How would a Solar Grand Minimum affect global warming?
peer-reviewed research has examined this very scenario, "On the effect of a new grand minimum of solar activity on the future climate on Earth" (Feulner & Rahmstorf 2010). What they found was even if the sun fell into a grand minimum, global temperature would be diminished by no more than 0.3°C. The sun is not our get-out-of-jail-free card.
For both the A1B and A2 emission scenario, the effect of a Maunder Minimum on global temperature is minimal. The most likely impact of a Maunder Minimum by 2100 would be a decrease in global temperature of 0.1°C with a maximum reduction of warming by 0.3°C.