BBC makes a locally-sourced meal of discussing Arctic sea ice melt

  • 12 Sep 2012, 10:33
  • Verity Payne and Freya Roberts

The BBC's fondness for pitting non-experts against each other over particularly complex areas of climate science reached surreal heights in a segment on Arctic sea ice loss on Newsnight last week. The debate between Conservative MP Peter Lilley and the Green Party's new leader Natalie Bennett eventually segued into an argument over the merits of locally-sourced food.

The segment begins by revealing "new evidence suggesting melting Arctic ice will have a dramatic effect on our climate", based on calculations by University of Cambridge ocean physicist Professor Peter Wadhams, who argues that Arctic sea ice loss "is massively compounding the effects of greenhouse gas emissions".

Given that scientists are currently debating the implications of this year's record-breaking sea ice melt, this statement really deserves to be followed up by a discussion between Arctic climate experts. That might be particularly important in this case because, as far as we can find out, Wadhams's calculations have not yet been published in a peer-reviewed journal.

Newsnight doesn't go for that approach. Instead it adopts a format which has become increasingly familiar at the BBC over the past few months - orchestrating a fight between a couple of people with completely opposed views about climate change and what to do about it.

Natalie Bennett, the new leader of the Green Party, focuses on talking about local food - arguing that shortening food supply chains will help curb greenhouse gas emissions. Meanwhile, Peter Lilley MP, who has just written a report criticising the Stern Review for climate skeptic thinktank the Global Warming Policy Foundation, sticks to his own comfort zone, arguing against any response to climate change where the costs outweigh the benefits.

Neither offer any useful insights on Wadhams's calculations, or on the current state of the Arctic sea ice.

Setting the scene - North Pole or Arctic Ocean?

The report kicks off with Susan Watts, Newsnight science editor, setting the scene: Arctic sea ice has declined since satellite records began, and this year's summer sea ice melt has set a new record low extent. She then looks to the future, saying:

"Estimates that the North Pole could be ice-free in summer in a few years contrast with the official views of the Met Office, that Arctic summers will not be completely free of ice before the summers of 2030."

It's worth pointing out here that an ice-free North Pole and an ice-free Arctic Ocean are quite different. An ice-free North Pole means the presence of open water at the geographic North Pole, and could be true even if the whole of the rest of the Arctic Ocean were covered in sea ice.

A sea ice-free Arctic Ocean, in contrast, means the loss of nearly all the sea ice in the whole of the Arctic Ocean - scientists define it as ice coverage going below a specific, low threshold. Wadhams has predicted both an ice-free geographic North Pole and a sea ice-free Arctic Ocean within the coming decade. But on this occasion, Wadhams is discussing the loss of nearly all the sea ice in the Arctic Ocean.

New evidence?

Watts then addresses Wadhams's new research. The decline of Arctic sea ice exposes more open ocean water, which is darker and can absorb more heat than the reflective sea ice it replaces. Wadhams calculates that once the Arctic Ocean becomes sea ice-free, over one per cent of the Earth's total surface will have changed from reflective sea ice to heat-absorbing open water.

Wadhams suggests, if his calculations are correct, that the change to the Earth's total reflectivity caused by losing all Arctic sea ice will have a warming effect for the whole globe of 1.3 watts per square metre - Wadhams reckons this to be "the equivalent of about 20 years of additional carbon dioxide being added by man".

As far as we can find Wadhams's work has yet to be published in a peer-reviewed journal, and is rather larger than previous estimates. For example, other studies based on observations suggest that the losing all Arctic sea ice would have a global warming effect of around 0.3 watts per square metre. And climate modelling puts the figure even lower.

Lilley on ice

A discussion putting Wadhams' work in context and comparing it to other similar studies would have clearly been useful.But instead Newsnight enlisted a couple of politicians to offer generic and predictable talking points about climate change.

Lilley even asserts that he "was told to come on [Newsnight] and not discuss the science" - this seems an unusual booking approach from Newsnight, given the starting point of the segment. But that doesn't stop him from dismissing Wadhams's work:

"[Newsnight has] presented something which purports to be new evidence that contains nothing new, which is tendentious, not peer-reviewed, by a well known alarmist, and absolute bunkum... compared with the IPCC."

Lilley sticks to projections from the Intergovernmental Panel on Climate Change (IPCC)'s 2007 report, arguing that the Arctic shouldn't be ice free until at least the 2070s.

But there are good reasons to move beyond the IPCC on this particular issue. IPCC models have since been found to underestimate Arctic sea ice loss, and peer-reviewed literature from the last few years does seem to suggest that we are talking decades rather than centuries before we see a seasonally ice-free summer - although it's hard to pinpoint an exact date much more accurately than this.

Interestingly, Lilley says he agrees with the basic tenets of climate science and that he is happy "to take the UN Intergovernmental Panel on Climate Change assessment as a correct projection of what the likely trends were going to be". Yet, as Bob Ward has pointed out, in his response to the Stern report he rejects one the IPCC's fundamental findings.

The odd couple

After this cursory discussion of the sea ice, the discussion moves on to "what needs to be done, or what can be done" about man-made climate change. Neither interviewee has anything particularly new to offer. Lilley suggests we "only do things where the costs are less than the benefits", while Bennett makes some general points about the importance of tackling climate change and developing green industries. She also  focuses on food supply chains, saying:

"Well, what we'd like to do is to relocalise our industries, bring farming back into the UK, stop flying peas from Peru and beans from Kenya, we want to bring jobs, we want to bring industries back into the UK, all of these are things which are very much positive for the UK and are good for reducing our carbon emissions at the same time."

Sounds nice, but unfortunately this a rather simplistic view of the link between food miles and emissions. For example, other factors besides where food has come from, such as the use of energy intensive farm practices or even the energy used in cooking the product at home, can often make a bigger overall difference to carbon emissions.

Lilley ends by saying:

"But hang on, I do want to resent the idea that we should impoverish people of Kenya and Peru by stopping trading with them. That seems to be manifestly cruel."

A piecemeal assemblage of slightly left-field Arctic sea ice science and arguments over local food and the Stern review. Read the rough transcript - the programme really descends into a bizarre ending of cross-cutting conversations. It's hard to understand how, over a year after the BBC Trust reviewed the corporation's science coverage, paying particular attention to topics such as climate change, this is what we end up with.


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