(Really, is it too much to ask for the five major groups to get together and decide on, and use, a common base period? And for UAH and RSS to decide if their results warrant 2 significant figures (UAH, though they give 3 on Roy Spencer's blog) or 3 (RSS)? They're using the same raw data, after all, though with slightly different methodologies.)
In any case, this is still the warmest 5 years in the UAH record, though this isn't a statisically significant statement at the canonical level.
Pretty stupid to make big deal of the last 5 (or last 14) years being the warmest on record. It comes from ignorance of the global temperature record. These years are the warmest because of the influence of the super El Nino of 1998, not because if an imaginary AGW. That super El Nino is a wild card that interrupted the regular sequence of El Ninos and La Ninas that are part of the ENSO oscillation. First, in the satellite records the 1998 El Nino peak is twice as high as any preceding peaks. There are none like that for a century before it and none since. Second, it carried a huge amount of warm water across the ocean that caused a step warming. In three years this raised global temperature by a third of a degree Celsius and then stopped. It was followed by a seven year warm platform called the twenty-first century high. The regular ENSO oscillations then resumed with the La Nina of 2008 but their mean temperature stayed at the level of the twenty-first century high. This created a standstill of global warming you people like to call hiatus because you do not like its real name - cessation of warming. That step warming, by the way, was the only warming during the entire satellite era that began in 1979. I know your ground-based temperature curves have been showing a "late twentieth century warming" in the eighties and nineties that does not exist. For your information, GISTEMP, HadCRUT and NCDC are not showing it any more since last fall. They changed their data for the eighties and nineties secretly last fall and did not give a reason. The reason was that I exposed this fraud in my book "What Warming?"
ReplyDeleteYou mean short-term trends are influenced by ocean cycles? This is what scientists have been saying for years! So it's fun to give the gander what they've been giving the goose.
ReplyDeleteyes it is, because otherwise the deniers would use it as a base for yet another conspiracy theory. Besides, it makes an attractive rehearsal for beginner statisticians.
ReplyDeleteThe WMO has written a proposal to update the climatological normals every decade, but it retains the 1961-90 for long term climate change assessments and keeps that unchanged as long as there are no scientific reasons to do so. The new 10-year periods are intended more for user products.
ReplyDeleteThe climate normal for long term climate change assessments is a bit of problem for the relatively short satellite datasets. But satellite data is anyway not very suited to study long term trends, because of very difficult to correct non-climatic changes, even if the datasets were longer.
The same dataset, produced this headline at WUWT one hour earlier:
ReplyDelete"UAH Global temperature, down slightly, “the pause” continues".
Interesting how flexible people can be.