However, it would force people to do something. Restricting supply increases price, and thus alternatives/efficiencies become more viable.

An effective climate preservation campaign would focus on production facilities - coal mines, oil rigs etc. Not necessarily directly - for example the best way to shut down North Sea oil production would be to make it impossible to fly helicopters out there - protest airfields, helicopter maintenance depos, protest to the pilots, disrupt the logistics. Of course this then becomes a national security threat, and would be dealt with accordingly.