The provision of healthcare creates significant environmental impacts, and their mitigation is being attempted in a variety of ways which vary from nation to nation in line with differing policy priorities and resource availability. The environmental performance of hospitals has been enhanced through, for example, green building, waste and energy management, and product design. However, unpredictable occupant behaviour, new research outcomes and evolving best practice requires healthcare to react and respond in an ever challenging and changing environment, and clearly there is no one set of actions appropriate in all jurisdictions. Many authors have pointed up negative environmental impacts caused by healthcare, but these studies have focused on particular aspects of mitigation in isolation, and are for this reason not optimal. Here it is argued that tackling impact mitigation through a whole system approach is likely to be more effective. To illustrate what this approach might entail in practice, an evaluation of a systematic implementation of impact mitigation in Ireland's largest teaching hospital, Cork University Hospital is presented. This approach brings together voluntary initiatives in particular those emanating from governmental and non-governmental organisations, peer supports and the adaptation of programmes designed originally for environmental education purposes. Specific measures and initiatives are described, and analysis of results and planned future actions provides a basis for evaluation of successes achieved in achieving mitigation objectives. A crucial attribute of this approach is that it retains its flexibility and connectivity through time, thereby ensuring continual responsiveness to evolving regulation and best practice in green healthcare. It is demonstrated that implementation in Cork resulted both in mitigation of existing impacts, but also a commitment to continual improvement. For such a systems approach to be widely adopted, the healthcare sector needs both leadership from regulators and stakeholders, and strong supports. In Cork it was found that environmental education programmes, especially action and reward based programmes, as utilised by the campus's academic affiliates in particular University College Cork, were especially effective as a framework to address sustainability challenges and should be developed further. However, within healthcare implementation of environmental initiatives must prioritise patient safety. This approach has now been adopted for delivery across the health services sector in Ireland. (C) 2016 Elsevier Ltd. All rights reserved.