Yet the oceans, forests, and grasslands of the world were thriving at this level which gave rise to human civilization. At current levels, none of that is true.

The grand solar minimum resulted in about a 1 degree (c) temperature decrease. If humans ever stop burning fossil fuels, the resulting loss of atmospheric particulates (which shade the planet and reduce temperatures) will more than overcome such small changes.

Perhaps our solar cycles won't follow recent patterns, if we're lucky. Oceans will still be acidified even if temps drop. Last time I checked about 7 years ago, record highs outnumbered newly recorded record lows by a factor of 11:1.