Two different climate change scientists at opposite ends of the political spectrum have backtracked on their positions in the last couple of days, indicating that Al Gore's method of simultaneously scaring and inspiring everybody with graphs, while effective, might not be sustainable.

On Monday, Edward Wegman, the leading critic of that famous "hockey stick" graph, which shows a sharp uptick in atmospheric carbon dioxide in recent years (and which plays a key role in An Inconvenient Truth), had his paper retracted because much of it was plagiarized. Then today Robert Socolow, who came up with those "wedges" that Gore uses at the end of his film to demonstrate that the problem is surmountable, said he regretted making the solution seem so simple

Those inspired by the theory took it farther.  If Socolow's wedges could stabilize emissions with a 3-degree rise, they said, even bigger wedges could actually bring greenhouse gases back down to a level resulting in only a 2-degree rise. (This is the goal that 140 nations have pledged to try to achieve in the Copenhagen Accord.)

"Our paper was outflanked by the left," Socolow said.  But he admits he did not protest enough: "I never aligned myself with the 2-degree statement, but I never said it was too much."

The two stories aren't necessarily analogous--one's about plagiarized research and the other's about a regrettable demonstration of data--but they both highlight the difficulty of getting hard, scientific facts into the debate on humans' effect on climate change and our approach to curbing it. In fact, scientists pretty much agree that the world is getting warmer, and humans are to blame, but demonstrating that proves a continuous challenge.