The organization's mission is to 'empower people to be leaders in protecting, restoring and enjoying healthy and safe ecosystems.

[20][21] The Ottawa-based Breath Easy program of the Ontario Chapter was responsible for providing air quality monitors to CBC News journalists during the Canada convoy protest, which showed that PM 2.5 air pollution levels (pollution which can have serious health effects and can make its way into people's homes) ranged from four to eight times higher than normal for the area.

[24][25] The Youth Chapter of the organization, based throughout the country, runs a podcast which has interviewed prominent Canadian political figures such as Elizabeth May, Laurel Collins, and Monique Pauzé.

The following list of milestones provides some of the campaigns that Sierra Club has been involved in, both in coalition with others and as a leading advocate.

2009 2008 2007 2006 2005 2004 2003 In 2003, Sierra Club Canada lobbied extensively to stop Canadian participation in the ITER project.