Some comment replies require more than just a few brief lines.
Richard Mallett | May 19, 2015 at 4:28 pm |
I see that somebody has been posting replies in italics and within square brackets that do not appear in my email client.
One claims that we can prove that warming has accelerated over time. Since we have had warming and cooling periods as shown below, I would be interested to see how one can prove from such varying data that the warming has accelerated over time.
http://www.realclimate.org/index.php/archives/2014/12/recent-global-warming-trends-significant-or-paused-or-what/ identifies the following warming and cooling periods in GISS since 1880 :-
1880-1912 cooling 32 years
1912-1940 warming 28 years
1940-1970 cooling 30 years
1970-2014 warming 34 years
Response: It appears that you don’t know the definition of “acceleration.” When velocity (generally, the rate of change which in this case means warming rate) itself changes, that’s acceleration. When it decreases one often distinguishes deceleration from acceleration, but mathematically they’re both still acceleration.
Then you want proof — after yourself posting numbers suggesting that yes indeed, the warming rate has changed.
Quite apart from arguing the technical definition of acceleration, the actual point is that you have entirely missed the point. Which is: when velocity has so clearly, provably, and sizeably changed, attempts to extrapolate a linear trend far into the future are a fool’s errand. Put more succinctly, that’s stupid.
But you sure did it. Not just with global temperature but with sea level as well.
It’s something I’ve been trying to get across for a while (read this), especially to the deniers of the danger of sea level rise, who seem the most likely to resort to this idiocy. They also have such blinders on that the only kind of “acceleration” they accept as worth paying attention to is constantly increasing, never reversing, always got to be going faster every minute of every day or — their inevitable conlusion — there’s not a thing to worry about.
The second asks me for statistical evidence that the trend from 1998 to 2014 is different from the trend from 1970 to 1998.
So, since these two comments are related, let’s examine the linear trend from 1970 to 1998 and from 1998 to 2014 on the three main data sets :-
NASA GISS 1970-1998 +1.67 C 1998-2014 +0.83 C per century.
HadCRUT4 1970-1998 +1.73 C 1998-2014 +0.62 C per century.
NOAA NCDC 1970-1998 +1.65 C 1998-2014 +0.56 C per century.
Response: Evidently you don’t know the meaning of the phrase “statistical evidence.”
But you still feel qualified to post what you think constitutes evidence, so soon after having referred to the same post on RealClimate by Rahmstorf which demonstrates the lack of such evidence. But then, I’ve done that myself, not just applying a suite of tests besides change-point analysis, but looking at 8 major data sets.
Perhaps you suffer from that disease where, if something you don’t want to accept involves a bit of complication beyond the simplistic, you’re unwilling to do the work required actually to know what you’re talking about.
The longer you persist in posting nonsense with an air of confidence, the harder it will be when the truth finally dawns on you.