Kevin Trenberth, one of the lead authors of the recent IPCC report has made some startling revelations.
First of all, he claims that the IPCC makes no predictions - just presents possible scenarios.
In fact there are no predictions by IPCC at all. And there never have been. The IPCC instead proffers “what if” projections of future climate that correspond to certain emissions scenarios. There are a number of assumptions that go into these emissions scenarios. They are intended to cover a range of possible self consistent “story lines” that then provide decision makers with information about which paths might be more desirable.
Then he admits that those predictions are made without giving consideration to other climate factors.
But they do not consider many things like the recovery of the ozone layer, for instance, or observed trends in forcing agents. There is no estimate, even probabilistically, as to the likelihood of any emissions scenario and no best guess.
Not sure what he means by "observed trends" - perhaps he is referring to the fact that methane emissions have flattened out and may even be falling - but it's clear that he means that the IPCC are choosing to omit "many" climate factors. And no estimate of the likelihood of these scenarios coming true, either - not even a "best guess". In other words, it's all just pure speculation.
Next, he admits that their climate models are pretty much useless.
None of the models used by IPCC are initialized to the observed state and none of the climate states in the models correspond even remotely to the current observed climate. In particular, the state of the oceans, sea ice, and soil moisture has no relationship to the observed state at any recent time in any of the IPCC models. There is neither an El Niño sequence nor any Pacific Decadal Oscillation that replicates the recent past.
So these models - on which we are supposed to gamble our economic future - are so poor they can not even be made to reflect the current climate. And yet we're supposed to believe that they can predict the future?
Finally, he admits that, far from the science being settled it has barely started.
However, the science is not done because we do not have reliable or regional predictions of climate.
So there have it - straight from the horses mouth. The IPCC cannot make even a guess, let alone a "best guess", they deliberately ignore many climate factors, the models are useless and they can not make even a reliable prediction about regional climate - today, tomorrow, in ten years or 100 years time.
But we should all believe it and hamstring our economic future based on this? Russell Grant, eat your heart out.