In 1989, representatives of many countries signed a treaty called the Montreal Protocols to protect the ozone layer. Use the Web to learn of the current status of the treaty. How many nations have...

In 1989, representatives of many countries signed a treaty called the Montreal Protocols to protect the ozone layer. Use the Web to learn of the current status of the treaty. How many nations have signed it? Has the treaty been amended? If so, how? List when various substances that destroy the ozone layer are being phased out.