For the moment, ignoring whether or not we can change the global climate, completely ignoring the CO2 and anthropogenic warming argument, what would be a good global temperature? Russian President Putin once said that global warming was a good thing because then they could grow crops in Siberia. The rest of the international community was pretty mad at him and threatened sanctions. He was quiet after that. This graph of ocean sediment from 5.5. million years http://en.wikipedia.org/wiki/Temperature_record#mediaviewer/File:Five_Myr_Climate_Change.svg shows what the global temperature was during earlier years of homo sapiens. We've been here 6-8 million years. That graph shows temperatures about 1-2 degrees Celsius above present. This site http://www.skepticalscience.com/global-warming-positives-negatives-advanced.htm shows IPCC report of postulated pros and cons of increased temperature over that of 1980-1999. What are the pros and cons of decreased temperature from 1980-1999?