Sustainable development is being embraced as a guide for policy and management by governments, businesses, and the Society of Environmental Toxicology and Chemistry (SETAC 2011). There has been much heated debate on its application, but fortunately, we have gone beyond haggling over definitions. Most accept that sustainable development requires that current economic activities do not impair the well-being of present and future generations in terms of the balance between economic, social, and natural capital. That said, there is still an argument about the extent to which growth in 1 of these 3 stocks (say economic capital) can occur at the expense of others (say natural capital)—while maintaining the overall balance (Dasgupta 2007).
Here, I draw attention to 2 other challenges for the implementation of the sustainable development concept. One is that approaches that focus on the sustainability of particular activities (including those that affect ecosystem properties such as integrity [capacity to resist change] and resilience [capacity to recover]), being partial analyses, do not necessarily optimize sustainable development. The other is that, because sustainable development involves consideration of a myriad of effects over a wide range of systems through space and time it will always be a challenge to manage optimally. These might be thought of, respectively, as the problems of reductionism and complexity.
The reductionist problem means that when sustainability is applied narrowly the decisions about how to achieve it might be made without consideration of other impacts and trade-offs. Take the sustainability—persistence—of a business producing chemicals that, under some circumstances, could result in toxicity to humans or the environment. Here the production processes might be made more efficient in terms of energy and resources. This would make the business more sustainable. However, the potential toxic effects of the chemicals on humans and the environment are not taken into account. The same goes for ecosystems; ensuring the long-term persistence—sustainability—of ecosystems without necessarily considering tradeoffs with social and economic capital provides only part of the story. Damming a river may well reduce the integrity and resilience of the fauna and flora present before the engineering, and yet, returns to the local economy in terms of food production, flood protection, and health may be profound.
In my view, the core to sustainable development is the recognition that there are trade-offs between the 3 capital stocks. How they should be balanced depends on the preferences of people. The problem with reductionist approaches is that they exclude important tradeoffs. However, the problem with a more comprehensive approach for sustainable development policy is that there are complex choices with all kinds of unforeseen ramifications in the connections between socioeconomic activities and the environment. For example, government interventions to favor biofuels while contributing to more sustainable fuel sources have run into numerous unforeseen negative consequences for land use, food supply, water use, rural development, habitat destruction, and so on.
In the face of all this complexity and the difficulties of the reductionist approaches, how to proceed? Hayek (1945) made the important point that no persons or authorities know enough to manage this kind of complexity effectively. Planned economies have famously failed. Markets are more efficient.
This assertion is based on the fundamental assumptions of welfare economics that the preferences (self-interest) of rational individuals should lead to the best outcomes and hence be the determinants of priorities. Price provides the mechanism through which producers and consumers meet in the marketplace. If there is too little supply for demand, prices rise; producers produce more and consumers consume less. The reverse occurs if there is too much supply. So as natural resources are used up they will become more expensive and thus modulate consumer behavior, shifting demand to other resources and possibly driving innovation. The markets, therefore, provide a basis for the protection of natural resources, putting a brake on use as resources become in short supply.
The well-known challenge for market-based environmentalism, however, is that many of the things we value in the environment are external to markets. Achieving sustainable development will depend on putting a price on these externalities—for example on carbon and biodiversity—in a way that reflects public preferences. Capturing these values—and making allowances for the separation of costs and benefits through space and time—is the job of economists (Hanley and Barbier 2009). Market-based instruments such as green taxes ought, therefore, to provide a better way of managing sustainable development than command and control approaches that are often based on reductionist analyses.
What role for natural scientists and SETAC in all this? Putting a price on carbon emissions depends on making quantitative links from them to temperature changes they cause and ultimately to the effects on people and the natural environment. Putting a price on biodiversity changes depends on quantifying the links to effects on ecosystem services that are valued. The natural science behind this should be about making the connections between our emissions and activities and the likely impacts that matter—and exposing the uncertainties in our understanding of these links.
There is a lot to be said for scientists being involved in the sustainable development debate as citizens but, given the complexity, there is always a risk that the value judgments of scientists (e.g., on how seriously to take uncertainty) are accepted as facts. There is a need for a science that is responsive to making the markets work for sustainable development through a value-relevant (not value-biased) approach (Calow and Forbes 2010).