I don't know about the tax credit, but I've said to friends and other forums what if the warming spell was only temporary blip that happens time to time and has been recorded for hundreds of years, and why is no one is considering the 2 billion year history of the Earths climate which shows that the Earth spends most of it's time in the tropic zone were there is no ice on the poles so what if we're heading back to the tropic period? Interesting article: http://scotese.com/climate.htm
As far as heading back into another ice age, it's entirely possible, just as it's possible we could be heading back into the tropic age. Scientist don't know everything, their guessing base on the data they have, and if they did know everything there was to know about predicting climate and weather then why is it they can't even get tomorrow's weather right all the time? And a weather report a week out is hit and miss! Yet we're suppose to believe that they can tell us what the weather will be like in 10 or 20 years? I have a difficult time swallowing that.