It's big. It's scary. But it's not unstoppable. To fight something you have to understand it first and global warming is no different.

Global Warming 101 The main cause of global warming is the carbon dioxide released when we burn fossil fuels like oil and coal for energy. Right now, fossil fuels are our primary energy source. The U.S. is responsible for a quarter of the world's CO2 pollution because of our fossil fuel habit - even though we make up just 4% of the world's population.

One of the easiest ways to fight global warming is to cut back on energy use - even small changes make a difference. After you start conserving, try looking into renewable energy. From wind power to biofuels, it's much more than the latest environmental trend.

Watch Climate: A Crisis Averted and imagine the future of global warming

Renewable energy goes from green to mainstream

Not even 2% of our power comes from renewable energy. Find out what fuel we are using

Your car can run on fuels made from plants OR vegetable oil