Last week a team of researchers from the UK Met Office, the University of East Anglia, the University of Gothenburg, the University of Southern Queensland and the Sorbonne published in the journal Science Advances an interesting paper showing that the recent much debated and researched 21st century “slowdown” in global surface temperatures was real and could be explained by reduced solar activity and increased volcanic counteracting climate forcing from greenhouse gases.
It achieved almost no media coverage despite being published in a high profile journal, writes Dr David Whitehouse @ The GWPF.
Its stated aim was to “place the slowdown in a longer term context.” It chose not to use the words “pause” or “hiatus” because it says warming did not entirely cease on decadal timescales.
That’s where I disagree. It depends upon when you start the decade. All the global databases clearly show that warming did cease between 2001 – 2013 (before the recent very strong El Nino), though I would advise the reader to experiment with trends by altering start and end dates to get a better picture of what is going on.
Over this period HadCRUT4 for example has a trend of -0.005 +/- 0.167 degrees per decade which is statistically equivalent to no trend in any researchers notebook.
The krigged HadCRUT4 has 0.051 +/- 0.185 degrees per decade, GISTEMP 0.038 =/- 0.175 degrees per decade, Berkeley 0.050 +/- 0.176, NOAA 0.044 +/- 0.185. The satellites also show the same effect RSSv4.0 TLT 0.001 +/- 0.301, RSSv4.0 TTT -0.069 +/- 0.294, UAH v5.6 TLT 0.044 +/- 0.292 and UAH v5.6 TTT -0.070 +/- 0.291. See graph here.
From 2001 to 2013 it is flat and after that period the El Nino takes over. Because of this the post-2001 period contains no information that can be extrapolated backwards to see if it is a continuance of previous warming statistics. It is a true break with the warming before it.
Some maintain that you can take the data starting in 1980 (the start of the most recent warming period) and fit a linear trend to it and maintain there is no slowdown whatsoever. They should take up their position with these scientists who say there was a slowdown.
Perhaps it would be interesting to read this paper alongside the famous Karl et al paper in 2015 that removed the slowdown by upgrading an ocean temperature database. It hasn’t stood the test of time, has it?
via Tallbloke’s Talkshop
June 13, 2018 at 04:43AM