The Death of the Hockey Stick
But the fact is that the infamous Hockey Stick (made famous in the IPCC Third Assessment Report, Al Gore's fictional movie An Inconvenient Truth, not to mention literally thousands of alarmist publications) has been the foundation of virtually all alarmist climatology, demonstrating that the 20th century warming was unusually large and rapid, and that no other period in the last thousand years had been warmer.
But now that entire foundation has crumbled, with the revelation that the authors had selectively used tree-ring data in order to ensure that their temperature reconstruction showed unusual 20th century warming (see my earlier post on this here).
This is HUGE. Not only does it undermine a significant part of the alarmists' cause, it shows the lengths that apparently reputable climate scientists will go to in order to fit data to their pre-conceived agendas.
Blogger Bishop Hill has prepared an excellent summary of the whole sorry tale, including gory details of how the scientists in question continually refused to provide their data for independent analysis, until eventually forced to by the Royal Society (which is ironic, given their own alarmist stance on climate change).
I highly recommend it - read it here.