The graphic above is from a PDF slide presentation by David Archibald. It provides a look at global temperatures and atmospheric CO2 levels over the past 600 million years. As you can see, modern CO2 levels are quite low compared with historical levels. If you go to the Watts Up With That posting of Archibald's slide show, you can see that modern temperatures are not particularly high in comparison with historical temperatures. You will also see that the correlation between temperature levels and CO2 levels is far from perfect.
geologic time scale as well as the temperature and CO2 curves.
The climate of Earth is not constant -- it is in fact chaotic. Climate is affected by orbital, solar, terrestrial, oceanic, and atmospheric phenomena, as well as by extra-solar phenomena. But it is kept within bounds by a complex system of feedbacks, both positive and negative.
When planning for the future, it is best to stay firmly grounded in reality, but to allow the imagination significant leeway within those bounds.
Unrealistic speculation and devious quasi criminal deceptions -- such as we see from the IPCC and climate grifters with their hands in the till -- should be slapped down as quickly and as hard as possible.