April 8 (Bloomberg) — A nuclear war involving 100 Hiroshima-size bombs would open a massive hole in the earth’s ozone layer, exposing life to dangerous levels of the sun’s rays, a new study shows.
Smoke caused by the atomic explosions would trap heat in the stratosphere and lead to the deterioration of more than 20 percent of ozone globally, according to a study published today in Proceedings of the National Academy of Sciences. The findings suggest a more severe “nuclear winter” resulting from a massive nuclear war than was predicted in the 1980s.
“There would be an ozone hole everywhere outside the tropics,” said lead author Michael Mills of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder. “The human health consequences would certainly be large increases in skin cancer and cataracts. The impacts could be greater on ecosystems.”
The study supports research published last year that said a nuclear conflict between Pakistan and India involving 100 Hiroshima-size bombs would cause enough smoke to cool the earth’s temperature to the dramatically lower temperatures, shortening growing seasons and rain levels in some areas.
“Although the risk of global nuclear war has diminished since the 1980s, the proliferation of nuclear weapons has produced greater risks of a regional nuclear conflict,” according to the study in Proceedings.
As ozone depletes, humans will more likely suffer from skin cancer, eye damage and other health problems because of higher exposure to the sun’s ultraviolet rays. Land and ocean-based plants also would be hurt, researchers said.
The atom bomb dropped by the U.S. on Hiroshima, Japan, in World War II killed at least 70,000 people instantly and destroyed two-thirds of the city. Three days later, the U.S. dropped a second nuclear bomb on Nagasaki, Japan, killing about 40,000 people. Tens of thousands more died from radiation exposure in the months following the blasts.
Using chemistry-climate models and new estimates of smoke levels that would result from fires in cities following a nuclear blast, the researchers from the University of Colorado, University of California and the National Center for Atmospheric Research concluded ozone levels would drop 20 percent globally, 25 percent to 45 percent at mid-latitudes and 50 percent to 70 percent at northern high latitudes. The depletion would last five to eight years, the scientists said.
A hypothetical nuclear attack between India and Pakistan would distribute soot around the globe and atmospheric temperatures would increase 30 percent to 60 percent, leading to the depletion of ozone, the study said. Meanwhile, temperatures on land would drop.