A study of the ancient world has revealed something remarkable about the possible future of our planet. Roughly 56 million years ago, a large release of greenhouse gases, likely spurred by volcanic activity, caused a period of sudden global warming known as the Paleocene-Eocene
The latest findings, reveal that there was an extra transient rise in atmospheric CO2 immediately before the PETM, which resulted in a brief period of ocean acidification and warming. Crucially, the amount of carbon released into the atmosphere during this precursor event was roughly equal to the current cumulative carbon emissions from fossil fuel combustion and other human activities.
The PETM is an important geologic climate event because it is one of best comparisons to current climate change and can help inform us how the Earth System will respond to current and future warming. The new findings are based on an investigation of marine sediments deposited in shallow waters along the United States’ Atlantic coast. Since sea levels were higher during the PETM, and parts of Maryland, Delaware, and New Jersey were under water at the time, the researchers chose sediment cores drilled from this location for the study.
The PETM is identified in marine sediments by a dramatic shift in carbon isotope composition and other indicators of severe changes in ocean chemistry caused by the absorption of large amounts of CO2.