I am extremely dubious that a) there is any meaningful increase in global temperatures beyond typical swings seen forever in the earth’s temperature record or b) that human releases of CO2 are responsible for any increase that does exist. The earth’s climate system is extremely complex and poorly understood, particularly in regard to multiple feedback mechanisms. The chart below shows the long-run relationship between temperature, as reflected in the longest-running actual thermometer record from England, and CO2 levels. You see the green arrow with the temperature trend (imagine the urbanization heat effect contribution to this trend) and you see the much sharper rise in CO2 levels. Clearly no linear relationship or probably any relationship at all.