Climate change will have an impact on biodiversity; most modern zoos are concerned with the conservation of biodiversity and therefore have an obligation to minimize their impact on the environment, particularly their contribution to factors causing climate change. An environmental management system (EMS) is a tool to identify, measure and reduce an organization's impacts on the environment in a systematic way and to continually improve environmental performance through a four-stage cyclical method, Plan–Do–Check–Act. Paignton Zoo Environmental Park began to implement an EMS in 2003 and achieved the international standard ISO14001 for environmental management in 2005. In addition to improving environmental performance and legal compliance, and reducing environmental risk, the main advantages of the EMS have been costs savings on utilities, improved credibility and media coverage, and improved access to grant funding for ‘green’ initiatives. However, there have also been cost implications in terms of staff time, administration, financial costs in setting up the system, capital costs in investment in processes and equipment with the best environmental ratings, and additional constraints on development because environmental issues can no longer be conveniently ignored. Despite these disadvantages, the EMS has been a very effective tool for Paignton Zoo Environmental Park, enabling it to become a recognized leader in this field and truthfully to live up to its name.