Scientists believe there have been five mass extinction events on Earth over the past 540 million-odd years, the latest being just 250 million years ago, which wiped out 95 percent of all life on the planet.
Understanding the causes that led to these events are crucial, especially seeing as those same scientists believe we¡¯re headed for another mass extinction very soon.
A new paper published in Science Advances suggests that a mass extinction event, similar to ones our planet has undergone in the past, is imminent, and all because we can¡¯t stop polluting the planet.
Every one of these past events has occurred at a time when the Earth¡¯s carbon cycle was interrupted. This is the process by which living things release carbon dioxide into the air, and plants subsequently recycle that through photosynthesis. But while there may have been natural factors interfering with this cycle in the past, this time we¡¯re to blame. Basically we¡¯re overloading the cycle by pumping way too much CO2 into the our environment way too fast.
We could trigger a mass extinction event when he hit a certain threshold of carbon in the oceans, home to most of our animal and plant life ¨C 310 gigatons. According to the paper, we¡¯re currently on track to cross that upper limit by 2100, entering into ¡°unknown territory¡±. What that means is, once we cross the threshold, there¡¯s no knowing what will happen, except that it¡¯ll be catastrophic for is.
In the past mass extinctions have been set into motion over the course of thousands or millions of years. Our reckless actions however, have sped the process up to mere centuries. Because of that, scientists can¡¯t really be sure of how such an event will progress.
According to MIT¡¯s Daniel Rothman, the lead author on the paper, every mass extinction coincides with a disruption to the carbon cycle. However, he also points out that it¡¯s not necessarily a defining factor, as there have been periods in our planet¡¯s history where the cycle was disrupted by most living things didn¡¯t die.
He says that, if the carbon cycle is disrupted over a long period of time, a mass extinction will follow depending on how fast the change is. If our ecosystem can adapt, we can survive. With more sudden changes in the carbon cycle however, it doesn¡¯t matter how fast it changes bu t by what magnitude.?
As such, Rothman derived a mathematical formula to calculate the danger, a Doomsday Theorem, if you will. Then he studied 31 disruptions to the carbon cycle in the last 542 million years, and was able to find the threshold the carbon content in the oceans stayed under during each incident, when they didn¡¯t cause species to die out.?
However, we¡¯re on track to easily cross that threshold in the next 80 years or so, unless some major changes are made soon. In fact worst-case predictions say that, by the year 2100, we¡¯ll have put 500 gigatons of carbon into our oceans .
People won¡¯t wake up the morning of the first day of 2100 and begin dying off. It¡¯s just that events will have been set in motion by that time that will eventually cause our demise. And by that point, it may be too late to fix anything.