In an alarming revelation, scientists have found that the current carbon emissions have no precedent in 66 million years. The current rate is higher than at anytime in fossil records since the end of the dinosaur age. According to a study published in the journal Nature Geoscience, the current rate of emissions is even higher than the biggest known natural surge that occurred 56 million years ago.
Carbon emissions 10 times higher than the PETM
The rapid ancient warming known as the Paleoeocene-Eocene Thermal Maximum (PETM) was largely driven by the release of frozen stores of greenhouse gases in the seabed. During that period, an estimated 1.1 billion carbon was emitted every year for 4,000 years. It increased the temperatures by 5 degrees Celsius, making the oceans acidic. It damaged marine life because CO2 forms a weak acid in seawater, hindering the ability of various creatures to develop protective shells.
Lead author Richard Zeebe of the University of Hawaii said the current carbon emissions are about 10 billion tons a year. The United Nations projects that greenhouse gas emissions could increase global temperatures by up to 4.8 degrees Celsius by 2100 compared to the pre-industrialization era. It would cause massive floods, droughts, and powerful storms. Zeebe said the future ocean acidification will be far more severe than during the PETM.
The sixth great extinction underway
Researchers see the PETM as a parallel to the risks from carbon build-up in the atmosphere due to the burning of fossil fuels. There are striking parallels between the two: massive carbon emissions, followed by steep rise in global temperatures and major loss of species. Most of the extinctions during the PETM took place in the ocean. But the current “sixth great extinction” is underway both on land and in the sea.
Scientists studied the chemical makeup of fossils of marine organisms in the seabed off New Jersey to gauge the ancient warming. If carbon was released rapidly, there would be a lag with warming in the sediment core. But if it is released slowly, the climate adjusts in sync. Scientists found that there was no lag at all.