300part per million max for co2 over past 400,000 years. 1912 was the rst time in 420,000 years we went over 300 parts per million. Increase was not that long after the industrial revolution. 40-60% of increase in temp, due to humans. Since 1861, average global temperature of troposphere risen 0. 74 degrees celsius. These are measured in troposphere, therefore changes in solar radiation isn"t contributing-->if it was solar, there would be changes in every other atmospheric level. The more you decrease re ective surfaces (albedo), less re ection, more warming. Air pollutant: anything at a high enough concentration that it will cause harm to organism and materials. Changes in climate change precipitation and temperature, change where we can grow food. Greatest increase over such a small amount of time. There is a temperature at which co2 stored in ocean begins to be released. Also, even though co2 in ocean helps troposphere, damages oceans.