Every year the world emits 51 billion tons of C02 carbon dioxide greenhouse gasses into the atmosphere with more than 84% of these emissions being caused by human activity. These molecules that we depend on everyday absorb and re-emit thermal radiation from the sun which causes them to escape into space more slowly. Because of this there is more warm air in our atmosphere which causes more frequent and more extreme weather.
(Here’s a paragraph to get you started.)
Talk about the areas affected for your second paragraph and call it a day.