That being said, assume a 2 - 4 deg C increase in Global avg temp and a doubling of pre-industrial GHG by the year 2100. (realclimate.org)
If the sun enters such a sustained period of low solar activity again, it could dampen the global avg temp by between 0.1 and 0.4 deg (eg recent paper by Rahmstorf; KNMI climate science update). (ourchangingclimate.wordpress.com)
Interesting, but I don't see that it changes global avg temps enough to matter. (realclimate.org)