I got a nice e-mail from Wille Soon this morning announcing his paper, co-written with the Connolly’s Ronan and Michael, has been accepted for publication. He attached a pre publication copy:
Re-evaluating the role of solar variability on Northern Hemisphere temperature trends since the 19th century
We have constructed a new estimate of Northern Hemisphere surface air temperature trends derived from mostly rural stations – thereby minimizing the problems introduced to previous estimates by urbanization bias. Similar to previous estimates, our composite implies warming trends during the periods 1880s-1940s and 1980s-2000s. However, this new estimate implies a more pronounced cooling trend during the 1950s-1970s. As a result, the relative warmth of the mid-20th century warm period is comparable to the recent warm period – a different conclusion to previous estimates.
Although our new composite implies different trends from previous estimates, we note that it is compatible with Northern Hemisphere temperature trends derived from (a) sea surface temperatures; (b) glacier length records; (c) tree ring widths. However, the recent multi model means of the CMIP5 Global Climate Model hindcasts failed to adequately reproduce the temperature trends implied by our composite, even when they included both “anthropogenic and natural forcings”.
One reason why the hindcasts might have failed to accurately reproduce the temperature trends is that the solar forcings they used all implied relatively little solar variability. However, in this paper, we carried out a detailed review of the debate over solar variability, and revealed that considerable uncertainty remains over exactly how the Total Solar Irradiance has varied since the 19th century.
When we compared our new composite to one of the high solar variability reconstructions of Total Solar Irradiance which was not considered by the CMIP5 hindcasts (i.e., the Hoyt & Schatten reconstruction), we found a remarkably close fit. If the Hoyt & Schatten reconstruction and our new Northern Hemisphere temperature trend estimates are accurate, then it seems that most of the temperature trends since at least 1881 can be explained in terms of solar variability, with atmospheric greenhouse gas concentrations providing at most a minor contribution. This contradicts the claim by the latest Intergovernmental Panel on Climate Change (IPCC) reports that most of the temperature trends since the 1950s are due to changes in atmospheric greenhouse gas concentrations (Bindoff et al., 2013).
Soon, Willie, Connolly, Ronan, Connolly, Michael, Re- evaluating the role of solar variability on Northern Hemisphere temperature trends since the 19th century, Earth Science Reviews (2015), doi: 10.1016/j.earscirev.2015.08.010
Copy of the prepublication PDF is SoonConnollyConnolly15-Sep4-ESRunformattedPreprint.