Sunday, April 21, 2019

Abdussamatov's Prediction of a Solar Irradiance Decline is Failing

Back in 2012, Habibullo Abdussamatov, head of a space research lab at the Pulkovo observatory in Russia, predicted a sharp decline in total solar irradiance (TSI), and "new Little Ice Age" soon in the future. It got the deniers all tingley (not thinking that cooling for a decline in solar irradiance is natural and wouldn't say a thing about anthropogenic warming).

How well did Abdussamtov's prediction do? Poorly:

The figure is from his 2012 paper; I added the black line to represent the present.

Abdussamtov was right that we'd now be in a sunspot minimum -- but that's a pretty easy prediction, given what's know about the length of the solar cycle. But his prediction for TSI is badly wrong, by a sizzling 2 W/m2.

He says he used PMOD data, but I couldn't reproduce his graph using the PMOD data I found, in particular the baseline prior to 2010 of 1365.5 W/m2.  (The baseline for the PMOD data linked above is more like 1360.5 W/m2. The difference isn't relevant here.) Here's a plot of my PMOD; the latest data only goes up to May 2, 2018:

No change in the baseline. But Abdussamtov's TSI prediction for the present can be easily discerned from his graph: a change in the baseline TSI (zero sunspots) from 1365.5 W/m2 to 1363.5 W/m2 -- a drop of 2.0 W/m2.

But the baseline change is zero. Here are TSI data from LASP (Laboratory for Atmospheric and Space Physics) in Colorado, updated to April 2019:

So, again, a different baseline, but not a change in baseline.

(Like a lot of measurements, determining the absolute value of a parameter is much harder than determining changes in it.)

There's no sign, at least yet, of a new Little Ice Age, or another Maunder Minimum, or any of that. Yes, the peak of Solar Cycle 24 was about half that of earlier peaks. (So how can anyone claim the Sun is responsible for modern warming? TSI averaged over a solar cycle has been declining since the 1960s.)

By the way, Abdussamatov wrote another paper, in 2016, doubling down. (Clarification: it appeared in a (non-peer reviewed) book, not a journal). He claims the new Little Ice Age did start, in 2015. But he (of course he did) moved out the start of the grand decline by about 30 years:
The start of a solar grand minimum is anticipated in solar cycle 27 ± 1 in 2043 ± 11 and the beginning of phase of deep cooling in the new Little Ice Age in 2060 ± 11.
I wonder if he's taken into account his failed prediction of 2012....

PS: The question of the cooling consequences of a future Maunder Minimum has been studied. It was found that anthropogenic greenhouse gas warming easily swamps any cooling from a Maunder Minimum-like sun. Cooling by 2100 would only be, at most, 0.3 C below IPCC projections.

"On the effect of a new grand minimum of solar activity on the future climate on Earth," G. Fuelner and S. Rahmstorf,  Geo Res Lett vol. 37, L05707 2010.

"Increased greenhouse gases enhance regional climate response to a
Maunder Minimum," Song et al, Geo Res Lett vol. 37, L01703 (2010)

"What influence will future solar activity changes over the 21st century have on projected global near-surface temperature changes?" Gareth S. Jones, et al, JGR v 117, D05103 (2012) doi:10.1029/2011JD017013, 2012.

See also:

1 comment:

Marco said...

Failed predictions by a climate naysayer? How surprising...