Earthquakes, floods, fires, droughts, blizzards, dust storms, natural releases of toxic gases and liquids, diseases, and other environmental variations affect hundreds of millions of people each year. Many such events are exacerbated or mitigated by human activities. In addition, humans affect the environment and natural biodiversity by adding contaminants to air and water, changing land use, reducing and fragmenting the habitat of some species, introducing non-native species, and changing natural fluxes and cycles of energy and materials. It is increasingly clear that human activities are driving many changes in Earth’s global environment; indeed, some scientists refer to this human-dominated period as the Anthropocene to indicate a new geologic epoch that succeeds the Holocene. The term Anthropocene has also recently come into use in the popular press (for example, New York Times 2011 and The Economist 2011) and a proposal to define and formalize the term is being developed by the Anthropocene Working Group for consideration by the International Committee on Stratigraphy (SQS 2012).
The challenges associated with environmental protection today are multi-faceted and affected by many interacting factors. The challenges operate on various, often large, spatial scales, unfold on long temporal scales, and usually have global implications (for example, carbon dynamics, nutrient cycles, and ocean acidification). Dealing with these problems will require systems thinking and integrated multidisciplinary science.
Achieving solutions to these challenges requires increased sustainability, the pursuit of which has been called a wicked problem. The term wicked problem has been used in the field of social planning to describe a problem that is difficult to solve because it is difficult to define clearly, resistant to resolution, and inadequately understood; it has multiple causes that interact in complex ways; it attracts attempted solutions that often result in unforeseen consequences; it is often not stable; it usually has no clear solution or endpoint but rather solutions that are considered better, worse, or good enough; it is socially complex and has multiple stakeholders who must consider the changing behavior of others; and it rarely sits conveniently within the understanding of one discipline or the responsibility of any one organization. Moreover, because of complex interdependencies, the effort to solve one aspect of a wicked problem may reveal or create other problems (Rittel and Webber 1973; DeGrace and Stahl 1990). There is no doubt that the environmental pollution problems of today fit the characteristics of wicked problems.
The environment is variable, complex, and difficult to predict. That difficulty is in part due to imperfect scientific knowledge about environmental processes, but it is also a consequence of imperfect knowledge about economic, demographic, and social processes that drive environmental change and the feedback effects of environmental change on economic, demographic, and social processes. Sustainable pathways to address environmental and human health challenges will only emerge if societies choose to pursue sustainable solutions