Question: If thousands and thousands of the world's climate scientists truly believe that developing the tar sands will make the world uninhabitable, why is only one climate scientist registered for this month's planet-saving White House tar sands protest?

Climate [junk] scientist willing to face arrest at tar sands pipeline protest | Environment | guardian.co.uk

Climate scientist Jason Box says oil sands are a moral issue that he feels compelled to address at Keystone XL pipeline protests
...as of mid-week he's evidently the only climate scientist who has registered to join about 2,000 other like-minded thinkers to line the fences surrounding the White House — where peaceful arrests are not uncommon for protesters of all stripes.
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Climate scientists have already done their homework, Box emphasized, adding that the results are irrefutable.
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Box sees no reason why he can't maintain his professional scientific credibility while making a foray into activism.

He said some of his fellow scientists already have complimented him for signing the letter and for deciding to travel to the Washington protest. His impression is that he won't be shunned by a community that's becoming more vocal about its convictions.
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Yes, he admits to being a bit apprehensive about being confronted by climate deniers who might accuse him of being part of a vast Al Gore conspiracy. But he's not worried enough to cancel his September flight.
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"I feel I'm on the high ground defending this position and that I have reason on my side," he continued. "The question is, will anybody listen?"

Hansen Says Development Of Tar Sands Would Mean “Game Over For Climate”

James Hansen, says klimaretter, warns of these “fatal” consequences. Klimaretter quotes the eccentric NASA scientist:

The known climate scientist James Hansen emphasizes that the extraction of tar sands would increase the CO2 concentration in the atmosphere by 50%. ‘When the development of the tar sands continues, then it means “game over for the climate,’ says Hansen.”