Cherry-Picking Your Starting Point

Steve McIntyre approvingly cites a piece in the Daily Telegraph by Bob Carter arguing that the planet has not warmed in the last eight years. And if you pick the El Nino year of 1998 as your starting point, that’s true, making this a rhetorically powerful argument. But there’s a problem. Given the variability in the temperature record, in any given year, even with a continuing upward temperature trend, you are likely to be a bit cooler than the previous record year – until you set a new record. So by cherrypicking the previous record year as your starting point, you can argue most of the time that things are really cooling off, not warming. This is what Carter has done. But the really interesting thing here is the evidence offered by Tim Lambert that Carter himself has complained, in other contexts, that the extreme El Nino year of 1998 is an outlier that you shouldn’t use to establish a temperature trend.

update: Dave Dardinger accurately points out that Steve’s post was neutral, rather than approving, of Carter’s piece. I stand corrected.


  1. The evidence provided by Bob Carter is that over the past 3 MILLION YEARS, the current warming, rate of warming and everything else is completely unexceptional.

    How’s that for cherry-picking?

    Lambert’s reproduction of the CRU’s unaudited and unauditable temperature graph is not evidence, still less that what Bob Carter said is materially untrue.

    You’re really going to have to give up on Lambert – he’s far too cavalier with the evidence.

  2. If you READ, the Carter piece, you will see that he already acknolwedges your point of how 8 years decline is irrelevant from a given point and cites a counterargument. You ought to deal with that. I’m not sure if you are too slow or are tendentious.

  3. From the Carter article: “In response to these facts, a global warming devotee will chuckle and say “how silly to judge climate change over such a short period”. Yet in the next breath, the same person will assure you that the 28-year-long period of warming which occurred between 1970 and 1998 constitutes a dangerous (and man-made) warming. Tosh. Our devotee will also pass by the curious additional facts that a period of similar warming occurred between 1918 and 1940, well prior to the greatest phase of world industrialisation, and that cooling occurred between 1940 and 1965, at precisely the time that human emissions were increasing at their greatest rate.”

    In addition, you ought to think about the point that if it’s irrational to trumpet publicly a decline from an El Nino, it’s also irrational to trumpet “warmest year ever”. Both sides ought to acknowledge the El Nino.

    In any case, you ought to consider the strongest points of your opponent’s argument. That’s the way to truth. Otherwise, your engaging in sophistry and PR. Not issue analysis in the search for truth.

    Oh…and if this seems harsh, I go after Steve too.

  4. Y’all are right, of course. I was just testing to see if John A would censor me too. 🙂

    As for Carter’s underlying argument, I’m quite familiar with the literature on the various climate forcings and the role ascribed to the various kinks, both up and down, in the 20th century temperature record. That Carter chooses to ignore them in his piece, rather than share them with readers, is not terribly helpful, and frankly misleading.

    And that John A spiked Tim’s trackback seems at odds with Steve’s claim that opposing views are not censored on Climateaudit.

  5. Like the enigmatic mid-century aerosol cooling which didn’t cause the unprecedented warming when they were cleaned up in the 70’s?

  6. TCO

    I only noticed that Spam Karma had spanked your posts while I was dealing with the latest Lambert defecation. They’ve been restored. You could have e-mailed me when it happened.


    If you want to see consistent and clear cherrypicking of start dates then look no further than James Hansen’s global warming index pages. There you’ll find that he always starts his analysis from the 1950s (ie a known cold period) rather than, say the 1930s. He does this because “that’s when a lot fo us were born”, although he seems to think the rest of us were born less than 24 hours ago.

  7. that John A spiked Tim’s trackback seems at odds with Steve’s claim that opposing views are not censored on Climateaudit.

    Lambert puts in the trackbacks because he’s desperate for attention, not because he debates anything. Steve has given up trying.

  8. Hans –

    Had Carter discussed the various forcings and explained why he disagreed with the conventional scientific explanation, I would have no problem. To ignore them and then argue that the conventional scientific story cannot explain the full 20th century record by invoking greenhouse gases alone is to use a dishonest strawman. As TCO rightly pointed out, “you ought to consider the strongest points of your opponent’s argument. That’s the way to truth. Otherwise, you’re engaging in sophistry and PR.”

    John A –

    I’d agree that starting in the 1950s is a bit dodgy, and I’ve never really used the index. I don’t think you should start in the 30s, either, as the Idsos love to do. I prefer to look at the entire available record, which GISS provides.

  9. John,

    I’m glad to hear you clarify that, but I think going to extremes of debate tricks from someone who used a debate trick is improper. Just say that you think he should cite the forcings. Leave it on that ground. Otherwise, you are muddying the waters.

    And that battlefield is not decided, btw. How many bets that if we’d not had the cooling, that we would not have had someone say “wait what about the aerosols”.

    I’m not saying the aerosols, etc. did not happen. Just that I’ve not seen a compelling case. The system may be capable of some swings on it’s own you know.

  10. John,

    I emailed Steve over the last spankings. Don’t know your address.

    A week ago, I had several posts spanked and posted on the blog that it had happened, but did not pursue it further. Some were silly posts, but a few were worthwhile.

  11. I also don’t know if I can post yet. Don’t want to make things worse with kharma by banging on a locked door.

    P.s. Why is it lashing out at me when I was fine for so long?

  12. John, I still have some very substantive recent posts (one with 10 points and Steve’s replies which I wanted to follow up on, on the Woodhouse versus Greybill.

  13. TCO – While I’m of course happy to provide a forum for discussion of the important questions of the day, could you perhaps find a more direct way of communicating with John A about Climateaudit comment issues than leaving comments for him here on Inkstain?

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