The purpose of this white paper is to explore and communicate potential new opportunities for using space-based Earth observation (EO) for monitoring biodiversity with a focus on ecosystem extent (the distribution of ecosystems on the Earth). It is part of a new activity of the Committee on Earth Observation Satellites (CEOS), a collaboration of the world’s space agencies that facilitates cross-agency coordination of EO. This activity, now manifested as the CEOS Ecosystem Extent Task Team, is focused on increasing the CEOS role in biodiversity applications, initially using ecosystem extent as a vehicle for discussion and exploration of ideas. The audience is two-fold: CEOS Principals that represent their agency, and the biodiversity community with a particular focus on the Convention on Biological Diversity (CBD) and their Parties as well as the UN System of Environmental-Economic Accounting (UN SEEA).