Going, going, gone: Sixth mass extinction on Earth by 2100, says MIT study
An MIT study says that our beloved mother Earth might face its sixth mass extermination by 2100 due to a significant increase in carbon emissions.
Earth has faced natural disasters like tsunamis, hurricanes and earthquakes but earth as an entity, and its inhabitants have survived it all.
But, we all know everything has an expiry date.
Earth has gone through five mass extinctions in the past 540 million years. These mass extinctions involved processes that turned the normal cycling of carbon through atmosphere and oceans upside down.
Daniel Rothman, professor of geophysics in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology and the co-director of MIT's Lorenz Center, came up with a study "thresholds of catastrophe" which shows that Earth might face its sixth extinction by 2100.
Mass extinctions were responsible for extermination of 95 per cent of the marine species around the world.
The carbon emissions are mainly responsible for such mass extinctions and have increased significantly in the 19th century.
WHAT IS THE STUDY ALL ABOUT?
In his study, Rothman analysed the five mass extinctions that occurred in the past 540 million years and the carbon cycles of the same.
He proposed his study on the basis of two thresholds, first, if the changes in carbon cycle occur for longer time frames and the rate is faster than global ecosystems can adapt.
Second, the carbon perturbations that take place over shorter time frames. The pace of the carbon-cycle changes will not matter, instead, the size of the change will determine the likelihood of an extinction.
Rothaman feels a sixth extinction will depend on whether a critical amount of carbon is added to the oceans. He also analysed that 310 gigatonnes carbon is required to lead Earth to its 6th mass extinction, which is likely to happen by the year 2100.
DOES THAT MEAN EARTH WILL SEE BEGINNING OF MASS EXTINCTION RIGHT AWAY?
According to Rothman, the entire process will take about 10,000 years. Ecological disasters like these cannot happen in a short span.
"If left unchecked, the carbon cycle would move into a realm which would be no longer stable, and would behave in a way that would be difficult to predict. In the geologic past, this type of behavior is associated with mass extinction."
WHAT HAPPENED DURING THE END-PERMIAN EXTINCTION?
Rothman also studied the end-Permian extinction, an ecological disaster in the history of Earth which wiped out 95 per cent of the marine species due to an increase in the carbon emission. And, that's when he decided to start the quest to explore the 6th mass extinction.
"How can you really compare these great events in the geologic past, which occur over such vast timescales, to what's going on today, which is centuries at the longest?" Rothman asks. "So I sat down one summer day and tried to think about how one might go about this systematically."
MATHEMATICS AND MASS EXTINCTIONS
Rothman derived a simple mathematical formula which helped him come to the conclusion that mass extinctions is on its way.
The formula was based on basic principles that related the critical rate and magnitude of change in the carbon cycle to the timescale that separates fast from slow changes. Rothman hypothesises that the formula should predict whether mass extinction, or some other sort of global catastrophe, should occur,
HISTORY VERSUS RESEARCH
Rothman searched through hundreds of published geochemistry papers and identified that 31 events in 542 million years witness an unavoidable change in Earth's carbon cycle.
For every event, which also includes the five mass extinctions, Rothman observed the change in carbon along with the duration of time. Rothman expressed in the geochemical record as a change in the relative abundance of two isotopes, carbon-12 and carbon-13.
The mathematical formula helped him convert these quantities into the total mass of carbon that was added to the oceans during each event. He plotted both the mass and timescale of each event.
"It became evident that there was a characteristic rate of change that the system basically didn't like to go past," Rothman says.
WHAT HAPPENS NEXT?
In July, a study published in the Proceedings of the National Academy of Sciences said that at least 50 per cent of the number of animals that once shared the Earth with humans are already gone, and that the next two decades would witness more powerful attacks on biodiversity.
"There should be ways of pulling back emissions of carbon dioxide," Rothman says.
"But this work points out reasons why we need to be careful, and it gives more reasons for studying the past to inform the present."
