Global warming is not solely a modern-day occurrence but has been a prominent feature of Earth’s geological history for millennia. One such event occurred approximately 40 million years ago, lasting ~400,000 years, known as the Middle Eocene Climatic Optimum (MECO).
Click here for original story, Clay formation prolonged global warming event 40 million years ago, according to new biogeochemical model
Source: Phys.org