I agree with Andrew. A positive feedback is not a runaway mechanism unless it does not saturate. For sure 540 million years of temperature history show there are long term temperature maxima and minima. That is not runaway. The positive feedback is clear but it saturates. If we are engineers let us be accurate and not fall back on careless prior nomenclature. There is pretty good evidence based on past climate history that long term temperature changes occur monotonically on a scale of thousands of years but not for shorter times so there is slow positive feedback that saturates (not runaway not even a slow jog.). As also a scientist I never fall back on hypothesis until it passes certain requirements that elevate it to theory (logical arguments based on established fact is not enough) . Comfort is fine but it is too casual. I think a more professional approach is to use the word "suggests" or "is a reasonable but not yet proven hypothesis." or :"is attractive but more work is needed."
_____ From: [email protected] [mailto:[email protected]] On Behalf Of Andrew Lockley Sent: Friday, February 06, 2009 7:28 AM To: John Nissen Cc: geoengineering Subject: [geo] Re: runaway arguments ripped to bits You might be convinced by this hypothesis, but science works by proof. All we have been able to demonstrate is a risk, not a probability. It's all a matter of gain. A positive feedback is NOT a runaway. It is only a runaway if the gain is sufficient. You need to prove the gain to prove the argument. Bearing in mind the water seems to re-freeze each winter, the feedback does not seem to be the principle forcing mechanism in operation here. The feedback may well dramatically accelerate the effect of CO2 emissions, but it does not seem to be the central effect. Fortunately, as the Arctic is dark for 6mo the system has plenty of time to recover from any seasonal runaway. Can you cite papers to show the ice-albedo feedback is sufficient to start a runaway effect? Which paper are you taking the 30W/m2 from? The methane effect similarly is unproven. This doesn't mean it's not true, just that you haven't demonstrated it to be true. I can find no papers which show a rapid degeneration of clathrates. Buffett and Archer specifically failed to show such an effect, but I understand that they considered only deep clathrates which are slow to outgass. Permafrost slumping may be a crucial mechanism in faster degeneration of clathrates, but has anyone modelled it and the outgassing rates that result? I can also find no papers which give the original research for the effect of increased atmospheric methane. I personally don't really need to be convinced that a massive outgassing of methane might be a slight problem, but others do. Can you cite papers which indicate the expected temperature increase from a predicted outgassing event? Don't take this all personally, John. I believe you're right. We just need to prove it. This is science, not dogma. A 2009/2/6 John Nissen <[email protected]> Hi Andrew, It depends what kind of proof you want. I myself am convinced of things if there is a logical argument based on established facts. I am convinced by anthropogenic global warming because if you put an extra 100 ppm CO2 in the atmosphere, you EXPECT to have greenhouse warming. I don't need "proof" to be convinced. To be persuaded otherwise, I would need a convincing explanation of why the CO2 wasn't causing global warming, or how this was somehow neutralised. I would need to be PROVED WRONG. Similarly with methane runaway feedback. There's a vast amount of methane trapped in frozen structures. Nobody disputes this fact. If you put enough of this methane in the atmosphere, you expect global warming. You then expect positive feedback as a result of this, as the frozen structures unfreeze to release more methane until it's all gone. Unless there is an argument against this logic, I will remain convinced by it. Similarly with the Arctic sea ice and domino effects. The "forcing" from the sea ice albedo effect is of the order of 30 Watts per square metre, so you expect this to drive regional warming. Nobody is suggesting how this warming would reverse naturally. So, as the region continues to warm, you expect the domino effects of methane release and Greenland ice sheet accelerated discharge. This is all highly uncomfortable to contemplate, and I'd like to be proved wrong. However we do have a possible way out of this situation with geoengineering. So all is not lost. Please can we now persuade politicians and potential funding bodies of the inescapable logic of this situation, so that they fund the necessary geoengineering developments? Or prove me wrong. Cheers, John ----- Original Message ----- From: Andrew Lockley <mailto:[email protected]> To: John Nissen <mailto:[email protected]> Sent: Friday, February 06, 2009 1:13 AM Subject: Re: [geo] runaway arguments ripped to bits I'm not saying you're wrong. I'm just saying I haven't been able to PROVE you're right. A 2009/2/5 John Nissen <[email protected]> Dear Andrew, That is very unfair - a stab in the back. 1. I have given you several references to methane in the past, e.g. from David Lawrence. And there are plenty of references already in wikipedia, e.g. here: http://en.wikipedia.org/wiki/Arctic_methane_release (I am sorry I can't help on the shoreline slumping.) 2. I am trying to answer your basic question: Is there REALLY a big and immediate risk from the clathrate gun/permafrost? You seemed to be arguing only about the methane, without taking into account the Arctic sea ice albedo effect. 3. The argument that the Arctic sea ice albedo effect is causing regional runaway feedback is new to this list. The argument that we should reverse the Arctic sea ice retreat is also new - previously I had argued we simply had to halt the retreat. 4. These are common sense arguments. If anybody can find some evidence to dispute them, may they come forth. 5. I have given my own conclusion repeatedly, because it bares repeating: If we do not act quickly with our SRM geoengineering, then thermal runaway from methane (and also disasterous sea level rise) could become inevitable. 6. Your criticism is a stab in the back, because you seemed to be one of the few people who accepted this conclusion, because of all the evidence I gave you. Et tu, Brute. John. ----- Original Message ----- From: Andrew Lockley <mailto:[email protected]> To: John Nissen <mailto:[email protected]> Cc: Geoengineering FIPC <mailto:[email protected]> ; Prof John Shepherd <mailto:[email protected]> ; John Gorman <mailto:[email protected]> Sent: Thursday, February 05, 2009 1:12 PM Subject: Re: [geo] runaway arguments ripped to bits John, You've repeated these arguments on this list on numerous occasions. However, you've failed to back them up with peer-reviewed science. I've already emailed the list asking for scientific support for these very ideas in the last 24hrs. Specifically we need help with the alterations to methane GWP, the decay rate of clathrates due to shoreline slumping in the Arctic and calculations of the overall warming load arising from a methane pulse. I hope you can assist with the search for solid backing for your case and not re-iterate oft-rehearsed arguments. The relevant wiki is actually at http://en.wikipedia.org/wiki/Runaway_climate_change#Current_risk A 2009/2/5 John Nissen <[email protected]> The term "runaway" has an accepted meaning in the context of "thermal runaway", and is characterised by positive feedback and resulting acceleration in temperature change. So the temperature rises more than linearly, and may even rise exponentially or "explosively": http://en.wikipedia.org/wiki/Thermal_runaway Eventually the feedback peters out, and the temperature change becomes linear again. This process is happening with the Arctic sea ice. At present the albedo feedback effect is causing an acceleration in temperature change in the polar region - but this positive feedback will eventually peter out, when all the ice and snow in the region has melted, including the Greenland ice sheet! So we are facing thermal runaway on a regional scale, affecting local climate and ecosystem. This will have a domino effect on methane release. As the Arctic region warms, methane will invitably be released in larger and larger quantities. The speed of methane release depends critically on the temperature above the frozen structure holding the methane. For permafrost on land, if the average surface temperature is maintained above freezing, the permafrost will inevitably melt. This is what is happening over vast areas of Canada and Siberia, as the isotherms (lines of equal temperature on a map) move northwards. The methane itself provides feedback equally to both regional and global warming, through its greenhouse effect. The regional warming will increase the rate of methane release. Thus there could be thermal runaway on a global scale and "we are toast", as Hansen puts it. We have to find a way to quickly halt the Arctic regional warming. I maintain that the key to this is to halt and partially reverse the retreat of the Arctic sea ice, by cooling the region. And I maintain that the key to cooling is use of solar radiation management (SRM) techniques - a combination of stratospheric aerosols and marine cloud brightening. If we do not act quickly with our SRM geoengineering, then thermal runaway from methane (and also disasterous sea level rise) could become inevitable. Cheers from Chiswick, John P.S. Note that geoengineering to reduce atmospheric CO2. ----- Original Message ----- From: "Andrew Lockley" < <mailto:[email protected]> [email protected]> To: "Geoengineering FIPC" < <mailto:[email protected]> [email protected]> Sent: Thursday, February 05, 2009 2:28 AM Subject: [geo] runaway arguments ripped to bits > > After getting thoroughly shouted at, I realised I needed to improve my > 'runaway' arguments. > > My current skeleton is below. However, it's currently missing a few > crucial bones which now need replacing. I need citations for the > following: > > 1) A clathrate gun effect that shows rapid release? Buffett and > Archer, and Archer alone, show a slow release, although from a large > reservoir. > 2) A calculation of the eventual warming that may result from methane > release from permafrost/clathrates. > 3) A study showing the impacts of such a level of warming on human > civilisation/survival. > 4) What happens to methane sinks under conditions of bulk outgassing? > Do they fail and massively increase the global warming potential of > methane? > > We've discussed all these issues before, but I think it's now time to > get any available research on the issue into the open. Is there > REALLY a big and immediate risk from the clathrate gun/permafrost? > > A > > <http://en.wikipedia.org/wiki/Effects_of_global_warming#Abrupt_climate_chang e> http://en.wikipedia.org/wiki/Effects_of_global_warming#Abrupt_climate_change > > The scientific consensus in the [[IPCC Fourth Assessment Report]] is > that "Anthropogenic warming could lead to some effects that are abrupt > or irreversible, depending upon the rate and magnitude of the climate > change." > > The phenomenon of [[Arctic shrinkage]] is leading some scientists to > fear that a runaway climate change event may be > imminent<ref>http://www.guardian.co.uk/environment/2006/oct/18/bookextracts. books</ref>, > and may even have > started<ref>http://www.terranature.org/environmentalCrisis.htm</ref>. > There is an [[albedo]] effect, as white ice is replaced by dark ocean. > Rapid [[Arctic shrinkage]] is occurring, with 2007 being the lowest > ever recorded area and 2008 being possibly the lowest ever recorded > volume.<ref>http://nsidc.org/news/press/20081002_seaice_pressrelease.html</r ef> > This will induce or accelerate other [[positive feedback]] mechanisms, > such as [[Arctic methane release]] from melting [[permafrost]] and > [[clathrates]]. Lawrence et al(2008) suggests that a rapid melting of > the sea ice may up a feedback loop that rapidly melts arctic > permafrost.<ref>http://www.ucar.edu/news/releases/2008/permafrost.jsp</ref>< ref>{{Citation > | year=2008 | title=Accelerated Arctic land warming and permafrost > degradation during rapid sea ice loss | first=David M. | last=Lawrence > | first2=Andrew G. | last2=Slater | first3=Robert A. | last3=Tomas | > first4=Marika M. | last4=Holland | first5=Clara | last5=Deser | > journal=[[Geophysical Research Letters]] | volume=35 | issue=11 | > doi=10.1029/2008GL033985 | > url=http://www.cgd.ucar.edu/ccr/dlawren/publications/lawrence.grl.submit.200 8.pdf} <http://www.cgd.ucar.edu/ccr/dlawren/publications/lawrence.grl.submit.2008.p df%7D> }</ref> > > Estimates of the size of the total carbon reservoir in Arctic > [[permafrost]] and [[clathrates]] vary widely. It is suggested that > at least 900 gigatonnes of carbon in permafrost exists > worldwide.<ref>http://www.terranature.org/methaneSiberia.htm</ref>{{fact}}. > Further, there are believed to be around and another 400 gigatonnes > of carbon in methane clathrates in permafrost regions > alone.<ref>http://www.springerlink.com/content/r4w867922g607w2j/</ref>. > Should this estimate of volume be correct or at least too low, and if > clathrates are omitted from the analysis completely, then 900 > gigatonnes of carbon may potentially be released as methane as a > result of human activity. [[Methane]] is a potent [[greenhouse gas]] > with a higher [[global warming potential]] than [[CO2]]. A release on > this scale will create [[catastrophic climate change]]. > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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