Around 30% of Earth’s land surface is covered by forest. It is estimated that this precious forest is home to around 80% of biodiversity on land, and tropical forest alone produces over 40% of the oxygen we breathe. We depend on forests for our survival, from the air we breathe to the wood we use. Forests also offer watershed protection and prevent soil erosion. After oceans, forests hold the world’s largest store of carbon and so help to regulate the climate. Even given huge importance of forests to the health of our planet and to all its inhabitants, it has been calculated that, on average, 200 sq km of forest is lost every day. The Biomass mission will measure forest biomass, height and disturbance to address gaps in our knowledge of the carbon cycle. It will deliver data with the resolution and accuracy needed for international reporting on carbon stocks and terrestrial carbon models. Biomass’ observations will also lead to better insight into rates of habitat loss, and the impact this may be having on biodiversity in the forest environment.