Environmental security examines threats posed by environmental events and trends to individuals, communities or nations. It may focus on the impact of human conflict and international relations on the environment, or on how environmental problems cross state borders. General The Millennium Project assessed definitions of environmental security and created a synthesis definition: Environmental security is environmental viability for life support, with three sub-elements: preventing or repairing military damage to the environment, preventing or responding to environmentally caused conflicts, and protecting the environment due to its inherent moral value. It considers the abilities of individuals, communities or nations to cope with environmental risks, changes or conflicts, or limited natural resources. For example, climate change can be viewed a threat to environmental security (see the article climate security for more nuance to the discussion.) Human activity impacts CO2 emissions, impacting regional and global climatic and environmental changes and thus changes in agricultural output. This can lead to food shortages which will then cause political debate, ethnic tension, and civil unrest. Environmental security is an important concept in three fields: international relations and international development and human security. Within international development, projects may aim to improve aspects of environmental security such as food security or water security, but also connected aspects such as energy security, that are now recognised as Sustainable Development Goals at UN level. Targets for MDG 7 about environmental sustainability show international priorities for environmental security. Target 7B is about the security of fisheries on which many people depend for food. Fisheries are an example of a resource that cannot be contained within state borders. A conflict before the International Court of Justice between Chile and Peru about maritime borders and their associated fisheries is a case study for environmental security. History The Copenhagen School defines the referent object of environmental security as the environment, or some strategic part of it. Historically, the definition of international security has varied over time. After World War II, definitions typically focused on the subject of realpolitik that developed during the Cold War between the United States and the Soviet Union. As tensions between the superpowers eased after the collapse of the Soviet Union, academic discussions of definitions of security significantly expanded, particularly including environmental threats associated with the political implications of resource use or pollution. By the mid-1980s, this field of study was becoming known as "environmental security". Despite a wide range of