Humans are releasing carbon 10 times faster than during any point in the past 66 million years, according to a study published online on March 21 in the journal Nature Geoscience. The study’s researchers from the University of Hawaii – Mānoa School of Ocean and Earth Science and Technology (SOEST) say the rate that carbon is released into the atmosphere and oceans places the world in uncharted territory, the most dramatic global change since the end of the age of the dinosaurs.
Scientists previously believed that a climate event 56 million years ago called PETM or the Palaeocene-Eocene Thermal Maximum had the highest carbon release in history. However, based on the researchers’ new analysis technique, PETM’s carbon release was actually smaller than the current human-driven carbon release into the atmosphere.
The researchers estimated the speed of carbon release, the speed of the Earth’s warming by studying the chemical and biological properties of PETM sediment cores with quantified simulations of the carbon cycle, and the Earth’s climate. This new approach enabled the team to extract sediment record change rates without using a sediment age model.
Apparently, the input of carbon has reached an all-time high in 2014, about 37 billion metric tonnes of carbon dioxide in the atmosphere. Meanwhile, the carbon release rates during PETM were only one-tenth of that estimation or about four billion metric tonnes of CO2 annual release.
“Because our carbon release rate is unprecedented over such a long time period in Earth’s history, it also means that we have effectively entered a ‘no-analogue’ state,” says Richard Zeebe, a professor at the university. “This represents a big challenge for projecting future climate changes because we have no good comparison from the past.”
The researchers cannot predict how massive amounts of CO2 emissions will affect everyone. They are continuing their research about PETM to gather more insight about the long-term changes in the Earth’s climate.
The team is also studying other global events such as ocean acidification and its consequences for marine life during PETM. This could help scientists predict the effects of current ocean acidification and help us prepare for the worst.