Burning fossil fuels like oil and coal is causing global warming. If we limit how much we use these fuels, we can keep the amount of CO2 in the air from getting too high. By using less coal and unconventional fuels, and by being more efficient with oil, we can prevent CO2 levels from going above 450 parts per million by 2100. To do this, we need to stop using coal power plants without capturing the CO2 they produce. We also need to raise the cost of emitting carbon to discourage using up all our fossil fuels.