Latest / Climate Analytics

Date30 April 2009

This interview is on the 30th April issue of the Nature Article by Meinshausen et al. (2009) “GHG targets for limiting warming to 2°C”. Thursday, 30 April , 2009 12:34:00, by Jennifer Macey

PETER CAVE: Scientists are warning that three-quarters of the world’s fossil fuel reserves have to be left underground to avoid dangerous climate change.
In two studies published in the latest ‘Nature’ journal scientists say there’s a limit to how much carbon dioxide can be pumped into the atmosphere before the world warms by a critical two degrees. That limit is one-trillion tonnes of CO2.

Scientists say that amount, say that half of that amount has already been burned and without major cuts, two degrees warming will be reached by 2050.

Jennifer Macey reports.

JENNIFER MACEY: Many scientists agree if global temperatures rise by two degrees the signs of dangerous climate change will be obvious: the Greenland icesheet could melt, sea levels could rise, droughts and cyclones will become more frequent and some animals and plants will face extinction.

A team of British and German scientists say it will take one-trillion tonnes of carbon dioxide to reach that temperature rise and the world has already burnt half that amount according to Dr Myles Allen the head of the Climate Dynamics group at the University of Oxford.

MYLES ALLEN: Just in the past few years, without any fanfare, we burnt the half-trillionth tonne. But on current trends we’re set to burn the next half-trillion in less than 40.

JENNIFER MACEY: Dr Allen says rather than setting a safe level of emissions each year his paper published in ‘Nature’ shows there’s a finite amount the world can release.

MYLES ALLEN: It’s not just a low carbon future we’re talking about. It’s a zero carbon future. But we’re not saying you don’t need to do anything until just before you release the trillionth tonne because that strategy would only make sense if you actually planned to shut down the entire world economy overnight at some point in the 2040s. That’s clearly a daft strategy.

So in order to avoid releasing the trillionth tonne we need to start reducing emissions soon.

JENNIFER MACEY: The scientists warn that coal may soon become redundant unless carbon capture and storage technology is introduced soon. And a second ‘Nature’ report suggests that most of the world’s coal reserves may have to stay underground.

One of the co-authors is Dr Malte Meinshausen from the Potsdam Climate Institute in Germany.

MALTE MEINSHAUSEN: It’s less than a quarter of the known economically recoverable fossil fuel reserves that we know of at the moment.

JENNIFER MACEY: But the mining industry is confident that within 10 years coal-fired power stations will be able to capture emissions and store them.

The CEO of the Minerals Council of Australia is Mitch Hooke.

MITCH HOOKE: What sort of conceptual understanding does the author have about the challenge of limiting coal when the IEA, the International Energy Agency says that coal production and consumption will double by 2030.

China alone has 540 gigawatts of capacity. That’s way, that’s about 12 times what we’ve got here in Australia which means that the emissions from those plants will be visited on generations to come. These are long-lived assets and therefore if we don’t get clean coal solutions we’re not going to have a global solution to managing climate change.

JENNIFER MACEY: Yet the scientists say the world may not be able to wait that long. Dr Meinshausen says global emissions will have to peak by 2015 and start dropping after that.

MALTE MEINSHAUSEN: If we continue to raise global emissions up to 2030, the emission reduction states thereafter are so incredibly steep that we just won’t manage to stay below two degrees.

JENNIFER MACEY: Erwin Jackson the director of policy and research at the Climate Institute says Australia’s 5 per cent target by 2020 is also not enough.

ERWIN JACKSON: They’re high risk targets in terms of the economy and also in terms of avoiding catastrophic impacts on the global climate system.

What we really need is the Government to put on the table internationally credible targets of at least 25 per cent by 2020 so that it can actually build the level of ambition that is required at a global level.

JENNIFER MACEY: The authors of the ‘Nature’ reports hope their new figures will inform UN climate talks in Copenhagen at the end of this year. Bill Hare from the Potsdam Climate Institute says delaying action isn’t an option.

BILL HARE: What our calculations show is that we’re simply out of time now. There’s very little flexibility left in the physical system for delay. And if you did delay in the belief that you could reduce emissions rapidly in future decades you would have to prove how the global economy would manage to make 6 to 12 per cent reductions per year.

JENNIFER MACEY: He says global temperatures have already risen by about 0.7 degrees during the industrial age and unless emissions start dropping soon, the world will reach two degrees by 2050.

PETER CAVE: Jennifer Macey with that report