The Ozone Layer GOALS: Explain how the ozone layer shields the Earth from harmful radiation. Describe how CFCs are damaging the ozone layer. What are impacts for a thinner ozone layer.

Ozone Layer Ozone Layer: An area of the stratosphere with high concentrations of ozone gas Acts like a sun screen blocking out UV rays Ozone = O3 Good ozone vs. Bad Ozone

Ozone Depletion Chlorofluorocarbons (CFCs) Man-made chemical “Miracle Chemical” Damages the ozone layer Takes a LONG time to get to ozone layer and destroys many ozone molecules

CFCs Used for decades Each CFC molecule can destroy 100,000 ozone molecules over decades

Ozone Hole Antarctic Ozone Levels

Impacts of Thinning Ozone Layer Damage to skin cells (including skin cancers) Damage to eyes UV Light damages DNA Kills phytoplankton (single-celled organisms) which are the base of most ocean food chains UV light damages crops

Wide Ranging Impacts

Protecting the Ozone Layer Montreal Protocol: international agreement in 1987 to phase out CFC usage Second conference in 1992 in Copenhagen WHY WILL IT STILL BE A PROBLEM FOR MANY MORE DECADES?

Section Review Explain how the ozone layer shields the Earth from harmful radiation. Describe how CFCs are damaging the ozone layer. What are impacts for a thinner ozone layer. OZONE DEPLETION IS NOT THE SAME AS GLOBAL WARMING!!! Exploring the Ozone Layer (video)