I hadn't intended to post another message this week, and I certainly hadn't intended to bore anyone with another climate-related discussion. But just yesterday, a new paper was published that is likely to have a significant impact on the direction and content of research into the causes of climate change. Not to put too fine a point on it, and at the risk of mixing metaphors, but this paper drives yet another nail into the dead horse of the anthropogenic global warming thesis.
I've already beaten the bejeezus out of that horse in other as-yet-unpublished fora, and if any of you are interested in the scientific arguments behind the points that follow (as well as detailed references for each of the points made below), feel free to contact me and I'd be happy to send you my draft paper on the subject. But in the interest of brevity, the situation is this.
The anthropogenic global warming (AGW) thesis that underlies the arguments of the IPCC and the policy decisions of the bulk of the Western world contends (a) that climate is changing unnaturally, and (b) that the changes are mostly being driven by temperature changes resulting from the human addition of carbon dioxide (and other, less important greenhouse gases) to the atmosphere. In the IPCC's own words, "Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations."[1]
There are many problems with that hypothesis, but two are crippling. The first problem is that there is no empirical data to support it. The thesis cannot explain past temperature changes, which have been both more rapid and more significant in magnitude than recent changes, and it has failed to make any predictions that have been subsequently observed by measured data. The second problem is that there is no statistically significant correlation between change in atmospheric CO2 concentrations and change in average global temperature, over any time period for which measured or proxy data exists - with one exception: the data from the Vostok and other Antarctic ice cores show a correlation between the two phenomena, but with changes in temperature preceding changes in CO2 concentration. This suggests that the former causes the latter, and not, as the AGW thesis suggests, the other way around. As a pair of astronomers put it, "over the past 500 million years, there has been no correlation between carbon dioxide and temperature; over the past million years, there has been a correlation, with increases in temperature preceding increases in carbon dioxide concentrations; over the past 10,000 years there has been no correlation between carbon dioxide and temperature; and over the past 100 years, there has been a “rough link” between increasing carbon dioxide and temperature."[2]
The AGW thesis is undermined by the fact that there is no possibility of a causal relationship between two non-correlating phenomena (we'll ignore the fact that the thesis also doesn't explain what caused documented periods of warming prior to human industrialization, to say nothing of changes prior to the evolutionary emergence of anthropoids). The non-correlation of CO2 and temperature has led innumerable scientists to look at phenomena that do correlate to average global temperatures in order to try to figure out what is causing temperatures to change. Most folks look at the big, hot yellow ball in the sky, because it has been known for centuries that solar activity (historically measured by sunspots, but more recently measured also by magnetic and other activity), not surprisingly, correlates closely with terrestrial temperatures. However, measured data suggested that simple fluctuations in solar output were insufficient to cause observed temperature changes (that's a gross oversimplification, but it's sufficient for now). Some sort of amplifying element would have been necessary to explain how the Sun was causing observed temperature changes. In the absence of such an identified amplification mechanism for solar activity, the IPCC entirely discounts the impact of "natural" (i.e., solar and volcanic) radiative forcings, arguing that these “are both very small compared to the differences in radiative forcing estimated to have resulted from human activities."[4AR, 2007, Report of WG I, Chapter 2, 137].
A few years ago, a Danish astrophysicist named Henrik Svensmark posited what has since come to be called the "GCR low-cloud nucleation thesis". Simply put, heavy galactic cosmic rays (charged particles) penetrate the upper atmosphere and survive into the lower atmosphere, where they nucleate low clouds. More GCR = more low clouds. More low clouds equal increased albedo (reflectivity), which reflects solar radiation back to space, cooling the Earth; fewer low clouds reduce albedo, allowing more solar energy to reach the Earth, causing warming. What's interesting is that there is also a documented correlation between solar activity and GCRs striking Earth (I mentioned this, along with Svensmark's GCR thesis, in a CoP message on the HAARP system back on 19 August). During periods of increased solar activity, the Sun's magnetic field reduces the amount of GCR reaching the Earth, and when the Sun is inactive, more GCRs reach the Earth. In other words, periods of low solar activity don't just mean less solar energy; they also mean more GCR, and therefore - according to Svensmark - more clouds, producing further cooling, while periods of high solar activity mean fewer GCR, and therefore fewer clouds, and therefore more warming. This is known as a feedback mechanism.
It's important not to underestimate the influence of clouds on temperature. Albedo is a critical factor, and it works on a global scale; a change of as small as 1% in global cloud cover could significantly impact the Earth's infrared radiation budget, "producing changes as great as the most exaggerated claims that are meant to derive from humans adding CO2 to the atmosphere."[4] The problem is, nobody really knows how clouds work; the IPCC acknowledges that the cloud albedo effect is estimated with a "low" level of scientific understanding and that where their aggregate impact is concerned, "uncertainty remains large" [4AR, 2007, Report of WG I, Chapter 2, 131-132].
The weakness with Svensmark's theory was that while he had posited a GCR low-cloud nucleation pathway the viability of which has since been validated in laboratory experiments [5] (which is at least one step further than the AGW thesis has ever gone), there was no real-world evidence to substantiate his idea. In the 4AR, the IPCC dismissed both the GCR thesis and the empirical results of laboratory testing, stating "Empirical associations between solar-modulated cosmic ray ionization of the atmosphere and globally averaged low-level cloud cover remain ambiguous." [4AR, 2007, Report of WG I, Chapter 2, 132].
This choice of words was a little ballsy given the complete absence of any "empirical associations" between atmospheric CO2 concentrations and average global temperature, apart from the very loose 20th-Century correlation…but, whatever. It's all about the data, right?
Well, the "empirical associations" aren't "ambiguous" anymore. The paper I want to bring to your attention was published yesterday in Atmospheric Chemistry and Physics, and it provides strong empirical support for the relationship that Svensmark posited.[3] While the abstract speaks for itself, I've taken the liberty of highlighting relevant passages:
The effect of the Galactic Cosmic Ray (GCR) flux on Earth's climate is highly uncertain. Using a novel sampling approach based around observing periods of significant cloud changes, a statistically robust relationship is identified between short-term GCR flux changes and the most rapid mid-latitude (60°–30° N/S) cloud decreases operating over daily timescales; this signal is verified in surface level air temperature (SLAT) reanalysis data. A General Circulation Model (GCM) experiment is used to test the causal relationship of the observed cloud changes to the detected SLAT anomalies. Results indicate that the anomalous cloud changes were responsible for producing the observed SLAT changes, implying that if there is a causal relationship between significant decreases in the rate of GCR flux (~0.79 GU, where GU denotes a change of 1% of the 11-year solar cycle amplitude in four days) and decreases in cloud cover (~1.9 CU, where CU denotes a change of 1% cloud cover in four days), an increase in SLAT (~0.05 KU, where KU denotes a temperature change of 1 K in four days) can be expected. The influence of GCRs is clearly distinguishable from changes in solar irradiance and the interplanetary magnetic field. However, the results of the GCM experiment are found to be somewhat limited by the ability of the model to successfully reproduce observed cloud cover. These results provide perhaps the most compelling evidence presented thus far of a GCR-climate relationship. From this analysis we conclude that a GCR-climate relationship is governed by both short-term GCR changes and internal atmospheric precursor conditions.
The conclusion offers the following assessment of the data and results of the study:
This work has demonstrated the presence of a small but statistically significant influence of GCRs on Earth’s atmosphere over mid-latitude regions. This effect is present in both ISCCP satellite data and NCEP/NCAR reanalysis data for at least the last 20 years suggesting that small fluctuations in solar activity may be linked to changes in the Earth’s atmosphere via a relationship between the GCR flux and cloud cover; such a connection may amplify small changes in solar activity. In addition, a GCR – cloud relationship may also act in conjunction with other likely solar – terrestrial relationships concerning variations in solar UV (Haigh, 1996) and total solar irradiance (Meehl et al., 2009). The climatic forcings resulting from such solar – terrestrial links may have had a significant impact on climate prior to the onset of anthropogenic warming, accounting for the presence of solar cycle relationships detectable in palaeoclimatic records (e.g.,Bond et al., 2001; Neff et al., 2001; Mauas et al., 2008).
In other words, the authors have (i) used measured data to identify the GCR-climate connection posited by Svensmark, a classical example of an hypothesis being validated post-facto by empirical observation (as opposed to being falsified post-facto by empirical observation, as has happened with the AGW thesis); (ii) demonstrated the amplification mechanism necessary to begin to explain the impact and magnitude of solar activity changes on average global temperature; and (iii) used measured data to blow a CostCo-sized hole through the IPCC's casual dismissal of natural radiative forcings as "very small compared to the differences in radiative forcing estimated to have resulted from human activities" (emphasis added for purposes of comparison).
There's a lot more work to be done to gather additional evidence to firm up Svensmark's GCR low-cloud nucleation thesis - and by "evidence", I mean both substantiating evidence to further validate the thesis, AND contrarian evidence, if any, to further refine it. But at least we now have a real empirical path to follow. And by "path", I mean an hypothesis that is based on correlating phenomena; that posits an explanatory mechanism that has now been confirmed by observed, real-world data; and that has the potential to explain both recent temperature changes, and temperature changes that we know took place tens of thousands of years ago, before human industrialization; hundreds of thousands of years ago, before human civilization; and millions of years ago, before humans. That's a heck of a lot more than the proponents of the AGW thesis, despite 20 years of trying, have been able to give us.
Or as Plimer puts it on p. 434 of his tome:
"Nature continues to surprise and belittle us and every new discovery shows that science is never settled."
Cheers,
//Don//
P.S. Why is this topic relevant to Defence? Because of http://www.admie.forces.gc.ca/dge/sd-sdd/nds-sdd/docs/ndsds-sdddn-eng.pdf, pp. 23, 30, and 36; and http://admie.ottawa-hull.mil.ca/dge/documents/Guide2006_EN_Final-update2%202008.doc, pp. 34-39. That's why.
Notes
(1) Intergovernmental Panel on Climate Change, Climate Change 2007 Synthesis Report: Summary for Policymakers (Valencia, Spain: 12-17 November 2007), 5.
(2) Henrik Svensmark and Nigel Calder, The Chilling Stars: A Cosmic View of Climate Change (Cambridge, UK: Icon Books, 2007), 247.
(3) B.A. Laken, D.R. Kinveton, and M.R. Frogley, "Cosmic rays linked to rapid mid-latitude cloud changes", Atmospheric Chemistry and Physics, Vol. 10 (2010). [http://www.atmos-chem-phys.net/10/10941/2010/acp-10-10941-2010.pdf]
(4) Ian Plimer, Heaven and Earth - Global Warming: The Missing Science (Lanham, Australia: Taylor Trade Publishing, 2009), 432.
(5) Jasper Kirkby, “CLOUD: A particle beam facility to investigate the influence of cosmic rays on clouds”, Proc. IACI Workshop, CERN, 18–20 April 2001, CERN 2001-007 (CERN, 17 January 2002), [http://cloud.web.cern.ch/cloud/documents_cloud/ kirkby_iaci.pdf].
