It is interesting because previous research looking at historical carbon dioxide examined ice cores from the Antarctic and found that temperature lagged CO2 by about 800 years. This is an often used by climate contrarians to suggest proof that Co2 can't cause warming, but all it really does is show that it doesn't have to be responsible for initial warming.
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| From New Scientist |
So the generally accepted scientific mechanism for past climate warming was that another forcing, and not CO2, was the initial trigger. That initial warming released enough GHGs, from permafrost, oceans etc., which then led to more warming. There is absolutely no doubt with the basic physics that CO2 causes warming. These other trigger forcings have usually been down to orbital variations known as Milankovitch cycles. This is still the accepted scientific cause for switches between Ice Ages and warmer inter glacier periods.
But this new research looked at 80 global proxy records of temperature, not just Antarctic ice cores, which can only reveal local conditions, for the last deglaciation and found that "temperature is correlated with and generally lags CO2 during the last (that is, the most recent) deglaciation."
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| Sites of the 80 temperatures proxies used in Shakun et al's paper |
So while the basic premise for the cause of de-glaciations remains, this research indicates that CO2 can be an early, even initial forcing of warming, which further undermines the contrarian argument of temperature causing increased CO2 and not the other way around.
So how was this interesting research reported on Steven Goddard's Real Science?
"Antarctica Is A Very Smart PlaceI understand that this is what passes for humour among those in denial, but rather than acting the idiot, shouldn't someone making a case against AGW, and who wants to be considered seriously, actually try to understand the scientific research that the conclusions are based on, and counter that? Well clearly of course they should, but in this case they obviously can't, so instead they act like a kid making faces and stupid remarks behind the teachers back.
According to the latest research from top Ivy League expert Dr. Shakun, Antarctica is able to anticipate changes in CO2 several hundred years in advance, and preemptively adjust its thermostat long before the CO2 decides to spontaneously increase or decrease.
CO2 found it frustrating at first that Antarctica always anticipated his moves, until Dr. Shakun explained to him that this mysterious teleconnection proves that CO2 controls the universe. "
Well, since you did ask, I suppose I could try and explain the flaw in this "scientific research" for you. First you need to understand this interesting scientific theory called "Cause and Effect". I believe Newton or Galileo or somebody came up with it, but don't worry it has a pretty good consensus behind it. basically it states that an action or event will produce a certain response. but see, the really interesting part is it ONLY works in one direction. The cause always comes first, then the effect. So if you think that something (like CO2) might be a cause of something else (like warming) then that cause has to happen FIRST. If it DOESN'T happen first, like say if nearly half the planet was warming before CO2 started to rise, Then CO2 can't be the cause of the warming, even if the rest of the planet doesn't start warming until after CO2 started to rise. And no, averaging all the warming together and then saying that the average warming didn't start until after CO2 started going up doesn't actually count. That would be like saying that all the warming since the end of the LIA (about 1850) was caused by the large anthropomorphic increase in CO2 (started around 1940)... Oh wait.
ReplyDeleteYou mean a bit like heat being able to produce fire but fire not able to produce heat?
DeletePerhaps you should leave the scientific analysis up to the qualified.
More like how fire can produce heat but only after heat STARTS the fire. There's that cause and effect again. Notice how the fire can't just spontaneously start producing heat. The heat is the Cause of the fire. and yes, once the fire starts it can cause MORE heat, just like how once the warming at the end of the ice age starts it releases CO2 and that CO2 can enhance the warming, which is what most skeptics are happy to agree with. I'll even go so far as to say there is probably a tipping point or 2 in there. Unfortunately for the warmist side of the argument the tipping point is clearly down around 210 ppm CO2 and equally clearly CO2's ability to cause additional warming maxes out around 280 ppm, otherwise it wouldn't stop around that level like it has at every previous warming for tens of thousands of years. If CO2 could continue to push warming past that level it would have at some point in the past. See, the 280 ppm level is another point, just not a tipping point. It's a stabilizing point. Now even if humans end up pumping even more CO2 into the atmosphere that CO2 is going to have less and less of an effect as the System itself is now working against additional warming. It's like pushing a rock up a hill that gets steeper the further up it you go, each additional step you go requires more force then the one before. And despite what the IPCC or others say there is no evidence that the hill is about to level out, much less that we're almost to the top and about to go rolling down the other side.
DeleteMy last comment was necessarily short because I was away and posted from my phone. But your first post is so confused and misses so much basic science.
DeleteFirst Cause and Effect is not a scientific concept but a philosophical one. Newton or Galileo or some other scientist did not come up with, Quantum physics turns the idea of Cause and Effect on its head in any case and I think you are getting confused with Newton’s third law of motion; “For every action there is an equal and opposite re-action.” This doesn’t bode well for the standard of scientific literacy you are basing your flawed reasoning on.
Second you need to accept that for an effect there can be multiple causes. Global warming can be caused by a variety of things including the direct release of GHGs. There is evidence of this happening for past warming - with the sudden release of methane hydrates for example.
Thirdly you don’t seem to realise that there is a concept of feedbacks that ‘has a pretty good consensus behind it’, which means that effect can feed the cause to increase the effect.
But then in you second comment you accept ‘that CO2 can enhance the warming’ which makes me confused as to what your point is. I had assumed that you were only talking about the Shakun research, which only relates to the last deglaciation. Chris Reynolds thinks you are talking about current warming which the Shakun research has nothing to do with but that is the subject of the post.
Then I am further confused by the rest of you posts and it unsubstantial claims, for example;
“If CO2 could continue to push warming past that level it would have at some point in the past.” - I have no idea where you get this idea from because that is exactly what the proxy evidence shows has happened. The last time CO2 was as high was 15-20 million years ago and global temperatures were 2-5 degrees higher than they are today.
“CO2's ability to cause additional warming maxes out around 280 ppm” - is just made up nonsense. The science shows that for every doubling of CO2 there is a temperature increase of over a degree C – and that is without considering feedbacks. There isn’t a magic number where it maxes out.
You really need to take a step back and try to understand the basic science that underpins climatology, avoid blogs from unqualified people and those with views country to the mainstream.
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DeleteActually when I said Cause and Effect was invented by Newton or Galileo or somebody I was being sarcastic. Sorry that I didn't explicitly state that in my first post, I assumed from the sarcastic tone in much of your own writing that you would see it as the joke I meant it as. My apologies. I am however glade to find out that quantum physics has now superseded and invalidated Cause and Effect. I'll have to tell my boss that from now on the Effect of my receiving a paycheck to no longer dependent on the Cause of my going to work. it's Quantum.
DeleteUm, That's more sarcasm in case you're wondering.
As for the rest of your post, I believe I see were the confusion has come about. Wile I (and almost all Skeptics I know) agree that an Increase in CO2 can 'Cause' an increase in global temp by increasing the greenhouse effect, when I was talking about what caused the warming from the last Ice Age I meant the actual triggering event. in that case rising CO2 is clearly not the 'cause' but simply a positive feedback, in that if the warming hadn't already started CO2 would have no reason to start increasing.
I went into more detail on why I think the positive feedback of CO2 maxes out over 280ppm in my reply to Chris. I'll add here that I completely agree with you about the direct effect of a doubling of CO2 being around a degree C. The problem isn't even just what the feedback to that warming is, it's that those feedback CHANGE the warmer the planet gets.
As for what the CO2 and Temp was 15-20 M years ago, we have no idea why it was warmer back then, but we already know that the warmer the Oceans get the less CO2 they can hold. That's the whole reason CO2 usually goes up when temperature does. That hardly means that the CO2 caused it to be that warm.
And That's the real question about the Cause and Effect of temperature and CO2, and why it's important to find which came first. Because, as far as I know, there is no evidence of an Increase in CO2 starting a warming by itself. that's what really sets today apart from the whole of known (or proxed) history. We're Increasing CO2 instead of natural warming doing it.
"when I was talking about what caused the warming from the last Ice Age I meant the actual triggering event. in that case rising CO2 is clearly not the 'cause' but simply a positive feedback,"
DeleteThat is the case for many of the past climate cycles. But it has no bearing on our current warming except that it is further evidence CO2 can become a driver of warming trends.
"As for what the CO2 and Temp was 15-20 M years ago, we have no idea why it was warmer back then,"
This isn't true. We have a very good idea why it was warmer. We know Co2 and temperature correlate and we know that CO2 causes warming and we know Co2 was as high and higher when it was warmer. And we know from the Shakun and other research that warming, however initially triggered can cause and be driven by released CO2 in a positive feedback.
So I find it difficult that you believe we know nothing. Can you not join the dots, or at least accept the science that already has?
"Because, as far as I know, there is no evidence of an Increase in CO2 starting a warming by itself."
This is wrong. There is evidence that GHGs have triggered warming in the past through methane release and CO2 through intense volcanism. Orbital cycles cannot be blamed for every switch in climate. But the Shakun research does show that CO2 can be a driver even if it wasn't a trigger. So there is no rational reason to be sceptical about current human release of CO2 causing warming. In fact using your logic we can say an orbital cycle was the trigger responsible for the last warming and Human burning of fossil fuels has been the trigger for the current one. In both cases Co2 was released and became a driver of a warming trend.
Schitzree,
ReplyDeleteYour reasoning is flawed.
We've pushed CO2 above 280ppm and we're seeing warming, there is no alternate explanation for the warming we're seeing - I used to be a sceptic and the alternate explanations I once had have fallen before the science.
A tipping point (not a term I'm a fan of) doesn't mean warming continues relentlessly after that point. Strictly speaking a tipping point is associated with a bifurcation, where the system jumps from one (pseudo) equilbrium state to another. For what it's worth I don't see evidence of a tipping point in the warming out of the glaciations: It's not even true to say that that warming leads to a new warmer state per se. Previous interglacials such as the Eemian and Holsteinian were warmer than the Holocene had been prior to anthropogenic warming, by the middle of this century we'll very probably surpass those interglacials.
Shakun et al explicitly state that they've found that CO2 didn't initiate the warming, but on a global and NH basis CO2 at least matched the timing of the warming, and probably lead it.
The idea that what we're seeing is continuing warming from the LIA is laughable. The LIA was caused by reduced solar activity, yet during the post 1975 warming solar activity has remained level (Lockwood & Frohlich) and ground insolation has fallen (Wild et al).
Finally, you have no evidence to support your claim that CO2 can't cause further warming as it did during the rise out of the last interglacial.
I'll agree that the term tipping point is probably a poor choice. What I meant is that as is shown in the second of the graphs above both temp and CO2 do seem to have an upper and lower band past which they don't usually go, and around which the seem to hover, the (pseudo) equilibrium states you mention. the 180 to 200 ppm CO2 level and corresponding temperature level is one of them. However at any time when something pushes temp above this level it would appear to start a feedback process (probably including CO2 outgasing from the ocean, albedo decrease from melting ice, more water vapor, and many others) that relatively quickly pushes global temperature up to Interglacial levels. And then it stops.
DeleteIt's that stop when CO2 levels are at about 280ppm and global temp anomaly is around 4c, that convinces me that CO2's ability to enhance warming has an upper limit, at least in the natural environment. If more warming would lead to more CO2, and More CO2 would lead to more warming, then the system would have gone into a runaway greenhouse at some point already. SOME negative feedback has come into play that negates the positive feedbacks of CO2 and the others. Maybe it reaches a point that the only large areas of ice that can melt for albedo loss is past the arctic circles were it isn't getting much direct light anyway. Maybe any more increase in water vapor causes such a large increase in cloud cover that it starts increasing albedo again. Probably it's a number of things adding together. Whatever it is the end result is that the warming stops.
This isn't to say that if Humanity puts more CO2 into the atmosphere it can't cause some warming, but that warming is going to be limited because the earth is already near the top of the interglacial temp level. Like the hill metaphor I used already we are already well up the incline and getting steeper.
I find you belief in a magic 280ppm interesting. If we look at the graph above it dos show CO2 peaking around that value and deuterium, representing temperature correlating. But that is just an indication of how stable the climate has been during the last 600,000 years. Co2 and temps have been higher together in the past.
DeleteHumans have now pushed CO2 to about 390ppm and there is no credible science that I'm aware of that suggests temperature wont follow, in fact the physics suggest it almost certainly will.
But another interesting thing has occurred to be about the graph above that isn't usually mentioned when it is displayed - it confirms the presence of positive feedbacks.
It is better demonstrated on a graph where the deuterium value is converted to a temperature one;
http://en.wikipedia.org/wiki/File:Co2-temperature-plot.svg
Where Co2 doubles - around 350,000 years ago for example it went from 150ppm to 300ppm - temperature didn't just rise by 1C it actually rose from about -8 to +4, 12 degrees C!
I'm not suggesting that will be the case for current warming, the science doesn't support that, but it does demonstrate that feedbacks are likely to be positive.