Science sidelined at Durban

By Bryan Walker 14/12/2011

An image that has lingered with me from all the reports of the Durban conference was the Democracy Now interview with a somewhat disconsolate Rajendra Pachauri, the IPCC chair. He was at Durban to represent the science, a rather thankless task since he detected very little interest in what the science has to say.

’I’d like to see the science driving some of the discussions and the decisions that are taken. I’m sorry I don’t see much evidence of that right now.’

He pictured the delegations being confronted with the scientific reality every day and how that might affect the progress of their negotiations.

’[There’s a] complete absence of discussion on the scientific evidence that we have available   I would like to see each day of the discussions starting with a very clear presentation on where we are going, what it’s going to mean to different parts of the world and what are the options available to us by which at very little cost and in some cases negative cost we can bring about a reduction in emissions   I would like to see an hour, hour and a half, every day being devoted to this particular subject   I think then the movement towards a decision would be far more vigorous, it would be based on reality and not focusing on narrow and short-term political issues.’

Nothing remotely like that happened of course, and Pachauri vented his exasperation:

’Actually, to be honest, nobody over here is listening to the science.’

One can understand his verdict. It won’t have been true of everyone present, but the negotiations hardly displayed a widespread awareness of the scientific reality.

Pachauri was robust in his defence of the trustworthiness of the IPCC reports and asserted the need for emissions to peak no later than 2015 if we hope to limit the temperature rise to 2 degrees or thereabouts. Delaying that peak to 2020 means a much larger cost to the reduction process.

This is certainly no time to be soft-pedalling the scientific message, or allowing the policy makers and negotiators to escape exposure to its full force. In which context I thought I’d draw attention to a recent release by NASA’s earth science news team on James Hansen’s new research into Earth’s paleoclimate history. He warned at a press briefing at the American Geophysical Union last week that a warming of 2 degrees would be sufficient to lead to drastic changes, such as significant ice sheet loss in Greenland and Antarctica.

Hot Topic readers will be familiar with Hansen’s concerns, but the new NASA statement is a particularly good summary for the lay person of the paleoclimate evidence underlying what he has to say about sea level rise. It’s well worth reading in full, but I’ll pull out a few of its major points here.

In studying cores drilled from both ice sheets and deep ocean sediments, Hansen found that global mean temperatures during the Eemian period, which began about 130,000 years ago and lasted about 15,000 years, were less than 1 degree Celsius warmer than today. If temperatures were to rise 2 degrees Celsius over pre-industrial times, global mean temperature would far exceed that of the Eemian, when sea level was four to six metres higher than today.

“The paleoclimate record reveals a more sensitive climate than thought, even as of a few years ago. Limiting human-caused warming to 2 degrees is not sufficient,” Hansen said. “It would be a prescription for disaster.”

Two degrees Celsius of warming would make Earth much warmer than during the Eemian, and would move Earth closer to Pliocene-like conditions, when sea level was in the range of 25 meters higher than today, Hansen said. In using Earth’s climate history to learn more about the level of sensitivity that governs our planet’s response to warming today, Hansen said the paleoclimate record suggests that every degree Celsius of global temperature rise will ultimately equate to 20 meters of sea level rise. However, that sea level increase due to ice sheet loss would be expected to occur over centuries, and large uncertainties remain in predicting how that ice loss would unfold.

It won’t be a linear process. GRACE satellite data relating to Greenland and West Antarctica has not been accumulating long enough to confirm the rate of acceleration of ice loss possibly occurring, but it is not inconsistent with multiple metres of sea level rise by 2100.

“We don’t have a substantial cushion between today’s climate and dangerous warming,” Hansen said. “Earth is poised to experience strong amplifying feedbacks in response to moderate additional global warming.”

Hansen acknowledges that using paleoclimate evidence to predict precisely how climate might change over much shorter periods than natural timescales is difficult, but he notes that the Earth system is already showing signs of responding, even in the case of slow feedbacks such as ice sheet changes.

Also, the vastly more rapid rate at which carbon dioxide is being released today by comparison with the slow increases from natural causes in the past adds to the difficulty of predicting how quickly the Earth will respond.

“Humans have overwhelmed the natural, slow changes that occur on geologic timescales,” Hansen said.

These warnings from Hansen relate to sea level rise, one of the most ominous prospects. There is equal reason to be concerned over a range of likely impacts which the science has detected, some of which are kicking in already. But it’s not apparent that the world’s political leadership is jointly capable of taking on board the enormity of what climate change means for humanity. The determination to press on with the continued exploration and exploitation of fossil fuels seems virtually unquestioned in the corridors of power of most countries.

While some governments are pushing the development of renewable energy it is not at a pitch to be compared with a wartime mobilisation. To suggest that coal, oil and gas should be left where they are just as soon as we can urgently organise to do without them is to appear foolish in New Zealand and presumably in most other countries endowed with the resources. Canada’s commitment to the tar sands development, to the extent of leaving the Kyoto agreement, is a case in point.

Pachauri’s concern that the politics is not being measured against the science is fully justified. The hopes for realism may prove incapable of fulfilment. But we must continue to demand unwaveringly that politicians look up and take notice of the desperate seriousness of the scientific warnings, and condemn them when they don’t.