Scientists have recently hypothesized that the majority of mass extinction events were the result of climate change, not directly caused by catastrophic events such as an asteroid collision.
There have been five separate mass extinction events identified by scientists. The most recent, known as the K–T extinction event, wiped the dinosaurs off our planet. Previously, it was thought that this mass extinction was caused by a massive asteroid collision, which cooled the climate and increased Earth’s albedo. The other four mass extinctions are thought to be directly caused by climate change.
One source of evidence is the bouquet-like crystals of aragonite formed on the ocean floor during two separate mass extinctions, 250 and 200 million years ago. USC doctoral student Sarah Greene suggests both events experienced similar processes, resulting in the mass killing of ocean coral reef populations.
“The fact that these deposits have only been found at these two specific times associated with mass extinction suggests at the very least, that maybe there’s some shared ocean geochemistry that could be related to the cause of the extinctions,” says Greene.
These are only a few examples of how climate change can affect life forms on Earth. According to the 2007 Intergovernmental Panel on Climate Change report, human activities are “very likely” to be the cause of today’s rapid climate change rates. We are gambling with the future of Earth’s species, knowing that climate alterations have resulted in mass extinction events in the past. Yet there is no consensus on how to slow down the rate of climate change.
World-renowned biologist E. O. Wilson emphasizes the devastating loss of biodiversity. “The loss of biodiversity is the most important process of environmental change,” he says. “This is because it is the only process that is wholly irreversible. Its consequences are also the least predictable, because the value of the earth’s biota is largely unstudied and unappreciated.”
