Breaking news

[harry]

Even in Yorkshire.

Even Scotland.

[harry]

[Chris Hogg]

One can argue that to select any section of the available data is cherry picking. For example, it's just as valid to argue that the period from 2000 to present is flat as it is to argue that the period from 1970 - 2000 showed significant warming. Both can be said to be cherry picking. Even selecting the data from 1980 to present is cherry picking, when a much wider data set is available. You can argue whatever you like by cherry picking data.

Much better to take all the data that's available, and look at as long a term trend as the data will allow,, such as here

taken from rather than cherry picking shorter time periods to support this or that hypothesis.

If cherry picking data is one's game, how about the warming period in the thirty years from 1910 - 1940, when temperatures rose by about

0.45 deg.C. comparable to the thirty year period 1970 - 2000 which exhibited a similar temperature rise. The former clearly wasn't due to anthropogenic CO2, but doesn't seem to attract much attention. Or what about the period of cooling from say 1958 to say 1976, shown here taken from the same reference as above.

In fact none of the variations are actually statistically significant, as has been discussed here

and here (thanks to TNP for those). I don't pretend to understand the detailed statistical arguments, but the gist is clear. It doesn't mean that the fluctuations didn't happen: they clearly did, but in the grand scheme of things they're not something to get too worked up about.

[Tim Streater]

And then some people are surprised that some of us are skeptics. Note carefully, though, what we are skeptical *about*. Not necessarily AGW itself, but the *process* that seems to be being followed by those who claim that AGW is real.

[Huge]

*applause*

[Vir Campestris]

Not from radioactivity.

Yes, plutonium is plain old poisonous, and there's cadmium and stuff like that in there too - but it isn't the radioactivity, so it's no more a problem than the soil in an old steelworks - which nobody panics over. (though perhaps they should!)

Andy

[michael adams]

Eh ? "AGW itself" ?

I thought the point was that while some skeptics accepted that some global warming was a possibility (GW), their skepticism rested on their rejection of the claim that there's overwhelming evidence of this being the result of human activity.(AGW)

You do realise I take it that you're contradicting what the OP actually posted ? While you're apparently prepared to accept that global warming exists, the OP is claiming that in the context of the grand scheme of things - in the long term - any short terms fluctuations as are being experienced at present, in no way represent "global arming

Figures

michael adams

...

[Tim Streater]

I'm prepared to accept that it *may* exist, in the apocalyptic sense that the warmists warn about. The OP says that what we have seen so far isn't it, and I agree with him.

Meanwhile the articles whose links he posted are an eye-opener as to the *process* - in particular the refusal of the Met Office to answer the question about the statistical approach shows that they have closed (and therefore non-scientific) minds, and that their pronouncements may safely be ignored.

You have to be careful with statistics, as we saw with the the cot-death nonsense. It showed that there are clever people (professors of medicine, judges) who can't do the right sums and so come up with rubbish answers.

Another case in point occurred during WW1, when the Navy complained that too many of their heavy shells (IIRC) were duds - e.g. only partially filled with explosive. The manufacturer said they had a rigorous process of checking the shell batches (I can't remember what it was) to ensure they were OK. The Admiralty promptly employed a professor of statistics who was able to demonstrate what twaddle this was, and that their procedures were essentially bound to let a large percentage of duds through undetected - procedures, mind you, that most people (I'm sure myself included) would look at and accept as rigorous.

Caveat emptor.

[dennis]

Only if they can get the batter to stick. Maybe chocolate coating them first?

[dennis]

So which ones are highly radioactive after 100,000 years then?

[dennis]

If you actually read that you would notice it carefully avoids giving any meaningful data. It carefully uses stuff like decays per unit so you don't know if its very radioactive or if its a tonne of rock radioactive.

So the question stands which ones are still highly radioactive after

100,000 years.

[Bob]

No it isn't and you more or less got the reason why in what you said later. If there is a lot of noise relative to the underlying trend, any conclusions about trends or statistical significance will be more unreliable. If you have a short period contained within a longer period what you can do is to analyse whether that shorter period is consistent with the overall trend and whether there is any evidence that the trend might have changed. It is not sufficient to eyeball the graph and say that that bit looks a bit flat. Even fairly simple techniques based on linear regression show that the data post 1998 is well within the range of variability around the same sort of continued trend, and more involved change point analyses have come to a similar conclusion.

On the other hand, my understanding is that similar sorts of analysis do pick out some changes in trend over the 20th century which you yourself highlighted...

There's a logical fallacy in there: it is possible to have similar effects arising from different causes. For example, solar activity was rising in the first part of the 20th century and aerosols peaked in the decades following the war. On the other hand, solar activity is relatively low now, aerosols have probably been relatively high in recent years, there's no reason to expect temperatures to be increasing because of Milankovitch cycles etc, and yet temperatures are on an upward trend.

At the end of the day, you can throw your hands up and say it's all random fluctuations or you can look for physically plausible explanations. The skeptic in me says that you don't get random fluctuations on the scale we are talking about and I'm also persuaded by the fact that this was all predicted before it actually started being measurable. It is possible to dig out the literature and confirm this with ones own eyes, and I'm not sure that even TNP would argue that the global conspiracy began in the 60s. Or maybe he would.

The problem with those references is that they are nothing *but* statistical arguments. They boil down to data fitting without any physics.

[The Natural Philosopher]

None of course. The most dangerous materials around these days are radon, which only is dangerous because the very very slow decay of natural uranium creates radon fleetingly as a step on the process, towards becoming polonium then bismuth and lead.

lead is dangerous forever, but not because it is radioactive, but because its are bloody poisonous, like mercury.

Uranium occurs naturally of course.At a half life of half a million years, there's still some left over from the creation of all the elements in the nuclear supernovae events that create heavy elements.

And cannot be destroyed except by turning it into nuclear fuel and burning it. Which is the best way of removing it from the environment.

It represents Natures long term nuclear waste, and it plays a nice part in keeping the earth a bit warmer than it would otherwise be, as it decays deep inside the crust and mantle

[Big Les Wade]

Bob posted

But that too is a cherry-picking argument. From the myriad of predictions made by climatologists in the 60s and 70s (many of which predicted global *cooling*) you are picking out a few predictions that turned out to be a reasonable match to what actually happened later, and saying, "look, those models must be the ones that describe what's actually going on".

Now I know the usual reply to this criticism is "well what else could you possibly do when testing statistical hypotheses?" OK, maybe there isn't anything else we could do, but that still doesn't make it a good scientific method.

[michael adams]

That would probably depend on what counts as "apocalyptic" nowadays. As compared with say the Black Death. No more heated towel rails perhaps?

Two points.

The popular literature of pseudo science, everything from Ben Goldacre to Michael Sharmer is replete with examples of how cranks and conspiracy theorists use a refusal by those in authority to answer their detailed "questions" as an tacit admission on their part, of a conspiracy and a cover up.

A quick perusal of the first quoted source

for

shows the main bone of contention to be the relative benefits of the trending autoregressive model as used by the MET Office as against the driftless ARIMA(3,1,0) model as proposed by Keenan among others.

The merits of this particular argument however pale into insignificance when reading the following

In statistics, significance can only be determined via a statistical model. As a simple example, suppose that we toss a coin 10 times and get heads each time. Here are two possible explanations.

a.. Explanation 1: the coin is a trick coin, with a head on each side. b.. Explanation 2: the coin is a fair coin, and it came up heads every time just by chance. (Other explanations are possible, of course.)

Intuitively, getting heads 10 out of 10 times is very implausible. If we have only those two explanations to consider, and have no other information, then we would conclude that Explanation 1 is far more likely than Explanation

2. A statistician would call each explanation a "statistical model" (roughly). Using statistics, it could then be shown that Explanation 1 is about a thousand times more likely than Explanation 2; that is, statistical analysis allows us to quantify how much more likely one explanation (model) is than the other.

Now I hope its not necessary to point out the howlers in this extract posted by a purported expert on the topic of statistics.

a) "Intuitively, getting heads 10 out of 10 times is very implausible"

Getting 10 heads out of 10 is no more or less implausible than getting any other sequence of heads and tails. The probability being 1 in 1024. Quite where "intuition" comes into this I'm not sure, as any inuition in people's minds has no influence on the actual probability

"Explanation 1 [false coin] is far more likely than Explanation

2 [1 in 1024 probability].

Again this is drivel, certainly in the absence of any information concerning the frequency of false coins.

"Using statistics, it could then be shown that Explanation 1 is about a thousand times more likely than Explanation 2;"

Yet more drivel, lent spurious credibility by the use of specific figures.

Given which I won't lose to much sleep over the fact that I'm not qualified to judge whether or not the trending autoregressive model as used by the MET Office really is so much inferior as compared with the driftless ARIMA(3,1,0) model

Don't you just.

Kahnemann and Taversky among others are/were very useful in pointing out flaws in our everyday perceptions of probabilities and risks. Even in situations where the actual statistics themselves are not open to question.

michael adams

...

[The Natural Philosopher]

actually the rise - and the pause - in global temperatures is a far better match to the growth in air traffic, if you put a 5 year lag in between

Correlation is not causation, but total *lack* of correlation is strong evidence that causation is non-existent. That is te current state of AGW, there is absolutely NO correlation between temperatures and CO2 over the last 100 years apart from a brief period from 1978-1998

[zaax]

What happens if the 100 years flood in Cumbria happens again next weekend, does that be come the normal?

[Dave Plowman (News)]

The likes of turnip will only believe in man made climate change when it happens in their village. Anywhere else is just a conspiracy.

[Tim Streater]

Why are you asking me? I'm not the one making apocalyptic pronouncements.

[snip]

In the example, that of tossing a coin 10 times, we're not talking about the likelihood of one sequence over another. We're talking about the likelihood of getting 10 heads rather than approx 512 heads and approx 512 tails. Which latter is *much* more likely.

[Tim Streater]

What is a "100-year flood", and whose definition is it? And on what basis is that definition made?