Convention on Biological Diversity in the context of "Ecosystem-based adaptation"

Brazil once had the highest deforestation rate in the world, and recent data still shows high rates of deforestation. Between 2001 and 2023, Brazil lost 68.9 Mha of tree cover (13% of its total tree cover lost since 2000), and in 2022, Brazilian forest loss accounted for 43% of global deforestation. In 2005, Brazil still had the largest area of forest removed annually. Since 1970, over 700,000 square kilometres (270,000 sq mi) of the Amazon rainforest have been destroyed. In 2001, the Amazon was approximately 5,400,000 square kilometres (2,100,000 sq mi), which is only 87% of the Amazon's original size. According to official data, about 729,000 km² have already been deforested in the Amazon biome, which corresponds to 17% of the total. 300,000 km² have been deforested in the last 20 years.

Rainforests have decreased in size primarily due to deforestation. Between May 2000 and August 2006, Brazil lost nearly 150,000 square kilometres (58,000 sq mi) of forest, an area larger than Greece. According to the Living Planet Report 2010, deforestation continues at an alarming rate. At the Convention on Biological Diversity's 9th Conference, 67 ministers signed up to help achieve zero net deforestation by 2020. Due to deforestation the Amazon was a net emitter of greenhouse gas in the 2010s.

The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations System. It was established by Maurice Strong, its first director, after the United Nations Conference on the Human Environment in Stockholm in June 1972. Its mandate is to provide leadership, deliver science and develop solutions on a wide range of issues, including climate change, the management of marine and terrestrial ecosystems, and green economic development. The organization also develops international environmental agreements; publishes and promotes environmental science and helps national governments achieve environmental targets.

As a member of the United Nations Development Group, UNEP aims to help the world meet the 17 Sustainable Development Goals. UNEP hosts the secretariats of several multilateral environmental agreements and research bodies, including The Convention on Biological Diversity (CBD), The Minamata Convention on Mercury, The Basel, Rotterdam and Stockholm Conventions, The Convention on Migratory Species and The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), among others.

Nature conservation is the ethic/moral philosophy and conservation movement focused on protecting species from extinction, maintaining and restoring habitats, enhancing ecosystem services, and protecting biological diversity. A range of values underlie conservation, which can be guided by biocentrism, anthropocentrism, ecocentrism, and sentientism, environmental ideologies that inform ecocultural practices and identities. There has recently been a movement towards evidence-based conservation which calls for greater use of scientific evidence to improve the effectiveness of conservation efforts. As of 2018 15% of land and 7.3% of the oceans were protected. Many environmentalists set a target of protecting 30% of land and marine territory by 2030. In 2021, 16.64% of land and 7.9% of the oceans were protected. The 2022 IPCC report on climate impacts and adaptation, underlines the need to conserve 30% to 50% of the Earth's land, freshwater and ocean areas – echoing the 30% goal of the U.N.'s Convention on Biodiversity.

Wildlife conservation refers to the practice of protecting wild species and their habitats in order to maintain healthy wildlife species or populations and to restore, protect or enhance natural ecosystems. Major threats to wildlife include habitat destruction, degradation, fragmentation, overexploitation, poaching, pollution, climate change, and the illegal wildlife trade. The IUCN estimates that 42,100 species of the ones assessed are at risk for extinction. Expanding to all existing species, a 2019 UN report on biodiversity put this estimate even higher at a million species. It is also being acknowledged that an increasing number of ecosystems on Earth containing endangered species are disappearing. To address these issues, there have been both national and international governmental efforts to preserve Earth's wildlife. Prominent conservation agreements include the 1973 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the 1992 Convention on Biological Diversity (CBD). There are also numerous nongovernmental organizations (NGO's) dedicated to conservation such as the Nature Conservancy, World Wildlife Fund, and Conservation International.

The World Database on Protected Areas (WDPA) is compiled and managed by the World Conservation Monitoring Centre, an executive agency of the United Nations Environment Programme. It uses the IUCN and CBD definitions of protected areas to determine whether a site should be included in the WDPA. The extent to which each area and the resources within are protected can vary significantly.

The largest protected areas – those exceeding an area of 250,000 square kilometres – are listed below in order of total area protected. All are marine protected areas except for Northeast Greenland National Park – which is mostly terrestrial but also has a marine component – and three entirely terrestrial biosphere reserves in Brazil. Protected areas with multiple coterminous or overlapping designations (e.g. Northeast Greenland National Park and the corresponding Biosphere Reserve) are listed only once.