“Over the past 50 years, humans have changed ecosystems more rapidly and extensively than in any comparable period of time in human history. This has resulted in a substantial and largely irreversible loss in the diversity of life on Earth” Millennium Ecosystem Report (2005). UNEP is entrusted with the responsibility within the United Nations family to keep the state of the environment under constant review. UNEP undertakes regular assessment of the state of ecosystems in collaboration with leading expert institutions/ organizations from around the world. The result of this assessment is contained in the Global Environment Outlook (GEO). Other thematic reports are also available.