Careers
Your standards of what is defined as "ruining a career" are a bit stiff. By this standard, Hansen has never been under any serious pressure since obviously he hasn't been silenced or kept from continuing his work.
I have already cited climate scientists who have been abused in the press and accused in public of being shills for energy companies and worse. Maybe you think this has no negative effect on a scientist since the scientist hasn't been fired or his work forcibly suppressed. They might think differently.