The Condition and Trends Working Group assessed the changing conditions of ecosystems and their services, the causes of changes to ecosystems, and the consequences of ecosystem change for human wellbeing. It considered terrestrial, freshwater and marine systems, and a range of ecosystem services, including food, timber, air quality regulation, nutrient cycling, detoxification, recreation and aesthetic services.As a contribution to the MA Condition Working Group, the Land Use and Cover Change Project (LUCC) of IGBP/IHDP and the Global Observations of Forest Cover and Land Dynamics (GOFC/GOLD) collaborated with the MA to develop a project showing areas of rapid land cover change over the last two decades.The Condition and Trends Working Group found that over the past 50 years, humans have changed ecosystems more rapidly and extensively than in any comparable period of time in human history, largely to meet rapidly growing demands for food, fresh water, timber, fiber and fuel. This has resulted in a substantial and largely irreversible loss in the diversity of life on Earth. In addition, approximately 60% (15 out of 24) of the ecosystem services it examined are being degraded or used unsustainably, including fresh water, capture fisheries, air and water purification, and the regulation of regional and local climate, natural hazards, and pests.