A new study of Earth’s history found that humans are sending carbon into the atmosphere at the fastest rate ever. The study looked at a period of time 56 million years ago called the Paleocene-Eocene Thermal Maximum, or the PETM. During the PETM, a lot of carbon went into the atmosphere and caused global temperatures to rise very high. However, carbon is going into the atmosphere even faster today. Scientists believe it is important to study the PETM because it might give us clues as to how carbon emissions might be changing the world today.