Sunday, June 28, 2009

A picture is worth ten thousand words

Image found at Paul Krugman's blog. Krugman goes on to say:
...temperature is a noisy time series, so if you pick and choose your dates over a short time span you can usually make whatever case you want. That’s why you need to look at longer trends and do some statistical analysis.

[snip]

What this tells me is that annual temperature is indeed noisy: there have been many large fluctuations, indeed much larger than the up-and-down in the last decade or so. But the direction of change is unmistakable if you take the longer view. The fitted line in the figure is a 3rd-degree polynomial, but any sort of smoothing would tell you that there is a massive upward trend.

Of course, trend-spotting is no substitute for causal modeling; and the models are getting truly scary in their implications.
John Cole also looks a bit at the "climate contrarians" who've been naysaying for too damned long.

In particular, I thought the Krugman post was useful in reminding readers that in order to understand what is happening with the planet's climate, one is required to search for long-term trends using what is rather noisy data (that is, data in which there is a great deal of variability). In the case of global warming, it appears that the signal, even with all the noise, is coming in crystal clear.

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