A reader writes:
I'm not a climatologist, but I am interested in climate change. Fortunately, I attend a college with a climatologist. I asked her about the data massaging trick and this is how she explained it.
The data in question is actually two sets of data. One being the data from 1BCE to now using tree rings and coral. Tree rings are larger when it is wet or hot and smaller when it is cold and dry. Because wet/hot and cold/dry aren't correlated, there are uncertainties with the data. But, the data from tree rings from 1BCE to now does show temperatures similar with other temperature markers. That is, until the middle of this century.
The other set of data comes from real thermometers, from the mid-19th century to now. The data becomes more reliable as data gathering methods become more precise. What the scientists at CRU did was splice and combine the two data sets. The tree rings data shows cooling that is in opposition to actual measured temperatures. So the CRU scientists combined the two data sets to make it look like one data set that shows more continuous warming.
The professor I spoke with was very clear that what the CRU scientists did may not have been ethically pure, but warming is happening. They probably should have made clear the "trick" they used was actually two different data sets, she said. The information that has become known through this "scandal" may call into question historical climate data, but not current climate data. The world is still warming now, and "climategate" doesn't change the need for significant carbon cuts in Copenhagen.