A new study has indicated that global warming 55 million years ago triggered a massive release of greenhouse gases into the atmosphere which led to a huge spike in temperatures.
Appy Sluijs, a paleoecologist at Utrecht University in the Netherlands, and his colleagues, carried out the study.
Evidence in support of this theory comes from the abundance and distribution of marine algae, which indicate that the environment started to change and the ocean surface began to warm several thousand years before the large temperature spike.
Scientists have long studied this ancient temperature spike, called the Paleocene-Eocene thermal maximum (PETM), for clues to what could happen as a result of today's global warming.
Research shows that during the PETM, global temperature shot up at least 9 degrees Fahrenheit (5 degrees Celsius), and swamp forests with redwoods and broad-leaved trees filled the Arctic.
But a key unanswered question here is that what triggered this substantial warming?
According to a report in National Geographic News, one theory is that the meltdown of methane hydrates—icelike deposits that store massive amounts of potent greenhouse gases in the seafloor—was responsible.
"According to the new study, pre-warming triggered the melt, releasing greenhouse gases into the atmosphere. Less clear is the nature of that pre-warming," said study author Appy Sluijs. "One possibility is a bout of volcanic activity that ripped Greenland from Europe," he added.
Today, Earth is also experiencing global warming, which scientists believe is largely driven by the burning of fossil fuels like coal and oil.
This warming could force a meltdown of hydrates on the seafloor as well, releasing methane into the ocean-atmosphere system.
"We really should know whether the carbon dioxide that's being added to the atmosphere now has the potential to generate some kind of unanticipated cascade of events," the journal quoted Wing, a Smithsonian biologist, as saying.