The distinctive global warmings during the modern era and the Medieval Period share similar causes - our solar system's sun, per China's climate scholars...
Researchers around the globe continue to build on the mountain of scientific evidence that the Medieval Period had warmer temperatures than the modern era.
And the evidence for a powerful solar influence on temperatures and climate change is substantial and growing.
====> "Here we present [Editor: Chinese scientists] decadally-resolved, alkenone-based, temperature records from two lakes on the northern Tibetan Plateau. Characterized by marked temperature variability, our records provide evidence that temperatures during the MWP were slightly higher than the modern period in this region. Further, our temperature reconstructions, within age uncertainty, can be well correlated with solar irradiance changes, suggesting a possible link between solar forcing and natural climate variability, at least on the northern Tibetan Plateau."