Originally Posted by skeptic-f";p=&quot

If you don't believe man can have that great an impact on the planet, how do you explain northern Africa? Historically the Sahara was much smaller and the coastal areas of north Africa were much more productive and species diverse than they are now. If the activities of pre-industrial humans was sufficient to make that great a change in that area, why is it so hard for you to understand that industrial-age humans can have a much greater impact?