As we move into the final week of the Season of Creation, Jesus’ choice of imagery and his message about dramatic action are especially pertinent. As Pope Francis declares in his encyclical Laudato Si’, climate change is an imminent threat to our world. For Christians, this raises two issues directly relevant to this passage from Mark. On the one hand, we have a duty to protect ourselves and each other from catastrophe by checking our own sinful behaviours and habits. We should seriously consider what we can do to reduce our reliance on fossil fuels through personal usage, investment options, and political choices. We cannot dodge responsibility on this issue. Our faith demands action. On the other hand, we also have a duty to find common cause with everyone else who shares this concern. Pope Francis encourages us to work with people of other religions ‘for the sake of protecting nature, defending the poor, and building networks of respect and fraternity.’ When it comes to protecting our common home, ‘Anyone who is not against us is for us.’