Solution

In 1987 an international meeting was held in Montreal to discuss the issue of CFCs. It was agreed that the emission of CFCs would be restricted. At another meeting in 1990 it was decided to phase out CFCs completely by 2000. Over 60 countries signed up and CFCs are now banned in most countries.

Even though CFCs are banned, it will be another 20 years until the atmosphere returns to a stable state. Chlorine and CFCs in the atmosphere take many years to destroy. In the image to the left you can see the largest ozone hole ever recorded, this was in 2006 well after CFCs had been banned.