It's all fine to protest but we have to find out if he took yet another leave of absence to engage in advocacy work. If climate scientists want to be regarded as trusted guides for complex science issues, they need to stop being kooky shills. Hansen goes to all of these things because he leverages the NASA brand - he isn't a climate scientist by degree, he is an astrophysicist.
Environmentalists oppose the Keystone pipeline project because they would apparently rather continue giving money to misogynist, human rights-violating dictatorships than add 120,000 jobs in North America and have fewer greenhouse gas emissions by lowering transport needs significantly.
A State Department report last week said that the pipeline across six U.S. states to carry oil from Alberta, Canada, to the Gulf Coast has low environmental risks provided TransCanada complies with U.S. law and follows recommended safeguards. A final decision will be made by Secretary of State Hillary Clinton this year, based on whether the project is in the U.S. national interest.
More: NASA’s Hansen Arrested Outside White House at Pipeline Protest - Mark Drajem, Bloomberg