text: We need to do something abut the human population on earth. There's over 7 billion of us right now (emitting millions of tons of CO2 each year) and, according to the UN, by the end of this century there will probably be 12 billion of us (almost certainly collectively emitting more CO2 than we are right now).
  
  It's unfortunate that global population very rarely features in the debate about man-made global warming.