I liked this bit from Monckton’s sock:
The IPCC has been making long-term predictions of future climate states on the basis of modeling: yet its 2001 Third Assessment Report says that the climate is a complex, non-linear, chaotic object, so that the prediction of future climate states is not possible.
The Third Assessment Report did not say that predication of climate was not possible, but rather:
A complex, non-linear system may display what is technically called chaotic behaviour. This means that the behaviour of the system is critically dependent on very small changes of the initial conditions. This does not imply, however, that the behaviour of non-linear chaotic systems is entirely unpredictable, contrary to what is meant by “chaotic” in colloquial language. It has, however, consequences for the nature of its variability and the predictability of its variations. The daily weather is a good example. The evolution of weather systems responsible for the daily weather is governed by such non-linear chaotic dynamics. This does not preclude successful weather prediction, but its predictability is limited to a period of at most two weeks. Similarly, although the climate system is highly non-linear, the quasi-linear response of many models to present and predicted levels of external radiative forcing suggests that the large-scale aspects of human-induced climate change may be predictable, although as discussed in Section 1.3.2 below, unpredictable behaviour of non-linear systems can never be ruled out. The predictability of the climate system is discussed in Chapter 7.