A limited nuclear weapons exchange between Pakistan and India using their current arsenals could create a near-global ozone hole, triggering human health problems and wreaking environmental havoc for at least a decade, according to a study led by the University of Colorado at Boulder.
The computer-modeling study showed a nuclear war between the two countries involving 50 Hiroshima-sized nuclear devices on each side would cause massive urban fires and loft as much as 5 million metric tons of soot about 50 miles into the stratosphere, said CU-Boulder Research Associate Michael Mills, chief study author. The soot would absorb enough solar radiation to heat surrounding gases, setting in motion a series of chemical reactions that would break down the stratospheric ozone layer protecting Earth from harmful ultraviolet radiation, said Mills.
We would see a dramatic drop in ozone levels that would persist for many years, said Mills of CU-Boulders Laboratory for Atmospheric and Space Physics. At mid- latitudes the ozone decrease would be up to 40 percent, which could have huge effects on human health and on terrestrial, aquatic and marine ecosystems.
A paper on the subject, titled Massive Global Ozone Loss Predicted Following A Regional Nuclear Conflict, appeared the week of April 7 in the Proceedings of the National Academy of Sciences. Co-authors on the study include CU-Boulder Professor Brian Toon, UCLA Professor Richard Turco and National Center for Atmospheric Research scientists Douglas Kinnison and Rolando Garcia.
According to the computer simulations, fires ignited in large cities by nuclear explosions would send several million metric tons of soot into the upper stratosphere, which would be heated by massive smoke injections. Higher temperatures would accelerate catalytic reaction cycles in the stratosphere, particularly reactions of nitrogen oxide gases known collectively as NOx that destroy ozone, Mills said.
|Contact: Michael Mills|
University of Colorado at Boulder