# Global warming has stopped? **URL:** \ **Category:** Great Debates\ **Created:** [March 23, 2008, 9:15am UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421 "2008-03-23T09:15:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![aldiboronti](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@aldiboronti](https://boards.straightdope.com/u/aldiboronti)\ **Post date:** [March 23, 2008, 9:15am UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/1 "2008-03-23T09:15:06Z")
With both sides having axes to grind one never knows what to believe in this debate but the implications in [this article](http://www.theaustralian.news.com.au/story/0,25197,23411799-7583,00.html) are rather startling, if the facts are correct. Are they? > [@](#): > > Duffy asked Marohasy: “Is the Earth still warming?” > > She replied: “No, actually, there has been cooling, if you take 1998 as your point of reference. If you take 2002 as your point of reference, then temperatures have plateaued. This is certainly not what you’d expect if carbon dioxide is driving temperature because carbon dioxide levels have been increasing but temperatures have actually been coming down over the last 10 years.” > > Duffy: “Is this a matter of any controversy?” > > Marohasy: “Actually, no. The head of the IPCC (Intergovernmental Panel on Climate Change) has actually acknowledged it. He talks about the apparent plateau in temperatures so far this century. So he recognises that in this century, over the past eight years, temperatures have plateaued … This is not what you’d expect, as I said, because if carbon dioxide is driving temperature then you’d expect that, given carbon dioxide levels have been continuing to increase, temperatures should be going up … So (it’s) very unexpected, not something that’s being discussed. It should be being discussed, though, because it’s very significant.” > [@](#): > > Duffy: “Can you tell us about NASA’s Aqua satellite, because I understand some of the data we’re now getting is quite important in our understanding of how climate works?” > > Marohasy: “That’s right. The satellite was only launched in 2002 and it enabled the collection of data, not just on temperature but also on cloud formation and water vapour. What all the climate models suggest is that, when you’ve got warming from additional carbon dioxide, this will result in increased water vapour, so you’re going to get a positive feedback. That’s what the models have been indicating. What this great data from the NASA Aqua satellite … (is) actually showing is just the opposite, that with a little bit of warming, weather processes are compensating, so they’re actually limiting the greenhouse effect and you’re getting a negative rather than a positive feedback.” > > Duffy: “The climate is actually, in one way anyway, more robust than was assumed in the climate models?” > > Marohasy: “That’s right … These findings actually aren’t being disputed by the meteorological community. They’re having trouble digesting the findings, they’re acknowledging the findings, they’re acknowledging that the data from NASA’s Aqua satellite is not how the models predict, and I think they’re about to recognise that the models really do need to be overhauled and that when they are overhauled they will probably show greatly reduced future warming projected as a consequence of carbon dioxide.” > > Duffy: “From what you’re saying, it sounds like the implications of this could beconsiderable …” ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [March 23, 2008, 12:39pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/2 "2008-03-23T12:39:45Z")
Do note that she’s not exactly unbiased: see her blog [here](http://www.jennifermarohasy.com/blog/). I’m sure **jshore** and **intention** will be along very shortly to explain it in detail. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [March 23, 2008, 1:29pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/3 "2008-03-23T13:29:16Z")
[QUOTE=aldiboronti] With both sides having axes to grind one never knows what to believe in this debate but the implications in [this article](http://www.theaustralian.news.com.au/story/0,25197,23411799-7583,00.html) are rather startling, if the facts are correct. Are they? [/QUOTE] 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](http://boards.straightdope.com/sdmb/showthread.php?t=460105) ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [March 23, 2008, 1:48pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/4 "2008-03-23T13:48:07Z")
> [@](#): > > The satellite was only launched in 2002 and it enabled the collection of data, not just on temperature but also on cloud formation and water vapour. What all the climate models suggest is that, when you’ve got warming from additional carbon dioxide, this will result in increased water vapour, so you’re going to get a positive feedback. That’s what the models have been indicating. What this great data from the NASA Aqua satellite … (is) actually showing is just the opposite On the other hand, if this is true, it’s obviously a potential problem for the CAGW hypothesis. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 23, 2008, 2:09pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/5 "2008-03-23T14:09:20Z")
[QUOTE=Quartz] Do note that she’s not exactly unbiased: see her blog [here](http://www.jennifermarohasy.com/blog/). [/quote] 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: > [@](#): > > The Institute of Public Affairs is a right-wing, corporate funded think tank based in Melbourne. It has close links to the Liberal Party, with it’s Executive Director John Roskam having run for Liberal preselection for a number of elections. Its key policy positions include advocacy for privatisation, deregulation, reduction in the power of unions and denial of most significant environmental problems, including climate change. > [@Quartz](#): > > I’m sure **jshore** and **intention** will be along very shortly to explain it in detail. Gotta run now but I will try to address the more scientific issues raised a little later. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 23, 2008, 6:36pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/6 "2008-03-23T18:36:04Z")
Discussing the quotes from the OP’s source in more detail… > [@](#): > > “No, actually, there has been cooling, if you take 1998 as your point of reference. If you take 2002 as your point of reference, then temperatures have plateaued. This is certainly not what you’d expect if carbon dioxide is driving temperature because carbon dioxide levels have been increasing but temperatures have actually been coming down over the last 10 years.” [Here](http://www.cru.uea.ac.uk/cru/info/warming/) is the HadCrut3 global global temperature record and [here](http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif) 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. > [@](#): > > “If you take 2002 as your point of reference, then temperatures have plateaued.” 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](http://www.realclimate.org/index.php/archives/2008/01/uncertainty-noise-and-the-art-of-model-data-comparison/) during the period since 1970 that temperatures have been rising. > [@](#): > > “The satellite was only launched in 2002 and it enabled the collection of data, not just on temperature but also on cloud formation and water vapour. What all the climate models suggest is that, when you’ve got warming from additional carbon dioxide, this will result in increased water vapour, so you’re going to get a positive feedback. That’s what the models have been indicating. What this great data from the NASA Aqua satellite … (is) actually showing is just the opposite, that with a little bit of warming, weather processes are compensating, so they’re actually limiting the greenhouse effect and you’re getting a negative rather than a positive feedback.” [This](http://www.sciencemag.org/cgi/content/abstract/310/5749/841) 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](http://www.nasa.gov/centers/goddard/news/topstory/2004/0315humidity_prt.htm) 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: > [@](#): > > In most computer models relative humidity tends to remain fixed at current levels. Models that include water vapor feedback with constant relative humidity predict the Earth’s surface will warm nearly twice as much over the next 100 years as models that contain no water vapor feedback. > > Using the UARS data to actually quantify both specific humidity and relative humidity, the researchers found, while water vapor does increase with temperature in the upper troposphere, the feedback effect is not as strong as models have predicted. “The increases in water vapor with warmer temperatures are not large enough to maintain a constant relative humidity,” Minschwaner said. These new findings will be useful for testing and improving global climate models. The full paper itself is available [here](http://www.ametsoc.org/amsnews/Minschwaner_March04.pdf) although I haven’t read it yet. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 23, 2008, 6:57pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/7 "2008-03-23T18:57:17Z")
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](http://www.ipcc.ch/ipccreports/ar4-wg1.htm) (Chapter 8, p. 634): > [@](#): > > Observations provide ample evidence of regional-scale increases and decreases in tropical UTRH [upper-tropospheric relative humidity] in response to changes in convection (Zhu et al., 2000; Bates and Jackson, 2001; Blankenship and Wilheit, 2001; Wang et al., 2001; Chen et al., 2002; Chung et al., 2004; Sohn and Schmetz, 2004). Such changes, however, provide little insight into large-scale thermodynamic relationships (most important for the water vapour feedback) unless considered over entire circulation systems. Recent observational studies of the tropical mean UTRH response to temperature have found results consistent with that of near-unchanged RH at a variety of time scales (see Section 3.4.2.2). These include responses from interannual variability (Bauer et al., 2002; Allan et al., 2003; McCarthy and Toumi, 2004), volcanic forcing (Soden et al., 2002; Forster and Collins, 2004) and decadal trends (Soden et al., 2005), although modest RH decreases are noted at high levels on interannual time scales (Minschwaner and Dessler, 2004; Section 3.4.2.3). Seasonal variations in observed global LW radiation trapping are also consistent with a strong positive water vapour feedback (Inamdar and Ramanathan, 1998; Tsushima et al., 2005). Note, however, that humidity responses to variability or shorter timescale forcing must be interpreted cautiously, as they are not direct analogues to that from greenhouse gas increases, because of differences in patterns of warming and circulation changes. 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. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [March 23, 2008, 7:37pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/8 "2008-03-23T19:37:02Z")
Damn! Global Warming has stopped again? This is like the 3rd time this week… -XT ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [March 23, 2008, 7:56pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/9 "2008-03-23T19:56:02Z")
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. ---
**Author:** ![ArizonaTeach](https://avatars.discourse-cdn.com/v4/letter/a/45deac/32.png) [@ArizonaTeach](https://boards.straightdope.com/u/ArizonaTeach)\ **Post date:** [March 23, 2008, 8:18pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/10 "2008-03-23T20:18:25Z")
[QUOTE=jshore’s source] The Institute of Public Affairs is a **right-wing** , corporate funded think tank based in Melbourne. It has close links to the\*\* Liberal Party\*\*, with it’s Executive Director John Roskam having run for Liberal preselection for a number of elections. [/QUOTE] I don’t…that doesn’t…whaaaaa? You Aussies do everything different, don’t you? ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 23, 2008, 8:23pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/11 "2008-03-23T20:23:11Z")
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](http://www.met.tamu.edu/people/faculty/dessler/minschwaner2006.pdf) 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.] ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 23, 2008, 8:25pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/12 "2008-03-23T20:25:16Z")
[QUOTE=ArizonaTeach] I don’t…that doesn’t…whaaaaa? You Aussies do everything different, don’t you? [/QUOTE] 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. ---
**Author:** ![Public\_Animal\_No.9](https://avatars.discourse-cdn.com/v4/letter/p/b9e5f3/32.png) [@Public\_Animal\_No.9](https://boards.straightdope.com/u/Public_Animal_No.9)\ **Post date:** [March 23, 2008, 9:48pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/13 "2008-03-23T21:48:15Z")
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. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [March 23, 2008, 11:34pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/14 "2008-03-23T23:34:47Z")
She was talking about [this paper](http://www.agu.org/pubs/crossref/2007/2007GL029698.shtml) by Roy Spencer et al. as well as another forthcoming paper by the same Dr. Spencer. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [March 23, 2008, 11:49pm UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/15 "2008-03-23T23:49:10Z")
[QUOTE=ArizonaTeach] I don’t…that doesn’t…whaaaaa? You Aussies do everything different, don’t you? [/QUOTE] Comes of living upside down. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 24, 2008, 12:40am UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/16 "2008-03-24T00:40:59Z")
[QUOTE=brazil84] She was talking about [this paper](http://www.agu.org/pubs/crossref/2007/2007GL029698.shtml) by Roy Spencer et al. as well as another forthcoming paper by the same Dr. Spencer. [/QUOTE] 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](http://www.jennifermarohasy.com/blog/archives/002857.html) in response to my comment/question: > [@](#): > > You can read more about Spencer’s work and link to published papers here: [Roy W. Spencer: Global Warming and Nature's Thermostat](http://www.weatherquestions.com/Roy-Spencer-on-global-warming.htm) > > There has been some discussion, initiated by me on the Aqua Satellite data here: [http://www.jennifermarohasy.com/blog/archives/002844.html](http://www.jennifermarohasy.com/blog/archives/002844.html) > > and also here: [Carbon rationing or freedom - On Line Opinion - 14/3/2008](http://www.onlineopinion.com.au/view.asp?article=7124) > > We might have to ask Dr Spencer for a guest post - but let’s wait until after Easter. ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [March 24, 2008, 1:24am UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/17 "2008-03-24T01:24:34Z")
[QUOTE=jshore] 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). [/quote] 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. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [March 24, 2008, 1:43am UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/18 "2008-03-24T01:43:44Z")
Well, for the past six months, the northern hemisphere’s temperatures have been well below average. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [March 24, 2008, 1:57am UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/19 "2008-03-24T01:57:23Z")
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. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [March 24, 2008, 2:00am UTC](https://boards.straightdope.com/t/global-warming-has-stopped/442421/20 "2008-03-24T02:00:54Z")
[QUOTE=Ludovic] Well, for the past six months, the northern hemisphere’s temperatures have been well below average. [/QUOTE] 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! [Next page](https://boards.straightdope.com/t/global-warming-has-stopped/442421.md?page=2)