[ click on image to enlarge ] |
The image below gives an idea of the height of this level, compared to historic levels, and how fast levels of methane (CH4) have been rising compared to levels of two other greenhouse gases, i.e. carbon dioxide (CO2) and nitrous oxide (N2O).
While CO2 levels are in ppm and CH4 in ppb, they are directly comparable, in that a CH4 cloud, 5 years after its abrupt release into the atmosphere over the Arctic Ocean, may have shrunk to 20% of its original size, yet will over those 5 years have exercized local warming more than 1000 times stronger than the global warming potency of the same mass of CO2. |
Above graph shows the dramatic rise in the levels of greenhouse gases over the past few centuries. Almost half of all global warming results from a 3 Gt rise in methane since the 1750s, as described in the recent post Quantifying Arctic Methane.
Why worry about methane rising from the seafloor in the Arctic? Sediments underneath the Arctic Ocean hold vast amounts of methane. Just one part of the Arctic Ocean alone, the East Siberian Arctic Shelf (ESAS, see map below), holds up to 1700 Gt of methane. A sudden release of just 3% of this amount could add over 50 Gt of methane to the atmosphere, and experts consider such an amount to be ready for release at any time.
Why worry about methane rising from the seafloor in the Arctic? Sediments underneath the Arctic Ocean hold vast amounts of methane. Just one part of the Arctic Ocean alone, the East Siberian Arctic Shelf (ESAS, see map below), holds up to 1700 Gt of methane. A sudden release of just 3% of this amount could add over 50 Gt of methane to the atmosphere, and experts consider such an amount to be ready for release at any time.
Just let those figures sink in for a moment. Total methane burden in the atmosphere now is 5 Gt. The 3 Gt that has been added since the 1750s accounts for almost half of all global warming. The amount of carbon stored in hydrates globally was in 1992 estimated to be 10,000 Gt (USGS), while a more recent estimate gives a figure of 63,400 Gt (Klauda & Sandler, 2005). The ESAS alone holds up to 1700 Gt of methane in the form of methane hydrates and free gas contained in sediments, of which 50 Gt is ready for abrupt release at any time.
Imagine what kind of devastation an extra 50 Gt of methane could cause. Imagine the warming that will take place if the methane in the atmosphere was suddenly multiplied by 11. Whiteman et al. recently calculated that such an event would cause $60 trillion in damage. By comparison, the size of the world economy in 2012 was about $70 trillion.
Smaller releases of methane in the Arctic come with the same risk; their huge local warming impact threatens to further destabilize sediments under the Arctic Ocean and trigger further methane releases, as illustrated by the image below.
Victor Hugo |
The challenges may seem huge, the opposition to change may seem formidable. Yet despite the saber rattling of armies, and despite covert efforts by powerful conglomarates and vested interests to resist change, common sense will prevail, because nothing is as strong as an idea whose time has come. [“On résiste à l'invasion des armées; on ne résiste pas à l'invasion des idées.” – From: Histoire d'un crime, Victor Hugo.]
As the prospect of climate catastrophe becomes ever more apparent and as the political imperative to take comprehensive and effective action becomes ever more urgent and obvious, this message will spread and the winds of change will grow stronger day after day. Be part of the solution and spread the message!
Post by Sam Carana.
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