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Climate Change: Past, Present, and Future

Posted on 30 September 2010 by John Cook

I love a simple, accessible graph that tells a clear story. A good example can be found in a new paper Climate Change: Past, Present, and Future (Chapman & Davis 2010). They plot past climate change over the past 1000 years together with what we can expect to experience over the next century. In a single figure, it tells us a number of stories which are fleshed out further in the paper.

The past 1000 years feature a number of temperature reconstructions (the thin coloured lines) using various proxies such as tree rings, corals, sediments, glacier length and boreholes. The black dotted line is the average temperature over the decade centered on 1 Jan 2000. Having a variety of independent proxy methods gives us confidence that current temperatures are warmer than any experienced over the past 1000 years.

The coloured areas represent future projections of global temperature. The yellow projection (C3) tells us what would happen if CO2 concentrations were held steady at year 2000 levels. In other words, what would happen if humanity had suddenly stopped emitting CO2 in the year 2000 (but it's okay, we'd still be allowed to breath). Even in this imaginary case, temperatures would still continue to increase due to the thermal inertia of the oceans.

The other coloured areas represent the IPCC scenarios. Scenario A2 has global population increasing to 15 billion, accompanied by a warming of 4°C by 2100. Scenario A1B has population peaking at 8.7 billion and a mix of fossil-fuel and renewable energy use. This gives us a warming of 2.5°C. Scenario B1 assumes the same population growth as A1B but also assumes more aggressive cuts in CO2 emissions, leading to a warming of less than 2°C.

It's a simple graph but quite useful to have past temperature history displayed with various future scenarios, providing the benefit of both hindsight and foresight. All the emission scenarios present global warming in the 21st century that dwarfs warming seen in the past millennium. Of course, it's also important to realise that this is the global average. Warming at high latitudes may be 3 times as much.

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Comments 51 to 87 out of 87:

  1. @Albatross #8. Yep, probably was. Well found. But my point remains: I'm surprised that I haven't seen more of this sort of demo and discussion. To my mind it more-or-less bypasses any discussion of historical temp records.
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  2. Ned (#34 etc.), "I know that "skeptics" like to claim that the only choices are burning fossil fuels or de-industrializing." I think you are making an unjustified generalization about "skeptics". Some of us advocate a drastic reduction in CO2 emissions without destroying our energy based civilization. This blog is not into "solutions" so I won't elaborate other than to say that the solution is to "build a Nuke a day". For those interested check out a typical thread on "Brave New Climate": http://bravenewclimate.com/2010/09/28/2060-nuclear-scenarios-p1 Here is a link to a paper by George Sanford et al. that contains some amazing speculations: http://tinyurl.com/jtop6
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  3. John Cook, My apologies for killing such a good thread. Given that this is a science blog I was expecting a strong reaction to my #52.
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  4. I'll bite, GC, but it'll swerve us off topic. Brave New Climate bugs me because it's a typical case of energy technology monomania, in this case with all roads leading to nuclear fission. I'm not fond of any form of monomania when it comes to energy manipulation because we can't afford that kind of self-indulgence. Central Planning by another name. That's all I'll say; you get the last word and then hopefully the thread won't be hopelessly degraded...
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  5. Blimey GC - do you think climate science is trying to destroy our civilization? I would say that I have struggled to find many "skeptics" interested in decarbonizing though. The biggest problem is the political inertia that misinformation creates preventing any solution at all.
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  6. Re: gallopingcamel (52)
    A. "Some of us advocate a drastic reduction in CO2 emissions" B. "without destroying our energy based civilization."
    How are parts A and B of your statement not mutually exclusive? I've yet to hear a true skeptic advocate A, while those of a more "skeptical" nature will allow for no controls on A to preserve B (the BAU approach).
    "This blog is not into "solutions" so I won't elaborate other than to say that the solution is to "build a Nuke a day"."
    The "solution" this blog follows is to debunk and rebunk "skeptic" memes that cannot withstand the cold light of science and logic. Any solution that does not also involve dramatic, immediate reductions in CO2 emissions is not a solution. We are too close to the point of no return. Do you advocate no controls on CO2 emissions until enough nukes are built to offload energy demands from fossil fuels in order to preserve our current standard of living? This path is recognized as another FF industry delaying tactic. If this is indeed your meaning, sir, you intend to consign our current civilization to a clear and certain extinction. And perhaps our species as well. Re: gallopingcamel (53)
    "Given that this is a science blog I was expecting a strong reaction to my #52. "
    Perhaps because this IS a science blog, most habitués recognized the incompatibility of your Points A and B I touched on in the top part of this missive. Points that, I might add, seem obviously designed to attract attention, like a baited trap attracts the unwary. So perhaps the strong reaction you did unintentionally elicit was that of aversion. The Yooper
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  7. That's better! (posts #54,55 & 56), Daniel Bailey doubts my motives so let's clear that up. I am not trying to bait a trap in the hope of shouting "Gotcha!". It is much simpler than that; I strongly support the idea of a sharp reduction in CO2 emissions (point A), one of the key notions on this thread. Many people seem to believe that points A and B are mutually exclusive so my task is to convince you otherwise. If you tell people that they have to give up heating/cooling their homes, motor transportation etc. etc. in the hope of limiting global temperature rise to <2 degrees Kelvin, nothing is going to change. doug_bostrom, it is clear that you are familiar with BNC (Brave New Climate). Marxists can be found there but also plenty of free market folks (like me). Persuasion works much better than coercion (IMHO). I want people to drive electric cars (as I do) because it makes sense rather than because they have no choice. scaddenp, John Cook will (rightly) censor me if I respond to your question about the motivations of "Climate Science". All I am suggesting is that there are ways to get the energy our civilization needs at an affordable price without burning fossil fuels.
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  8. gallopingcamel #57, without getting into the political downfalls around taking 'free market' ideology to extremes... I always find the free market argument against controlling fossil fuels inherently illogical. The amount of money spent to subsidize fossil fuels is enormous. Even leaving out the cost of wars instigated, at least in part, over these resources we are talking about amounts far in excess of anything which has even been proposed in the way of subsidies for other energy sources. Ridiculous amounts of public funding are provided to oil companies for exploration and research. Entire aircraft carriers have been built and permanently assigned to the gulf region with the sole, officially stated, purpose of protecting oil shipments. Switch all public funds currently supporting fossil fuels to renewable energy (even ignoring the larger disparity which has accumulated over the past ~150 years) and it is the fossil fuels which are not economically viable.
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  9. GC - I completely agree that we can find the energy for our civilization without fossil fuel. What I am amazed about is the apparent assumption, too political for you to post, that somehow climate scientists would disagree.
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  10. CBDunkerson (#58), I have no argument with you as I am trying to make a case against burning fossil fuels. We appear to be on the same side as far as the big picture (cutting CO2 emissions) is concerned. Even so, your closing statement is absurd on many levels: # Switch all public funds currently supporting fossil fuels to renewable energy (even ignoring the larger disparity which has accumulated over the past ~150 years) and it is the fossil fuels which are not economically viable. # I would like to set you straight but that would get us into the realm of "solutions".
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  11. Re: gallopingcamel (57, 60)
    "Daniel Bailey doubts my motives so let's clear that up."
    Nothing personal, GC. Perhaps if you had phrased your comments with a bit more clarity so that there would be no doubt as to your intentions then I would have worded my response differently. My position is unchanged until I have seen evidence supporting the compatibility of A & B. I do have an open mind on it, but the intractability of humanity leaves me skeptical about its ability to change its behavior until its too late to have any meaningful impact. Given where we are now and the emerging picture of the nearness of the cliff we approach, the more my doubts about Lovelock's stance dissipate. Only my nature's staunch refusal to give up, even in the face of insuperable odds, keeps me searching for a way forward. CBDunkerson & scaddenp summarize the remainder of my position well (kudo's to those estimable gentlemen), only with greater eloquence than I. If the electric automobile had been developed first, then there would be no need for widespread internal combustion engine use. Coal is another bugger, tho. The Yooper
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  12. Daniel Bailey (#61). Most of the time I am flying against the wind on this blog and the faithful are used to applying ritual flagellation. Once in a while I agree with them but the knee jerk reaction is to beat up on me, regardless! Actually, the electric automobile was developed first but somehow the internal combustion engine has gained a temporary ascendancy. Real electric cars do not have on board generators powered by internal combustion engines as in the Chevrolet "Volt" or the Toyota "Prius". They are very simple vehicles with batteries and electric motors. Test marketing shows that people love such vehicles even though they have limited range with today's battery technologies. For a thoroughly entertaining and informative story about electric automobiles I recommend Sony's movie called "Who Killed the Electric Car?" Here is a two minute intro but you should seek out the entire (90 minute) movie about GM's EV1: http://www.youtube.com/watch?v=nsJAlrYjGz8 I own a Jeep "Grand Cherokee", a Honda "Odyssey" and an electric car. If I could get my hands on an EV1 it would replace my existing electric car and one of the gas guzzlers. This would improve my cash flow so nobody would have to hold a gun to my head.
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  13. Re: gallopingcamel (62) My apologies for being less than clear with my comments about the development of the electric auto. I should have said something along the lines of "If the electric auto had achieved widespread market penetration before the development of the internal combustion engine...". Thanks for the additional background info. If an electric car could put up with the deep snows of winter and the 200-250 miles per day work entails, I would have one instead of my Jeep Patriot POS 'fine example of American engineering' my company furnishes me with. FYI: It IS possible to fly against the wind without drawing flagellating fire, depending upon the idiom employed. :) The Yooper
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  14. @gc (#62): "Actually, the electric automobile was developed first but somehow the internal combustion engine has gained a temporary ascendancy." Indeed, at some point electricity, steam and internal combustion all competed. The main reason the latter won is that it was much easier to set up a gasoline distribution network (i.e. gas stations and trucks) throughout the US than have an electric power grid covering the majority of such a vast therritory (unlike what we have now). Steam engines used coal, so you can imagine what that would have done for pollution... :-)
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  15. gallopingcamel wrote : "Most of the time I am flying against the wind on this blog and the faithful are used to applying ritual flagellation." Do you see everything in life in religious terms ? I suggest you should lean less on religion and more on science, when it comes to AGW at least.
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  16. GC #60, "I would like to set you straight but that would get us into the realm of "solutions"." Solutions are bad? Political arguments are to be avoided, but reality based solutions are fine. On the whole 'electric auto' front... I'm not looking to trade in my 2001 Prius yet because I drive more than the Leaf's 100 mile range several times a year and more than the Volt's 40 miles electric range every day. The 200+ mile range of the Tesla Roadster would be enough... but it's a ridiculously ostentatious 'look at me' mobile. Given current technology it ought to be possible to build a car with ~100 mile electric range AND a backup gasoline powered electrical generator. That would allow 99% of the drivers in the world to complete their daily commute on electric power. People would only ever need to put gas in their tank for the few trips a year (if that) where they were going further. No 'range anxiety' problems and gasoline usage cut to an insignificant fraction of current... yet nobody seems to be building such a car. Instead we've got all electric or electric with gasoline backup, but too short an electric range to ever leave the gas tank empty. Sure, going directly to all electric would be great... but realistically it isn't going to happen without massive infrastructure changes. A 100 mile electric / gasoline hybrid could get us most of the way to zero gasoline usage NOW. No waiting on a network of charging stations, faster charging battery technologies, batteries that don't deteriorate as much over time, and/or batteries with higher energy density... all of which would also get developed much faster if electric powered driving were already predominant due to hybrids. Thus, I see well designed hybrid cars (not the illogical designs we're getting now) as a stepping stone getting us to an all electric infrastructure much faster than we would without them.
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  17. CBD, certainly it's possible to "build a car with ~100 mile electric range AND a backup gasoline powered electrical generator" with today's technology. GM is doing -almost- exactly that, with the difference their offering "only" goes 40 miles on batteries at the modeled fleet end of life. The challenge of the next 60 miles is primarily money, not technology, plus a bit of the same physics rocket scientists face. Leaving aside the lunatic marketers responsible for the soccer-moms-and-accountants-in-work-trucks fad, GM is actually quite good at figuring out how to build things that are affordable for their market. Especially they're good at looking at what happens when they have to make a lot of copies of a product. Given some fairly tight prognostication on constraints and limits of future battery costs, GM has found that adding 60 miles of battery range to the Volt while leaving their rather nicely implemented gasoline-electric drive train in place will push the Volt's price up in a way that leaves it far outside the price range even of most "early adopters," with little prospect for a decline to realistic levels. Remember, to be useful these cars have to go beyond the boutique, they've got to slip into a family budget as a drop-in replacement. Also, as with rockets, the more potential energy stored, the less efficient the vehicle becomes for its primary requirement, delivering payload. All this w/-present- technology, mind. The world of electrochemistry still continues to deliver surprises.
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  18. Massive infrastructure changes? I already thought of cars when I read about a wind generation problem in Germany. They're actually paying some people to leave lights on all night when the turbines are putting in more power than is needed. If cars or other battery storage facilities were recharged at low use periods, there's no reason why the recharge shouldn't be overridden - on or off - depending on imbalance in turbine output and network requirements. Cars, buses and other equipment could function as a network equaliser. Neat, huh?
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  19. doug, you make good points about cost constraints. I'd be willing to pay the extra amount to avoid gas stations most of the time, but that isn't universal. Hopefully there will be enough people who drive less than 40 miles per day on average for the Volt design to really take off and thereby help push changes. adelady, yes there are alot of benefits to electric cars even with current infrastructure. I was talking more about getting people to buy the cars. For instance, the 100 mile Leaf... if you have to go more than 100 miles you want to be able to find a charging station somewhere along the route. Right now chances are you won't. Even if you do you'll be charging for hours rather than stopping a couple of minutes for gas... unless we develop faster charging technology. Also, battery life is still an open question for all of these cars, but we know it will degrade over time... so that 100 miles may become 80 or 60 and replacement costs could be prohibitive. Et cetera. There are limitations which will prevent alot of people from using electric vehicles right now. All of them seem possible to overcome, but that won't happen so long as most driving is still done via gasoline.
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  20. As for batteries. It would be a great deal easier to just have drop off / drop in battery exchange stations, just as we already do for BBQ gas bottles. And a station with multiple recharging points would be an ideal first take-up arrangement for the kind of grid balancing arrangement we might end up with in places where wind is a signficant element in the power supply.
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  21. CBDunkerson (#66), Mostly agree with your points. I just checked the Tesla sticker price; at over US $101,000 it is way too expensive for me but the performance seems pretty nifty! Most of my motoring amounts to under 40 miles a day so plugging into a charger on my garage wall works for me. No need for an extensive charging infra-structure. I wonder if folks like me will constitute a sufficient market to interest an automobile manufacturer. JMurphy (#65), It makes me uncomfortable when people mix religion and science. I wish Steven Hawking would stop talking about "knowing the mind of God".
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  22. GC @71, The Nissan Leaf sounds just right for you. IMHO, EV's will follow a similar trajectory to hybrids and the Leaf will be to EV's what the Prius was to hybrids. There is also the Volt....
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  23. Albatross, (#72), Thanks, the Leaf sounds quite similar to the EV1 and the price is in the right ball park. John Cook, Picking up on what you said at the top of this thread: "Of course, it's also important to realise that this is the global average. Warming at high latitudes may be 3 times as much." This appears to be an accurate statement. The evidence from ice cores shows temperature swings of greater than 20 degrees Kelvin as the planet undergoes cycles of glaciation. It follows that it should be easier to measure warming or cooling by studying temperatures at high latitude. Back in 2000, Richard Alley published a paper on temperatures in Central Greenland at a latitude of 73N: http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.html This paper shows a number of interesting things, at least for central Greenland. 1. The temperature swings ARE much greater than shown in reconstructions for low latitudes. 2. Current temperatures are higher than during the LIA. 3. Current temperatures are lower than during the MWP and various earlier warm periods. 4. The temperature has been higher than today for 8,500 years out of the last 10,000. 5. Ice accumulation increases during warm periods so declining ice volume is not necessarily evidence of warming.
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  24. Full text of Alley 2000 as mentioned by GC is here (pdf).
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  25. Re: doug_bostrom (74) Thanks, Doug. I took the time to read it first...to find you beat me in posting the actual link. Re: gallopingcamel (73) Are we reading the same paper? Alley's 2000 paper deals with the termination of the Younger Dryas event, circa 11,500 BP...nowhere in the paper is a discussion of the LIA, the MWP or temperatures over the last 10,000 years. Please give us the actual source(s) for your point 1-5 claims. The Yooper
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  26. I just have a thing about trying to supply links for complete articles instead of abstracts, Daniel. No way can I read 'em all, heh! I suspect GC's conclusions are largely based on the graph found at the URL he supplied but GC can say better.
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  27. GC - I am extremely puzzled by your summary of what the paper purports to show. For starters perhaps, how is ice core supposed to show us anything at all about last 100 years? How about this graphic then? Of course you could write to Richard Alley and ask his opinion of your interpretation.
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  28. Re: doug_bostrom (76) Thanks, Doug. The graph, not found in the paper (nor can I locate it on the GISP2 website), must be what he was referring to. The graph hardly has the resolution to make any claims about the Central Greenland location of the core during the LIA or the MWP, let alone any further extrapolation outside that area. Maybe I can find it on Alley's website. Re: scaddenp (77) Nice hauling out the secret weapon! The Yooper
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  29. Many thanks for your thoughtful responses. My speculations in #73 are based on the link to the NOAA web site. However, I did take the time to download the actual data from NOAA and plot it using my spreadsheet program. You can do the same by clicking on the "Data" link. Here is the URL again: http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.html Alley's data was published 10 years ago, so an update covering recent years would be helpful. That is one of the reasons for my planned visit to NCDC in Asheville in two weeks time. I don't expect to meet with Alley himself but there are several other people who worked on central Greenland. A related question for my Asheville visit concerns the "station drop off" at high latitudes. Given the "magnification" of warming and cooling effects at high latitudes, why have the number of reporting stations fallen? For example, the GHCN only includes Resolute and Alert in its database when it comes to the Canadian arctic and the situation is similar for northern Russia. It has been my experience that people will tell you many things in conversation that are not evident by reading their published papers, so I hope to be able to share some additional insights next month. With the above in mind do any of you have questions for the staff at NCDC?
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    Moderator Response: Comments about station dropoff belong in a different thread. You know how to find it.
  30. GC - the data from Alley wont have changed. Ice core data is no use for modern time because upper parts of snow pack still exchange data with the air. The graphic I pointed to has modern temperature - definitely NOT the same as 1905 - the latest point in the ice core record. Make your "zero" point 1905 and add met data. Also for your points - ice sheet volume is function of accumulation minus ablation. In warmer times, there is more precipitation (as snow) affecting high, cold central parts (same is true of east Antarctica, and in NZ western glaciers) However, ablation at edges will overwhelm it - as shown by the various ice sheet mapping techniques. And is it only you that doesnt understand what is happening with stations? But I guess they will be happy to tell you.
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    Moderator Response: Please take the dropped stations discussion to the relevant page. Thanks.
  31. scaddenp, (#80), Alley's interest was the Younger Dryas. I am hoping someone at NCDC has looked carefully at the last 2,000 years and how to fill in the interval since 1905. Is there an instrumental record that can be "spliced on"? That is one of the things that got Michael Mann into trouble! The snow accumulation issue is a tough one, especially if the flow rates are as strongly affected by thickness as Alley claims (8th power?).
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  32. GC - it takes time for air in accumulating snow to become isolated from atmosphere which is why ice core is no help to you for past 100 years. Dont splice the instrument record on (though this shows you are misinformed about Mann) - just put current central greenland average temperature onto the graph - see that graphic - higher than any time is last 3000 years.
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  33. GC, why don't you contact Alley himself at Penn State? The Yooper
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  34. Daniel Bailey (#83), Several staff members at NCDC have agreed to meet me and I expect to learn more than can be achieved through written communications. If my business takes me anywhere near Penn State I will certainly try to meet Richard Alley.
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  35. GC - that is good to here and we will be very interested in your report back. Please tell us who you talked to. If you get to talk to Richard Alley, then I suggest you swat up on ice-core temperature determination (eg Grootes and Stuiver and here). Just so you dont waste time. I will especially look forward you putting up a revised analysis of Alley 2000.
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  36. scaddenp, Thanks for that Grootes & Stuiver paper. I hope to have something to report in about a month. Before my trip to Asheville I will be visiting a 75 MW photo-voltaic power plant and a solar generator located on an 18,000 acre site. I wonder whether these technologies come within the scope of this blog?
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  37. Surely there must be some reasonably technology-neutral site for discussing energy liberation, capture, transmission, storage, general manipulation? I can't think of one but perhaps somebody else can make a suggestion. Maybe a case of "be careful what we wish for"-- too many obsessions, not enough time...
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