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.


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.

No comments:

Post a Comment