I really don't think it was that hard to prove. If you look up the injunction against the horns, it specifically cited the volume being well into what the law considered harassment. The fact that it was granted and extended shows that the judge felt the people of downtown as a whole were being harassed.
If you can get the majority of people to agree that they feel unsafe due to climate destruction and neither the municipal nor provincial governments respond accordingly, then, by all means, invoke the emergency act. I'd certainly be on board.