LIMITS TO GROWTH: A “healthy” economic growth rate of 4% per year  corresponds  to  an  increase  by  a  factor  of  50  in  a  century,  by  a factor of 2,500 in two centuries and 125,000 in three centuries.  No one can maintain that resource-using, waste-producing economic activities can continue to grow except by refusing to look more than a certain distance into the future.