Considering the less variable solar reconstruction shows such strong agreement with past temperature, the authors conclude the most likely impact of a Maunder Minimum by 2100 would be a decrease in global temperature of 0.1 °C. (skepticalscience.com)
Putting aside papers where Soon was only a minor contributing author, and the hopelessly slanted «forecasting principles» papers with Green and Armstrong (see here for why they add nothing to the discussion), most of Soon's work has been related to finding correlations of a very specific solar reconstruction (see figure below) to some observational time - series. (realclimate.org)
However, Stott et al. (2003b), using the same solar reconstruction but a different model, are not able to completely rule out the possibility that solar forcing might have caused more warming than greenhouse gas forcing over the 20th century due to difficulties in distinguishing between the patterns of response to solar and greenhouse forcing. (ipcc.ch)