Jeremy Grantham: Climate change, population pressure, and toxicity: the threat to biodiversity. We are as you probably know by now the sixth great extinction, the rest were caused by meteorites and great shifts in the climate caused by the sun. This one is caused by us, we the people. Toxicity effects humans, also. In the developed world, over 50% loss of sperm count and no one is concerned. This is a meta study of 200 individual studies, it's hard to imagine how they could get that wrong. In China, coming from way behind us, they have a 25% loss in the last 15 years. Will we worry at 75%? How about 87%? This very well may be why the fertility rate of the Western world is dropping. Older age of marriage and less effective.