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Hi Steve & All, Nov 16, 2015
Thanks for pointing me to this. I followed a link to 'Clathrate gun
hypothesis' which includes an interesting phase diagram for Methane Hydrate
and Methane gas at various temperatures and pressures. The abscissa is
strange in that evenly spaced ticks variously represent increments of from1
to 6 back to 1 and then up to 3 degrees; an accordion abscissa.
But the significant message is clear; at sufficiently low pressures
Methane gas will be released from Methane Hydrate at temperatures as low as
0oC.
Kilopascals are no longer part of my vocabulary but starting with the
definition that 1 cm of water is equivalent to 98.06 Pascals and rounding
up; ten (10) Metres of water will be approximately equivalent to 1000
Kilopascals. And because density of water is a maximum at 4oC (not sure how
salinity would affect this) one would expect bottom sediments to usually be
4o or warmer. And from the graph, Methane at 4o C would be released at
depths less than about 40 metres.
A map in the NG issue shows temperature change between 1960 and 2014 as
colors ranging from green (cooler) through yellow, orange, and red to black;
black representing the greatest increase in temperature (unnumbered pages 18
& 19).
All of the bright red (>10oC increase) and black (~15oC increase) areas
are north of the Arctic Circle. The black areas look like plumes of warmth
extending west from the shallows north of Svalbard and Novaya Zemlya. It
appears to me that the situation north of the Arctic Circle is a smoking
Clathrate Gun. I wonder how Methane/altitude profiles in the fall compare
with those in Temperate or Tropical areas.
Yt, Dave Webster, Kentville
----- Original Message -----
From: "Stephen Shaw" <srshaw@Dal.Ca>
To: <naturens@chebucto.ns.ca>
Sent: Monday, November 16, 2015 12:53 PM
Subject: RE: [NatureNS] Little Ice Age; right.
> Dave: Good reminder -- there's a bit of info at the end of the Wikipedia
> article on 'methane clathrates' (hydrates) that is worth a look. Two
> researchers in Sept 2013 in a 'Nature' offshoot reinforced Hansen's
> earlier warning, saying that the most likely cause of further
> strengthening of global warming is large scale future thawing of the
> Arctic permafrost. The total amount in the sea is large but estimates
> range widely, while estimates of land-based methane hydrates are also
> large, of comparable value to the lower estimates of the marine deposits.
> Presumably these land deposits are mostly too thinly distributed to be
> extracted commercially before they eventually will escape during
> permafrost thawing, so no hope there. The article mentions an earlier
> land-based successful drilling exercise to release gas, but that was into
> a concentrated deposit in deeper rock in the MacKenzie River delta, not
> from superficial permafrost. Recent info cited indicates that widespread
> release of marine derived methane is occurring around certain continental
> margins.
> As you say, Earth may be on the way to being severely disrupted in the not
> too distant future.
> Steve
> ________________________________________
> From: naturens-owner@chebucto.ns.ca [naturens-owner@chebucto.ns.ca] on
> behalf of David & Alison Webster [dwebster@glinx.com]
> Sent: Sunday, November 15, 2015 9:00 PM
> To: NatureNS@chebucto.ns.ca
> Subject: [NatureNS] Little Ice Age; right.
>
> Dear all, Nov 15, 2015
> I just ran across an item on Facebook (tried to copy link but got a
> page
> full) which featured activities of John Coleman, a global warming denier,
> who claims that the sea is not rising, that we are entering a Little Ice
> Age
> etc, etc. Total hogwash but I expect many will swallow this sugar-coated
> poison pill.
> I may be repeating myself but the Nov issue of National Geographic is
> entirely about climate change. Greenland is facing a near future in which
> traditional native culture will not be able to exist; communities are
> isolated and unable to hunt except during periods of firm ice and this
> will
> soon be transient or absent.
> But I find it unsettling that I have seen no mention or Methane hydrate
> in the last 5-10 years because, logically, it feeds the main feedback loop
> which powers unusual surges in warming. If this source of Methane is not
> used before it is released in significant amounts then I think we are
> toast.
> Are all researchers or all of the research funds chasing the carbon
> puck
> and ignoring Methane hydrate ? Or is the news too dire to leak to the
> press
> ? Or have I just not tripped across recent Methane Hydrate articles ?
>
> Yt, Dave Webster Kentville
>
>
>
> -----
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