Tag: methane

Marvellous distempered: the Copenhagen diagnosis

The Copenhagen climate conference (COP15) opens its doors in a little under two weeks. To update participants on the science of climate a new assessment report, The Copenhagen Diagnosis, was released yesterday, and it makes grim reading. Designed to inform “a target readership of policy-makers, stakeholders, the media and the broader public” about the evidence that’s emerged since the 2005 cut-off for the IPCC’s Fourth Report, it is especially strong on the accumulating signs of climate change as it happens.

Evidence of melting of the Greenland and Antarctic ice sheets supports a revision of the expected sea level rise by the end of the century: it “may well exceed” a metre. The rapid sea ice loss in the Arctic in recent years highlights the risks of methane releases from permafrost, but the most direct message is that with global carbon emissions surging up to and beyond the highest of the IPCC’s scenarios, and with pretty strict limits on the amount of carbon we can add to the atmosphere and stay under a 2ºC rise, we need to start cutting emissions soon.

Here’s what the emissions growth looks like:

CopCO2emissions.jpg

And here’s what we need to do to stay under 2ºC:

CopDiagtargets.jpg

It’s a simple enough message. The longer we leave it before starting to cut emissions, the steeper the cuts will need to be. And there’s an obvious corollary: steep cuts will be more expensive. Inaction now means more cost in the future. Where does that leave any government promising to “balance the economy and the environment”?

Below the fold: the full executive summary.

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(Arctic) Change is now

The World Wide Fund for Nature (WWF) has just published a new report on climate change in the Arctic — Arctic Climate Feedbacks: Global Implications [PDF], and it’s a fascinating read. Over the last two years I’ve blogged regularly on the changes being seen in the Arctic — sea ice reductions, melting of the Greenland ice sheet, the danger of increased carbon release from permafrost and sea floor methane hydrates, and the possible impacts on northern hemisphere weather patterns and climate. WWF’s report — written by some of the leading names in the field (including Serreze, Stroeve, Cazenave, Rignot, Canadell, and for the methane hydrate chapter Shakhova and Semiletov) — pulls together all those strands to paint a picture of a region undergoing rapid change. The authors provide a fully-referenced review of our current understanding of the processes at work as the pole warms, with chapters covering atmospheric circulation feedbacks, ocean circulation changes, ice sheets and sea level, marine and land carbon cycle feedbacks, and sea floor methane hydrates. It’s compelling stuff, and well worth reading in full, but for this post I want to focus on the excellent overview of methane hydrate feedbacks provided by Natalia Shakhova and Igor Semiletov.

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And now the bad news…

methaneSpits.gifActive methane plumes over the West Spitsbergen shelf discovered last summer are being driven by warming of an ocean current over the last 30 years, a new study(*) reports. The team on the British research vessel the James Clark Ross from the National Oceanography Centre Southampton (working with scientists from the University of Birmingham, Royal Holloway London and IFM-Geomar in Germany) found more than 250 plumes of bubbles of methane gas rising from the seabed of the West Spitsbergen continental margin at depths of 150 to 400 metres. From the press release:

Graham Westbrook Professor of Geophysics at the University of Birmingham, warns: “If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year – equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ocean.”

New Scientist expands the story somewhat, and looks at the total potential methane release in the region:

The methane being released from hydrate in the 600-square-kilometre area studied probably adds up to 27 kilotonnes a year, which suggests that the entire hydrate deposit around Svalbard could be releasing 20 megatonnes a year.

With global methane emissions of the order of 500 – 600 megatonnes per year, that’s a substantial potential addition to the global budget — and there’s a lot more methane hydrate on the East Siberian Shelf that is already showing signs of breaking down.

(*) Westbrook, G.K. et al. Escape of methane gas from the seabed along the West Spitsbergen continental margin. Geophysical Research Letters, 2009; DOI: 10.1029/2009GL039191 (preprint here: well worth a read)

The first cut is the deepest

targetThis week climate minister Nick Smith and international negotiator Tim Groser start their 2020 emissions target roadshow, ostensibly taking the pulse of the nation on the question of what target New Zealand should commit to in the run-up to Copenhagen in December. Much of the argument will undoubtedly centre around the costs of taking action. The government has already signalled it won’t commit to targets likely to damage the economy, but there is a bigger question to consider — what emissions cuts does the world have to consider in order to avoid the worst effects of climate change, and how should New Zealand play its part? Any cost to the NZ economy is only a small part of that overall equation, and (arguably) not the most important. I want to examine what “the science” is telling us about a global goal and how we get there, and what that means for New Zealand. The leaflet produced to accompany the consultation process is pretty feeble in this respect, so I make no apologies for going into some detail here.

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Hit the road, Nick

targetClimate minister Nick Smith and international negotiator Tim Groser have published the schedule for their recently announced consultation exercise on a 2020 emissions target for New Zealand. The hastily arranged exercise (announced only last month, and a surprise to many) has already drawn calls for an interim target of 40% by 2020 from the recently-formed NZ Climate Action Partnership and Greenpeace. In an interesting development, Carbon News is reporting that Green Party climate change spokeswoman Jeanette Fitzsimons has floated the idea that NZ could adopt a split target — setting separate 2020 targets for carbon dioxide, nitrous oxide and methane:

Fitzsimons says that with the technology not yet available to reduce methane emissions from farmed animals – responsible for half of New Zealand’s total greenhouse gas emissions – this country should be thinking about setting separate targets for carbon, nitrous oxide and methane for 2020.

“If we set an overall target that is mainly determined by the difficulty of reducing agricultural emissions, it looks to the rest of the world like we are doing nothing,” she said.

It’s an interesting concept, at the very least, though I have to say I’m not keen on giving agriculture a wholly free ride. Federated Farmers like to insist that the “technology is not available”, but there are a range of options farms can use to reduce emissions, from the use of nitrification inhibitors to better handling of manure (not to mention shifting to low-carbon crops or carbon farming).

Full details of the public meetings below the fold. I’ll be making an effort to attend the Christchurch meeting next Wednesday evening.

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