Significant global climate change is inevitable. Tree species have a limited capacity to tolerate climate change or migrate through natural or artificial means. We do not know enough about the comparative resilience of forest-based, agricultural, marine or fresh water ecosystems. But it is clear that biodiverse forest ecosystems are under threat. And the threat extends beyond forests themselves. An estimated 60 million indigenous people are heavily dependent on the world’s rainforests. Some 350 million people live in or close to dense forests and rely on them for subsistence or income. A further 1.2 billion people in developing countries depend on trees on farm to generate food or cash.