Global warming is where the earth is heating up from the depletion of the ozone layer. Because of this, the earth's glaciers will melt and the ocean temperature will rise causing parts of the earth's land to go underwater and creating really dangerous hurricanes like hurricane Katrina. The average temperature will begin to rise and it because there is a hole in the ozone layer it lets in harmful rays from the sun that can cause skin cancer. The main thing that is causing global warming are fossil fuels. They pollute the earth and release greenhouse gases such as carbon dioxide and methane. Here's a couple resources.