There is no question that it is being a green house gas...So 800 thousand years going from 160 to 300 ppm...Remember the 160-200 ppm happens during the ice ages as the ocean temperature went down they could store more co2...With the growing glaciers This my friends worked to compound the ice ages. The main forcing is the orbit around our star, so imagine the energy going down=decreased amount of energy into our oceans=oceans becoming better co2 stores=enhanced ice ages. Now the opposite occurs during interglacial periods in which co2 goes up to 280-300 ppm...This occurs because oceans warm becoming less abe to store co2, which forces them to release the co2 into the Atmosphere, which increases the co2 in the Atmosphere and causes the warm periods to compound and increases the rate of warming. On a shorter time span our climate is controlled by the sun spot cycles, which have cycles of 11, 22, and some believe even longer cycles. Mid evil warm period was a period of very warm weather and occurred during high sun spot activity. We had a short term ice age from 1300-1800 ad which occurred during a time of weaker activity of our sun... So we proved that the sun has a negative or positive forcing on our climate. We proved that the orbit of our planet has a effect on temperature of our planet and co2 moves up and down and may have a compounding effect on them. Now what got us out of the short term ice age that we where in? You got that right the strongest increase in sun spot activity in 2,000 years. BUT it peaked in 1950 and has been decreasing ever since. Between 1950-2000 it was decreasing! What does decreasing activity equal? decreasing temperatures. But we went up. Meaning there is a positive forcing, which is stronger then the negative forcing of the decrease in sun spot activity. To make things even more interesting the decade between 2000-2010 the suns activity has dropped into the crapper, 1910-1915 was the decade which had the lowest temperatures of the 130 years record period. Why? Because it had the lowest sun spot activity, which is much like todays. So that is a huge negative forcing on our planet and what do we find? A less but rising temperature of our planet. So if you think about it, every fucking year this goes on means a compounding. Meaning our temperatures should be decreasing at a ever faster rate, but what do we got...Read above. A stable or even a raise in earths avg temperature. So here we sit at 390 ppm going up 2 ppm per year within the weakest fucking sun spot cycle possible since the Dalton of 1810-1840 and we are warming, even so at a weaker rate of doing so. Screw 1998 that is .4c+ outside the norm...1998 was not normal and in fact was a monster that we may not see for another 50 or 100 fucking year...2005 was .3 outside the norm, but what be this year? Thats right...Not even .25c outside the avg baseline. So the enso has a effect on temperature and guess what most of this year was within a mother fucking nina that is stronger then 2008, 1999-2001. You would have to search back to the mid 70s to find a monster like where seeing now, but here we sit discusing the warmest or second warmest year of the 130 year record and quite possible the hottest year in 1,000 years. In people think co2 is not even a fucking green house gas? WTF? A warmer earth=more co2 which enhances the effect to...And add methane. Now we got something. Water vapor increases too for you water vapor people. In guess what more warming.