The authors also find "solar activity may have contributed 40% or more to the last century temperature increase" and "For 3 North Atlantic stations we get 63–72% solar contribution [to the temperature increase of the past 150 years]. This points to the Atlantic currents as reinforcing a solar signal."
A co-author of the paper is geoscientist Dr. Ole Humlum, who demonstrated in a prior paper that CO2 levels lag temperature on a short-term basis and that CO2 is not the driver of global temperature.
Update: As pointed out by commenters at WUWT, this paper was published in 2012. For some odd reason it appeared for the first time in my RSS feed from the Journal of Atmospheric and Solar-Terrestrial Physics today and thus was incorrectly stated to have been published online today.