I know I've said this before elsewhere, but either Douglas Adams was a visionary or he could see into the future. In the second radio series of the Hitch Hiker's Guide to the Galaxy, there is a character called The Wise Old Bird who mentions that all the imprisoned robots from Brontitall's first plague are working to build "continent toupees" for planets that have used up all their forests.
Now today, we get an article hitting the news stands about more ideas to reduce the CO2 in the atmosphere using mechanical trees!
I must admit, the idea of artificially reducing the levels of CO2 in the atmosphere has its merit, but it has to be practical with no long-term side effects of it's own. The two main contenders are to reduce it by filtering it out and storing it in empty oil wells or by converting it with algae using photo-synthesis.
Not too keen on the first idea. this could just be saving up more trouble for future generations, who have enough to worry about already with global warming and another nasty man-made product of excessive energy consumption.... nuclear waste.