AGW -- Cold Enough For You?

So, we got a big deep freeze in the US to start off the new year. Who woulda thought? It is true that this cold spell does not disprove global warming, but it is just as true that hot spells of the recent past don't prove it's validity either. Indeed, experiments never prove a hypothesis; the best they can do is fail to falsify one. In the case of observational experiments, like climate forecasting, the best you can do is say that observations are consistent with the hypothesis. But the operational definition of "consistent" has to be sufficiently robust to distinguish something significant from the "well, duh!"

In the case of AGW, that the earth has been getting slightly warmer is not in dispute since that has been happening since the little ice age of about 200 years ago. That it has gotten significantly warmer than it otherwise would have is not so easy to show. The AGW crowd not only claim that they have shown this "extra" warming, but that it is occurring faster than in the past. And beyond that, it's accelerating!

I have a real problem with that idea. We've only had thermometers up to modern snuff for about 100 years or so. So to figure out what the temperature was in the past, you need to use "proxy measurements." However, validating a proxy measurement is a Herculean task in and of itself. Tree rings have of late been used as proxy measures, but how reliable are they? Seriously, as a bench top physicist, I won't trust the validity of tree rings as a proxy measurement of temperature until someone grows a stand of a hundred trees for a hundred years, monitors the temperature the whole time, then cuts them down and shows me how well the tree ring width corresponds to average temperature.

Think about those trees for a minute. You can't grow them under controlled conditions because the ones in the wild you want to use for your proxy measurements weren't grown that way. But, if you grow the trees today, uncontrolled or not, you're growing them in an industrial environment that did not exist in pre-thermometer days. Also, tree ring thickness is dependent upon more than just average local temperature, and exactly how many other variables are relevant, and which are relevant at what latitudes and elevations, and how the variables interact with each other....

All of these things matter if you're going to use growth rings as a proxy measurement, and most of it we don't understand very well at all. Indeed, the now infamous "hide the decline" comment from the Climategate e-mails referred to removing tree ring proxy data from the plotted data set and replacing it with thermometer readings. The reason? Because the proxy measurements used to show warming from previous centuries started showing a temperature decline after the middle of the 20th century. Rather than accept that tree rings might not be a good proxy measurement for temperature and not use them at all, they just stopped using the data beyond the dates for which it gave them the warming they expected.

C'mon! If they understood tree rings in the first place, wouldn't they have been able to account for why the rings were showing a decline, even though real temperature measurements with thermometers were showing an increase? They couldn't, so they fudged it.

I don't know which is worse. If they fudged it knowing it was bad science. Or if they did it because they were too stupid to know it was bad science. Either way, there is no trusting these people.