Jane Carter Ingram is director of the Ecosystems Services Program for the Wildlife Conservation Society (WCS). Ingram contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

The recent encyclical "On Care for Our Common Home" by Pope Francis focused attention on the critical importance of our natural environment. As a response to the environmental crisis, he calls for an economy that favors business creativity and integrated solutions based on the notion that protection of the natural environment is a critical part of economic development and society.

Similarly, a broad range of leaders in conservation, development, government and business also appreciate the urgent need to find cost-effective ways to protect nature while meeting the needs of a human population that has surpassed seven billion people .

Nature as a cost-effective water filter

Water filtration is a perfect example. New York City pays landowners in the Catskills watershed to implement land-use practices that benefit water quality for the city downstream and is billions of dollars cheaper. In addition to naturally filtering the Catskills water, similar payment arrangements have helped preserve carbon stocks stored in Madagascar's rainforests, maintained wildlife populations important for tourism in Tanzania, and protected watersheds in France.

Such wide-ranging benefits that nature provides to humanity are called "ecosystem services" and include tangible goods like food, medicine and fuel; "invisible" benefits, such as the regulation of climate, water filtration, flood control, storm protection, pollination and disease control; and cultural benefits like tourism, recreation and spiritual nourishment.

Payments for ecosystem services (PES), as in the Catskills, can be made by individuals, businesses, nonprofits, or governments and are conditional on the continued delivery of a specific ecosystem service. Collectively, ecosystem services are estimated to be worth over $100 trillion per year. As important benefits like clean air and water have grown scarcer their value has increased. Paying for nature's services makes a lot of sense, particularly, when nature delivers benefits to society just as effectively — and less expensively — than other alternatives.

But as investments in nature increase in number and form, it's important that buyers get what they pay for and that nature is protected in the process. To do this, buyers, sellers, and intermediaries must understand the way the natural world functions and delivers benefits to communities, businesses and governments.

And yet, that understanding has been lacking. A group of leading researchers, practitioners, policy makers and investors coordinated by Columbia University and the Wildlife Conservation Society (WCS) recently identified six scientific principles that can guide payments for nature's services.

The six principles, published in the journal Science, are scientifically robust and practical for a wide range of situations:

Understand the dynamics characterizing the ecosystem. For example, if farming practices have a greater impact on water quality, or quantity, than the climate, then payments to improve those practices may be warranted. If climate plays a larger role, then probably not. Document existing conditions before a given investment is made. If there is no such record, it will be impossible to assess if a payment has generated benefits from nature. Monitor changes in an ecosystem throughout an investment period. Many factors may affect an ecosystem and the services it generates throughout time — tracking how those factors change will clarify an investment's impact. Use metrics that support future decisions. Metrics (standards of measurements) used to assess changes in an ecosystem service should be appropriate for size of the area of interest and the service’s duration, informative with respect to capturing changes in an ecosystem, and compatible with metrics used by existing standards or regulatory agencies. Identify connections among components within a natural system. For example, planting trees may increase carbon stocks, but could also decrease water availability or biodiversity. Thus, investments may have unintended consequences if ecological linkages are not considered in advance of a project. Assess the sustainability of an investment relative to how an ecosystem may change through time. Climate or demographic changes could affect land use or water supplies, making the long-term success of a given investment uncertain.

These principles balance scientific rigor with practicality to guide a wide variety of transactions involving ecosystem services. If followed, investments in nature will be less risky and yield better results while protecting critical resources .

Consensus on these principles from a diverse group of experts — from disciplines including economics, ecology, finance and sociology who have researched and worked extensively on PES — represents an important milestone in the use of these and similar financial mechanisms for achieving social and ecological goals.

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Will they need fine-tuning based on users' feedback? Undoubtedly. Trial and error are a part of all scientific endeavors, but a necessary one when developing principles to guide payments for nature.

PES mechanisms are being implemented and promoted around the world as a cost-effective way to balance increasing human needs with conservation of ecosystems that provide critical goods and services.

We have too much to lose — ecologically, socially and financially — to get these mechanisms wrong. Thanks to Pope Francis, we have the moral guidance on how to get these kinds of approaches right, while the six principles will provide the scientific guidance to ensure PES and similar approaches are successful.

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