The latest attempt by the global warming alarmists to make the Medieval Warming Period disappear came into the crosshairs of Watts Up With That – and ended up looking a lot like the gel torsos on Deadliest Warrior.
First up is Don J. Easterbrook, who notices something about the data…
Eighty percent of the source data sites were marine, so temperatures from 80% of the data set used in this paper record ocean water temperatures, not atmospheric temperatures. Thus, they may reflect temperature changes from ocean upwelling, changes in ocean currents, or any one of a number of ocean variations not related to atmospheric climates. This in itself means that the Marcott et al. temperatures are not a reliable measure of changing atmospheric climate.
Making matters worse, one of the land datasets was a tree ring reconstruction from none other than Michael Mann himself (he of “Mike’s Nature Trick”). Keep in mind, Mann has already admitted to errors in his tree ring data.
Meanwhile, David Middleton reveals another problem with the data – time intervals. He graphically explains why using old data that measures by 140-years-plus along with new annual data can cause problems.
Back to the penalty box.