CO2 is the mayor culprit when it comes to climate changes. The IPCC – Intergovernmental Panel of Climate Change - estimates a rise of the average temperature at 2-4 degrees in this century, if we do not change behavior. It means that the ice at the poles will melt and that the sea level will rise about 0,2 – 0,6 meters during the next 100 years. If this development is to be curbed we have to reduce the emissions of CO2 – we must - in other words – save energy.