Oh boy, get out the tinfoil. Here’s one the conspiracy nuts will howl over.
The temperature record that has been showing the lowest anomaly in the recent decades, HadCRU, the dataset managed by the UK’s Met Office and the University of East Anglia’s Climate Research Unit (CRU), is about to be revised upwards.
Met Office scientists have reviewed the whole sea surface temperature data set between 1850 and 2006 to take account of this bias. A paper has been submitted to the Journal of Geophysical Research which looks in more detail at all the biases in sea-surface temperature measurements from ships and buoys between 1850 and 2006
Apparently, the steadily increasing number of in-situ bouy measurements relative to ship measurements has been introducing a cooling bias. Ship measurements are on average .15oC higher than bouy measurements of the same part of the ocean, so as more buoys are deployed, as has been going on since the 1980’s, the warming trend has been artificially depressed by perhaps as much as .03oC/decade.
The problem seems to be related to the way that some ships measure the temperature of the water which leads to the average temperature measured by ships being higher than the average sea surface temperature measured by a thermometer on a buoy. “On average the difference ranges between 0.13C and 0.18C,” Kennedy told Reporting Climate Science .Com. The scale of this difference across the globe and over the years is sufficient to add a warming of 0.03C per decade to the HadCRUT surface temperature record.
Also prepare your irony meters as the WUWT crowd complains about a nefarious “data adjustment” that actually brings this record more in line with the satellite record. You know, the record that was the cat’s thermal underware (if I may topically adapt a common expression) when it was showing a cooling trend. This is the record of Spencer and Christy, darlings of the denialists, so surely there’s no “hiding the decline” going on there, right?
Satellite data has reported a bigger increase in sea surface temperatures than in situ data from buoys and ships, according to Met Office scientist John Kennedy. “We suspect that there has been this difference for quite a while. And when we make a correction for the data from buoys we find that the trend from in situ data is much closer to the trend observed by the satellites,” explained Kennedy.
“One more nail in that coffin…” right?