In the video below Professor William Happer of Princeton University explains that more carbon dioxide, rather than being a threat to the continuance of life on earth, is actually needed for the sake of increased plant growth.
In addition to the fact that a rise in CO2 would increase crop yields, thereby helping to alleviate world hunger, the increase in temperature from more of this greenhouse gas follows a logarithmic scale. In other words if doubling CO2 concentrations increases temperatures by one degree then you most double it again in order to increase temperatures by another degree. So, the amount of warming which will occur becomes less and less the more CO2 one adds to the atmosphere.
Also, plants release water vapor (the primary greenhouse gas) in order to take in CO2 (their food) from the atmosphere. An increase in CO2 concentrations would decrease the use of groundwater by plants, by decreasing the amount of water vapor released by plants when pulling in CO2.
In addition as has been said elsewhere, there would be a greater reduction in cold related deaths than an increase in heat related deaths if moderate warming occurs (i.e. a couple more degrees)
What one realizes after watching the video below is that every effort to fight climate change which centers around decreasing CO2 will actually result in more deaths, do harm to the environment, increase the cost of living, and decrease the quality of life. Obviously we acknowledge that there are real pollutants which should be limited, the point is that CO2 isn't a pollutant, it's plant food, and limiting it is a self-destructive effort.
Watch this video for the source of many of the arguments made in this article.