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4th National Climate Assessment report

Filed under: — gavin @ 23 November 2018

In possibly the biggest “Friday night news dump” in climate report history, the long awaited 4th National Climate Assessment (#NCA4) was released today (roughly two weeks earlier than everyone had been expecting).

The summaries and FAQ (pdf) are good, and the ClimateNexus briefing is worth reading too. The basic picture is utterly unsurprising, but the real interest in the NCA is the detailed work on vulnerabilities and sectorial impacts in 10 specific regions of the US. The writing teams for those sections include a whole raft of scientists and local stakeholders and so if you think climate reports are the same old, same old, it’s where you should go to read things you might not have seen before.

Obviously, since the report was only released at 2pm today without any serious embargo, most takes you will read today or tomorrow will be pretty superficial, but there should be more considered discussions over the next few days. Feel free to ask specific questions or bring up topics below.

103 Responses to “4th National Climate Assessment report”

  1. 101

    It seems quite unlikely to me that forcing estimates are off by that much.

    And your incredulity on this matters because–? No offense, but I think the assessment by Santer et al. (and in which they are not alone) carries rather more weight.

    The rest about the Santer paper and the asymmetry doesn’t say anything really about model physics at all.

    No, if you mean discussion of the model physics per se, because its finding is that model physics are unlikely to be the problem. And you still haven’t explained how model physics could produce the ‘asymmetry’ between 20th- and 21st-century model success.

    If you want to add something here I would suggest googling Rayleigh Taylor instability and read up a bit on it and then explain how our experience with turbulence models is not applicable to convection

    If you’ll explain why you believe it is actually relevant to the topic at hand, which is climate model sensitivity. Feel free to be specific: for example, how did Rayleigh-Taylor instability in the atmosphere change following the turn of the millennium such that the mid-tropospheric warming rate altered?

    And for that matter, you still haven’t addressed why you think mid-tropospheric tropical warming is crucial for climate sensitivity in the first place.

  2. 102
    nigelj says:

    Zebra @99, because you don’t listen to what people say. David Young is not talking about a general global discrepancy between satellite data and model predictions. He is talking about a discrepancy in model / real world data in the ‘tropics’ specifically. This suggests it could be more than just problems with satellites measuring temperatures. You would expect all areas to be off if it was a measuring issue wouldn’t you.

    But as far as I’m concerned the total weight of evidence still points at medium to high climate sensitivity.

  3. 103
    Chuck says:

    #62 gkoehler says:”I’m fiscally conservative.”

    That phrase rings hollow these days. I haven’t seen a “fiscally conservative” politician since the 1970’s or a fiscally Conservative political party for that matter. It’s like trying to find a Pink Unicorn… it doesn’t exist. In fact, Conservatives don’t conserve anything at all, ever. Our environment can’t withstand another Republican “conservative” President, Congress or Senate.

    Climate Change is a political problem as much as anything else. We must break this grip “Conservatives” have on being in a position to make decisions concerning Climate Change and the environment. They’re killing us!