
But Lateline can confirm that Tim Flannery and the other commissioners have decided to continue on initially as a voluntary body called the Climate Council and will release further reports and engage in ongoing public debate on climate change.
Margot O'Neill, Lateline.
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