기왕의 연구에 의하면, 수나라 때부터 북송 초까지 거의 400년 동안 기후가 비교적 온난 다습하였으나, 이후 소빙하기에 접어들면서 남송 중기까지 약 200여 년간은 한랭하였다.
According to Kiwang's research, the climate was relatively warm and humid for nearly 400 years from the Sui Dynasty to the beginning of the Northern Song Dynasty, but it was cold for about 200 years until the middle of the Southern Song period as it entered the Little Ice Age.