While there seems to be a consensus in the scientific community about global warming, there seems to be some problem with the temperature data from the 1980s. To be specific, the raw data is missing and the remaining data is modified data. The exact quote is as follows:
Since the 1980s, we have merged the data we have received into existing series or begun new ones, so it is impossible to say if all stations within a particular country or if all of an individual record should be freely available. Data storage availability in the 1980s meant that we were not able to keep the multiple sources for some sites, only the station series after adjustment for homogeneity issues. We, therefore, do not hold the original raw data but only the value-added (i.e., quality controlled and homogenized) data.
This is obviously a serious problem. After all, it is rather critical to keep raw data. After all, anyone wishing to check on the conclusions drawn from the data would need to be able to examine that data. Having only “value added” data is not adequate. After all, this “value adding” changes the original data and might do so in ways that bias the data. Of course, without the original data it cannot be determined whether the “value adding” was legitimate or whether it involved changing the data to support a specific hypothesis (rather than drawing the hypothesis from the data).
Does this prove that global warming is a hoax? Not at all. The fact that some data is missing does not disprove the hypothesis. However, it does raise serious and reasonable questions about any findings that are based on the missing data and it also provides some rather high caliber ammunition to those who are critical of the global warming view.