Economists have successfully branded themselves as scientists with mathematical exactitude who can artfully negotiate the vagaries of human consumption patterns through pricing mechanisms. Yet the life support systems that sustain the planet have eluded their grasp, and have often been relegated to the residual category of externalities. Until recently, if you asked a conventional economist about pricing nature you risked being ridiculed as a green hippie or a neo-Marxist. Professional economic associations and journals marginalized any dissent from conventional pricing etiquette which could only be determined under strict market conditions. The most accommodation which economists could grant was trading of emission permits for air pollution and that too was considered a side show within the halls of dominant economics programs.

Given this strong ostracization, a parallel field of ecological economics had to develop, led by a few rebel researchers. Most notably, the Romanian-American economist Nicholas Georgescu-Roegen, who had been a protégé of Joseph Schumpeter at Harvard, dared to embrace other physical sciences, such as physics and biology in his analysis. His seminal book The Entropy Law and the Economic Process (1971), was the first treatise to consider physical constraints on capitalism described by his mentor, Schumpeter, as “a process of creative destruction.” However, at a time when even a nuanced challenge to capitalism was considered with communist innuendo, much of the core ideas of such works were dismissed along with more qualitative and normative writings such as E.F. Schumacher’s Small is Beautiful (1973).

Interestingly enough, a challenge to consumer sovereignty had been presented several years earlier by the far more influential economist John Kenneth Galbraith in his work The Affluent Society (1958). However, his work was considered more in the realm of political science than economics and did not have the ecological cadence that was to follow as the field of ecological economics developed. Disciplinary reductionism has been pervasive in economics far more than any of the other social sciences primarily because the dominant use of statistical methods made the field esoteric to the public. Meanwhile the ecological economists matured to build bridges with other disciplines insofar that you didn’t need to have a Ph.D. in economics to be labeled an ecological economist. They argued that economics was essentially a study of human responses to scarcity of resources, and hence required an eclectic assemblage of tools and fields of inquiry.

Ironically, ecological economists also began to develop more rigorous mathematical models and followed some of the same methodological paths as their conventional cousins. However, neither side communicated much with each other and built ideological walls between the fields. The ecological economists developed their own professional society and journals and were less reliant on the peer review filters of the conventional economists.

In the last decade there seems to be a promising shift across the tectonic plates of economic thought that just might close the fault lines. Ecological economists have moved closer to pricing strategies that have been the pulse of conventional economic analysis. To traverse this journey, they had to encounter criticism from existential environmental philosophers such as Mark Sagoff who has chided them for selling out and commodifying nature. However, the ecological economists have admirably gone beyond utopianism and moved towards a pragmatic approach to addressing environmental concerns. While they might not have the prices right at this stage, at least they are trying to delineate monetary indicators in tangible terms rather than using the polemics of priceless value.

At the same time, conventional economists are also beginning to think outside their hallowed box and consider the consequences of neglecting ecological constraints and also allowing other disciplinary scholars to cross their fence. An important manifestation of this change was the awarding of the Nobel prize in Economics in 2002 to Daniel Kahneman, who is a psychologist. The citation stated that the prize was awarded for having “integrated insights from psychological research into economic science, especially concerning human judgement and decision-making under uncertainty.” Much of the challenge of environmental policy revolves around the issue of decision-making under uncertainty and Kahneman's work has provided important insights for ecological economists as well.

A recent conference in Costa Rica, organized by the Gund Institute for Ecological Economics at the University of Vermont under the leadership of Robert Costanza also reflected the changes underway. In attendance were not only researchers and environmental NGOs such as Conservation International, but some key government officials and representatives from the Inter-American Development Bank and the Organization of American States. The presentations were not merely theoretical but showed how tangible results of pricing ecosystem services in Costa Rica could lead to positive development trajectories. While this tiny Central American country is often considered an outlier because of unusual policy decisions such as not having an active army, the challenges and successes encountered here are just as real here as they would be in other parts of the world. The first environment minister of the country shared how difficult it had been for him to initially convince the finance ministry about a system of allocating revenues from targeted taxes to communities that were conserving ecosystems. However, once the program was launched there were clear win-win opportunities for the country that became evident from the improvement in development indicators for some of the most remote communities where ecosystems were being conserved. The former prime minister of Suriname shared how the leading newspaper in his country had dismissed initial efforts at conservation but had now come around to realizing the value of ecosystem conservation. The idea had even caught on with BHP-Billiton, one of the world’s largest mining companies which was working with the government to establish buffer zones for its new mining projects in the country as a pay off for ecosystem services disrupted.

For the skeptics who would relegate such efforts to small countries with unique circumstances, let us consider the case of China’s “Grain for Green” program that was launched in partnership with the World Wildlife Fund (WWF). The program has allowed for farmers who conserve the environment to be paid for this process through a fund created by a tax on polluting industries elsewhere in the country. By 2010, the program aims to conserve 14 million hectares of cropland. It is also important to note that the conserved land can still be productive for food crops as long as minimal environmental criteria are met.

Another research effort on payments for ecosystem services is also emanating from the biological sciences, led by Gretchen Daily at Stanford University, which is targeting investment banks in an attempt to make such efforts more mainstream in accounting processes. Conservation set-aside programs have been practiced in OECD countries as well, such as the U.S. Department of Agricultures Conservation Reserve Program (authorized under the Farm Bill of 1985). However, the refinement and targeted implementation of such programs in developing countries is particularly important.

Despite the ostensible convergence of ecological economics and conventional economics on the issue of ecosystems services, major differences remain over other matters related to development models. At the heart of the controversy is the tenacious allegiance to economic growth among conventional economists and the equally adamant antipathy to growth among ecological economists. "Steady-state" economics, a term coined by Herman Daly at the University of Maryland, has become a common refrain for the ecological economist. However, economic growth has empirically been an important driver in development and has led some economists such as Benjamin Friedman to argue for its moral predication. Neveretheless, even a senior economist such as Friedman has acknowledged, in a recent interview, that he is not familiar with the literature on ecological economics.

Where models of growth have been questioned or criticized by classically trained economists such as William Easterly, environmental factors have largely been neglected. Instead a colonial narrative has been invoked that can only escalate further defensive posturing among the dominant strains of economic thought.

The globalization discourse has also muddied the waters in this regard by resurrecting misplaced visions of socialist emancipation (as exemplified by the World Social Forum) on the one hand and institutional critiques of development donors on the other. Well-intentioned activists and visionaries such as Bill McKibben have also conflated some of the virtues of community capital and used it to advocate a rather insular vision of a “deep economy.” While the importance of community networks and reducing ecological harm is important at one level, the larger issues of poverty eradication must be considered at a global level if we are to have a pragmatic inculcation of environmental norms.

The World Bank has been the stage on which many of these dramas have been played out including vitriolic exchanges between celebrity economists such as Joseph Stiglitz and Kenneth Rogoff. Several disgruntled World Bank employees such as Stiglitz, Easterley and Herman Daly have managed to claim legitimacy in their subsequent critiques of the Bank with the public. Equally strident defenses of the World Bank leadership have also come forth from writers such as Sebastian Mallaby.

At the core of these exchanges is an inability of either side to address issues of massive inequality which is seminal in our struggle for charting development paths. Must inequality be endured as a necessary storm surge until the rising tide of economic growth lifts all vessels to safety? Are there better ways to define inequality than conventional indicators of income or wealth? Perhaps the most promising arena in this regard is research ensuing from the Santa Fe Institute under the leadership of Samuel Bowles that has provided a refreshing eclecticism to the debate. The research finds that egalitarianism is challenged by globalization but that if we want to spread the wealth from rich to poor countries, ultimately some form of global trade is essential. In addition nascent research by James Boyce has linked inequality and environmental decline, perhaps closing the circle on the need for pricing nature. Research at the Global Development and Environment Institute at Tufts University is also opening avenues for communication, through enagement on matters such as environmental reform proposals on world trade. The institute awards the annual "Leontief Prize" in honor of the economist who gave impetus to input-output modeling that is also an important tool for the ecological economist.

If there is a nefarious necessity in this whole debate, it is perhaps the specter of regulation that tends to lead either side towards positional entrenchment. If we are to have payments for ecosystem services, some form of regulation is likely to be essential to allocate costs and benefits. The common good of environmental protection will have a political price that pits proponents of individual liberty against the regulators. Yet, in this day and age many of the erstwhile proponents of individual choice on the conservative edge of the political spectrum have been all too willing to dispense with individual liberties at the altar of national security. Surely, the specter of physical constraints on our environment to support and sustain human societies would merit due consideration on similar terms. Not only would addressing such matters be essential for sustaining security but it is also likely to be most economically efficient. As any economist would certainly agree, wastage in an economy is inefficient in the long-term and not ascribing price to valuable services is likely to lead to wastage and profligacy that defies common sense.

Pricing nature in rigorous and tangible ways provides an opportunity for the idealists and pragmatists to finally find some common ground on the economic battlefield. Let’s not lose this opportunity for collective victory.

Saleem H. Ali is associate professor of environmental planning at the University of Vermont and is on the adjunct faculty of the Watson Institute for International Studies at Brown University