Methane: be afraid…be very afraid (and that’s putting it mildly)

The failure to understand the consequences of methane release in the Arctic remind me a lot of payday loans. Here in the UK, we’re suffering a rash of usury. Venal lenders, taking advantage of those poor souls who can never make their wages last until the next payday, offer short term loans the interest rates of which are nothing short of criminal. Rates of 5000% APR (yes, you read that right) are not uncommon, yet damn fools queue up to borrow from these exploitative money-lenders, ignoring the consequences, just as others (or perhaps the same people) ignore their ever-growing credit card debt, and the way their repayment problems escalate in direct proportion to the amount they owe.

If this seems strikingly irresponsible, then bear in mind that the borrowers are emulating other sections of society. While the economic costs of climate change are perhaps the most contentious of all projections, there are no credible analyses that suggest the costs of mitigation exceed the costs of a failure to address the problems. Yet we all plunge on, madly in love with novelty and the disposable, inured to waste and profligacy by our complacency and short-sightedness. And when it comes to the Arctic, nowhere can we find a better example of this head-in-sand attitude.

Setting the Scene

I’d best do this quickly; the Arctic is melting very fast now. Last year (2012) saw a rate and intensity of mass loss that took everyone by surprise – records broken all round. Of course, such anomalies should be seen in a context that separates natural variability from anthropogenic causes. The infamous 1997-98 spike in global temperatures was, as it turned out, an aberration, not some new ‘normal’ (well, not yet anyway).

Unfortunately, the loss of Arctic ice doesn’t look like any kind of aberration. Viewed over the last few decades, the reduction in ice extent, area and volume (mass) are consistent, the trend entirely – and unarguably – in one direction:

Arctic sea ice extent (NSIDC) and volume anomaly (Polar Science Centre) as of July 25th 2013.

Note the blue 2013 plot of Arctic ice extent in the left hand graph. Until mid-May, ice was tracking at near normal extents. Then the late spring set in, and it now seems the thaw only delayed the continued acceleration of ice loss. Melt rates for July are now exceeding all previous years.

The Canary Stops Singing

If the Arctic is the ‘canary in the coal-mine’, then methane could be the cat that swallowed the canary (or at least anaesthetised it).

The more I study climate change, the more I’m convinced it will be the unexpected consequence that really catches us out. We don’t talk about runaway feedbacks much, perhaps because it’s such a dramatic notion, and because there’s a tendency in the climate science community to downplay the more extreme scenarios.

The inbuilt conservatism, part occupational, part defensive, leads to underestimation. A suitable example is the contribution to sea-level rise from the Greenland and Antarctic ice caps, which was omitted from the last IPCC report (AR4 – 2007) because there was too much uncertainty about the rate of mass loss, and too little science on which to base projections.

Now, with AR5 in the final stages of preparation, it seems that methane may be consigned to a similar fate. I’m currently preparing a guide to Representative Concentration Pathways, the replacement for SRES scenarios that will be used throughout the next IPCC report. One thing I noticed early on was that Arctic methane emissions up to 2100 do not figure in any of the pathways – only agricultural and industrial contributions seem to figure prominently in the RPCs.

I have yet to confirm that my understanding is correct, or that Arctic methane has not been accounted for – an omission I would find strange (although the specifications for the RPCs were developed between 2007 and 2009, and may not reflect recent acceleration in negative Arctic mass balance).

Even if the IPCC are behind the curve, that doesn’t stop researchers from studying specifics. A new study authored by Gail Whiteman, Chris Hope and Peter Wadhams, published in the journal Nature (Vast Costs of Arctic Change – PDF), finds that the obsession with as-yet untapped Arctic resources (oil and gas in particular), and the savings to shipping companies made by using polar routes now opening up reliably for the first time, are blinding people to both the economic and environmental risks they are running. Lloyd’s of London for example project Arctic investments to reach US$100 billion within a decade.

What seems to be ignored, rather like the interest rates charged by payday lenders, are the potential costs.

We calculate that the costs of a melting Arctic will be huge, because the region is pivotal to the functioning of Earth systems such as oceans and the climate. The release of methane from thawing permafrost beneath the East Siberian Sea, off northern Russia, alone comes with an average global price tag of $60 trillion in the absence of mitigating action — a figure comparable to the size of the world economy in 2012 (about $70 trillion). The total cost of Arctic change will be much higher.

The warnings are timely and appropriate (if rather controversial). The amount of gas hydrate deposits in the East Siberian Arctic Shelf (ESAS), estimated at 50 gigatons, is prodigious enough, but when you also factor in the melting of permafrost right across the northern hemisphere, and the possible contribution of methane that this could produce, the scale and speed of the problem could well be subject to the same under-estimation as the Arctic melting itself. The authors note that, should there be a sudden release of methane, the time we have left before reaching the 2 degree C ‘safe’ limit to warming would shorten considerably:

The methane pulse will bring forward by 15–35 years the average date at which the global mean temperature rise exceeds 2°C above pre-industrial levels — to 2035 for the business-as-usual scenario and to 2040 for the low-emissions case.

This dire scenario could play out over 50 years, or quite suddenly – or not at all. Other scientists have expressed considerable doubts about the likelihood of a methane ‘pulse’. None the less, the potential for accelerated global warming remains, as do the knock-on effects. The combination of albedo loss, warming waters, ice melt, methane release, additional water vapour and melting permafrost have all the hallmarks not only of a positive feedback, but one that could accelerate so fast it could become self-fuelling; runaway warming, unstoppable, and at a speed that makes adaptation extremely problematic; far too little, far too late. If we allow ourselves to reach such a point, the rate of man-made emissions of greenhouse gases, particularly CO2, will be largely irrelevant. If methane triggers runaway warming, in effect we will have driven over the cliff edge.

After that, all that remains is the inevitable crash.