Climate change, science and cricket

Commentators on recent articles on climate change in this journal have argued that the scientific study of climate change is useless and/or untrustworthy. Useless because all we should and do care about is the weather, and it is not possible to attribute any particular weather event, no matter how unusual, to climate change. Untrustworthy because the basis for identifying what counts as the accepted science is expert peer review and this process is corrupt or unreliable.

So far as I can recall these are recent claims. The relationship between weather and climate used to be thought straightforward, and peer reviewed publication followed by peer reviewed criticism was accepted as the basis of progress in science. But now both have become hot issues.

Happily light can be shed on these hot issues by considering the comparable relationships and processes in other less politically charged fields of human endeavour. Indeed, cricket can teach us much of what we need to know about these matters.

Consider first the relationship between the weather and the climate. It is just like the relationship between a batswoman's performance in any particular innings, and her form. (See below for more on why I discuss batswomen rather than batsmen.)

We don't get in a muddle about the relationship between performance and form in cricket, even though the relationship between the two is not easy to define.

For example, no one would think of saying that a batswoman was in continuing good form if she got out for a duck in each of her last ten innings, nor in continuing poor form if she had recently been the top scorer for her team. But neither would we say that she had fallen into poor form when bowled first ball in one innings, if previous to this she scored highly in a run of innings.

We are equally relaxed in saying that her getting out for a duck is explained by her being in poor form, if this has been typical of her recent performances, or that her scoring a double century in an innings is explained by her being in good form, rather than mere good luck, if she is happily enjoying a run of good innings.

Clearly the relationship between performance and form is a complex one but it is not one which causes us any particular difficulty.

When we talk about a batswoman's form, we have two distinct but related concepts in mind. First, her longish term average performance, such as her average score in the last ten innings. Second, the collection of skills which we take her to exercise when batting, which explains her (current) usual performance at the crease.

In the first sense, the relationship between performance and form is simply arithmetic and definitional. Recent average performance is form. If performance changes, by definition so does form. A one-off higher or lower-than-usual score does not shift the average much, but a few such aberrations shifts the average significantly, and so we revise our estimate of her form.

In the second sense, the relationship is causal rather than definitional: form causes (and thus explains) performance. But the causal relationship is, shall we say, probabilistic rather than necessary or certain. In her best form she may unluckily be dismissed early in her innings by an unplayable ball. But if she gets out to a simply played delivery, and especially if she has been making a habit of this, we explain this by her being in poor form.

Just so with the climate and the weather.