Climate Science Process Explained

Normally, when I cite the above as the process, I get grief from folks who say I am mis-interpreting things, as usually I am boiling a complex argument down to this summary.   The great thing about alarmist Trenberth’s piece is that no interpretation is necessary.   He outlines this process right in a single paragraph.  I will label the four steps above

Given that global warming is “unequivocal” [1], to quote the 2007 IPCC report [2], the null hypothesis should now be reversed, thereby placing the burden of proof on showing that there is no human influence [3]. Such a null hypothesis is trickier because one has to hypothesize something specific, such as “precipitation has increased by 5%” and then prove that it hasn’t. Because of large natural variability, the first approach results in an outcome suggesting that it is appropriate to conclude that there is no increase in precipitation by human influences, although the correct interpretation is that there is simply not enough evidence (not a long enough time series). However, the second approach also concludes that one cannot say there is not a 5% increase in precipitation. Given that global warming is happening and is pervasive, the first approach should no longer be used. As a whole the community is making too many type II errors [4].

Are you kidding me — if already every damn event in the tails of the normal distribution is taken by the core climate community as a proof of their hypothesis, how is there even room for type II errors?  Next up — “Our beautiful, seasonal weather — proof of global warming?”

Remember that the IPCC’s conclusion of human-caused warming was based mainly on computer modelling.  The IPCC defenders will not admit this immediately, but press them hard enough on side arguments and it comes down to the models.

The summary of their argument is this:  for the period after 1950, they claim their computer models cannot explain warming patterns without including a large effect from anthropogenic CO2.  Since almost all the warming in the latter half of the century really occurred between 1978 and 1998, the IPCC core argument boils down to “we are unable to attribute the global temperature increase in these 20 years to natural factors, so it must have been caused by man-made CO2.”  See my video here for a deeper discussion.

This seems to be a fairly thin reed.  After all, it may just be that after only a decade or two of serious study, we still do not understand climate variability very well, natural or not.  It is a particularly odd conclusion when one discovers that the models ignore a number of factors (like the PDO, ENSO, etc) that affect temperatures on a decadal scale.

We therefore have a hypothesis that is not based on observational data, and where those who hold the hypothesis claim that observational data should no longer be used to test their hypothesis.    He is hilarious when he says that reversing the null hypothesis would make it trickier for his critics.  It would make it freaking impossible, as he very well knows.  This is an unbelievingly disingenuous suggestion.  There are invisible aliens in my closet Dr. Trenberth — prove me wrong.  It is always hard to prove a negative, and impossible in the complex climate system.  There are simply too many variables in flux to nail down cause and effect in any kind of definitive way, at least at our level of understanding  (we have studied economics much longer and we still have wild disagreements about cause and effect in macroeconomics).

He continues:

So we frequently hear that “while this event is consistent with what we expect from climate change, no single event can be attributed to human induced global warming”. Such murky statements should be abolished. On the contrary, the odds have changed to make certain kinds of events more likely. For precipitation, the pervasive increase in water vapor changes precipitation events with no doubt whatsoever. Yes, all events! Even if temperatures or sea surface temperatures are below normal, they are still higher than they would have been, and so too is the atmospheric water vapor amount and thus the moisture available for storms. Granted, the climate deals with averages. However, those averages are made up of specific events of all shapes and sizes now operating in a different environment. It is not a well posed question to ask “Is it caused by global warming?” Or “Is it caused by natural variability?” Because it is always both.

At some level, this is useless.   The climate system is horrendously complex.  I am sure everything affects everything.  So to say that it affects the probability is a true but unhelpful statement.   The concern is that warming will affect the rate of these events, or the severity of these events, in a substantial and noticeable way.

It is worth considering whether the odds of the particular event have changed sufficiently that one can make the alternative statement “It is unlikely that this event would have occurred without global warming.” For instance, this probably applies to the extremes that occurred in the summer of 2010: the floods in Pakistan, India, and China and the drought, heat waves and wild fires in Russia.

  • hunter

    “Remember that the IPCC’s conclusion of human-caused warming was based mainly on computer modelling”

    Is there no end to your disgusting ignorance? Are you seriously incapable of understanding even a single thing about climate science? You’re too mentally backward ever to come up with even so much as a word in response to comments on your blog, so it’s utterly unsurprising that you aren’t capable of doing anything other than churning out the same bullshit endlessly.

  • Metro Gnome

    So, hunter, what was the IPCC’s conclusion based on, experimentation?

  • netdr

    Good question.

    Hunter. Name calling is simple takes no intelligence and anyone can do it ! You are so good at it you must get lots of practice.

    Tell us exactly what the conclusion of AGW is based on if not the fact that the models didn’t work without it. Be sure to tell us where the Catastrophe in CAGW comes from if not models.

    The models didn’t include the PDO which is enormously important. See PDO below:

    For temperature trends use:

    The warming from 1978 to 1998 is the only warming which could be AGW. Notice that the PDO is almost continuously positive during this period.

    Prior to that, from 1940 to 1978 there was cooling and AGW certainly didn’t cause that. Notice that the PDO was negative during this period.

    From 1998 to present the PDO has been both positive and negative and the temperature has gone essentially flat. Is this a coincidence ?

    From 1920 to 1940 the PDO was positive and temperature went up. More coincidence ?

    As I understand it a positive PDO means there will be more El Nino’s than La Nina’s so the temperature should go up.

    Models which don’t include accurate PDO influences are useless.

  • Hunter = Skeptic ?

    So is Hunter a childlike skeptic in disguise? If not the logic of his/her (cough) “arguments” could only sway an objectionable reader towards skepticism. If I was on any side of a belief system I would rather not be on the same side as hunter.
    By the way to find ignorance as disgusting is redundant , and “utterly unsurprising” is an oxymoron.
    Hmmm maybe homeschooling maybe not the way to go.


    hunter is a paiduh duhr when people duh llike he does itvproven duh2him and u doing good

  • kdk33

    There’s been a rash of a-posteriori attribution claims – floods in pakistan, australia; drought in Russia. Completely non-falsifiable, utterly unscientific abominations. The hallmark of charlatans and carnival seers.

    Yesterday, my Yahoo had a story: Global warming puts California at risk for SuperStorm – just like the one 150 years ago. The claim is absurd on it’s face.

    Is this a lack of education – nobody remembers the scientific method – or is it simple fraud.

  • Mcgyvr

    @netdr: The temperature has been rising consistently in the last 10 years, so there goes your PDO argument.

  • day2

    @Mcgyvr: its fun to say things on the internet, isn’t it? Seeing all your words appear right there on the screen. Wow.


  • Mcgyvr
    The question is; is it warmer now than it was 1926 to 1938? Without the GISS “adjustment” it is not.
    The question might be; is it warmer than during the Minoan, Roman and Mideviel Warm Periods? Clearly it is not.
    Present tempuratures are not unusual and certainy not “unprecedented”. Ergo, let us do nothing in response to….nothing.