This section summarizes how we track a population’s biological resource demand and domestic availability. We also explain which income metrics we chose. A more complete discussion of the resource metric method is included in the Supplementary Methods.
Measuring the biological resource balance
The sustainable development literature has consistently recognized the importance of biological resource security. For example, the foundational Brundtland report expressed it as the need to live “within the planet’s ecological means” or “in harmony with the changing productive potential of the ecosystem”43.
These principles call for comparing biological resource regeneration with a population’s demand on nature. Since people’s demands compete for nature’s products and services, one way of measuring this relationship between regeneration and human demand is by tracking how much mutually exclusive, biologically productive area is necessary to provide the resource flows that people demand. Humans demand biologically productive areas in several quantifiable ways: production of food, fibre and timber; physical infrastructure such as roads and buildings; and absorption of waste, particularly the carbon dioxide from fossil fuel combustion. The total demand for biologically productive surfaces can be compared with the productive areas available that provide regeneration. Since the productivity of areas varies, they need to be measured not in terms of their physical extension, but in terms of biological regeneration they represent. For example, one can use a biologically productive hectare with world-average productivity as the common measurement unit that then allows expression of both demand and availability of productive areas in units that become comparable across space and time.
Ecological footprint accounting is a well-documented concept to measure the total supply and demand of biological regeneration. In ecological footprint accounting, the ecosystem capacity to regenerate biomass is called biocapacity. It is measured in standardized ‘global hectares’, which represent the productivity of a world-average biologically productive hectare. The human demand for biocapacity is called the population’s ‘ecological footprint’, and it is the sum of all the mutually exclusive demands on these bioproductive areas. Ecological footprints are also expressed in global hectares.
The principles of ecological footprint accounting, and the derived methods for national and sub-national assessments, are documented extensively within scientific literature6,7,8,9,38,44,45,46. The national accounting methodology has also been reviewed and documented by numerous national government agencies47.
The essence of the approach is that regeneration is used as the lens to analyse both availability and demand because biological assets are materially the most limiting factor of the human economy1,2. In addition, biocapacity and ecological footprint can be tracked and compared with each other on the basis of two principles:
- 1.
By scaling every area proportionally to its biological productivity, each biologically productive area becomes commensurable with any other one. This is the essence of the global hectare.
- 2.
By including only areas that exclude other uses, that is, by making sure that every area is counted only once, the areas can meaningfully be added up, both for all the competing demands on productive surfaces (the ecological footprint) and for the surfaces that contain the planet’s regenerative capacity (the biocapacity).
The country-level accounts, called the National Footprint and Biocapacity Accounts, show that humanity’s demand exceeds Earth’s biocapacity, and the gap has been increasing since the 1970s8,38,40. This is consistent with research on planetary boundaries or ecosystem health1,2,10,11.
Countries’ resource demand can be analysed from a consumption or a production perspective. The consumption perspective, which is the one used in this study, adjusts for trade and indicates the total resource consumption demand of a population. The production perspective identifies how much demand activities within a country directly put on ecosystems. This could be interpreted as the demand associated with generating the country’s GDP.
Countries that demand more than their domestic ecosystems regenerate run a biocapacity deficit. It is made possible by three mechanisms: (1) overuse of domestic ecosystems, or local overshoot; (2) net import of biocapacity; and (3) use of the global commons, as in the case of emitting CO2 from fossil fuel into the atmosphere or fishing international waters38.
Global results indicate that as of 2017, Earth had about 12.1 billion biologically productive hectares, according to Food and Agriculture Organization land-use statistics48. This includes productive ocean areas. By definition, this equals 12.1 billion global hectares, as each global hectare represents the productive average of all these 12.1 billion hectares. By contrast, human demand in 2017 added up to 20.9 billion global hectares, 73% higher than the regeneration of all the planet’s ecosystems combined (in per-person numbers, an average footprint of 2.8 global hectares contrasted to 1.6 global hectares of biocapacity available per person worldwide). This 73% overshoot may have dropped to 56% in 2020 due to lockdowns during COVID-194. In 2017, ecological footprint country averages varied from 0.5 global hectares per person (Eritrea) to 14.7 global hectares per person (Qatar). Biocapacity averages among countries stretch from 0.1 global hectares per person (Singapore) to 84 global hectares per person (Suriname)40.
The accounts include only human demands (including domesticated animals) and not those of the millions of other living species, which together make possible the continuous functioning of the global ecosystem. To maintain biodiversity, which is critical for the integrity of the global ecosystem, humanity’s footprint would need to be less than the planet’s total biocapacity. E.O. Wilson, for example, proposed to only use half the planet’s capacity to secure 85% of its current biodiversity49. Using this objective as reference would imply that humanity’s current biological metabolism would be three times too large. It also makes clear that zero biocapacity deficits are a necessary but not sufficient condition for planetary resource stability. Still, for simplicity, we use the zero biocapacity deficit line as the demarcation line.
Currently, the single-largest competing demand on the biosphere is the need for carbon sequestration capacity to neutralize emissions from fossil fuel burning. In 2020, this demand made up 57% of humanity’s ecological footprint. To comply with the Paris Agreement’s stated goal (Article 2 of ref. 30), this portion of the footprint would need to fall rapidly to zero. This reduction may come at the cost of increasing other parts of the ecological footprint. For example, more forest or agricultural products may be used to substitute for fossil fuels. If the Paris Agreement is fully implemented, there will be legal pressure to eliminate the carbon-related part of the deficit. If it is not implemented, the reduction pressures will emerge more slowly, which will increase the likelihood that the biocapacity will become increasingly damaged by climate change. Taking either path forces a country to eliminate its carbon footprint one way or the other. Fossil fuel dependence is therefore turning into an ever-growing risk. The pressure of increased land use has historically been the leading factor in the extinction of biodiversity, but unless nations can effectively control climate change, it will soon predominate as the major factor responsible for the massive extinction event that we humans have already started as a result of our unsustainable consumption—the sixth such event in the history of our planet.
Measuring ability to purchase resources from abroad
Annual value production of an economy is measured by its GDP. It can be calculated as the value add of all its produced goods and services, as the sum of all the incomes or as the sum of all expenditures. Therefore, GDP can be used as a measure for a country’s income50,51.
The analysis here focuses on the relative purchasing power of countries’ economic actors on global markets. Therefore, we use nominal US$ (or for time series, constant US$) instead of purchasing-power-adjusted US$, which reflect purchasing power on local markets. As economic actors compete for global resources in the same global market, each dollar has approximately the same weight, independent of the dollar’s purchasing power in the actor’s domestic market (called purchasing power parity). While this simplifies the fact that many commodities do not have a single homogeneous global market, the price range for resources in international markets is much narrower than that between domestic markets.
For the sake of this analysis, we use average country income. Although incomes within countries vary vastly, we assume that nominal per-capita GDP is a reasonable approximation for national purchasing power in international markets. As a medium of exchange, money gives its owner the option to trade it in for physical assets, including biological resources; hence, more money means access to more resources.
Not all international resource transfers are traded on global markets. Purchases could be under the protection of government-to-government arrangements or long-term contracts. The more of the international resource exchanges that occur in global markets, the tighter the competition on the global market for the remaining resources. Such increased competition makes the implications of the analysis presented here even more dramatic.
In the context of global ecological overshoot, biocapacity scarcity will increase; therefore, the competition for purchasing additional resources will become even fiercer. In this case, using world-average income as an approximation for the dividing line between those who can net-purchase from abroad and those who cannot is too lenient. This demarcation indicates only that statistically those above the line can net-purchase from abroad. It does not indicate, however, whether they can purchase enough from abroad to cover their biocapacity deficit. This means that even more national economies than those identified by the 72% in this paper are excluded from being able to purchase sufficient resources from abroad.
Source: Ecology - nature.com
