With both sides having axes to grind one never knows what to believe in this debate but the implications in this article are rather startling, if the facts are correct. Are they?
Do note that she’s not exactly unbiased: see her blog here.
I’m sure jshore and intention will be along very shortly to explain it in detail.
The real question is whether the recent “plateau” in some temperature measures is sufficient to discredit the CAGW hypothesis. Standing alone, I would say probably not, since there is clearly a lot of natural variability in temperatures and it’s been only a few years so far.
You might want to check out this recent thread
On the other hand, if this is true, it’s obviously a potential problem for the CAGW hypothesis.
Indeed. Note that the article says that she is “biologist and senior fellow of Melbourne-based think tank the Institute of Public Affairs”. Here is what SourceWatch has to say about that institute:
Gotta run now but I will try to address the more scientific issues raised a little later.
Discussing the quotes from the OP’s source in more detail…
Here is the HadCrut3 global global temperature record and here is the NASA GISS global temperature record. As you can see, the running averages suggest that, when averaging over fluctuations, global temperatures have continued to increase since 1998. It may be true that the HadCrut3 still shows 1998 as the warmest year (although in the NASA data, 2005 beat it out by a bit) but that means about as much as a few days in Rochester here in April where the temperature shoots up to 70deg followed by it dropping back down to seasonable levels in the 40s and 50s for the following several weeks disproves the seasonal cycle. And, as you can see, 1998 was a doozy of a fluctuation (“the El Nino of the Century”) and thus it is a convenient date to cherry-pick as a starting point if you want to claim there has been no warming.
The climate has fluctuations…Rising CO2 levels don’t repeal this, they just cause an upward rise drift imposed upon this fluctuatiing climate.
Again, this is too short a period to say anything about the trend, as can be seen by looking at other periods of comparable length over the time during the period since 1970 that temperatures have been rising.
This earlier paper looked at the moistening of the upper troposphere over the period from 1982 to 2004 and found it to be in very good agreement with what the climate models predicted and in good agreement with the assumption of constant relative humidity (which seems to be approximately what the models predict). When they artificially turned off the water vapor feedback in the models, the agreement was much worse.
I am not sure what study Marohasy is referring to but it is presumably this one…or, at least, that was the only one I could find that seemed relevant using google. It seems, however, that Marohasy didn’t quite get the conclusions of that study correct. She is right that they argue that the positive feedback doesn’t seem to be as strong as predicted by the climate models, i.e., they find that the moisture increases with warming but not enough to maintain constant relative humidity. However, she is wrong to say that they find a negative feedback. Here is the scoop according to that NASA press release on that paper:
The full paper itself is available here although I haven’t read it yet.
By the way, for some context on that paper by Minschwaner and Dessler that Marohasy was apparently referring to, here is the relevant discussion on the subject from the IPCC report (Chapter 8, p. 634):
So, I think Marohasy has spun what seems to be the one paper that found any significant disagreement with the constant relative humidity assumption into being a much bigger deal than it was, while ignoring all of the other papers.
Damn! Global Warming has stopped again? This is like the 3rd time this week…
-XT
Living on ground less than ten feet above sea level as I do, I sure hope global warming has stopped; but let’s wait for some peer-reviewed analysis of the findings.
I don’t…that doesn’t…whaaaaa?
You Aussies do everything different, don’t you?
Not to beat a dead horse too much, but I should note that if indeed that Marohasy was referring to the Minschwaner and Dessler that I found, then she has not only spun that original paper quite a bit, but she has neglected to look at this more recent paper by the same authors (plus a 3rd co-author). In it, they look at what climate models say about what the relative humidity should do in upper troposphere and find that the oft-repeated statement that the climate models predict the amount of water vapor to go up with temperature so as to retain roughly constant relative humidity is not quite true…The models actually seem to predict a small drop in relative humidity which is, within the limits of the uncertainty in the modeling and their experimental data, in agreement with what they see from the Aqua measurements and they thus conclude “current global climate models are simulating the observed behavior of water vapor in the tropical upper troposphere with reasonable accuracy.”
[I left a comment on Marohasy’s website asking her if the Minschwaner and Dessler paper was indeed the work that she was referring to in that interview.]
Don’t worry, our resident libertarian Liberal should be along shortly to explain how modern day “liberals” have corrupted the word from the more classical definition of liberal (which, at least roughly speaking, would be what we now call “libertarian”). So, I guess the Aussies are just sticking with the more classical definition.
We should not lose sight of the fact that the term “global warming” is somewhat misleading. It’s probably more accurate to say “global heating.” This may seem a bit silly, but warming implies increasing temperature, while heating refers to increasing energy. We deal with systems every day in which heating occurs, but temperature does not change, such as boiling water, where the temperature is constant during boiling until the water is evaporated, then temperature increases again. I’m not saying that we’re looking at such a simple system by any means - just that we should not expect a nice, linear change in temperature for such a complex system.
She was talking about this paper by Roy Spencer et al. as well as another forthcoming paper by the same Dr. Spencer.
Comes of living upside down.
Yeah…Apparently, she was talking about some work by Roy Spencer (although the paper you linked to is more about clouds than water vapor…although perhaps she is sort of convolving the two together—they are of course related by the fact that clouds are condensed water vapor although the two effects are most often discussed separately). This is what she wrote in the comments section of her blog in response to my comment/question:
Actually she was going by a talk given by Dr. Spencer which was based on that paper plus another one that is forthcoming. The audio to the talk is linked to at Dr. Spencer’s Wikipedia entry. However, without seeing the pictures he is referring to, it is difficult to assess his argument, which apparently is basically that based on his empirical analysis any temperature feedback from increased CO2 would be negative. If this can be confirmed, it would obviously be a big problem for the CAGW hypothesis.
Well, for the past six months, the northern hemisphere’s temperatures have been well below average.
I don’t think global warming has stopped because I don’t see any evidence that shows it started. There is a premise that Co2 is a modeling predictor but it can’t be shown to predict anything in the short term. If short term models don’t work why are we listening to long term models.
3 years ago we were given the chicken little treatment about the end of the world. Global warming was going to cause more hurricanes. The following year there were fewer hurricanes so the prediction was corrected to mean there would be fewer but more powerful hurricanes. The following year it didn’t happen. The modeling, as it relates to the rise in Co2, doesn’t appear to work.
The largest percentage of greenhouse gas is water vapor. We could actually increase the level of water vapor by switching to a hydrogen based fuel. In effect, we may chicken little ourselves into a real crisis. While I’m a huge advocate of energy independence I’m not in a rush to listen to people who can’t back up their modeling predictions with accurate forecasts.
Okay…I have to admit that you almost whooshed me there. I was desperately trying to look up the Northern hemisphere global temperature anomaly over the last 6 months…But then I got it!