I'm not seeing much agreement between this graph and others I've seen. The graph below seems almost bistable in behavior.
The graph at http://en.wikipedia.org/wiki/Geologic_temperature_record#Overall_view tells a very different story, it seems - and this concurs with other sources I've seen. Whilst I'm on the phone, I may as well mention something else interesting I stumbled across today. Apparently there is a new theory to explain the PETM, namely the 'hot blobs' (yes, that's the proper name) of magma rise up and lift the crust. If that crust happens to be clathrate-covered ocean floor, this causes depressurisation and dissociate of the clathrates, followed by methane excursion. A blob spreading out over a few 10's of K yrs would neatly explain the pulsed temperature rises of the PETM. A On 19 April 2011 22:27, Glyn Roberts <[email protected]> wrote: > Gene: > > Wow! It seems you -- sorry, I mean Dr. Scotese, has a very dark > vision of the future. > > You say: "This is Scotese’s data and his interpretation." I hope > you're not putting words in Dr Scotese mouth. Could you please point > out where he claims the current warming trend is due to plate > tectonics. I don't see any published works from him making any such > postulation - peer reviewed or otherwise. BTW. His publications are > found here: http://www.uta.edu/ra/real/editprofile.php?pid=145#7. > > Your drawing shows the temperature flipping about 8 times in half a > billion years. It seems a cosmic coincidence that we hit another such > flip just as humanity's GHG footprint soars. > > Theory should be predictive. Take these two points for example: > > In 1937 Guy Stewart Callendar published an early quantitative analysis > of AGW [1]. He wrote: “It is well known that the gas carbon dioxide > has certain strong absorption bands in the infra-red region of the > spectrum, and when this fact was discovered some 70 years ago it soon > led to speculation on the effect which changes in the amount of the > gas in the air could have on the temperature of the earth’s surface.” > > Then in 1965 the Report of the Environmental Pollution Panel, > President’s Science Advisory Committee [2] “By the year 2000 the > increase in atmospheric CO2 will be close to 25%. This may be > sufficient to produce measurable and perhaps marked changes in > climate. [AGW] could be deleterious from the point of view of human > beings.” > > 1. The artificial production of carbon dioxide and its influence on > temperature, Callendar 1938. > 2. Restoring the Quality of our Environment, President’s Science > Advisory Committee, 1965 > > Glyn > > On Tue, Apr 19, 2011 at 3:25 PM, Eugene I. Gordon <[email protected]> > wrote: > > > > Glyn: > > > > > > > > Here is another earlier version of Scotese’s data going back several > hundred million years to which I had added time on the horizontal axis. He > has made corrections to this graph which is what is shown on his current > website. > > > > > > > > > > > > Several points to note. Once the temperature started to increase from an > ice age low of actually about 10 C after -520 MA it continued to increase to > actually 25 C. (there are two blips to higher temperature at about -250 MA > and one about -60 MA These caused major die outs.) It always did the steady > increase; sometimes taking millions of years to increase through the full > temperature range but it never stopped increasing until it asymptoted at 25 > C. It is currently at almost 16 C and rising; having risen from about 12 C > in the last 10,000 years. I am interpreting nothing. This is Scotese’s data > and his interpretation. If one reads Scotese's website one can conclude that > the changes are triggered by motion of land masses, which of course > influence ocean currents. The GHG independent component of warming is > happening now and heading toward 25 C. I am not claiming that current > warming has no GHG component. I did not say but will say it here that the > AGHG dependent component of the warming is not nailed down, except to say > that some of the warming since late 1700s is no doubt geological. > > > > > > > > I suspect we will wait another 20,000 years at least before the > temperature asymptotes at 25C. Long before that life as we know it will end. > Perhaps only Antarctica will have a viable ‘conventional’ life style. The > rest of humanity will live in domed cities, using thermonuclear power > generation or equivalent. One major asteroid hit such as occurred at -250 MA > near the Antarctic will end it for virtually all life on earth. Over 95% of > species disappeared at -250 MA. As you may know that 10 to 15 km asteroid > cracked the earth’s crust and triggered a million years of volcanic > eruptions throughout Siberia. > > > > > > > > Hope this helps a little. I have not read his book but that might help: > > > > Palaeozoic Palaeogeography and Biogeography > > > > by Christopher R. Scotese, W. Stuart McKerrow > > > > -gene > > > > > > > > > > > > From: Glyn Roberts [mailto:[email protected]] > > Sent: Tuesday, April 19, 2011 12:12 PM > > To: [email protected] > > Cc: [email protected]; Geoengineering > > Subject: Re: [geo] On what research I would suggest > > > > > > > > Gene: > > > > > > > > You say the paleoclimate record tells us that the Earth will flip into a > warm state - increasing its average temperature by almost 10 degrees C from > current values? - without GHGs no less! Please connect the dots for me/us > on how you arrived at this bold interpretation of the data. Dr. Scotese's > website doesn't seem to offer this projection. I would have thought the > paleoclimate record suggests a return to another glacial epoch - if we were > to ignore the effect of GHGs. So when is your GHG independent warming going > to happen? Within the next few decades I presume - clearly this is what you > suggest if we need a geoengineering society established now to deal with it. > > > > > > > > Glyn > > > > On Tue, Apr 19, 2011 at 6:11 AM, Eugene I. Gordon <[email protected]> > wrote: > > > > If the documented history of the Earth's climate for the past 450 million > > years (see www.scotese.com) has any relevance, the global average > > temperature is headed for 25 C, up almost 10 degrees C from current > values, > > even without the benefit of anthropogenic CO2. Needless to say, but worth > > emphasizing, even if we stopped producing CO2 tomorrow and could remove > > current excess atmospheric values we are headed for serious climate > warming > > problems. The social implications are enormous and there is little doubt > > that techniques for minimizing the temperature rise will become essential > if > > they are not now extremely important. Hence I argue for formalizing the > > study of geoengineering techniques/technology before leaping in to do > > something about current concerns with a particular approach. Having a > formal > > geoengineering society would have immense value. Plant some of the seed. > > Don't simply eat it all now. > > > > -----Original Message----- > > From: [email protected] > > [mailto:[email protected]] On Behalf Of Mike MacCracken > > Sent: Tuesday, April 19, 2011 12:00 AM > > To: Geoengineering > > Subject: [geo] On what research I would suggest > > > > Ken et al.--Note that I am going to focus on SRM approaches here. A word, > > however, on CDR, which, it seems to me, is just not at all likely to make > an > > important contribution to limiting climate change until global emissions > are > > brought down a good bit through efficiency, essentially giving up coal, > etc. > > With global C emissions nearing 10 GtC/yr and rising, working on > approaches > > that at maximum might make it up to sequestering 1-2 GtC/yr is just > > premature--we need to take other steps first. The one exception here, it > > seems to me, is to see if we can figure out how to deal with ocean > > acidification such as through Greg Rau's approach--I'm not sure if that > is > > more mitigation or not. > > > > On SRM approaches, as I have been saying for a couple of years, it seems > to > > me that the highest priority for early research should be on determining > if > > it is possible to use various of the proposed SRM techniques in very > focused > > ways to limit worsening impacts in the near-term (in places like the > Arctic, > > the loss of sea ice, ice sheet mass, and permafrost is an emergency now, > or > > nearly so, and so waiting to move toward implementation seems too > hesitant > > to me. With this perspective, I would set up a very mission-focused > program > > goal of coming up with a tested approach for dealing with one or more of > the > > most severe impacts, aiming for making a decision to move forward with > > implementation starting in of order of five years (so a 5-year research > > program to get to the implementation stage, and then ongoing research as > > implementation is in progress). > > > > The types of impacts that I would choose to focus on would include some > > combination of the following (and there are of course interlinkages): > > generally reducing Arctic warming (which would also lead to some likely > > beneficial cooling in mid-latitudes); slowing the loss of ice from the > major > > ice sheets; keeping permafrost frozen; redirecting or intensifying > seasonal > > storm tracks into increasingly arid regions like southwestern North > America > > and/or Australia; cooling the waters where hurricanes/tropical cyclones > > intensify; and similar steps. There are those who argue that nothing can > be > > done primarily regionally--that everything leads to global responses; > > determining whether such global connections are statistically significant > or > > not (and whether varying details of the implementation could be done to > > reduce them) would be a clear issue to research--including whether what > > long-distant linkages there are are beneficial or harmful. > > > > With focused objectives such as these, I would think that there could be > > much more focused environmental and social science research as well--much > > more clearly presenting the issue as a risk-risk evaluation than arises > in > > discussions of future global geoengineering. On the benefit side there > would > > at least be a clear beneficial change being sought, which can get much > more > > confused in the global case. I should also note that I think focusing on > > moderating regional-scale impacts, there would hopefully be less of a > > tendency to reduce effort on mitigation (if that really is a problem), > > because, of course, there are a whole host of impacts not being > addressed. > > > > Not only would success in coming up with an approach for dealing with > severe > > impacts such as mentioned above, but it would also help to build > > understanding about the various approaches and the basis for ongoing, but > > lower priority research on potential global implementation, which I think > > should also be considering what I think would be more realistic > > implementation scenarios (e.g., implementing incrementally to stop and > > slowly reduce radiative forcing starting in the near-term) than imagining > > we'd figure out and agree on when some threshold has been passed and do a > > large and sudden emergency implementation (not even being clear that when > so > > far along everything can be reversed). > > > > I've written up some of these ideas over the past year or too for various > > studies, but had not passed them around, so will attach to this message. > The > > first memo offers some thoughts on how I would organize a US program, and > an > > accompanying table suggest some specific research efforts. Note that this > > memo envisions not just the very focused applied effort, but also an > > independent research and evaluation effort to keep make sure questions > get > > raised and considered--again relating to moving toward the specific > proposed > > objective, but in this effort on real and potential shortcomings, and not > > just a general research effort (we need more money for that). The second > > memo was prepared as a more detailed example of how one might structure > the > > component of the program aimed at moving rapidly to limit Arctic warming. > It > > is posed as a letter dated a few years hence seeking approval for moving > > ahead with a major field program to test approaches that have already > been > > tested in computer simulations, etc. Clearly an optimistic timetable, but > > really the type of one that is needed given what seem to be irreversible > > changes (like loss of mass from Greenland, loss of biodiversity, etc.) > that > > we seem headed toward. > > > > Note that the ideas written up are over a year old, so a bit dated. And > > these are just ideas--they would greatly benefit from some intense > > discussion about how to do even better, etc. I just think we are moving > far > > too slowly right now. > > > > Best, Mike MacCracken > > > > > > > > -- > > You received this message because you are subscribed to the Google Groups > > "geoengineering" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group at > > http://groups.google.com/group/geoengineering?hl=en. > > > > > > -- > > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > [email protected]. > > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > > > > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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