Saturday, October 5, 2013

Methane over deep waters of Arctic Ocean

The image below shows a lot of methane over deeper parts of oceans, in particular the Arctic Ocean.

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Let's zoom in and take a closer look at what's happening.

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As earlier discussed in the post Methane release caused by earthquakes, there has been a lot of seismic activity in the Aleutian Islands region all the way up into Alaska, including an earthquake with a magnitude of 7 on the Richter scale on August 30, 2013, and several more recent earthquakes with a higher magnitude than 6 on the Richter scale.

An earthquake with a magnitude of 4.6 on the Richter scale hit the Laptev Sea on September 28, 2013. Furthermore, there have been several earthquakes in Siberia, while an earthquake with a magnitude of 6.7 on the Richter scale recently hit the Sea of Okhotsk, which occurred at a depth of 359.3 miles (578.24 km). Earthquakes at such a depth can be felt at great distances from the epicenter and can destabilize methane hydrates.

The presence of methane over the deeper parts of the Arctic Ocean has been discussed in a number of post at this blog recently (see under related, below). It should serve as a warning to those who believed that all methane escaping from deep-sea hydrates would be oxidized in the water by microbes before entering the atmosphere.

The IPCC appears to still close its eyes for such scenarios. Look at this screenshot from IPCC AR5 WGI TS.3.7:

Low release this century? Well, the danger may seem low now in many places, but the situation is already very dangerous in the Arctic, where hydroxyl levels in the atmosphere are very low, where water temperatures can show huge anomalies and where seas can be very shallow and at times become super-saturated with methane, to the extent that oxygen depletion in the water prevents methane oxidation. In the case of large abrupt release, waters will soon become super-saturated with methane locally, especially in the shallow parts of the Arctic Ocean. Furthermore, low sea temperatures and the peculiarities of currents create conditions in the Arctic Ocean that are not beneficial to the kind of growth of microbes that would decompose methane in oceans elsewhere.

How much methane are we talking about? One look at the top image shows that there's a huge amount of methane over the Arctic Ocean. On October 3, 2013, a peak reading was recorded of 2283 ppb and that wasn't even the highest recent reading, as illustrated by the graph below.


Where were these large amounts of methane released? The animation below shows methane methane readings of over 1950 ppb on October 3, 2013, on the afternoon only and with readings at only four relatively low altitudes, with methane over the Arctic Ocean dominating the picture.



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As the animation further shows, methane seems to perforate ice that currently has the highest concentration levels. Or, the methane could have been bubbling up along the edges of the sea ice. Anyway, methane over deep waters is a worrying development, as it could indicate hydrate destabilization that could become worse.

Does the IPCC point out such dangers? In TS.4.5, the IPCC seems to reach the opposite conclusion, adding that it does so with high confidence:

This is not a trivial matter. A study by Gail Whiteman, Chris Hope and Peter Wadhams, recently published in Nature, concludes that a 50Gt methane release in the Arctic would cause $60 trillion in damages. By comparison, the size of the world economy in 2012 was about $70 trillion. The study adds that such a methane pulse will "bring forward 15–35 years the average date at which the global mean temperature rise exceeds 2°C above pre-industrial levels".

Given that warnings such as addressed by such studies have been sounded for years, one would have expected the IPCC to have taken a very close look at such scenarios. So, what made the IPCC so confident that such catastrophic developments will not eventuate this century? Was there robust evidence behind such a conclusion? Or did the IPCC simply overlook concerns about methane release from the Arctic Ocean seabed? More about that in the next post.

Related

- Methane hydrate myths
http://methane-hydrates.blogspot.com/p/myths.html

- Methane hydrates
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

- Vast costs of Arctic change, in Nature, vol 499, pp 401-403, July 25, 2013
by Gail Whiteman, Chris Hope and Peter Wadhams
http://www.nature.com/nature/journal/v499/n7459/full/499401a.html
http://www.nature.com/nature/journal/v499/n7459/pdf/499401a.pdf

- Methane release caused by earthquakes
http://arctic-news.blogspot.com/2013/09/methane-release-caused-by-earthquakes.html

- Earthquake hits Laptev Sea
http://arctic-news.blogspot.com/2013/09/earthquake-hits-laptev-sea.html

- North Hole
http://arctic-news.blogspot.com/2013/09/north-hole.html

- Sea of Okhotsk
Methane-hydrates.blogspot.com/2013/06/sea-of-okhotsk.html

- Seismic activity, by Malcolm Light and Sam Carana (2011)
Arctic-news.blogspot.com/p/seismic-activity.html

- Thermal expansion of the Earth's crust necessitates geoengineering (2011)
Arctic-news.blogspot.com/p/thermal-expansion.html



7 comments:

  1. The evidence for the escape of methane from deep ocean waters is here. A well written article by Sam Carana as well.

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  2. January 2013 broke with huge methane release between Norway and Norwegian Svalbard island group.
    Then substantial and sustained methane release over nearly the whole of the Barent's Sea. That huge event lasted a month and then resumed after a week or so. And since this year began anomaly levels for methane and Arctic temperatures have spiked and often held for some periods of time. It seems impossible the IPCC isn't paying attention but UN likes the corporate money that flows into it.
    So the report they produce won't include possibility of mention of the gully washer events of Geologic history -But the little guys like the methane eating bugs in the mats on the edges of continental shelf -What if bacteria had long lives and could speak- what a story they could tell.. Perhaps beg a bit of copper needed to eat up more methane faster.. -But does the UN or IPCC suggest giving a copper nutrient to a poor bug bacteria there trying to gobble up runaway methane release, No -Hell NO.. Do the environmentalists even try to help Krill in Southern Ocean sequester carbon to Sea Floor sanctuary. There is no place that is Sanctuary now unless earth is saved and we get the job done.

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  3. Maybe Gulf stream is heading up further this year and heats up the arctic floor. Sea water salinity reveals how far Gulf is going: http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticsssnowcast.gif

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  4. Sam Carana has built up an overwhelming case for emergency attention to Arctic methane emissions.

    I suggest this needs to be put down as a letter insisting that the IPCC do a special report on all +ve amplifying feedbacks. The IPCC AR5 did not response to the 2012 UNEP Policy Implications of Warming Permafrost recommendation.

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  5. To make matters worse, the IPCC’s latest report reports that methane is 34 times stronger a heat-trapping gas than CO2 over a 100-year time scale, so its global-warming potential (GWP) is 34. That is a nearly 40% increase from the IPCC’s previous estimate of 25.

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    1. Yes, and from a perspective of abrupt climate change, it's even more relevant that the IPCC now gives methane a global warming potential of 86 over 20 years when including climate-carbon feedbacks. And of course, Shindell et al. already said back in 2009 that methane's GWP is 105 over 20 years when including direct+indirect radiative effects of aerosol responses to methane releases. A calculation based on the figures by Shindell et al. and using a horizon of 10 years results in a GWP of more than 130 times that of carbon dioxide, as described at Methane hydrates. As Shindell et al. added, responses by ecosystems could increase methane's warming potential even further. This is especially relevant in the Arctic where hydroxyl levels are low and where methane releases could accelerate the decline of snow and ice cover and trigger further methane releases. It's also worth noting that the IPCC now gives methane a Radiative Forcing of 0.97 W/m2 (up from 48 W/m2 in 2007), as discussed at the methane hydrates myths page.

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