Archive for November 4th, 2011

The Null Hypothesis and Global Warming

November 4, 2011

The Reference Frame points out an interesting article about the Null Hypothesis and Climate Change.

For those who don’t know, the Null Hypothesis is a way to run experiments and generate meaningful results. It starts with a simple statement that can be easily disproven, the Null Hypothesis. Then you collect your data, and you evaluate what the probability of the Null Hypothesis being true is, given the data.

As an example, consider the Null Hypothesis “this coin is fair”. If you flip the coin 5 times, and you get 5 heads in a row, then you note that the probability of getting a run of 5 heads with a fair coin is 6%, so the Null Hypothesis is only 6% likely to be true.

It’s important to note that you can’t ever really rule out a Null Hypothesis, unless it is stated in terms of absolutes. In our coin example, there is still a tiny change the Null Hypothesis is true, even if you flip the coin a thousand times and get heads every time. However, the chance of the Null Hypothesis being true in such a case is very, very small. Conversely, you can never really show a Null Hypothesis to be true, unless it is stated in terms of absolutes.

What does this have to do with Climate Change or Global Warming?

In the article I cited above, one scientist says, “The Null Hypothesis should be that Global Warming is true.” Another scientist says, “No, it shouldn’t be, and Null Hypothesis are pointless anyway.” A third person, a mathematical physicist says, “You’re both wrong.”, and goes on to say that the Null Hypotheses (plural here–multiple hypothesis-es) that have been proposed in the past have never been shown to be wrong.

Of course, the Reference Frame goes on to point the silliness about the whole thing with basic and clear science and observations.

To date, I haven’t seen many Null Hypothesis that even survive the laugh test from climate science. I certainly haven’t seen many genuine experiments.


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