The greenies want to concentrate only on whether the climate is changing, but never get into how man is causing it, other than to say that the Indusrial Age is concurrent with climate change. This is a 'post hoc, ergo propter hoc' argument, and is all the proof they have. They choose to ignore the history of climate change, not the least of which includes waxing and waning of the Ice Age.
What about the data from NASA that shows that Mars, Earth's moon, and Pluto are also warming? What is George W Bush doing to warm those places?