The debate about global warming is about the outcome of a gamble. We are betting that the benefits of our industrial and agricultural activities--increasing standards of living for the rich and poor alike--will outweigh possible adverse consequences of an unfortunate by product of our activities,an increase in the atmospheric concentration of green house gases that could lead to global warming and global climate changes.Some experts are warning that we are making poor bets, that global warning has started and that disasters are imminent.