Hot Spot the Difference

Quite often you will here Nova comment about the “missing hotspot” as if  this were evidence against global warming. It’s not. For intricate details of why, please see previous explanations (1, 2, 3, 4, 5, 6, 7, 8). For a simple summary … Initially Nova made some bold claims in her first handbook.

The greenhouse signature is missing. Weather balloons have scanned the skies for years but can find no sign of the telltale “hot spot” warming patter that greenhouse gases would leave. There’s not even a hint. Something else caused the warming.

Nova’s inexperience in the field of climate science is displayed once more.

Signature of Warming vs Signature of Greenhouse Gas

The hotspot is not the signature of greenhouse gas, it’s a signature of surface warming and can be caused by anything that warms the surface. Realclimate showed this best by modelling the expected warming from an additional 2% solar output vs that of doubled CO2. The hotspot appears in both cases, not just from greenhouse gases. It is not a signature of greenhouse gas, but an expected result of surface warming. The major difference between the two images is the stratospheric cooling, the purple cold patch in the top of the left hand image.

Source

Stratospheric Cooling

The real “signature” of greenhouse gas related warming is the cooling of the stratosphere, and that is cooling, although the effect due to greenhouse gases is masked by the effect from ozone depletion. Read more here if you’re so inclined.

What’s the Hot Spot?

So what is the “Hot Spot” if it’s not a signature of greenhouse warming?

It’s a signature of any surface warming. I won’t dwell on this since it has been covered already - see previous explanations (12345678)

Does the Hot Spot Exist?

Jo’s claim that weather balloons find NO SIGN is more than a little exaggerated. When stitching together radiosonde temperature data from different systems, the hotspot shows up in seasonal and annual scales but not on decadal timescales. When using estimates based upon wind shear, which does not suffer the same problems temperature data does, then the hot spot does appear.

Of course our cherry picking Nova will exclude the science that finds the hotspot and only consider the science that supports her own beliefs.

But in the end, even if the hot spot didn’t eventuate, that means the models, on this account, would be incorrect. It does not mean that the planet isn’t warming, we already know from multiple lines of evidence that the planet IS warming and that it is due to mankind’s activities.

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7 Responses to “Hot Spot the Difference”

  1. lolwot Says:

    I am beginning to lean toward the conclusion that a large number of the skeptics just can’t reason straight. They can’t take information and derive logical inferences. All they can do is recall whole “ideas” fed to them by their chosen sources of bias.

    So when they are told that the hotspot is missing and it’s a signature of greenhouse gas warming. They don’t understand why, they just insert that into their heads as a Fact.

    If I do what you’ve done and show them that the solar forcing produces a hotspot too and also so does falling aerosols, it has no effect because they can’t engage the critical reasoning step necessary to understanding the implications of that.

    I can and I do tell them what the implication is – The hotspot cannot be called a GHG *signature* if aerosols and solar forcing produces it too. A signature has to be at least somewhat unique by definition. But why would they believe my word? They don’t want to overwrite their “fact” with the idea I am pushing their way.

    And they seem incapable of actually reasoning about the information to figure it out for themselves. I usually find them later repeating the same claim about how the signature of greenhouse gas warming is missing.

  2. lolwot Says:

    Also it’s worth pointing out that the absence of a hotspot doesn’t imply lower climate sensitivity.

    The skeptics have a point that the absence of a hotspot would call the models into question, but it doesn’t itself constitute a reason to expect climate sensitivity to be lower. Any potential correction to the models could even result in climate sensitivity being higher.

    In fact a while back when I looked (but you shouldn’t trust my ability to do this right, it was casual) at the amount of “hotspot” in various models (I think they were given in a skeptic paper in fact) and compared that to the climate sensitivity of those models documented elsewhere, I found that some of the models with a lower tropical tropospheric “hotspot” had a higher sensitivity. Although that’s a bit anecdotal because I could only check a few cases.

  3. Lotharsson Says:

    Nova tries to defend her hotspot claims here in comments, claiming that:

    If you explain a significant error in The Skeptics Handbook I’ll fix it. Cook tried with the help of 4 or 5 profs, but it took him two years and I took it apart in 4 days.

    The evidence supplied by the subsequent comments on that thread does not support her promise.

  4. Drapetomania Says:

    “But in the end, even if the hot spot didn’t eventuate, that means the models, on this account, would be incorrect.”

    LIke swallowing a bit of concrete wasnt it.
    Bingo..so all the hand waving here meant nothing. :)
    The models were wrong..Nova was right.
    mext

  5. Drapetomania Says:

    and you “forgot” to mention the hadley radiosonde data.. with no hotspot

    http://joannenova.com.au/2012/05/models-get-the-core-assumptions-wrong-the-hot-spot-is-missing/

    or this paper

    http://joannenova.com.au/2011/10/this-is-90-certainty-really-yet-another-paper-shows-the-hot-spot-is-missing/

    and colour scale games by sherwood and games with wind shear

    http://joannenova.com.au/2010/07/sherwood-2008-where-you-can-find-a-hot-spot-at-zero-degrees/

    If..your so good ar talking to a few people here..at not demolishing nova..get some massive traffic to your site by demolishing her on her site..the fact that you hide here with..nothing..and dont do this speaks voulmnes. :)
    I love cagw..data dont match..mo matter..on to another scary story.
    too easy..as usual

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