Ecosystem transformation and climate change evolve over long time scales. The effects of the economic decisions on the natural environment are also of a long-run character because they relate to investment decisions and capital stocks. At the same time, the economy is short-sighted and subject to different kinds of market failures. The time it takes to notice the changes and adequately address the associated problems affects the dynamics and inertia of the process. We discuss some recent contributions and new research questions that deal with time and timing in environmental and resource economics.