Guest post by R. Gates
Recently on Judith Curry's blog, a guest post was submitted by DocMartyn which was a rather nicely (from a math perspective) done extrapolation of past tropospheric temperature trends and cycles out to 2040 and beyond. It was essentially a nice job of, as he put it, "graphology", or in other words "curve fitting". Not great science, but some nifty math. Essentially DocMartyn's curve fitting graphology approach has led him to conclude that tropospheric temperatures will remain flat to 2040 or so before accelerating upward once more.
I happen to strongly feel that DocMartyn's projective curve fitting approach will prove to be grossly in error (as almost all such curve fitting is, except for pure chance), but here's the thing-- in the big picture of Earth's energy imbalance caused by accumulating anthropogenic greenhouse gas emissions, the tropospheric temperatures are quite secondary. The troposphere is a low thermal inertia part of the overall energy system of the planet and contains only a fraction of the overall energy. It seems however, that there is an undue preoccupation with focusing on this part of the system-- probably because we as humans happen to live in it, and also because it is easy to measure. And since the troposphere can be fickle and far more subject to short-term noise from natural variability, it makes the most sense to look at the parts of the system such as the oceans and cryosphere that have greater thermal inertia and are hardest to change from short-term noise. When doing this, and comparing it to the constant upward trend in CO2 emissions, the following four charts become the most salient in terms of understanding what is really happening:
These four charts have very similar slopes, with the bottom two being inverted from the top two, of course. Their similar slopes are not coincidental, as this is the shape of the true warming of the Earth system. These are the four charts that really matter in answering the question as to whether or not Earth is still warming. CO2 (and methane and N20) never sleep, and their continual accumulation in our atmosphere will continue to add to the energy imbalance of the planet, and that imbalance will be seen in these four charts continuing their long-term slopes, until such time of course in the not too distant future when the Arctic sea ice chart hits zero for the first ice free summer Arctic in many thousands of years.
So whenever someone says to you that there's a pause or a halt to global warming, refer them to these four charts that really matter.