[Vision2020] Huge methane belch in Arctic could cost $60 trillion

[Art Deco]

 Huge methane belch in Arctic could cost $60 trillion

   - 11:17 24 July 2013 by *Fred
Pearce*<http://www.newscientist.com/search?rbauthors=Fred+Pearce>
   - Magazine issue 2927 <http://www.newscientist.com/issue/2927>. *Subscribe
   and save*<http://subscribe.newscientist.com/bundles.aspx?prom=6005&intcmp=SUBS-nsarttop&promcode=6005>
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Change*<http://www.newscientist.com/topic/climate-change>Topic Guide

  [image: Huge quantities of methane are locked in the Arctic ice
<i>(Image: Danita Delmont/Alamy)</i>]

Huge quantities of methane are locked in the Arctic ice *(Image: Danita
Delmont/Alamy)*

A sudden methane burp in the Arctic could set the world back a colossal $60
trillion.

Billions of tonnes of the greenhouse gas methane are trapped just below the
surface of the East Siberian Arctic shelf. Melting means the area is poised
to deliver a giant gaseous belch at any moment  - one that could bring
global warming forward 35 years and cost the equivalent of almost a year's
global GDP.

These are the conclusions of the first systematic analysis of the economic
cost of Arctic melting, which delivers a sobering antidote to other, more
upbeat assessments that say melting in this area would improve access to
minerals on the ocean bed, increase fishing and create ice-free shipping
lanes.

Previous work has estimated that more than a trillion tonnes of methane lie
under the shelf, trapped inside lattices of ice known as hydrates, at
depths as shallow as 20 metres. Concern about a possible eruption has grown
since 2010, when research cruises over the shelf by Natalia Shakhova and
Igor Semiletov, both now at the University of Alaska at Fairbanks, found
plumes of methane as much as a kilometre wide bubbling to the
surface<http://www.newscientist.com/article/dn18614-methane-bubbling-out-of-arctic-ocean--but-is-it-new.html>
.

The pair calculated that a release of 50 billion tonnes would be possible
within a decade, through known areas of melting and geological faults.
Since methane is a greenhouse gas 25 times as potent as carbon dioxide,
such a scenario would trigger a "climate catastrophe", they say, increasing
the methane content of the planet's atmosphere twelve-fold, and raising
temperatures by 1.3 ˚C.

Now, environmental economist Chris Hope and Arctic Ocean specialist Peter
Wadhams, both at the University of Cambridge, together with climate policy
analyst Gail Whiteman of Erasmus University in Rotterdam, the Netherlands,
have analysed the likely consequences of such a release occurring between
2015 and 2025. They did so by adding the extra emissions to an existing
model used in the UK government's 2006 Stern
Review<http://webarchive.nationalarchives.gov.uk/+/http:/www.hm-treasury.gov.uk/sternreview_index.htm>,
designed to assess the economic cost of coping with climate change between
now and 2200.
Economic time bomb

"The global impact of a warming Arctic is an economic time bomb," says
Whiteman. A release of 50 billion tonnes of methane would bring forward by
15 to 35 years the date at which global temperature rise exceeds 2 ˚C above
pre-industrial levels, the model shows, with most of the damage in the
poorer parts of Africa, Asia and South America. The largest costs envisaged
include loss of crops to heat and drought, coping with sea level rise and
worsening tropical storms.

So how likely is a giant belch? An abrupt release of 50 billion tonnes is
"highly possible at any time", Shakhova says.

Around 10 million tonnes of methane a year are already leaking from the
shelf, according to Shakhova's calculations. However, it is not clear
whether this is a new phenomenon, or even whether human activity is to
blame. Shakhova says it may have been going on since the frozen shelf was
inundated by seawater at the end of the last ice age.

Journal reference: *Nature*, vol 499, p
401<http://www.nature.com/nature/journal/v499/n7459/pdf/499401a.pdf>

*This article appeared in print under the headline "Vast methane belch
possible at any time"*
  [image: Issue 2927 of New Scientist
magazine]<http://www.newscientist.com/issue/2927>


-- 
Art Deco (Wayne A. Fox)
art.deco.studios at gmail.com
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