"‘For the management of renewable resources there are two obvious principles of sustainable development. First that harvest rates should equal regeneration rates (sustained yields). Second that waste emission rates should equal the natural assimilative capacities of the ecosystems into which the wastes are emitted. Regenerative and assimilative capacities must be treated as natural capital, and failure to maintain these capacities must be treated as capital consumption, and therefore not sustainable.’"
- Mathis Wackernagel 
"Natural capital assets fall into two categories: those which are non-renewable and traded, such as fossil fuel and mineral “commodities”; and those which provide finite renewable goods and services for which no price typically exists, such as clean air, groundwater and biodiversity.
During the past decade commodity prices erased a century-long decline in real terms , and risks are growing from over-exploitation of increasingly scarce, unpriced natural capital. Depletion of ecosystem goods and services, such as damages from climate change or land conversion, generates economic, social and environmental externalities. Growing business demand for natural capital, and falling supply due to environmental degradation and events such as drought, are contributing to natural resource constraints, including water scarcity.
Government policies to address the challenge include environmental regulations and market-based instruments which may internalize natural capital costs and lower the profitability of polluting activities. In the absence of regulation, these costs usually remain externalized unless an event such as drought causes rapid internalization along supply-chains through commodity price volatility (although the costs arising from a drought will not necessarily be in proportion to the externality from any irrigation). Companies in many sectors are exposed to natural capital risks through their supply chains, especially where margins and pricing power are low. For example, Trucost’s analysis found that the profits of apparel retailers were impacted by up to 50% through cotton price volatility in recent years.
Economy-wide, these risks are sufficiently large that the World Economic Forum cites ‘water supply crises’ and ‘failure of climate change adaptation’ along with several other environmental impacts among the most material risks facing the global economy." (http://www.naturalcapitalcoalition.org/js/plugins/filemanager/files/TEEB_Final_Report_v5.pdf)