MWP & LIA caused by changes in solar activity

Solar activity proxies show the MWP & the LIA in Japan and China as follows:

Chart above: Kitagawa, H. & Matsumoto, E., Geophysical Research Letters, Vol. 22, 2155-2158, 1995

Graphic above: Quansheng GE. et al., Advances in atmospheric sciences, Vol. 34, 941-951, 2017.
There are hundreds of other proxies worldwide that support solar activity as the main climate driver.