Arctic methane melt 'could cost $60 tn'
Methane leaking through leads and cracks in the Arctic Ocean ice north of Alaska
Image: NASA’s Earth Observatory via Wikimedia Commons
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If the Arctic Ocean warms enough to release much of the methane stored beneath the seabed, the cost could almost equal the value of the global economy, scientists say.
LONDON, 24 July – The true cost of an ice-free Arctic summer could be counted in lives lost, communities flooded and economies ruined, three scientists warn.
Methane in the submarine permafrost could be released on such a scale that the cost to the world’s economy could reach $60 trillion. The value of the entire world economy in 2012 was $70 trillion.
Gail Whiteman is at the school of management at Erasmus University in Rotterdam, Peter Wadhams is a professor of ocean physics at the University of Cambridge and Chris Hope is at the Judge Business School in Cambridge.
All three argue, in the journal Nature, that while businesses consider the benefits of Arctic warming in terms of shorter sea routes and easier access to fossil fuel reserves, the potentially catastrophic consequences are being ignored.
The problem they foresee is relatively straightforward and has been of concern to climate scientists for years. For all human history, the Arctic Ocean has been capped by ice. Beneath the ice is sunless ocean, and beneath the ocean is permanently frozen seabed, and within the seabed are billions of tonnes of marsh gas or natural gas stored as frozen methane hydrate.
Catalogue of problems
For the past 30 years, the ice has been reducing both in volume and in area, and in September 2012 reached an all-time low. Some researchers calculate that by the 2050s, the Arctic Ocean will be ice-free in September.
But, says Wadhams, beneath the ice cap the ocean was effectively maintained at freezing point, which meant that the ocean floor below remained permanently at freezing point, which meant that methane hydrate, held under pressure for millions of years below the ocean floor, stayed safely locked away. Once the ice is gone, the sea starts to absorb solar radiation, and last year reached almost 7°C.
The East Siberian Sea covers a shallow shelf, 50 to 100 metres deep, and in recent summers a joint Russian-US research team has been measuring releases of methane from the warming sea bed.
Methane is a powerful greenhouse gas: it is relatively short-lived in the atmosphere, but it is also 23 times more potent than carbon dioxide as an agent of global warming.
So a massive and sustained release of 50 billion tonnes of methane from the East Siberian shelf alone, they calculated, would speed up global warming, bring forward the date at which the world would warm by 2°C by between 15 and 25 years, change weather patterns, precipitate extremes of flooding, drought and storms, bring health risks, mostly for those in the developing world – and have major implications for national economies.
To find out just how much of a disaster could occur, they took an economic model used for the British Government’s 2006 Stern Review of the Economics of Climate Change, and ran it 10,000 times to find a mean economic cost, which is how they arrived at the $60 trillion figure.
But, of course, had they factored in other consequences of global warming – ocean acidification is one of them – the figure could have been still higher. Gail Whiteman described the data they had arrived at as “incredibly compelling” and warned that it presented an economic timebomb.
“All nations will be affected, not just those in the far north, and all should be concerned about changes occurring in the region”, the authors warn. “More modelling is needed to understand which regions and parts of the world economy will be most vulnerable.”
They also warn that it may be impossible to avoid large releases of methane without major reductions in global emissions of carbon dioxide, and they urge the World Economic Forum to ask world leaders to consider what might lie beyond short-term gains from a more open Arctic.
“Arctic science is a strategic asset for human economies because the region drives critical effects in our biophysical, political and economic systems”, they write. “Without this recognition, world leaders and economists will miss the big picture.” – Climate News Network