Matt Ridley on solar effects

Matt Ridley reviews evidence of solar effects on the climate.

Carbon dioxide certainly can affect climate, but so for sure can other things, and in explaining the ups and downs of past climate, before industrialisation, variations in the sun are looking better and better as an explanation. That does not mean the sun causes current climate change, but it certainly suggests that it is at least possible that forcings more powerful than carbon dioxide could be at work.

Comments

[HaroldW]

Link.

[Rob Schneider]

Link: http://www.rationaloptimist.com/blog/keeping-open-mind-about-sun

[Bruce]

Bright sunshine hours have fluctuated up and down with the temperature records -- see global dimming/brightening.

The UK is up 4% since 1929. Japan is up 10% since 1900.

[BBD]

Bruce

Can you give me the source for this:

The UK is up 4% since 1929. Japan is up 10% since 1900.

Thanks.

The reference paper on global brightening/dimming (which is caused by changes in atmospheric transparency and is an internal climate variability, not an external forcing like solar variability) is:

Wild, M. (2009), Global dimming and brightening: A review, J. Geophys. Res., 114, D00D16, doi:10.1029/2008JD011470.

1.4Mb pdf here:

www.leif.org/EOS/2008JD011470.pdf

Wild has been working on this for a long time, and his review is well worth reading. Especially if you are interested in aerosols and clouds. Do have a look at Figure 9, where GATA is correlated with episodes of brightening and dimming.

Abstract:

There is increasing evidence that the amount of solar radiation incident at the Earth’s surface is not stable over the years but undergoes significant decadal variations. Here I review the evidence for these changes, their magnitude, their possible causes, their representation in climate models, and their potential implications for climate change. The various studies analyzing long-term records of surface radiation measurements suggest a widespread decrease in surface solar radiation between the 1950s and 1980s (‘‘global dimming’’), with a partial recovery more recently at many locations (‘‘brightening’’). There are also some indications for an ‘‘early brightening’’ in the first part of the 20th century. These variations are in line with independent long-term observations of sunshine duration, diurnal temperature range, pan evaporation, and, more recently, satellite-derived estimates, which add credibility to the existence of these changes and their larger-scale significance. Current climate models, in general, tend to simulate these decadal variations to a much lesser degree. The origins of these variations are internal to the Earth’s atmosphere and not externally forced by the Sun. Variations are not only found under cloudy but also under cloud-free atmospheres, indicative of an anthropogenic contribution through changes in aerosol emissions governed by economic developments and air pollution regulations. The relative importance of aerosols, clouds, and aerosol-cloud interactions may differ depending on region and pollution level. Highlighted are further potential implications of dimming and brightening for climate change, which may affect global warming, the components and intensity of the hydrological cycle, the carbon cycle, and the cryosphere among other climate elements.

[Bruce]

http://www.metoffice.gov.uk/climate/uk/actualmonthly/

Pick UK, Sunshine, Annual.

The 1971-2000 average was 1350 hours. The smoothed kernel filter value has 2010 at 1430 hours. And 1929 at 1340.

80 hours above the 1971-2000 average = 5.9%
90 hours above the 1929 average = 6.7%

The CET graph (bottom of page) shows a similar rise.

http://www.halesowenweather.co.uk/cet_sunshine.htm

Spain:

http://www.iac.es/folleto/research/preprints/files/PP08038.pdf

“There is an overall increasing trend in the number of
bright sunshine hours, amounting to about 100 h in
the last 100 years (0.96 h/year), which represents an
increase in bright sunshine hours of about 4% in a
century.”

It appears I misremembered the 4% for Spain as UK changes. But UK is higher.

Greater Alpine Region:

17 - 29%

"The recent trends in winter precipitation have been accompanied by respective trends in sunshine (significant increase in all subregions of 17 to 29%)"

http://coast.gkss.de/G/Mitarbeiter/storch/pdf/Auer.histalp.2007.pdf

http://i54.tinypic.com/30auot1.jpg

Japan:

http://www.jstage.jst.go.jp/article/jmsj/86/1/57/_pdf

"During the 20th century SS in Japan increased by 10%."

[BBD]

Bruce

Very helpful, thanks. Fits in with what Wild is saying too. See his Fig. 9.

This is fascinating, although technically OT, since of course Matt Ridley's article is about changes in TSI.

BTW I don't share Wild's tendency toward anthropogenic attribution. The sources of aerosols are not so well understood.

[Spen]

Historical surface temperature readings over the last 100+ years do not show a consistent year on year rise. The pattern is more of a saw tooth.

Conclusions.
1. There are periods where 'cooling' trends exceed warming trends and predominate over AGW effects..
2. There are no significant global AGW effects and natural modes predominate.
3. One is looking at the wrong metric. It takes less heat to warm dry air by 1 deg. than damp air. Therefore, temperature records without humidity reference are not meaningful.

Heat change not temperature is the issue. Look to the oceans which cover more than 70% of the earth's surface and several hundred times the heat capacity.

[Bruce]

BBD, I think TSI is a red herring allowing the GAW crowd to dismiss the sun. Sunshine hours increases are not a red herring.

If you compare Global Brightening/Dimming/Brightening cycles to the PDO. there is an amazing correlation.

Now, what causes the PDO? I don't know.

[BBD]

Spen

Heat change not temperature is the issue. Look to the oceans which cover more than 70% of the earth's surface and several hundred times the heat capacity.

Have a look at the NODC OHC reconstruction:

http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

But, as I have said before, claims of recent substantial warming of the upper ocean layer depend on a reconstruction which shows an increase in OHC of about 8*10^22 J between 2003 and 2005 (NODC) or the same between 2002 and 2004 (Lyman et al. 2010).

This is the period when ARGO becomes dominant and expendable bathythermograph (XBT) data is phased out.

Which makes one wonder how reliable the reconstruction actually is.

[BBD]

Bruce

With you on the way in which TSI is craftily and misleadingly used to trump UV variation. Not prepared to venture out into correlation with the PDO, but I'm not disagreeing with you as such.

[BBD]

Spen

Sorry, missed this:

John M. Lyman, Simon A. Good, Viktor V. Gouretski, Masayoshi Ishii, Gregory C. Johnson, Matthew D. Palmer, Doug M. Smith, Josh K. Willis (2010) Robust warming of the global upper ocean, Nature, Volume: 465, Pages: 334–337 DOI: doi:10.1038/nature09043

Abstract:

http://www.nature.com/nature/journal/v465/n7296/abs/nature09043.html

Full pdf:

http://www.indiaenvironmentportal.org.in/files/Robust%20warming%20of%20the%20global%20upper%20ocean.pdf

[hmm]

Given that solar variables correlate poorly with temperature during the recent warming you'd have thought that correlation would be a bad argument to use that "forcings more powerful than carbon dioxide could be at work". If anything the lack of correlation suggests that solar forcings are probably just not that powerful.

[Pascvaks]

Chiefio has a related piece:

Temps Clouds and Food
2 April 2011 by E.M.Smith
http://chiefio.wordpress.com/2011/04/02/temps-clouds-and-food/

[Bruce]

hmm, global brightening/dimming/brightening correlate real well the minor fluctionas in temperature in the 20th century. And that has to do with aresols, clouds etc. The amount of sunshine reaching the earth has changed substantially in many regions of the earth.

Consider that bright sunshine can produce 200,300, 400W/sqm or more depending on time of day/time of year and lat/long. The IPCC completely ignores sunshine.

At most, a doubling of CO2 produce 3.7W/sqm.

You only need something like an extra 10 minutes a day of bright sunshine to match that.

The UK is up 80 hours a year. Japan even more.

The amount of sunshine reaching the earth can explain all warming. And not only that, it matches the up and down changes of temperature.

http://tallbloke.wordpress.com/2010/06/21/willie-soon-brings-sunshine-to-the-debate-on-solar-climate-link/

[BBD]

hmm

You are missing the point raised by Wild. Changes in atmospheric transparency (see linked paper above) are enough to account for changes in T. And they correlate very well since the start of the C20th.

I think that RIdley is probably correct to ascribe some past climate change to shifts in solar activity, but that doesn't seem to be what is going on now (even with changes in solar UV taken into account).

[HaroldW]

BBD (Apr 2, 2011 at 10:42 PM) -
Thanks for the link to the latest WIllis/Lyman paper. I think I had been using 2008 information. As you say, the ARGO period (still) shows a fairly trendless OHC. As you wrote earlier, the jump in OHC is pre-ARGO, and, as the paper admits, "raises the possibility of a yet-undiscovered bias in the observing system."

I find myself still amazed at the difficulty of making a fairly basic observation (temperature) reliable -- the satellite-based temperatures are subject to effects due to orbital decay, the ocean temperatures seem to have difficulty reliably combining XBT & ARGO data, and we're all aware of the various confounding effects in measuring land temperatures. It seems that we can only hope that *trends* are less subject to measurement issues.

[BBD]

HaroldW

Yes, the full extent of measurement uncertainty is... surprising, isn't it?

I have most confidence in the satellite data, moderate in surface, less in SST and almost none in OHC reconstructions. As far as I can tell, ARGO (which started off biased cold) is now biased hot but probably consistently, so the lack of trend may be real. XBT was supposed to be biased warm but perhaps not so much as researchers have assumed, hence the completely implausible jump in OHC around 2003 - 4 when ARGO displaces XBT.

Frankly, it's a bit of a mess.

[One-off Guest]

I used to believe variation in insolation could explain climate change, but my take on current science is that varying solar activity (sunspots, CME's) causes variation in the solar wind. Variations in the solar wind causes variation in cosmic rays reaching the troposphere. Variations in cosmic rays causes variation in cloud cover. Variation in clouds causes variations in T/climate. Despair of computer modeling; it's too complex.

[Pharos]

Nigel Calder has mothballed his fascinating blog (on the sidebar) since 23 Oct last year, working on a solar related paper. Perhaps this link from the comments is relevant. Something exiting is certainly in gestation.

http://blogs.nature.com/news/thegreatbeyond/2010/12/sunny_days_for_cloud_experimen.html

[BBD]

Pharos

Something exiting is certainly in gestation.

Here's hoping. I have always liked the Svensmark hypothesis, but experimental confirmation by CLOUD is not yet in. We just have to wait and see.

The vitriol directed at Svensmark and the obstacles strewn in the way of getting CLOUD done are telling. Anyone looking for the dead hand of consensus can see it here.