Back in 2007, I participated in a climate change fast. It seems an appropriate sort of moral gesture to make in response to the problem, given that it is highly likely that climate change will disrupt agricultural patterns and lead at least some people to suffer from hunger as a result.
This year, between September 21st and October 2nd, another fast is being held in response to climate change: A Fast and Vigil for Climate Justice. The main twelve-day fast will be happening on Parliament Hill. The organizers are calling on people to contact their elected representatives, asking them to take action on climate change and eliminate fossil fuel subsidies. They also encourage people to write letters to the editors of newspapers, and to participate in one day of the fast themselves.
There is a website where people can pledge their support for the event.
I was also sent this program for the event by one of the organizers.