Why is 500,000 years a good baseline, as opposed to say 100,000,000 years? How do we know whether a rising atmospheric CO2 level is bad? How do we know rising global temperatures are bad? After all, millions of species flourished, and even during the age of man people and crops thrived, when global temperatures and CO2 levels were higher than they are now.
When we begin ask the more fundamental questions it quickly becomes clear that mankind does not know anything like enough about how climate works to try to have global climate control policies. It's just ludicrous.