Thanks Sam. All these uses of the term seem to be for the venusian-style ocean-boiling type runaway. This is different from the limited runaway expected on earth. Are there academic citations for the Earth type?
Is there a 'standard' definition of the terms: Runaway greenhouse effect runaway climate change runaway global warming anywhere you're aware of? A 2009/2/4 Sam Carana <[email protected]>: > > The phrase "runaway greenhouse effect" was used as far back in the > 1980s and is still used today, e.g. regarding Venus. > > Runaway and moist greenhouse atmospheres and the evolution of earth > and Venus (June 1988) > http://adsabs.harvard.edu/abs/1988Icar...74..472K > > The phrase "runaway greenhouse effect" is used twice on the Wikipedia page at: > http://en.wikipedia.org/wiki/Atmosphere_of_venus > > "... led to a powerful positive feedback response known as the runaway > greenhouse effect," says Grinspoon. > http://www.esa.int/SPECIALS/Venus_Express/SEM2EHMJC0F_0.html > > putting the planet in a 'runaway greenhouse state'. > http://www.esa.int/esapub/bulletin/bulletin135/bul135a_svedhem.pdf > > The Runaway Greenhouse and the Accumulation of CO2 in the Venus Atmosphere > http://www.nature.com/nature/journal/v226/n5250/abs/2261037a0.html > > The phrase "runaway greenhouse effect" is used in many scientific > publications, e.g see: > http://www.nature.com/search/executeSearch?sp-a=sp1001702d&sp-sfvl-field=subject|ujournal&sp-q=runaway%20greenhouse%20effect&sp-p=phrase&sp-d=custom&sp-s=0&sp-c=25&sp-q-min-15=18690101&sp-q-max-15=20090218&sp-x-15=pubdate_ymd > > Cheers! > Sam Carana > > > > On Wed, Feb 4, 2009 at 5:50 AM, Oliver Wingenter > <[email protected]> wrote: >> >> Dear Andrew, >> >> We need to read the explanation of Runaway Greenhouse Efffect in Wayne >> 1st ed pg. 49. I will dictate into an email soon. >> >> Sincerley, >> >> Oliver Wingenter >> >> On Feb 2, 4:50 pm, Andrew Lockley <[email protected]> wrote: >>> I have an alternative theory as to why we don't see too many instances >>> of runaway climate change from the 'clathrate gun' effect, or from >>> permafrost. >>> >>> Methane has a very short life in the atmosphere, but is a potent >>> greenhouse gas. If the rate of warming is low, a little methane is >>> released, which quickly degrades to CO2 which has little short term >>> effect and can then disappear into sinks. As warming continues, more >>> methane is released, but never fast enough to make a significant >>> difference to the climate before it degrades again to CO2. >>> >>> HOWEVER: >>> >>> In AGW, the temperature is rising very fast. This has the potential >>> to make methane belch out from soils and seas very quickly. This >>> speed is of the essence, as large quantities of methane will be enough >>> to influence future methane release to create a runaway event. >>> >>> The process is like pull starting a chainsaw. A little tug gets you >>> the odd cough. Tug hard, the the chainsaw motor gets started and runs >>> on its own. >>> >>> Now, pretty please with sugar on top, can someone tell me what the >>> proper, scientific, not-to-be-argued with name for that process is? >>> The people on wikipedia really don't like 'runaway climate change' - >>> as apparently 'proper' climate scientists don't use that term. >>> Citations much appreciated, thankyou!! >>> >>> A >>> >>> 2009/2/2 Alvia Gaskill <[email protected]>: >>> >>> > Not enough CO2 in the atmosphere. >>> >>> > ----- Original Message ----- >>> > From: Andrew Revkin >>> > To: [email protected] ; [email protected] >>> > Cc: [email protected] ; Tom Wigley ; Andrew Lockley ; geoengineering ; >>> > Prof John Shepherd ; Tim Lenton ; David Lawrence >>> > Sent: Monday, February 02, 2009 3:29 PM >>> > Subject: [geo] runaway climate change >>> > Who on this list knows why the Arctic warming ~ 8,000 years ago (quite >>> > protracted and significantly warmer than today) did not lead to "runaway" >>> > warming? >>> > Presumably something kicked in the other direction? >>> > I'm pursuing a clearer picture of lessons from the Holocene and the Eemian >>> > (the previous interglacial) related to feedbacks and whether there are, or >>> > are not, one-way doors in the climate system. Leads eagerly pursued. .. >>> > Andy >>> > At 5:29 PM +0530 2/2/09, Govindasamy bala wrote: >>> >>> > Runaway feedback means running its course completely. It is feedback >>> > specific. >>> >>> > A good example is the presumed water vapor feedback on Venus. >>> > Apparently, earth and venus started with similar amount of h2o. >>> > Because Venus started with much higher surface temperature, the evolution >>> > of >>> > temperature and water vapor never intercepted the phase line of vapor and >>> > liquid. The climate warmed until all the water got evaporated. Basically, >>> > there was no sink for vapor which precipitation. On earth, this is not >>> > going >>> > to happen because we got the precipitation sink on earth...how lucky we >>> > are. >>> >>> > But I guess we do have runaway ice-albedo feedback on earth. we could get >>> > ice-free planet or snowball earth........ >>> >>> > Cheers. >>> > Bala >>> >>> > On Mon, Feb 2, 2009 at 5:03 PM, Eugene I. Gordon <[email protected]> >>> > wrote: >>> >>> > I guess it is not going to end. >>> >>> > A runaway train meets only #2 and even that has to be qualified because >>> > the >>> > train eventually runs out of (fossil?) fuel or track. Certainly climate >>> > has >>> > run away a half dozen times in 540 million years but always hits a limit >>> > which seems to be 24C except when an asteroid hits. It eventually turns >>> > around after remaining at the limit temperature for many millions of >>> > years. >>> > We have been in a runaway mode for the last 18,000 years but with some >>> > superimposed small wiggles in temperature. Without geoengineering the >>> > temperature will certainly get to the 24 C limit. >>> >>> > I think runaway is appropriate for the current situation even if there may >>> > be better suited terms. >>> >>> > -----Original Message----- >>> > From: [email protected] >>> >>> > [mailto:[email protected]] On Behalf Of John Nissen >>> > Sent: Monday, February 02, 2009 6:08 AM >>> > To: Tom Wigley; Andrew Lockley >>> > Cc: geoengineering; Prof John Shepherd; Tim Lenton; David Lawrence >>> > Subject: [geo] Re: runaway climate change >>> >>> > Dear Tom, >>> >>> > The concept of "runaway" has certain connotations: >>> >>> > 1. Significant in resultant effect >>> > 2. Uncontrollable >>> > 3. Exponential initial behaviour - characteristised by acceleration of >>> > process 4. No obvious limit 5. Irreversible 6. Rapid. >>> >>> > These can all be applied to climate change: >>> >>> > 1. "Significant" could be over 5 degrees global warming, sufficient for a >>> > mass extinction event. Or it could be applied to several metres of sea >>> > level rise. >>> > 2. "Uncontrollable" could be where anthropogenic greenhouse gas emissions >>> > reduction would not have a significant effect on the rate of climate >>> > change. >>> > 3. Exponential behaviour could be caused by a "tipping" of some part of >>> > the >>> > climate system, such as Arctic sea ice or methane release, where there is >>> > strong positive feedback. >>> > 4. There would be no obvious final equilibrium temperature - mainly >>> > because >>> > of the difficulty of modelling positive feedback and its behaviour over >>> > time. >>> > 5. It would be extremely difficult or impossible to reverse processes >>> > such >>> > as methane release or Greenland ice sheet disintegration, although it is >>> > conceivable to halt these processes or even reverse their effects >>> > (presumably through geoengineering). >>> > 6. "Rapid" could be anything from one season to 3000 years, on a >>> > geological >>> > timescale. >>> >>> > Therefore I think that "runaway" captures the semantics that we require >>> > for >>> >>> > the climate change that would result from, for example, a massive methane >>> > release, triggered by Arctic sea ice disappearance. Can you think of a >>> > better word to capture the six characteristics above, especially as >>> > applicable to climate change? >>> >>> > Cheers, >>> >>> > John >>> >>> > ----- Original Message ----- >>> > From: "Tom Wigley" <[email protected]> >>> > To: "Andrew Lockley" <[email protected]> >>> > Cc: <[email protected]>; "geoengineering" >>> > <[email protected]>; "Prof John Shepherd" >>> > <[email protected]>; "Tim Lenton" <[email protected]>; "David >>> > Lawrence" >>> > <[email protected]> >>> > Sent: Monday, February 02, 2009 3:43 AM >>> > Subject: Re: [geo] Re: runaway climate change >>> >>> >> Andrew, >>> >>> >> Poor analogy. running does not equal running away. >>> >>> >> More importantly, just because a term has been misused in the >>> >> past does not mean we should perpetuate its misuse (or use). >>> >> If the word is to be used at all (and, as a practicing scientist, >>> >> I never have or will), one should start off by saying that the >>> >> word runaway is open to misinterpretation, that it does not >>> >> mean running off to infinity, and that it's real meaning is ... >>> >> etc. etc. Then talk about irreversible changes (with the caveat >>> >> that even these are probably not irreversible), positive >>> >> feedbacks (which also have limits), etc. >>> >>> >> Tom. >>> >>> >> +++++++++++++++++++++++==== >>> >>> >> Andrew Lockley wrote: >>> >>> For better or worse, the term is now in general use in scientific, >>> >>> industrial, environmental and general media. (See >>> >>>http://en.wikipedia.org/wiki/Runaway_climate_changefor refs.) >>> >>> >>> I don't agree with Tom about 'to infinity and beyond'. I run as a >>> >>> hobby, and I've never run to infinity (or beyond). I think most >>> >>> people realise that runaway doesn't mean run-for-ever. >>> >>> >>> However, a general definition would be very useful. >>> >>> >>> A >>> >>> >>> 2009/2/2 <[email protected]>: >>> >>>> Dear All, >>> >>> >>>> I've said this before, but here goes again. >>> >>> >>>> If one sticks to dictionary definitions of words (which I >>> >>>> think is wise) then there is no such thing as "runaway" >>> >>>> climate change. Strictly, using the words of Buzz Lightyear, >>> >>>> "runaway" must mean "to infinity and beyond". >>> >>> >>>> Further, the word "runaway" is loaded and should be eschewed >>> >>>> in the climate context. >>> >>> >>>> The confusion here is that what some people are calling >>> >>>> "runaway" climate change is really better referred to as >>> >>>> "irreversible" climate change. For instance, the sudden release >>> >>>> of a large amount of CH4 would possibly cause large warming >>> >>>> that would put the globe in a new state that was much warmer >>> >>>> than present. But the climate (or global-mean temperature) would >>> >>>> *not* runaway -- it would eventually stabilize. Even this change >>> >>>> would not strictly be irreversible, as the excess CH4 would >>> >>>> slowly be oxidized (more slowly than today because of the well >>> >>>> known positive feedback of CH4 on its own lifetime due to OH loss), >>> >>>> but a lot of the excess CH4 would slowly disappear and be replaced >>> >>>> by CO2 that has less forcing. This CO2 would, of course, stay >>> >>>> around for a long time. >>> >>> >>>> If anyone is interested, this case can easily be run with MAGICC, >>> >>>> but some minor tweaks are needed to get the CH4 to CO2 flux right. >>> >>>> Conceptually trivial. >>> >>> >>>> So, please, please try not to cry wolf with these loaded and sadly >>> >>>> oft-misused words. >>> >>> >>>> Tom. >>> >>> >>>> ++++++++++++++++++++++++++++ >>> >>> >>>>> Andrew, >>> >>> >>>>> 1. I think the concept of runaway climate change is kosher. See this >>> >>>>> quote >>> >>>>> from >>> >>>>>http://www.meridian.org.uk/_PDFs/FeedbackDynamics.pdf >>> >>> >>>>> "The possibility of a tipping point in the earth system as a whole >>> >>>>> which >>> >>>>> prevents the recovery of stable equilibrium and leads to a process of >>> >>>>> runaway climate change, is now the critical research agenday, >>> >>>>> requiring >>> >>> >>>>> the >>> >>>>> concerntration of global resources in a "Manhattan Project" style >>> >>>>> engagement. All other work on impact assessment, mitigation and >>> >>>>> adaptration >>> >>>>> depends on the outcome of thie overarching issue" >>> >>> >>>>> I would prefer to have "runaway global warming", because that's what >>> >>>>> we >>> >>>>> are >>> >>>>> really talking >>> >>> ... >>> >>> read more ยป >> > >> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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