What is the general trend of climate change in the past 100 million years?

At the beginning of the 20th century, the famous German geologist Punk and his assistant carefully studied the geological data of the European Alps, and found that in the recent 600,000 years, this area experienced four cold periods and three warm periods. Generally speaking, the cold period is called the glacial period and the warm period is called the interglacial period. Punk's discovery is described as four glacial periods and three interglacial periods in the Alps.

Geology calls the last 2 million years Quaternary, and geologists who study the geological conditions of this period are called Quaternary geologists, and punk is one of them. At that time, geologists all over the world regarded Punk's research as a model. In Northern Europe, North America and Asia, they established four classical models of Quaternary climate change similar to Punk's research.

Then, naturally, someone will ask: Why have there been four ice ages in the past 600,000 years? In other words, why did the earth's climate experience four warm and cold alternation in 600,000 years? Besides, was there an alternation of cold and warm before this? And after that?

A Yugoslav scientist named Milankovic tried to answer the above questions. Milankovic's view on the changes of the three elements of the earth's orbit. He believes that if the earth's orbit around the sun changes, even if this change is small, it will change the amount of solar radiation received by the earth, thus causing climate change. As it turns out, his eyes are extremely keen.