HOW DID THE DINOSAURS DIE?
Dinosaurs have always been mankind’s favourite extinct animals. Stories and pictures abound about how the great reptiles ‘ruled the planet’ before the arrival of man. The extinction of the dinosaurs is seen as a seminal event in the arrival of mammals. This article asks the question again, and gives some answers unearthed by new research.
Ever since Steven Spielberg captured our imaginations with Jurassic Park, humans have been fascinated with dinosaurs, and especially their story of extinction to a meteor impact, which brought an end to the age of the great reptiles and ushered in the countdown to mammals, and eventually to man himself. Every once in a while, therefore, a new theory emerges that attempts to answer the question of how exactly did the dinosaurs die. Here’s the latest answer.
Evidence is mounting that the meteor impact was not the only reason for the extinction. In fact, the extinction of dinosaurs happened not as a swift process but as a long, grinding, torturous slide in response to climate change, both before and after the impact.
The comet or an asteroid is believed to have hit the Earth around 66 million years ago; yet, as many as ten of the 24 species have been found to be extinct before this event. After the event, the other 14 died in a second extinction wave due to events set in motion with the impact.
Nearly half of all life on Earth – including all non-avian dinosaurs – were wiped out.
There are two periods of global warming that came about around this time, one due to the impact and two due to massive volcanic eruptions in the Deccan Plateau of present day India. These two climate change events constituted a ‘one-two punch’ which knocked out the dinosaurs and reset the evolutionary clock for the rise of mammals.
Whether these two events were related or independent of each other is still debated. What is definitely known is that the current ice-covered continent of Antarctica was likely covered by a coniferous forest around 69 million years ago, where volcanic eruptions caused a temperature rise of around 7.8 degrees Celsius.
In this model, the accepted narrative is that pre-impact global warming, caused by volcanic activity increased the stress level of the ecosystem, and the impact came along to ‘snap the stretched rubber band’. This is being called the press and pulse mechanism, where long term climactic changes ‘press’ the environment and increase pressure, where a ‘pulse’ event like an impact releases all the energy and causes a large catastrophe.
In today’s world, scientists warn that global warming caused by humankind’s burning of fossil fuels is contributing to another mass extinction event, the sixth in half a billion years.