Computer simulations run by scientists at the Planetary Science Institute in Tucson have revealed that if an asteroid 500 m to 1 km in diameter were to hit the Pacific Ocean, it would eject enough water vapor and sea salt high enough into the atmosphere to affect the protective ozone layer.

The scientists say the water vaporwould contain chlorine and bromine from the vaporized sea salts, and this would result in significant global depletion of the ozone layer by destroying it faster than it is created naturally. Such an asteroid would produce “an ozone hole that will engulf the entire Earth,” and produce a huge spike in ultraviolet (UV) radiation with levels higher than anywhere on the surface today.

Other effects would include increased rates of skin cancer and cataracts. People may also have to remain indoors during the daylight to avoid serious sunburn.