Bishop Hill Santer: pause now 20 years long
Feb 28, 2014 Climate: Models David Whitehouse has taken a look at the Santer et al paper in Nature Geoscience that claims to find a partial explanation for the hiatus in surface temperature rises in the cumulative effect of a series of small volcanic eruptions.
As an aside, Whitehouse notes that once you have adjusted the temperature data for the non-AGW effects, the pause in warming is very long indeed:
Their Fig 1 shows raw lower temperature data (a), that with the El Nino removed (b) and that with El Nino and El Chichon and Pinatubo removed (c). Looking at 1c one sees that the lower atmosphere shows a standstill since 1993, that is 20 years! This is in itself a remarkable graph extending the ‘pause’ into the start of its third decade.
And suffice it to say, the attribution to volcanoes is shonky indeed.
Reader Comments (106)
Hi DS,
The idea that CO2 was unvarying for hundreds of years "pre-industrial" does seem rather unlikely. The chemical measurements have quite high accuracy, although they are sparse and poorly distributed in time and place there are quite a lot of measurements and they do suggest that the CO2 was constant 285 ppm pre-industrial is pretty naive.
I have collected some of the information on these measurements. Science was pretty carefully done back then , especially chemistry. The reconstructions make some sense but are simply dismissed with a handwave by IPCC.
Thanks for the link - note the CO2 apparently lags temps by 5 months/1 year depending on study...looks like CO2 lags temperature at all timescales for which we have data.
I linked to one thread where BART gave the link to the CO2 lag, but I think there was another thread around the time Salby Murry ideas came out which also included the epic putdown of climate models by rgbatduke - not sure same thread or not.
Let's posit, for sale of discussion, that there is no ACO2 at all.
But let us then posit that CO2 levels are still rising as they modern record indicates.
Where would the CO2 be coming from and under what conditions could its increase mirror the current understanding of levels and rates?
hunter,
On another thread, I wrote this [with minor edits]:
So, while there are sources of additional CO2 (e.g. volcanoes), the size of the O2 decrease implies that the majority of CO2 arises from combustion. [Omitting implausible explanations such as a reduction in photosynthetic activity.]
HaroldW,
Interesting analysis. It is obvious now that you mention it to think of checking the other side of the combustion reaction.
However, what I am after is to take the "A" part out completely for the sake of the "thought experiment", as it were.
What are other sources of CO2 and how could they increase as we see CO2 increasing today?
hunter,
Hmmm...Cement production adds CO2, but that also falls under "A". Volcanoes, of course, submarine and surface. Oceans can out-gas CO2, but it seems that of the combination of increasing temperature (which reduces gas solubility) and increased atmospheric pCO2 (which promotes higher dissolution), the stronger force is towards increasing the dissolved CO2. Decomposition. Respiration. "Land use" -- generally, deforestation -- is considered a net contributor to CO2 concentration, although this may be double-counting with combustion & decomposition. [If a forest is cleared for agriculture, the trees are presumably burned or left to decompose.]
That's about all I can come up with. One can also consider, rather than the processes which produce CO2, a reduction in the processes which consume CO2, e.g. photosynthesis and marine carbonate formation.
HaroldW,
Since ACO2 is a small part of the budget, and the increase is in terms of % decreasing in its rate of increase, I was simply making a conjecture about the oceans. They contain the available CO2.
How much is out gassed by temp changes, on a net basis? What about when deep ocean currents so rich in CO2 shift and come to the surface- certainly they are going to be net emitters of CO2 as well?
Yes we are adding CO2- the burning of coal and other fossil carbon makes that inevitable.
But clearly, ~100 years into massive CO2 pumping, we can look at the impact with the confidence to dismiss the alarmist stories of apocalypse. There are good reasons to manage CO2 emissions- the other pollutants released in burning most fossil fuels can cause problems. But even that, if we simply look at population, longevity, arable land, it is obvious that the CO2 pumping of the last 100 years has been a good thing for humans, not a bad thing. And if we measure the environment by its biocapacity, it is clear we are not killing the environment. And it is now clear that weather 'extremes', except where seen by fanciful bored politicians looking out windows, is not being driven by CO2 either. The AGW promoters depend on arm waving to distract from these points.