Printer Friendly

Did hurricanes blow dinosaurs away?

Pity the poor dinosaurs. Though the immense saurians and many of their neighbors disappeared from the planet 65 million years ago, scientists never tire of dreaming up ways to kill off the beasts.

The newest theory, proposed by Massachusetts Institute of Technology atmospheric scientist Kerry A. Emanuel and his colleagues, revolves around monster hurricanes called hypercanes. While studying factors that limit hurricane size, Emanuel recognized that tropical storms could, in theory, grow much larger than they do at present if ocean water warmed to 50oC, almost double current temperatures in the tropics. Ocean water does not get that warm under normal conditions, but a large meteorite impact into the ocean or a major volcanic eruption in shallow water could drive temperatures into the hypercane zone, according to simulations done with a computer model of the atmosphere, the scientists report in the July 20 Journal of Geophysical Research.

Therein lies the dinosaur connection. Emerging evidence suggests that a large extraterrestrial body hit the Gulf of Mexico at the end of the Cretaceous period, about the same time as the mass extinction recorded in the fossil record. The crash could have warmed water enough to spark a series of hypercanes that reached altitudes of 45 kilometers, well up into the stratosphere. Normal hurricanes top out at the base of the stratosphere, about 19 kilometers up.

Because of their height, the storms could have transported water vapor, ice particles, and dust into the stratosphere, where they would block out sunlight and decimate the life-protecting ozone layer, speculate the researchers. "The idea is a little far-fetched," admits Emanuel. "But I don't think it's so far-fetched as to be outrageously unlikely."
COPYRIGHT 1995 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1995, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Earth Science; "hypercanes" may have caused mass extinction at end of the Cretaceous period
Publication:Science News
Article Type:Brief Article
Date:Sep 23, 1995
Words:276
Previous Article:Weaving the cosmic web; bottom up or top down: now the twain shall meet.
Next Article:Missing carbon traced to northern lands.
Topics:


Related Articles
Diamonds not a dinosaur's best friend.
Dinosaurs' swan song: out with a bang.
Counting the dead.
Cretaceous die-offs: a tale of two comets?
A buried Iowa crater finally comes of age.
Oxygen-extinction theory draws counterfire.
Mud time line clarifies dinosaurs' demise.
Craters and extinctions: time of reckoning.
Chunk of Death-Dealing Asteroid Found.
Extinctions tied to impact from space.

Terms of use | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters