Sudden temperature drop, not comet strike, behind extinction of dinos

Washington, April 24 (ANI): A sudden drop in global temperatures, and not a comet strike, led to the mass extinction of dinosaurs, according to a new research.

Scientists are now advising the constant monitoring of the present warning signs like influxes of fresh water into the North Atlantic, and slowdowns of the Atlantic Gulf Stream, lest the temperature shift may occur again.

While some theories blame the dinosaurs' extinction on an asteroid hit or volcano eruption, new research appearing in Nature Geoscience and the journal Geology, says climate was responsible.

According to the study, the greenhouse climate of the Cretaceous period experienced a sudden drop in world temperatures.

"We believe dinosaurs were most likely to be cold-blooded creatures and would have needed the warmth to keep them alive. If they were unable to migrate south, they could have been wiped out," Discovery News quoted Gregory Price of the University of Plymouth, as telling the Daily Mail.

"Climate change is now very much on the agenda in trying to determine how the dinosaurs became extinct," he added.

Scientists believe the first big Cretaceous temperature drop took place 137 million years ago and caused ocean temperatures to fall as low as 4 degrees centigrade.

Although it is difficult to imagine such a dramatic ocean cooling now, given global warming, climate change is said to cause extreme shifts of all kinds, from harsher than normal storms to this type of major ocean temperature shift.

Price and his team examined fossils for dinosaurs that once lived at Svalbard in the Arctic Circle.

This region during the Cretaceous was characterized by warm, shallow seas and swamps before the ocean changes took place.

Price said: "At certain times in the geological past, the world has been dominated by greenhouse conditions with elevated CO2 levels and warm Polar Regions, and hence, these are seen as analogues of future global climate.

"But this research suggests that for short periods of time, the Earth plunged back to colder temperatures, which not only poses interesting questions in terms of how the dinosaurs might have coped, but also over the nature of climate change itself."

Price and his team arrived at their conclusions after examining the Svalbard dinosaur fossils and those for giant marine reptiles like pliosaurs and icthyosaurs.

Price said: "The flourishing of the dinosaurs and a range of other data indicates that the Cretaceous period was considerably warmer and boasted a high degree of CO2 in the atmosphere.

"But over a period of a few hundred or a few thousand years, ocean temperatures fell from an average of 13 degrees centigrade to between eight and four degrees.

"Although a short episode of cool polar conditions is potentially at odds with a high CO2 world, our data demonstrates the variability of climate over long timescales." (ANI)