Guest Essay by Dr. Gavin Schmidt, NASA GISS
Yesterday, I carried this story: An alarmist prediction so bad, even Gavin Schmidt thinks it is implausible
Today, on Twitter, Karel Haverkorn asked why. To his credit, Dr. Schmidt replied on Twitter in multiple tweets with an essay of bullet points. This marks the first time Dr. Schmidt publishes on WUWT, as well as the first essay here ever composed on Twitter.
I’ve collated his responses below.
Also the PETM (55 My) and Eocene small events. But no evidence under near-current temps. Outside of quaternary range of arctic temps, many fewer constraints…. Pliocene CH4 may well have been higher (but no direct evidence), multiple sources though…
Some more context on Arctic methane release story to follow:
1) Methane is an important part of the anthropogenic radiative forcing over 20thC. Human caused increase from 0.7ppm to 1.8ppm
2) Methane emissions have a direct GHG effect, and they effect atmospheric chemistry and strat water vapour which have additional impacts
3) Direct forcing from anthropogenic methane ~0.5 W/m2, indirect effects add ~0.4 W/m2. (For ref: CO2 forcing is ~1.8W/m2)
4) natural feedbacks involving methane likely to be important in future – via wetland response to T/rain chng, atmos chem &, yes, arctic src
5) monitoring and analysis of atmos conc of CH4 is very important. However, despite dramatic Arctic warming and summer sea ice loss ….. > …. In recent decades, little change has been seen in atmos concentrations at high latitudes.
6) There are large stores of carbon in the Arctic, some stored as hydrates, some potentially convertible to CH4 by anaerobic resporation
7) there’s evidence in deep time records of large, rapid exogenous inputs of carbon into climate system; leading theory relates this to CH4
8) it is therefore not silly or alarmist to think about the possibilities, thresholds and impacts for these kinds of events
9) in more recent past, there have been a number if times when Arctic (not necessarily globe) has been significantly warmer than today.
10) Most recently, Early Holocene, which had significantly less summer sea ice than even 2012. Earlier, Eemian 125kyrs ago was sig warmer
11) At neither of these times is there any evidence for CH4 emissions or concentrations in excess of base pre-industrial conditions.
12) this means that we are not currently near a threshold for dramatic CH4 releases. (Though we may get there)
13) Much of the concern re dramatic changes in Arctic methane come from one off surveys and poorly calibrated remote sensing
16) But we should not take what-if sensitivity experiments as predictions.
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Addenddum:
Dr. Judith Curry also thinks the “methane time bomb” is implausible.
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We’re about 11k years into the current interglacial, about the fifth one in the last 400k years, and that’s way past the average length of the peak of those interglacials. If The Eemian and the early Holocene and apparently interglacials in general are good enough evidence of the pattern of climate change for the warmists why aren’t they more concerned with our impending descent into another glaciation more than the potential warming over the next hundred or more years? That’s a 10-11 degree centigrade drop we’re staring at. A few degrees rise in temperature is merely a stay of execution.
Bevan says:
July 26, 2013 at 12:17 am
“The main absorption peak for methane is at a wavelength of about 3.3 microns”
Very nice; that should correspond to a color temperature of about 1200 K or 900 deg C.
( Wien’s displacement law)
Methane should be great in capturing and re-emitting radiative heat of furnaces then.
Interesting new evidence the Jai postings are an autoresponder that is biased to respond to comments that don’t follow the alarmist talking points list. Somebody will need to tweak the code to become aware of context as this kind of “friendly fire” is likely to continue. Perhaps there are some climate model coders out there who are having some fun with their faulty algoreisms while waiting for the observed data to get in line with modeled data.
If Jai posts are automated then report the IP to Google spam and other spam block lists. If other websites, blogs and forums report it the responder will get added to an rbl list and posts blocked by services such as http://www.projecthoneypot.org/
KPO:
Why not stop watching CNN? I only watch them in airports.
—-
Or watch it with the sound turned off, then you can laugh at the faces they pull.
Man Bearpig says:
July 26, 2013 at 12:11 pm
“If Jai posts are automated then report the IP to Google spam and other spam block lists. ”
Nonsense. He once even answered me.
An interesting quote from Neven on the weather for future reference Anthony
That’s 10 days from now. The forecast will change.
Posted by: Neven | July 24, 2013 at 13:38
The Naming of Arctic Cyclones | Main | Arctic time bombs »
Second storm Gac2013There’s another storm brewing in the Arctic,
@Tom 9.39 am
The only reason the put CNN on in airports is that by the time you finished watching you haven’t thought about flying you are to p’d off
papertiger says:
July 26, 2013 at 2:48 am
Thanks for the wonderful data from the moons of Saturn.
On Gavin’s engagement here, however indirect, please reply if you feel slighted, Dr. Schmidt, but I quit commenting on your RealClimate, which you maintain at my tax dollar expense during “working” hours, when, in response to another commenter’s request for the names of scientists who questioned the “consensus, settled” conclusion of Warmunistas, I provided dozens, you, Dr. Schmidt, told me that such lists weren’t allowed.
Is bureaucrat Gavin now trying to appear more like a real scientist, given the looming possibility of a return to the scientific method at GISS?
FU, Dr. Schmidt, & the nag you rode in on, namely the raving lunatic Dr. Hansen.
@jai Mitchel
“To contend that these events provide any doubt to the potential for catastrophic CH4 release from the ESAS within the next 100-200 years under current warming scenarios is simply wrong.”
++++++++++
The key word there is ‘scenarios’. The ‘scenarios’ are bunk. That is what the graphs show. There are not believable ‘scenarios’ and thus no believable ‘potential’ nor ‘catastrophic CH4 release’.
I have read a number of your posts recently and they amaze. Your unique parascientific approach is likely to mislead. Without getting into details, please try to keep up:
The models are junk,
Their predictions are bunk.
The ship of methane catastrophe has sunk.
Perhaps there is a ‘potential catastrophe’ were the world warming ‘as predicted’. It is not, and won’t.
‘Potential catastrophe’ averted.
Rejoice, for heaven’s sake.
jai mitchell says:
…………….
Again, I will point jai mitchell here. He seems to be living in fairy wonder land. An Arctic ocean that is ice free for more than a millenium in summer is not in better shape than todays Arctic sea ice.