Three articles about the usefulness or otherwise of computer modelling of climate:
"There has been some discussion about a paper in Nature Climate Change by Gleckler et al that says they detect “a positive identification (at the 1% level) of an anthropogenic fingerprint in the observed upper-ocean temperature changes, thereby substantially strengthening existing detection and attribution evidence.” What they’ve done is collect datasets on volume-averaged temperatures for the upper 700 metres of the ocean.
But Yeager and Large, writing in the Journal of Climate, looking at the same layer of ocean, come to a different view. They conclude that it is natural variability, rather than long-term climate change that dominates the sea surface temperature and heat flux changes over the 23 years period (1984 – 2006). They say the increase in sea surface temperatures is not driven by radiative forcing. It’s a good example of how two groups of scientists can look at the same data and come to differing conclusions. Guess which paper the media picked up?"
the article continues here
Also today, Ross McKitrick writes:
"Computer models utterly fail to predict climate changes in regions
A few years ago a biologist I know looked at how climate change might affect the spread of a particular invasive insect species. He obtained climate-model projections for North America under standard greenhouse-gas scenarios from two modelling labs, and then tried to characterize how the insect habitat might change. To his surprise, he found very different results depending on which model was used. Even though both models were using the same input data, they made opposite predictions about regional climate patterns in North America."
Rest of article here
And Anthony Watts discovers that climate models are outperformed by random walks:
"A random walk is a mathematical formalisation of a trajectory that consists of taking successive random steps. For example, the path traced by a molecule as it travels in a liquid or a gas, the search path of a foraging animal, the price of a fluctuating stock and the financial status of a gambler can all be modeled as random walks."
Carries on here