What was the weather like during the cold period of the earth 300 years ago?

I'm not sure, but some people say that the demise of China in the Ming Dynasty was due to social unrest caused by the drastic reduction of agricultural production in the Little Ice Age 300 years ago, otherwise it would not be the Dalai Lama's turn to enter the Central Plains.

The cold climate, reduced agricultural production and relatively cold winter have caused many animals in the grassland to freeze to death, which has led nomadic people to plunder the Central Plains materials south to solve their urgent needs.

1. First of all, there is no direct evidence that human emissions of carbon dioxide have directly caused the current global warming (humans can't change the climate on a large scale without using radioactive weapons), but it is definitely a factor of global warming.

2. At present, the sun is in an unusually active period. At present, the sun has been measured for 9 years, 1 1 year, 25 years, 88 years and 146 years, and the sun is in the most active stage since 2000. Perhaps this is the direct cause of global warming.

3. After global warming:

First, polar glaciers melt and sea level rises (Greenland ice shelf melts, sea level rises by 3-5 meters, Antarctic ice shelf melts, sea level rises by more than 60 meters). New york, Shanghai and other cities around sea level were flooded.

Then, due to the smaller temperature difference between the poles and the equator, the Pacific Rim airflow and the North Atlantic warm current disappeared, and the winter temperature in northern Europe, western Europe and eastern North America became unstable and the climate was dry. East Asia and South China will be controlled by Mongolian high pressure in autumn and winter.

Finally, the hysteresis of polar glaciers melting and absorbing a lot of heat began to appear, the global temperature dropped sharply, a lot of fresh water rushed into the ocean, the salinity of the ocean decreased, the temperature control system was destroyed, the specific heat ratio of the ocean and the land gradually became the same, and typhoons began to form on the land. Moreover, due to the small temperature difference between different places, typhoons can exist for more than a month, and super typhoons will blow down the air in the stratosphere at MINUS 170, indicating the coming of the ice age and the destruction of the global atmosphere and ocean circulation.