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Noctilucent
clouds: further confirmation of large methane releases
10
December, 2013
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in September 2013, extremely high methane readings were recorded over
the heights of Antarctica, as illustrated by the image below.
These
high methane readings over Antarctica have not been discussed much
among climate scientists, let alone in the media. Yet, large methane
releases can contribute significantly to climate change, given
methane's high potency as a greenhouse gas. Furthermore, the vast
amounts of methane contained in the permafrost comes with the danger
that, as global warming continues, such releases could increase in a
non-linear way.
Noctilucent
clouds could confirm that such emissions have indeed taken place from
Antarctica. Methane will rise in the atmosphere, turning into water
vapor as it rises up in the sky, and form ice crystals around meteor
smoke at 83 kilometers altitude, showing up as noctilucent clouds.
      |      |      Noctilucent Clouds over the Southern Hemisphere from November 21, 2013, to December 6, 2013. Click on each image to view enlarged versions. |
It
takes a while for methane to rise up to such altitudes, making it
hard to pinpoint which methane releases are responsible for these
noctilucent clouds. As methane rises, it tends to move closer to the
equator, which is another reason to conclude that these noctilucent
clouds are the result of large amounts of methane that have been
released from the heights of Antarctica earlier in 2013.
As
such high methane concentrations transform into water vapor and
carbon dioxide, they may no longer register as methane on satellite
measurements, yet they will continue to contribute to global warming.
Therefore, large methane releases should be closely monitored, even
if they do not appear to immediately translate into mean global
methane level rises.
The
question remains what caused such huge releases from the heights of
Antarctica in the first place. The graph below may provide some of
the answers. Look at the sharp temperature anomaly rise of 6 degrees
Celsius over Antarctica in September 2013, preceded by a -3 anomaly.
That's a difference of about 9 degrees Celsius. As temperature
differences increase, there will be greater pressure changes, in line
with compacting, expanding, tearing and other movements of the ice.
Furthermore, more snowfall followed by more melting and vice versa
will come with increased differences in weight. These two forces
combined could be destabilizing the permafrost and the hydrates and
free gas it contains.
 |
| Diagram showing area weighted Antarctic (70-90oS) monthly surface air temperature anomalies (HadCRUT4) since January 2000, in relation to the WMO normal period 1961-1990. The thin blue line shows the monthly temperature anomaly, while the thicker red line shows the running 37 month (c.3 yr) average. Last month shown: September 2013. Last diagram update: 17 November 2013. From: http://www.climate4you.com/Polar%20temperatures.htm |
The
temperature differences are even more striking when looking at
individual days in September 2013. The NOAA images below show a
difference of well over 20°C over a few days in September 2013.
This
spells bad news, as such wide and rapid temperature changes on
Antarctica look set to become even more frequent and intense with
further global warming.
References
-
Is Global Warming breaking up the Integrity of the Permafrost?
- Noctilucent
clouds indicate more methane in upper atmosphere
-
Noctilucent Clouds Get an Early Start
-
Aeronomy of Ice in the Mesosphere (AIM) satellite, exploring Polar
Mesospheric Clouds (PMCs), also called noctilucent clouds
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