This authoritative dictionary provides over 9,000 entries on scientific and social aspects of the environment-its key thinkers, treaties, movements, organizations, concepts, and theories. It covers subjects such as sustainable development, biodiversity, and environmental ethics, it is at the cutting edge of environmental and conservation studies. Expanded to contain more detail on complex topics such as deepwater horizon, and hydraulic Fracturing, and new entries such as angular velocity, and solution mining, this new edition offers definitions on topical and developing issues. It also features new resources including a list of the world's major national parks and IUCN categories for endangered species, as well as new web links and illustrations, providing useful context additional to the entries in the dictionary. This is the essential reference for students studying environmental and natural sciences, environmental studies, conservation, and technology, and related disciplines, as well as anyone with an interest in environment and conservation.