Climate law has often been framed as a component of environmental law. Under this conception, environmental law and climate law are mutually supportive endeavours towards sustainable development. Yet, in a growing number of instances, climate action has been shown to undermine the protection of other environmental values, or even the enjoyment of human rights. For instance, hydroelectricity, often embraced as pro-climate, has been promoted as a source of (relatively) clean energy, but hydroelectric dams often have a significant negative impact on human settlements and river ecosystems. In other cases, the UNFCCC regime may be read as ‘giving up’ on some impacts of climate change, possibly in contradiction to certain states obligations on environmental protection. The author asks whether climate law is inevitably on a collision course with environmental law, or whether there exist credible ways to reconcile the objectives and operation of these two regimes.