Now Here Is An Idea For All Of The Greenies And Tree Huggers,

that bang on about greenhouse gases and carbon footprints,

 whatever they are, offset your cars carbon footprint by using the unused space on the roof to grow grass,

the grass would absorb the carbon dioxide that it produces then we would all be saved, so greenies and tree huggers drive to the garden centre today, buy some grass seeds and plant the car roof, you know it makes sense!