Continued Growth of Technosphere Capital by Destruction of Natural Capital is not Sustainable

Figure 1.  An aerial view of the edge of Manaus (Brazil), where the city meets the forest. Image credit: Greenpeace.

David P. Turner / January 27, 2022

Environmental scientists define natural capital in the context of natural resources management.  It commonly refers to a “stock of materials or information” that yields a flow of ecosystem services: an ocean fishery produces a yield of fish; a forest landscape produces a yield of wood.  In practice, most ecosystem services are produced by a combination of natural capital and human management.

In the case of hunter/gatherers, the human contribution to production of harvested food was limited.  But as technology became more important in provision of ecosystem services, the human element (including machines and knowledge) began to dominate.

A problem has arisen because humans have tended to consume not only ecosystem services (flows) from natural capital, but also the nature-built capital (stocks) itself.  A striking example is the cod fishery in the North Atlantic Ocean:  overfishing led to a collapse of the cod population and an abrupt decline in productivity.   

For centuries, humans have gotten away with depleting or destroying natural capital by simply moving on to the next unexploited natural resource.  Commodity frontiers often have a geographic dimension, e.g. the wave of primary forest exploitation in temperate North America that extended from the New England hardwoods, through the pines of the Great Lakes states, and on to the Pacific Northwest conifers.

A massive erosion of nature-built capital over the last two centuries is evident in the spatial patterns of land use change, distortions in animal and plant population structure, and outright extinction of species.  As natural capital is depleted, human interventions (often subsidized by energy from fossil fuels) must be ramped up to maintain the same level of ecosystem services.

From an Earth system science perspective, we can describe the interaction of the human enterprise and natural capital in terms of interaction of the technosphere with its natural resources base. 

The technosphere is the global aggregate of human made artefacts and includes machines, buildings, transportation infrastructure, and communications infrastructure, along with the humans and their knowledge needed to maintain it.  Estimates of technosphere manufactured capital are on the order of 800 Pg. 

The technosphere requires a large stream of materials and energy to maintain itself and to produce the outputs of goods and services that keep the 7.8 billion people on Earth alive.  Here, I am particularly interested in the interaction of the technosphere with the biosphere.

Biosphere capital is the sum of all organisms and the associated information in the form of genetic material.  It is a subset of global natural capital. 

Biosphere mass is estimated at 550 Pg (carbon) and the estimates for the number of species range from 5.3 million and 1 trillion.  Inputs to the biosphere include solar energy and material flows from the geosphere (minerals) and hydrosphere.  Besides sustaining itself, the biosphere outputs vast flows of food and fiber (including wood) to the technosphere. 

From the global perspective, technosphere manufactured capital is clearly increasing and biosphere capital is clearly decreasing.  Examples include:

  1. The aforementioned degradation of marine fisheries by overharvesting.  Correspondingly, the mass of fishing boats is thought to be on the order of 30% higher than needed for a sustainable global catch of high value species.
  2. The continued conversion of intact ecosystems to agriculture use (estimated at 50% of the land surface) or urban development (Figure 1).
  3. The loss of soil organic matter by erosion and oxidation associated with agriculture. 

Our limited understanding of the biosphere makes it difficult to even quantify the on-going loss of biosphere capital.  Note that the biosphere contributes to regulation of atmospheric and marine chemistry by way of the global biogeochemical cycles.  Thus, as we lose biosphere capital, we are beginning to lose those free regulatory services.

Meanwhile, technosphere manufactured capital is growing at a rate of 1-8% per year, depending on the level of development in a given country.  It will likely peak at a much higher level than at present because of the still growing global population and increases in per capita manufactured capital in the developing world.

In principle, biosphere inputs to the technosphere can be derived in a sustainable manner.  A landscape of tree plantations can be continuously harvested and replanted to produce a sustained yield of wood.  Plantation forests supplied about one third of industrial roundwood in 2000.  Likewise, there is such a thing as a sustainable marine fishery if the harvest is properly managed. 

However, much of the current material transfer from biosphere to technosphere is drawing down biosphere capital.  Differentiating between sustainable and depleting production of food and fiber, and increasing attention to sourcing, will play an important role in the transition to a soci-economic metabolism that is sustainable.  Accounting practices that treat all forms of capital – including natural capital and technosphere capital in its various forms (manufactured, financial, human, social) – is necessary.

The view of ecosystem services as a co-production of technosphere capital and natural capital offers a way forward.  Essentially, all ecosystem services must now be managed as socio-ecological systems, i.e. as a coupling of a human subsystem, having full stakeholder participation, and a regenerating biophysical subsystem.

Since different natural resources must be managed at different scales, a hierarchy of socio-ecological systems is needed.  This arrangement points to the importance of zonation on the Earth surface in terms of the strength of the coupling between technosphere and biosphere.  We can have large areas of relatively undisturbed intact ecosystems (e.g. marine reserves and terrestrial wilderness areas), significant areas of heavy technosphere dominance (as in urban and industrial zones), significant areas of intensive food and fiber production (e.g. forest plantations), and a scattering of areas with a moderate intensity of biosphere/technosphere interaction.  This view supports the development of spatially-explicit simulation models – implemented at a range of spatial scales – that can be used within a socio-ecological system to organize the co-production of ecosystem services. Potentially, with a well-designed combination of monitoring, modeling, and environmental governance, the technosphere will drive increases rather than decreases in biosphere capital (e.g. the recovery of whale populations).

The Biodiversity Bottleneck

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Figure 1. The biodiversity bottleneck displays the ongoing reduction in biodiversity caused by human actions. The fate of biodiversity after the bottleneck is uncertain, but some degree of recovery is possible if humanity self-regulates. Image Credit: Monica G. Whipple and David P. Turner

David P. Turner / May 29, 2020

Earth’s biodiversity is under siege by the global human enterprise (the technosphere).  Most species will survive into the distant future, possibly a future in which the human population has shrunk, and the value of biodiversity is more widely appreciated.  But many species will go extinct along the way. 

Biologist E.O. Wilson and others have evoked the image of a bottleneck in this context (Figure 1).  A bottleneck implies a tightening of constraints on flow.  In the case of the biodiversity bottleneck, flow refers to the survival of species through time.

As the future unfolds and the technosphere continues to grow, the possibilities for species to pass through the biodiversity bottleneck diminish.  But there is a lot of room for maneuver here.  A worthy project for humanity – especially over the next few decades − is to keep that bottleneck as wide as possible.  After passing through it, global biodiversity may recover to some degree as the technosphere begins to weigh less heavily on the biosphere.  It all depends on us.


Evidence of human impacts on biodiversity surrounds us.  Comparisons of current rates of extinction and those in the fossil record indicate that vertebrate species are now going extinct at a rate 100 or more times faster than is observed in most previous geologic periods.  The human-driven Sixth Extinction began perhaps 50,000 years ago when primitive humans arrived on Australia and wiped out many prey species that were unfamiliar with the new bipedal super predator.  Anthropologists refer to the “Pleistocene Overkill” to describe the wave of mammal extinctions that occurred when humans first crossed from Asia to North America about 15,000 years ago.

Modern humans continue to exterminate species directly by overhunting for food (e.g. the passenger pigeon) but also by widespread trafficking in wildlife and animal parts for food, as well as for medicinal and prestige purposes.  Various plant species are also endangered, notably several tropical hardwoods known as rosewood.  Sustained pressure on wildlife habitat from land use change and disruptions in geographic ranges caused by climate change adds further stress on top of overexploitation.  Genetic variation within many species is shrinking as their populations and geographic ranges contract, hence reducing their capacity to survive environmental change (formally termed a population bottleneck).

In essence, the expansion of technosphere capital (the mass of human made objects) is consuming biosphere capital (the biodiversity and biomass of the biosphere).  This loss of biodiversity − usually defined in terms of diversity of species and ecosystems − will likely continue over the coming decades.  As noted, though, the magnitude of the loss will depend heavily on human decisions. 

There are pragmatic, aesthetic, and ethical rationales for conserving Earth’s biodiversity.  Conservationists argue that retaining biodiversity maintains the functional integrity of ecosystems, and hence the full array of their ecosystem services.  Each species has a unique niche and contributes to ecosystem processes like nutrient cycling and recovery from disturbances.  With respect to aesthetics, the earlier mentioned Professor Wilson has suggested that humans have genetically determined biophilia − we get spontaneous pleasure from interacting with diverse forms of life.  The ethical argument is made strongly by the Deep Ecology movement.  For supporters, there is no human exceptionalism – all species have an equal right to survive and prosper on this planet.

Given the multiple rationales for wishing to widen the biodiversity bottleneck, what collective actions (besides the overriding one of limiting climate change) can help?  Scientists and policy experts have identified biodiversity-friendly practices such as reducing pesticide use, buying certified products, reducing invasive species, and reducing water pollution.  But here are four others that have high relevance.

1.  Stop Trafficking in Wildlife and Wild Animal Parts

The global trade in wild animals and wild animal parts puts tremendous downward pressure on the populations of many species.  Wild animals are commonly sold in Southeast Asian food markets despite laws against it.  Tigers, rhinos, and pangolins continue to be poached for dubious medicinal purposes.  Wild caught animals are sold as “bush meat” in parts of Africa and South America.  

A global trade in live animals intended as pets also flourishes.  Millions of  songbirds are collected every year in the primary forests of Indonesia and sold as pets or trained as contestants in bird song competitions.  Tropical fish are collected in the wild for marketing to aquarium owners.  

Multiple international agreements aim to stem wild animal trafficking, especially the Convention on International Trade in Endangered Species of Wild Fauna and Flora.  Under its auspices, national law enforcement agencies regularly confiscate illegal shipments of wild animals, animal parts, and wood from endangered tree species.  However, these efforts face deep resistance for cultural and economic reasons. 

A new brake on wild animal trafficking is fear of zoonotic pathogens.  The SARS-CoV-2 virus that is causing the Covid-19 global pandemic likely jumped from a wild animal host to a human in a market where wild animals are sold illegally.  New legislation passed in China limits sales of wild animal meat.  Unfortunately, enforcement is spotty, and the new law still allows sales of wild animal parts for medicinal purposes.  Sustained international pressure on wildlife traffickers is needed.

The Covid-19 pandemic is apparently impacting wildlife protection in other ways.  Conservationists fear that the loss of the tourist ‘halo’ or proximity effect, because of Covid-19 shutdowns, will increase the incidence of poaching in nature reserves.  Resumption of tourism would help in that regard.

2.  Expand the Size and Number of Protected Areas

A key driver of declining biodiversity is habitat loss.  To bring as many species as possible through the biodiversity bottleneck will require protection of representative areas for all unique types of ecosystems.

The Rewilding Movement has argued for creating protected areas that are large enough to support the whole complement of native species characteristic of each ecosystem type, along with the entire range of abiotic processes such as floods and fires that help maintain it.

Presently, about 15% of global land plus inland waters is protected to some degree.  For the oceans within national jurisdictions, the figure is about 13%.  Not all ecosystem types are represented.  For many types of ecosystems, the current protected area is quite small relative to its original geographic distribution (e.g. the Atlantic rain forest in Brazil).

Aspirations for expanding the protected areas of land and ocean range from 17% of land to half of Earth as a whole (the latter courtesy of the illustrious Professor Wilson).

Protected area plans can be developed over large domains, e.g. the entire United States.  These plans rely on integration of different managed lands such as wilderness areas, national parks, national forests, urban areas, and private reserves.

An international scientific advisory body (IPBES, Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) is dedicated to biodiversity assessment and conservation.  Like the Intergovernmental panel on Climate Change, IPBES produces periodic assessments and examinations of policy options.  IPBES is supported by member countries, including the U.S., and sustained national contributions are warranted.

In the private sector, land trust organizations such as The Nature Conservancy have as their key strategy the purchase of lands for conservation purposes; contributions are encouraged.  Public/private conservation partnerships are proliferating; participants are welcomed.

3.  Design Sustainable Cities

The proportion of the global population that lives in an urban setting recently passed the 50% mark and is expected to keep climbing in the coming decades.  A potential benefit to biodiversity conservation lies in the land that is abandoned as people supported by subsistence agriculture and nomadic herding move to towns and cities.  The freed-up land can potentially be repurposed in part or whole for wildlife conservation.  An underlying assumption is that agricultural intensification can take up any slack in food production and keep everyone fed. 

Urban greenbelt areas, parks, and gardens may serve directly as another assist to biodiversity conservation.  They support native and alien species and could serve as refuges for plant and animal species that are extirpated regionally by climate change and land use change.  Urban rivers and streams can likewise be managed to protect and support wildlife.

4.  Strategically Increase Ecotourism

In theory, the local economic benefits of nature-based tourism inspire local conservation efforts.  However, high tourist demand produces pressure to increase supply.  More local economic development (e.g. hotels and restaurants) plus more intensive visitor utilization of natural resources may end up degrading local ecosystems.  The research literature contains ecotourism case studies of successes, as well as failures.

Ecotourism narrowly defined refers to tourism that allows visitors to experience local wildlife and landscapes, creates incentives to protect those organisms and landscapes, and supports local communities.  More ecotourism is probably not appropriate in many places where it already exists because capacity is limited.  Rather, it is needed where wildlife is under threat and conservation incentives might be effective.      

Building socio-ecological systems is an emerging route to local sustainability.  These stakeholder groups optimally self-regulate to conserve the economic health and ecological health of the local environment.  Nobel Prize winner Elinor Ostrom has developed principles for structuring and operating these groups.  Monitoring the social, economic, and ecological dimensions of sustainability is a key requirement for successful ecotourism management.

Ecotourism, and tourism more generally, cannot be discussed in the context of biodiversity conservation without considering their global scale impacts.  As noted, climate change is a threat to biodiversity, and the carbon footprint of tourism is estimated to be 8% of total greenhouse gas emissions

Air travel is the foundation for much tourism, but it is especially difficult to decarbonize.  Short hop electric airplanes and long-haul flights powered by renewable energy based liquid fuels are technically feasible.  They could replace fossil fuel powered flights, but more government supported research is needed, and air travelers must be willing to pay an increased fare as these fuels are brought online.  Airline-associated carbon offset programs − although varying in effectiveness and not a permanent solution − contribute significantly to biodiversity conservation.  They help expand protected area and, by sequestering carbon, help slow climate change.


The human capacity to extinguish other species on this planet, and to pervasively alter wildlife habitat, means that we are in many ways responsible for which species and ecosystems will survive.  As we move through peak human population this century and begin to more purposefully manage our impacts on Earth’s biota, let’s keep the biodiversity bottleneck of our own making as wide open as possible.  Progress towards that goal would be both pragmatic and gratifying.

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