There are a range of ways in which public health can contribute to sustainability; including the sustainability of the environment in which we live, the resources we use and the contribution we collectively and individually make to ecological sustainability. However, it is very important for us to remember that whatever contribution we allocate to environmental health or public health in the debate about sustainability, the fundamental issue is that without the contribution of many disciplines to ecological sustainability we will see limited success. One of the key issues that many governments are facing now is balancing the requirement to limit global changes, and their consequent impacts on ecological sustainability, with the social, political and economic problems that may result from imposing these limits. As Smyth [1] indicates “… our environment is the totality of what we live in, natural or constructed, spatial, social and temporal. It is an extension of ourselves, its health requiring the same care as our own health”. It is clear that our current way of life and reliance on resources are not sustainable. As McMichael [2] points out “our prevailing cultural values, technologies, and behaviours are not ecologically sustainable: on current trends the natural world cannot continue to furnish the ‘services’ upon which our societies, health, and lives depend”. He goes on to state: “Until the public health community highlights the centrality to the overall sustainability project of long-term population health, and particularly its dependence on maintaining Earth’s life-support systems, society will continue to miss the real point—namely, that ‘ecological sustainability’ is not just about maintaining the flows from the natural world that sustain the economic engine nor maintaining iconic species and iconic ecosystems. It is about maintaining the complex systems that support health and life. Population well-being and health, understood thus, become the real bottom line of sustainability” [2].

As early as 1972, at the Stockholm Conference on the Human Environment, the concept of sustainable development was being discussed – it was to mark a “significant paradigm shift in approaches to dealing with the environment and development, and heralded a major advance in thinking” [3]. In addition to that paradigm shift, “the value of reconnecting environmental and public health is related to the long-term benefits that will accrue. Proponents in both [the environmental health and public health] professions recognize that public health and environmental health are flip sides of the same coin. In truth, they are not separate fields at all. Public health is environmental health” [4]. For example, “Two of the greatest health-endangering correlates of urban environments and living are, first, overweight and obesity and, second, the increasing contribution of cities to greenhouse gas emissions and the attendant risks to safety, health and survival” [5].

Public health interventions can be informed in a variety of different ways by environmental health, ecology and health, and human ecology. The contribution of each of these elements to public health is not mutually exclusive, because approaches that deal with complex issues can also provide useful insights to deal with more basic issues. Environmental health, ecology and health, and human ecology can “be seen as complementary approaches to addressing overlapping problems in the areas of health, environment, and development” [6].

This paper highlights the extent to which there has been a convergence over the last 20 years in the work of each of these areas and strongly supports a further conceptual and methodological integration of knowledge and action to ensure comprehensive and sustainable environmental health gains. As Parkes et al. [6] quite rightly argue “research and applied programs that integrate biophysical and social sciences with public health practice can go some way toward addressing the deficiencies in each approach when taken on its own”.

The roles of social and economic development, as both drivers and mediators of hazardous environmental exposures, and the need for an ecologically sustainable development are increasingly important challenges in environmental health and in public health [6–8].

Public health’s mission has long been to investigate and address the impacts of significant social and environmental change on the public’s health; however, now that the ecosystems that support us are so endangered, the sustainability and integrity of our planet must be considered synonymous with the sustainability of humans [9].

As long ago as the late 1980s the World Health Organization (WHO), through the Ottawa Charter [10], was advocating for the creation of supportive environments. This notion reinforces the contention that our societies are complex and interrelated and that health cannot and should not be separated from other goals. “The inextricable links between people and their environment constitute the basis for a socio-ecological approach to health” [10]. This idea of sustainable environments clearly suggests that we need to encourage reciprocal maintenance–to take care of each other, our communities and our natural environment. The WHO was arguing for an emphasis on the conservation of natural resources throughout the world as a global responsibility over 20 years ago [10]. In particular, the WHO argued for a systematic assessment of the health impact of a rapidly changing environment, –particularly in areas of technology, work, energy production and urbanization–as being essential to ensure positive benefit to the health of the public [10].

Despite these issues being raised by the WHO [10] there are still numerous examples of continuing changes to our environment that are likely to impact on our wellbeing. These include climate change, the decline in the ozone layer, the reduction in biodiversity, and alterations in the physical environment and ecological processes [3]. In addition to these global changes, the effects of climate change will, as the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report [11] clearly states, “fall disproportionately upon developing countries and people without the necessary economic resources, and thereby exacerbate inequities in health status and access to adequate food, clean water, and other resources”. This is echoed in the recent Human Impact Report from the Global Humanitarian Forum which concludes that the people who are “least responsible for greenhouse gas emissions are the world’s poorest communities who suffer most from climate change” [12]. This report further concludes that climate change currently results in over 300,000 deaths, seriously affects 325 million people and results in economic losses of US$125 billion. In addition, it estimates that over the next twenty years, the number of people affected by climate change will more than double, “making it the greatest emerging humanitarian challenge of our time” [12].

Links between health and economic development have been well documented for many years, but in more recent times they have become increasingly recognised, especially with respect to the relationship between health and poverty. Furthermore, the growing burden of both non-communicable and communicable diseases has become more evident. In the twenty first century, the world is facing the challenges associated with the re-emergence of infectious diseases, as well as the increasing burden of non-communicable diseases. Never before have we in public health faced the complexity associated with increases in infectious disease mortality, with growing mortality and morbidity from non-communicable diseases. During the past few decades, the health effects of development policies and practices have been insufficiently stressed, although the need for assessment of these effects has been highlighted. As von Schirnding [3] suggests, the opportunities and threats to health posed by globalisation have only recently been realised, with the implications of global interdependency highlighted by the threat of global climate change and the HIV/AIDS pandemic.

The United Nations Conference on Environment and Development (UNCED or ‘Earth Summit’) in 1992, in Rio de Janeiro [13] was a defining moment in recognizing the relationships between development and environmental issues. The ‘Earth Summit’ [13] resulted in the adoption of “Agenda 21, a wide-ranging blueprint for action to achieve sustainable development worldwide” [14]. Agenda 21 also acknowledged the significance of protecting and promoting human health [3]. More recently, the 2002 World Summit on Sustainable Development (WSSD) [15] yielded two documents: the first being the Political Declaration, which supports principles that were approved in 1992 at the ‘Earth Summit’ [13] and the Millennium Summit in 2000 [16]. This Declaration recognized that “poverty eradication, changing consumption and production patterns, and protecting and managing the natural resource base for economic and social development are overarching objectives of, and essential requirements for sustainable development” [15]. In addition, it identified that the ever-widening gap between rich and poor countries poses an increasing threat to global security, prosperity and stability, which, when combined with increasing adverse environmental change and global market forces, substantially threatens the long-term sustainability of the planet [15]. The second is the Plan of Implementation (the ‘action plan’), which outlines a number of recommendations on a range of issues, including water and sanitation, natural resources and biodiversity, and health [15]. The 2002 World Summit demonstrated clear relationships between sustainable development, human health and the environment [17].

Health has been given more prominence by the WHO for sustainable development, and is now one of the important concerns selected as necessitating particular consideration, together with biodiversity, water, agriculture and energy [3]. In addition, the WHO has chosen Climate Change and Health as its theme for 2008–09. McMichael [18] points out that the public health community needs to focus on efforts to undertake multi-sectoral actions that seek to create environmental and social conditions able to sustain population health. Probably “a quarter of the world’s total loss of healthy years of life is associated with environmental factors” [3]. In 1990, 23% of total DALY burden worldwide was caused by environmental factors [19]; and in 2004 it was 24% [20]. However, the real figures are probably higher, as there is limited data available for many diseases at present [20]. In addition, with the total number of healthy life years lost per capita due to the environmental burden (per capita) being 15 times higher in developing countries than developed, clearly, the environmental disease burden is unequally distributed [20].

The fundamental issue around global environmental change is that humans are collectively overloading the capacity of the Earth to supply, absorb, replenish, and stabilise, and this poses a profound, potentially irreversible, form of non-sustainability. McMichael [2] provides us with clear evidence from a number of examples about the impact of environmental change including the loss of species that cannot be regained; damage to our ecosystems (wetlands, forests, reefs, etc.) that cannot easily be rebuilt, if at all; the incredible variability of global climatic conditions; and the degradation and acidification of land, that even if possible, will take years to restore. Other authors have pointed out that excessive amounts of material and energy use and waste production jeopardize global sustainability, which inevitably results in delayed, indirect health effects [3,17]. “In between these extremes, many developing countries are experiencing the worst of both worlds: traditional risks associated with poverty; and new and emerging risks associated with large-scale, rapid industrialisation, urbanisation, and technological development” [3]. The impact of these changes extends “beyond the boundaries of cities and affect the population at large. For example, energy use in cities and the resultant greenhouse gas emissions have consequences, via climate change, for humans everywhere. The resultant health risks involve the impact of heatwaves, especially in cities; exacerbation of local air pollution; intensified extreme weather events; and heightened transmission of temperature-sensitive infections” [5].

It is clear that the challenges posed by global environmental change are substantial and require urgent and ongoing commitment and leadership at all levels of government and society. As the interconnectedness of the environmental, economic, political, social, and spiritual challenges is becoming increasingly obvious, it is also clear that there is a need for a “shared vision of basic values to provide an ethical foundation for the emerging world community” [21]. Such a vision is provided by the Earth Charter which provides sixteen “interdependent principles for a sustainable way of life as a common standard by which the conduct of all individuals, organizations, businesses, governments, and trans-national institutions is to be guided and assessed” [21]. From an educator’s perspective, Principle 14 emphasises the need to “integrate into formal education and life-long learning the knowledge, values, and skills needed for a sustainable way of life” [21]. Therefore, “from the outset, education has been at the center of the Earth Charter’s purpose and a major focus of the Earth Charter Initiative’s programmes” [22].

What is the role for universities through undergraduate and postgraduate education, and continuing professional practice education, particularly in the public health arena, in making a significant contribution to ecological sustainability?

Agenda 21 [14] unambiguously reaffirmed that education was critical for promoting sustainable development and improving the capacity of the people to address environment and development issues. Why is education so important? Both formal and non-formal education are indispensable in changing people’s attitudes so that they have the capacity to assess and address their sustainable development concerns. It is also critical for achieving environmental and ethical awareness, values and attitudes, skills and behaviour consistent with sustainable development, and for effective public participation in decision-making [14]. In addition, as universities are “an integral part of the global economy and since they prepare most of the professionals who develop, manage and teach in society’s public, private and non-government institutions, they are uniquely positioned to influence the direction we choose to take as a society” [23]. Therefore, universities have a critical and fundamental role (and some say a responsibility) for sustainability through their teaching and research activities [24,25]. The Association of University Leaders for a Sustainable Future state that “the success of higher education in the twenty-first century will be judged by our ability to put forward a bold agenda that makes sustainability and the environment a cornerstone of academic practice” [23].

Based on the way in which universities operate and the influence they have within the community, there would seem to be four interconnected elements that need to be addressed for them to achieve their role for sustainability: institutional policy and commitment, operational activities, teaching and research, and professional development/extension activities.

As Parks et al. state, “recent trends in environmental health, ecology and health, and human ecology all suggest that the interface between sustainability, ecosystems, social systems, and health is fertile ground for optimizing environmental health interventions and maximizing public health gain” [6]. With an accelerated rate of economic development, the substantial increase in the world population and the globalisation of trade, these modern realities have dramatically changed production methods and demand for goods in both developed and developing countries, and have become contemporary challenges for disciplines like public health and environmental health. These changes in the way we live and the ever-increasing impacts of human activity on environmental resources and systems highlight an ever-increasing urgency for all to understand that population health is an important part of the concept of sustainability [5]. Accomplishing sustainable social, economic and environmental conditions therefore underpins the achievement of population health [47]. Further, documents such as the Earth Charter argue for the integration into formal education and more broadly into life-long learning the knowledge, values, and skills needed for sustainable living [21]. In this context, universities play a critical role in embedding sustainability principles and understanding in society, through the training of future leaders and professionals, cutting-edge research, and community outreach activities that empower local communities to implement sustainable principles and practices. However, universities currently have a mixed track record when it comes to sustainability–they have embraced various ‘greening of campuses’ approaches, but there seems to be limited transformation of genuine university practice, particularly due to a lack of high-level commitment with little accountability, as well as minimal integration of sustainability into mainstream curriculum.

This article has argued that the development of a workforce that recognises and responds to local agendas, as well as recognising that we are now players on the global stage, is only one component of the necessary actions for ecological sustainability. The University sector needs to be committed to the concept of ecological sustainability and put that concept into practice. Ecological sustainability is our biggest challenge – as educators, as practitioners and as citizens. The future poses its challenges and if those challenges are met the sustainability of our total environment will be our reward.