Final answer:
Environmental security arose in IR as a response to environmental threats to national security, and it encompasses global warming, deforestation, and conflicts over resources. The concept gained attention in the 1950s and 1960s, and it is useful in highlighting the interdependence of environmental issues and national security.
Step-by-step explanation:
Environmental security in the field of International Relations (IR) emerged as a concept in response to global and regional environmental issues that pose threats to national security. It encompasses concerns such as global warming, deforestation, and conflicts over limited resources. The concept gained attention in the 1950s and 1960s, with environmental activists like Rachel Carson drawing attention to environmental problems. Environmental security is useful as it highlights the interconnectedness of environmental issues and national security, allowing for the exploration of solutions to these challenges.