On Thursday 3rd April BBC News website’s Richard Black penned an article entitled, ‘No Sun link’ to climate change, based on a flawed paper (not discussed in detail here) in a lesser known journal called Environmental Research Letters, which refers only to Palle/Butler and Marsh/Svensmark (2000), but not Shaviv/Veizer.
The article begins:
Scientists have produced further compelling evidence showing that modern-day climate change is not caused by changes in the Sun’s activity.
The research contradicts a favoured theory of climate “sceptics”, that changes in cosmic rays coming to Earth determine cloudiness and temperature.
The idea is that variations in solar activity affect cosmic ray intensity.
But Lancaster University scientists found there has been no significant link between them in the last 20 years.
The paper referred to is: ‘Testing the proposed causal link between cosmic rays and cloud cover’
The paper concludes:
In conclusion, no corroboration of the claim of a causal connection between the changes in ionization and low cloud
cover, made in [1, 2], could be found in this investigation. From the distribution of the depth of the dip in solar cycle 22 with geomagnetic latitude (the VRCO) we find that, averaged over the whole Earth, less than 23% of the dip comes from the solar modulation of the cosmic ray intensity, at the 95% confidence level. This implies that, if the dip represents a real correlation, more than 77% of it is caused by a source other than ionization and this source must be correlated with solar activity.
Not exactly, ‘no link.’ and Giles Harrison from Reading University, is quoted as saying that the work was important “as it provides an upper limit on the cosmic ray-cloud effect in global satellite cloud data”.
Harrison’s own UK study from 2006 concluded,
Changes in diffuse fraction (DF) and the frequency of overcast days represent changes in the weather and the atmospheric energy balance. The decrease in the proportion of direct solar radiation associated with an increase in DF will lead to a local reduction in daytime surface temperature. Further, because the net global effect of cloud is cooling (Hartman 1993), any widespread increase in the overcast days could also reduce temperature. At Reading, the measured sensitivity of daily average temperatures to DF for overcast days is K0.2 K per 0.01 change in DF for 1997–2004). Consequently the inverse relationship between GCR and solar activity will lead to cooling at solar minimum. This might amplify the effect of the small solar cycle variation in total solar irradiance, believed to be underestimated by climate models (Stott et al. 2003), which neglect a cosmic ray effect. In summary, our data analysis confirms the existence of a small, yet statistically robust, cosmic ray effect on clouds, that will emerge on long time scales with less variability than the considerable variability of daily cloudiness.
No mention is made by the BBC of the more favourable 2008 review of the evidence for a cosmic ray-climate link by Usoskin and Kovaltsov, which concluded: “a CR-climate link seems to be a plausible climate driver, as supported by the bulk of statistical studies and existing theoretical models. However, further studies, in particular a clear case study as well as improved model development, are foreseen to improve our understanding of the link between cosmic rays and the climate on Earth.”
NOW YOU SEE IT, NOW YOU DON’T!
Moving on to the strange happenings surrounding a subsequent 4th April article by the BBC’s Roger Harrabin, blogged here, entitled, Global temperatures ‘to decrease’ , which was later changed to, Global warming ‘dips this year, ‘ and then subsequently changed back to Global temperatures ‘to decrease.’ The changes in the text, however, did not revert back to the text in the original article.
The two alternative headings an be viewed on this google search:
Referring to the forecast a record high temperature within five years, “probably associated with another episode of El Nino” was permanently removed from the re-written article. If the Freedom of Information Act is applicable to the BBC, I shall make a request in order to try and uncover the sequence of events and the reasons behind them.
See also NewsBusters: BBC Changes ‘Temperatures Decrease’ Article to Incite Climate Hysteria