· Global warming means an increase in the earth’s average temperature. It is caused mainly by an increase in greenhouse gases. Global warming is a global (not local) problem and is mainly a global climate change
· Global warming is a different problem from ozone depletion. The so-called “ozone hole” is caused by the release of chlorofluoro- carbons (CFCs), which break down the ozone layer. CFCs, are implicated in global warming, too. But their main impact is destruction of the ozone layer.