Scientists recently confirmed the Amazon rainforest is now emitting more carbon dioxide than it absorbs, due to uncontrolled burning and deforestation. It brings the crucial ecosystem closer to a tipping point that would see it replaced by savanna and trigger accelerated global heating. This is not an isolated example of nature being damaged at a mass scale. The Intergovernmental Panel on Climate Change this month confirmed global heating is now affecting every continent, region and ocean on Earth. That includes Australia, which is a global deforestation hotspot and where the Great Barrier Reef is headed for virtual extinction. In the face of such horrors, a new international campaign is calling for “ecocide” – the killing of ecology – to be deemed an international “super crime” in the order of genocide. The campaign has attracted high-profile supporters including French President Emmanuel Macron, Pope Francis and Swedish activist Greta Thunberg. Making ecocide an international crime is an appropriate response to the gravity of this harm and could help prevent mass environmental destruction. But whether it does so will depend on how the crime is defined.