The Intergovernmental Panel on Climate Change (IPCC) is preparing what is known as its Fifth Assessment Report for publication next year .. and somebody has leaked a draft. It’s an open process, but reviewers are not supposed to publish. The BBC Reports …
In a statement, the IPCC says it “regrets this unauthorized posting which interferes with the process of assessment and review”.
The draft posted online is of what’s called Working Group 1 (WGI), the first stage of the next report.
This covers the physical aspects of climate science, including observations of temperature and computer models of possible scenarios for future warming.
The IPCC statement read: “The unauthorized and premature posting of the drafts of the WGI AR5, which are works in progress, may lead to confusion because the text will necessarily change in some respects once all the review comments have been addressed.
“It is regrettable that one out of many hundreds of reviewers broke the terms of the review.”
So who blabbed and why? It turns out that it was climate change denier Alec Rawls, who runs a blog called Stop Green Suicide. What he has done is to pluck out just one sentence and then manufacture a climate denial stance out of it …
Compared to the First Order Draft, the SOD now adds the following sentence, indicated in bold (page 7-43, lines 1-5, emphasis added):
Many empirical relationships have been reported between GCR or cosmogenic isotope archives and some aspects of the climate system (e.g., Bond et al., 2001; Dengel et al., 2009; Ram and Stolz, 1999). The forcing from changes in total solar irradiance alone does not seem to account for these observations, implying the existence of an amplifying mechanism such as the hypothesized GCR-cloud link. We focus here on observed relationships between GCR and aerosol and cloud properties.
The Chapter 7 authors are admitting strong evidence (“many empirical relationships”) for enhanced solar forcing (forcing beyond total solar irradiance, or TSI), even if they don’t know what the mechanism is. This directly undercuts the main premise of the report, as stated in Chapter 8 (page 8-4, lines 54-57):
There is very high confidence that natural forcing is a small fraction of the anthropogenic forcing. In particular, over the past three decades (since 1980), robust evidence from satellite observations of the TSI and volcanic aerosols demonstrate a near-zero (–0.04 W m–2) change in the natural forcing compared to the anthropogenic AF increase of ~1.0 ± 0.3 W m–2.
The context here is a section entitled “Correlations Between Cosmic Rays and Properties of Aerosols and Clouds” where they review research into a hypothesis that galactic cosmic rays (GCR) amplify relative small variations in solar activity into climatologically significant effects, and in there the above quote has been cherry picked. It is a review of the work in the area and … well gosh, lets put it all back into its proper context …
Many empirical relationships have been reported between GCR or cosmogenic isotope archives and some aspects of the climate system (e.g., Bond et al., 2001; Dengel et al., 2009; Ram and Stolz, 1999). The forcing from changes in total solar irradiance alone does not seem to account for these observations, implying the existence of an amplifying mechanism such as the hypothesized GCR-cloud link. We focus here on observed relationships between GCR and aerosol and cloud properties. Such relationships have focused on decadal variations in GCR induced by the 11-year solar cycle, shorter variations associated with the quasi-periodic oscillation in solar activity centred on 1.68 years or sudden and large variations known as Forbush decrease events. It should be noted that GCR co-vary with other solar parameters such as solar and UV irradiance, which makes any attribution of cloud changes to GCR problematic (Laken et al., 2011).
Some studies have shown co-variation between GCR and low-level cloud cover using global satellite data over periods of typically 5–10 years (Marsh and Svensmark, 2000; Pallé Bagó and Butler, 2000). Such correlations have not proved to be robust when extending the time period under consideration (Agee et al., 2012), restricting the analysis to particular cloud types (Kernthaler et al., 1999) or locations (Udelhofen and Cess, 2001; Usoskin and Kovaltsov, 2008). The purported correlations have also been attributed to ENSO variability (Farrar, 2000; Laken et al., 2012) and artefacts of the satellite data cannot be ruled out (Pallé, 2005). Statistically significant, but weak, correlations between diffuse fraction and cosmic rays have been found at some locations in the UK over the 1951 to 2000 period (Harrison and Stephenson, 2006). Harrison (2008) also found a unique 1.68-year periodicity in surface radiation for two different UK sites between 1978 and 1990, potentially indicative of a cosmic ray effect. Svensmark et al. (2009) found large global reductions in the aerosol Ångström exponent from AERONET, liquid water path from SSM/I, and cloud cover from MODIS and ISCCP after large Forbush decreases, but these results were not corroborated by other studies who found no statistically significant links between GCR and clouds at the global scale (Čalogović et al., 2010; Kristjánsson et al., 2008; Laken and Čalogović, 2011). Although some studies found small but significant positive correlations between GCR and high- and mid-altitude clouds (Laken et al., 2010; Rohs et al., 2010), these variations were very weak, and the results were highly sensitive to how the Forbush events were selected and composited (Laken et al., 2009).
Quote-mining one phrase from a draft report does nothing except perhaps identify Mr Rawls as a complete kook. The report gets it right, there is no grand conspiracy operating here, no effort to suppress or befuddle. Instead we find every question, every hypothesis being carefully considered and all the research being looked at, not just in isolation, but in the proper context of the full conversation taking place.
Science is like that … a group of isolated individuals might publish some results that confirm their specific hypothesis, so they publish. They then expect to face criticism, that is why they publish. Others will then review and perhaps confirm, or, as can be seen above, point out that there are other factors that were not taken into account and can explain what was observed without recourse to the original hypothesis.
We are human … it is easy to not just fool others, but to also fool ourselves, that is why scientists encourage their peers to review and to criticise. Sadly, I suspect Mr Rawls has already reached a conclusion before he read the report and so his confirmation bias means that he sub-consciously rejects anything that conflicts with that conclusion, and simply quote-mins the stuff that re-enforces his belief.
Climate scientists, reacting to the leak, have condemned the “cherry picking” of this one point in a long report and have said that other sections reinforce the central argument about the cause of climate change.