The Cenozoic Era experienced a variation of climates. It went from Ice Ages to Global Warming.
For parts of the Cenozoic Era the climate was much warmer than it is today, but for other parts of the Cenozoic Era it was much colder because of the ice ages. The Earth started cooling about 50 million years ago . In this time period there was a develop of glaciation in the Antarctica about 35 million years ago. As the effect of the glaciation there were created geologic records like the creation of predominantly unconsolidated tills and glacial moraines. As a result, Illinois, Ohio, Long Island, and New York were created. Also, the creation of ice bergs happened in this time period.
The most change happened at the end of the Cretaceous period. It had a broad change in climatic variation caused by the global warming and then cooling. In this period the Earth experienced extreme warmth and extreme cold.