A quick reminder for you, the main arguments why green energy is so important:
1. Currently the western world is very dependent on oil and gas. Increasingly we have to import this from unstable and/or totalitarian countries like Nigeria, Libya, Iran, Venezuela and Russia. Our own oil+gas supplies are depleting fast. Most fields in the USA, Norway, Netherlands and UK are already long over their production peak and they are declining fast. Most gas in western Europe used to be from Norway and the Netherlands but in 20 years from now it will all be from Russia. This is bad for the western economy and political position so we simply need to consume less gas.
2. The greenhouse effect. I tend to believe scientists who claim that humans are creating a rise in temperature and sealevels because of burning fossil fuels. It is a fact that temperature has been rising sharply for the past 50 years and this is probably (though not certainly) linked to emission of carbondioxide. More windmills and less coal plants is the solution. (or nuclear plants??)
3. Air pollution is bad for our health so more electric cars - especially in big cities where it is proven that air quality is pretty bad mainly because of cars - can give a great contribution to clean air in cities.
4. Depletion of oil reserves. After the 'peak oil' production of oil will drop but demand will still remain the same or even rise, creating high oil prices and potentially civil unrest and shortages of electricity and gas. To prevent this chaos we need to convert to wind/solar/nuclear in time.
pic: solar plant in spain