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Value of Earth
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The value of Earth, i.e. the net worth of our planet, is a debated concept both in terms of the definition of value, as well as the scope of "Earth". Since most of the planet's substance is not available as a resource, "earth" has been equated with the sum of all ecosystem services as evaluated in ecosystem valuation or full-cost accounting.[1]
The price on the services that the world's ecosystems provide to humans has been estimated in 1997 to be $33 trillion per annum, with a confidence interval of from $16 trillion to $54 trillion.[vague] Compared with the combined gross national product (GNP) of all the countries at about the same time ($18 trillion), ecosystems would appear to be providing 1.8 times as much economic value as people are creating.[2] The result details have been questioned, in particular the GNP, which is believed to be closer to $28 trillion (which makes ecosystem services only 1.2 times as precious), while the basic approach was readily acknowledged.[3] The World Bank gives the total gross domestic product (GDP) in 1997 as $31 trillion, which would about equal the biosystem value.[4] Criticisms were addressed in a later publication, which gave an estimate of $125 trillion/yr for ecosystem services in 2011, which would make them twice as valuable as the GDP, with a yearly loss of 4.3–20.2 trillion/yr.[5]
The BBC has published a website that lists various types of resources on various scales together with their current estimated values from different sources, among them BBC Earth, and Tony Juniper in collaboration with The United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC).[6]
See also
[edit]References
[edit]- ^ Pimm, Stuart L. (1997). "The value of everything". Nature. 387 (6630): 231–232. Bibcode:1997Natur.387Q.231P. doi:10.1038/387231a0. ISSN 0028-0836.
Economists and ecologists have joined forces to estimate the annual value of the services that Earth's ecosystems provide. Most services lie outside the market and are hard to calculate, yet minimum estimates equal or exceed global gross national product.
- ^ Costanza, Robert; d'Arge, Ralph; de Groot, Rudolf; Farber, Stephen; Grasso, Monica; Hannon, Bruce; Limburg, Karin; Naeem, Shahid; O'Neill, Robert V.; Paruelo, Jose; Raskin, Robert G.; Sutton, Paul; van den Belt, Marjan (1997). "The value of the world's ecosystem services and natural capital". Nature. 387 (6630): 253–260. Bibcode:1997Natur.387..253C. doi:10.1038/387253a0. ISSN 0028-0836. S2CID 672256.
We have estimated the current economic value of 12 ecosystem services for 16 biomes, based on published studies and a few original calculations. For the entire biosphere, the value (most of which is outside the market) is estimated to be in the range of US$16-54 (1012) per year, with an average of US$33 trillion per year. Because of the nature of the uncertainties, this must be considered a minimum estimate. Global gross national product total is around US$18 trillion per year.
- ^ Pearce, David (1998). "Auditing the Earth:The Value of the World's Ecosystem Services and Natural Capital" (PDF). Environment: Science and Policy for Sustainable Development. 40 (2): 23–28. doi:10.1080/00139159809605092. ISSN 0013-9157.
- ^ "GDP (current US$)". Data. Retrieved 2018-06-06.
- ^ Costanza, Robert; de Groot, Rudolf; Sutton, Paul; van der Ploeg, Sander; Anderson, Sharolyn J.; Kubiszewski, Ida; Farber, Stephen; Turner, R. Kerry (2014). "Changes in the global value of ecosystem services". Global Environmental Change. 26: 152–158. doi:10.1016/j.gloenvcha.2014.04.002. ISSN 0959-3780. S2CID 15215236.
• Global loss of ecosystem services due to land use change is $US 4.3–20.2 trillion/yr. • Ecoservices contribute more than twice as much to human well-being as global GDP. • Estimates in monetary units are useful to show the relative magnitude of ecoservices. • Valuation of ecosystem services is not the same as commodification or privatization. • Ecosystem services are best considered public goods requiring new institutions.
- ^ "Cost the Earth sources / How we derived financial values for the natural world". Retrieved 2018-06-05.
in a world that often focuses on money, it can be a useful tool to help remind us that nature does have a value, and what might be lost if aspects of it disappear.
Value of Earth
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Conceptual Foundations
Definitions of Planetary Value
Planetary value encompasses the assessed worth of a planet's biophysical systems, resources, and processes, primarily in relation to their capacity to sustain life, ecosystems, and human endeavors. In environmental economics, this is formalized through the total economic value (TEV) framework, which quantifies benefits derived from natural capital via market and non-market methods, including revealed and stated preferences.[4] TEV distinguishes between instrumental values—those serving human ends—and attempts to incorporate non-anthropocentric elements, though empirical assessments prioritize measurable utility to avoid unverifiable assumptions.[5] Use values within TEV are divided into direct uses, such as extraction of minerals, timber, or agricultural products from Earth's crust and biosphere; indirect uses, encompassing regulatory functions like atmospheric carbon sequestration, water purification, and biodiversity maintenance that underpin global stability; and option values, representing the premium for preserving potential future benefits amid uncertainty, such as untapped genetic resources or adaptive resilience to perturbations.[6] Non-use values include existence value, derived from the welfare gain of knowing Earth's systems endure without personal interaction, and bequest value, reflecting intergenerational equity in transmitting planetary integrity.[7] These categories aggregate to estimate Earth's instrumental worth, often expressed in monetary terms via hedonic pricing, travel cost methods, or contingent valuation surveys calibrated against biophysical indicators.[4] Intrinsic value posits that Earth possesses worth independent of human instrumental benefits, viewing the planet as an end in itself due to its complexity, uniqueness, or role in cosmic processes.[8] This perspective draws from ecological ethics, arguing that self-organizing systems like the biosphere warrant preservation regardless of utility, though it resists quantification and has limited operationalization in policy, as decisions require trade-offs grounded in observable causal impacts rather than abstract rights.[9] Instrumental and intrinsic framings are not mutually exclusive, but truth-seeking evaluations emphasize the former for verifiability, as intrinsic claims often embed untested normative priors from philosophical traditions rather than empirical data on planetary dynamics.[10] Hybrid approaches, such as relational values integrating cultural and stewardship dimensions, emerge in interdisciplinary assessments but remain subordinate to TEV's structured decomposition for comprehensive planetary accounting.[11]Valuation Methodologies and Approaches
Economic valuation of the Earth focuses on quantifying the benefits derived from its natural systems, primarily through assessments of ecosystem services—flows of benefits such as pollination, climate regulation, and water purification—and natural capital stocks like soils, forests, and mineral reserves. These methodologies draw from environmental economics, adapting micro-level techniques to aggregate planetary-scale estimates, often using monetary units to enable policy comparisons. Central challenges include handling non-market values, spatial heterogeneity across biomes, and long-term sustainability, with estimates typically representing annual service flows rather than perpetual stock values.[12][13] Market-based approaches value services with observable prices, such as harvested timber or captured fish, by applying global commodity market data adjusted for sustainability limits; for instance, timber values incorporate stumpage fees and processing costs. Replacement cost methods estimate the expense of human-engineered alternatives, like the capital and operational costs of wastewater treatment plants to proxy natural filtration by wetlands or aquifers. Avoided cost methods calculate damages prevented, such as the engineering expenses for flood barriers versus mangrove protection. These cost-oriented techniques underpin valuations for regulatory services like erosion control, where global aggregates rely on engineering benchmarks scaled by land area.[14][15][13] Revealed preference methods derive values from human behavior in related markets. Hedonic pricing regresses asset prices, such as real estate, against environmental proxies like air quality or proximity to greenspaces, isolating marginal contributions; global extrapolations apply these to urban-rural gradients. Travel cost models assess recreation by analyzing visitor origins, expenditures, and time costs as demand curves, with planetary applications transferring site-specific recreational values to total biome areas. These behavioral inferences avoid direct hypotheticals but require assumptions about substitutability across scales.[16][15] Stated preference techniques, including contingent valuation, survey hypothetical willingness-to-pay or accept for services like biodiversity maintenance, using dichotomous choice formats to mitigate bias; conjoint analysis ranks attributes for bundled services. At global levels, these inform non-use values (existence, bequest) via meta-analyses, though response biases and strategic answering necessitate statistical corrections. Benefits transfer integrates all methods by mapping local study values to similar global ecosystems, as in biome-specific unit values multiplied by areas, forming the core of comprehensive planetary assessments.[14][16] The seminal planetary application, by Costanza et al. in 1997, aggregated literature-derived values for 17 services across 16 biomes using the above techniques, estimating annual global ecosystem service flows at US$16–54 trillion (average $33 trillion in 1995 dollars), exceeding contemporaneous global GDP of approximately $18 trillion. This synthesis employed value transfer for data gaps, with services like atmospheric gas regulation valued via replacement costs for ozone depletion mitigation. Updates, such as a 2014 revision incorporating expanded datasets and services, raised the estimate to $125–145 trillion annually, reflecting biophysical modeling refinements but facing critiques for potential double-counting of interdependent services and underemphasis on biophysical limits over anthropocentric metrics.[12][1][17]Historical Context
Pre-20th Century Perspectives
In ancient Greek philosophy, the value of Earth and its resources was conceptualized through the lens of oikonomia, or household management, aimed at achieving self-sufficiency and human well-being rather than unlimited accumulation. Aristotle, in his Politics, argued that land and natural resources possess value insofar as they support the polis's stability, advocating private property in land to incentivize care and efficiency, as communal ownership often led to neglect and conflict.[18] He recognized Earth's finitude, emphasizing population limits to match fixed arable land and avoid resource depletion, viewing excess acquisition (chrematistike) as unnatural and detrimental to virtue.[19] This utility-based valuation prioritized resources' role in sustaining ethical life over any independent planetary worth. Medieval scholastic thought, exemplified by Thomas Aquinas, integrated Aristotelian ideas with Christian theology, positing that Earth's creation ex nihilo endows it with intrinsic goodness derived from participation in God's existence, yet ordered hierarchically for human dominion and use. In the Summa Theologica, Aquinas described creatures as valuable because they exist and manifest divine wisdom, but their worth remains instrumental, serving rational beings' perfection and ultimate union with God.[20] Economic exchanges of earthly goods followed natural law, with "just price" determined by labor, scarcity, and communal needs rather than arbitrary fiat, reflecting Earth's resources as providential means for justice and sustenance.[21] This framework rejected pantheistic deification of nature, attributing primary value to spiritual ends over material abundance. By the 18th and 19th centuries, Enlightenment and classical economic views increasingly emphasized Earth's productive capacity through land and extractable resources, influencing colonial expansions and agricultural reforms. Physiocrats like François Quesnay regarded land as the sole originator of net wealth, with value arising from agricultural surplus rather than trade or manufacture, positing Earth's fertility as the foundation of societal prosperity.[22] Estimates of global wealth during this era, often dominated by landed estates, highlighted massive asset-to-income ratios, underscoring land's centrality amid emerging recognitions of resource limits amid industrialization.[22] These perspectives remained anthropocentric, treating planetary value as aggregate utility for human improvement, without holistic monetary appraisals of the biosphere.20th Century Economic Models
The development of economic models for valuing Earth's resources in the 20th century transitioned from sector-specific analyses of extractive industries to broader assessments of environmental externalities and natural capital flows. Early efforts, rooted in neoclassical economics, addressed scarcity and optimal depletion. In 1931, Harold Hotelling formulated a rule for exhaustible resources, asserting that the shadow price (net of extraction costs) of a non-renewable asset, such as minerals or fossil fuels, should increase at the prevailing interest rate to ensure intertemporal efficiency in extraction paths.[23] This model implied a rising scarcity rent for planetary reserves, influencing valuations of global oil and mineral stocks by framing their worth as the present value of future rents discounted against alternative investments. Similarly, mid-century models for renewable resources, like H. Scott Gordon's 1954 analysis of open-access fisheries, demonstrated economic overexploitation due to unpriced common-pool dynamics, leading to estimates of sustainable yields and lost rents for oceanic biomass.[23] Post-World War II, environmental economics expanded to incorporate externalities, with Arthur Pigou's earlier (1920) framework of corrective taxes gaining application in pollution and resource damage assessments. Valuation techniques emerged, including hedonic pricing for air quality impacts and travel cost methods for recreational resources, often applied at national scales but laying groundwork for aggregation. By the 1970s, amid resource crises like the 1973 oil embargo, preliminary global models attempted holistic appraisals. A static general equilibrium input-output framework circa 1970 estimated the total value of ecosystem services supporting human production at US$9.4 trillion annually (in 1972 dollars, equivalent to about US$34 trillion in 1994 dollars).[1] Another approach, focusing on maximum sustainable surplus, pegged the range at US$3.4–17.6 trillion per year, derived from ecosystems' contributions to marketed outputs.[1] These inputs highlighted Earth's biophysical flows as underpriced inputs but relied on partial equilibrium assumptions, often ignoring substitution possibilities or irreversible losses. The late 20th century saw synthesized global valuations, culminating in Robert Costanza et al.'s 1997 study, which aggregated unit values from over 100 prior analyses across 17 ecosystem services (e.g., pollination, water purification, climate regulation) and 16 biomes. Using methods like replacement cost, avoided damage, and production function approaches, the study calculated an average annual flow value of US$33 trillion (1994 dollars), with a range of US$16–54 trillion—roughly 1.8 times the era's global gross national product of US13 trillion from ocean productivity), underscoring the dominance of non-market services. While pioneering in scale, the model treated values as static annual flows rather than dynamic stocks, and its reliance on extrapolated willingness-to-pay measures drew scrutiny for potential overaggregation, as services like nutrient cycling exhibit interdependencies not fully captured in additive sums.[12] These efforts marked a paradigm shift toward integrating Earth's regulatory functions into economic accounting, influencing subsequent national adjustments for natural capital depreciation.Ecosystem Services Valuation
Core Components of Ecosystem Services
Ecosystem services represent the benefits humans derive from natural processes and biodiversity, categorized into four core components by the Millennium Ecosystem Assessment (MEA) framework developed between 2001 and 2005.[24] These components—provisioning, regulating, cultural, and supporting services—underpin human well-being by providing essential resources, maintaining environmental stability, offering intangible benefits, and enabling the production of other services.[25] The MEA, involving over 1,360 experts worldwide, emphasized that these services are interdependent and often undervalued in economic models due to their non-market nature.[26] Provisioning services include the tangible products obtained from ecosystems, such as food, fresh water, timber, fiber, fuel, and genetic resources. For instance, global fisheries provide approximately 17% of the world's animal protein intake, with capture fisheries yielding 96 million tonnes annually as of 2018 data integrated into ecosystem assessments. These services directly support agriculture and industry; for example, wild pollinators contribute to 35% of global food production by volume through crop pollination. Without these, human sustenance and material needs would require synthetic alternatives, often at higher costs. Regulating services encompass the ecosystem processes that regulate environmental conditions, including climate regulation, flood control, water purification, disease regulation, and pollination. Forests and oceans absorb about 50% of anthropogenic CO2 emissions, mitigating climate change at a rate of roughly 2.5 billion tonnes of carbon annually from land sinks alone as estimated in 2020 global carbon budgets. Wetlands filter pollutants, providing natural water purification equivalent to billions in treatment costs; the U.S. alone benefits from $23.6 billion in annual flood protection from coastal wetlands.[27] Pollination by insects and birds sustains $235–$577 billion in annual global crop output. Cultural services provide non-material benefits, such as recreation, aesthetic value, spiritual enrichment, educational opportunities, and cultural heritage. These services foster mental health and social cohesion; for example, national parks in the U.S. generate over $40 billion in visitor spending yearly, supporting 318,000 jobs as of 2022. Indigenous communities often derive identity and traditional knowledge from ecosystems, with biodiversity hotspots preserving irreplaceable cultural artifacts and practices tied to specific species. Supporting services are foundational processes that maintain ecosystems' capacity to deliver other services, including primary production, nutrient cycling, soil formation, and habitat provision. Soil formation, driven by microbial and faunal activity, replenishes arable land at rates of 0.025–0.125 mm per year in temperate regions, essential for long-term agriculture. Nutrient cycling recycles elements like nitrogen and phosphorus, preventing deficiencies that could collapse food webs; disruptions, such as eutrophication from excess fertilizers, have degraded 20% of assessed freshwater systems since 2005.[28] These services are indirect but critical, as their loss cascades to undermine provisioning and regulating functions.[24]Landmark Studies and Estimates
A seminal study by Costanza et al. (1997) estimated the annual economic value of 17 ecosystem services across 16 biomes at US33 trillion) in 1995 dollars, derived from published valuations using techniques such as replacement cost, avoided cost, and hedonic pricing.[12] This figure substantially exceeded the global gross domestic product of approximately US$18 trillion at the time, emphasizing the scale of non-market benefits like air quality regulation, climate regulation, and pollination.[12] The analysis aggregated data from over 100 studies, focusing on service flows rather than natural capital stocks, and highlighted uncertainties due to incomplete data for certain biomes and services.[1] In a 2014 update, Costanza et al. expanded the scope to 22 biomes and additional services, yielding an estimated annual value of US$125–145 trillion in 2007 dollars.[29] This revision incorporated post-1997 literature and adjusted for biome area changes, but the authors cautioned against direct comparability with the 1997 estimate owing to broader coverage and refined methodologies, including production function approaches for some services.[30] The higher figure reflected growing recognition of overlooked services like cultural and spiritual values, though it remained an order-of-magnitude approximation subject to valuation inconsistencies across studies.[29] The Economics of Ecosystems and Biodiversity (TEEB) initiative, launched in 2007, compiled a valuation database with over 1,300 peer-reviewed monetary estimates for ecosystem services across biomes, facilitating biome-specific syntheses rather than a singular global total.[31] De Groot et al. (2012), drawing from this database, reported mean annual values per hectare for 10 major biomes—ranging from US$6,872 for lakes/rivers to over US$1 million for coral reefs (in 2007 international dollars)—and extrapolated global totals exceeding US$33 trillion when scaled by biome areas, aligning with Costanza's framework but emphasizing regulatory and habitat services.[32] These estimates underscored provisioning services like food and timber as lower-valued compared to supporting services, with total global flows conservatively bounded below contemporary GDP multiples.[31]| Study | Publication Year | Estimated Global Annual Value (Average) | Base Year/Currency | Key Scope |
|---|---|---|---|---|
| Costanza et al. | 1997 | US$33 trillion | 1995 USD | 17 services, 16 biomes |
| Costanza et al. | 2014 | US$135 trillion | 2007 USD | 22 biomes, expanded services |
| de Groot et al. (TEEB) | 2012 | >US$33 trillion (synthesized) | 2007 Int'l $ | 10 biomes, database of 1,300+ vals. |
Resource and Asset-Based Valuations
Mineral and Elemental Resource Estimates
Estimates of Earth's mineral and elemental resources distinguish between reserves, which are economically viable for extraction under current technology and prices, and resources, which encompass broader identified and undiscovered deposits that may become viable in the future. The U.S. Geological Survey (USGS) provides annual assessments through its Mineral Commodity Summaries, compiling data from industry, governments, and geological surveys worldwide; these figures reflect 2023 production and reserve updates as of early 2024.[34] Global reserves for key metals remain substantial, supporting centuries of demand at current rates for many commodities, though extraction faces environmental, geopolitical, and technological constraints.[34] Major ferrous and base metals dominate reserve estimates by volume. World iron ore reserves stand at approximately 87 billion metric tons of contained iron, primarily in Australia, Brazil, and Russia, sufficient for over 200 years at 2023 production levels of around 2.6 billion tons annually.[34] Copper reserves total about 1 billion metric tons, concentrated in Chile, Peru, and Australia, with resources extending to 5.6 billion tons including undiscovered deposits.[34] Precious metals like gold have smaller reserves of 59,000 metric tons globally, valued for their scarcity and industrial uses, though total resources may exceed 100,000 tons when including sub-economic deposits.[34] Aluminum, derived from bauxite, has world reserves of 30 billion metric tons of bauxite ore, equivalent to roughly 5-6 billion tons of alumina, with resources up to 55-75 billion tons; major holders include Guinea, Australia, and Brazil.[34] Critical minerals for energy transitions, such as lithium (28 million tons reserves) and cobalt (11 million tons), show more limited reserves relative to rising demand, prompting concerns over supply chains dominated by Australia, Chile, and the Democratic Republic of Congo.[34] Rare earth elements aggregate 110 million tons in reserves, largely in China and Vietnam, essential for electronics and renewables but vulnerable to processing bottlenecks.[34]| Mineral | World Reserves (metric tons) | Major Reserve Holders | Years at Current Production |
|---|---|---|---|
| Iron (content) | 87,000,000,000 | Australia, Brazil, Russia | >200 |
| Copper | 1,000,000,000 | Chile, Peru, Australia | ~50 |
| Gold | 59,000 | Australia, Russia, South Africa | ~20 |
| Bauxite (Al) | 30,000,000,000 | Guinea, Australia, Brazil | >100 |
| Lithium | 28,000,000 | Australia, Chile, Argentina | ~80 |
| Cobalt | 11,000,000 | DR Congo, Australia, Indonesia | ~40 |
Land and Infrastructure Valuations
Global agricultural land, comprising arable, pasture, and other farmable areas totaling approximately 4.8 billion hectares, was valued at $47.9 trillion as of the end of 2024, reflecting increases driven by commodity prices and scarcity perceptions.[38] This estimate primarily captures market-based assessments of productive capacity, with values varying widely by region—higher in developed markets like North America and lower in underutilized tropical areas. Urban and suburban land, covering less than 1% of Earth's surface but underpinning high-density human settlement, contributes disproportionately to total land valuations, embedded within broader real estate metrics that do not consistently isolate bare land from overlying structures. Comprehensive global land valuations excluding improvements remain limited due to data aggregation challenges and varying national accounting standards, which often bundle land with depreciable assets. McKinsey's 2020 global balance sheet analysis places total real estate—including underlying land for residential, commercial, and governmental uses—at approximately $340 trillion, or two-thirds of estimated global net worth of $510 trillion, with residential land and structures alone at $235 trillion.[39] Savills reports aggregate real estate at $393.3 trillion by late 2024, incorporating agricultural land alongside urban and commercial properties, though without explicit land-structure splits. These figures derive from market transactions, appraisal models, and capitalization of rental yields, prioritizing locations with proximity to economic centers, resources, and infrastructure; vast expanses of desert, tundra, or remote wilderness typically register negligible asset value under such approaches, as their utility hinges on extraction potential rather than inherent scarcity in isolation. Infrastructure valuations, encompassing constructed assets like transportation networks, utilities, energy facilities, and non-residential buildings, emphasize replacement costs, depreciated book values, or income approaches to reflect ongoing societal utility. McKinsey attributes $102 trillion (20% of 2020 global net worth) to other fixed assets, including infrastructure alongside machinery and equipment, highlighting their role in enabling production and connectivity.[39] Specific components, such as global commercial real estate (a proxy for some infrastructural buildings), stood at $58.5 trillion in 2024.[38] Replacement cost models, used by engineering firms and governments, account for material, labor, and technological obsolescence; for instance, aging transport infrastructure in developed economies often exceeds $10 trillion in collective retrofit needs, underscoring underinvestment relative to asset longevity. These estimates, drawn from institutional balance sheets and investment analyses, undervalue non-monetized resilience factors like redundancy against disruptions, while over-relying on current GDP correlations that may inflate figures in high-growth regions.Planetary-Scale Economic Models
Mass and Physical Property-Based Calculations
Mass and physical property-based calculations derive estimates of Earth's value by leveraging geophysical data on total mass, density, and internal structure to determine bulk composition, then applying commodity market prices to the masses of constituent elements or minerals. Earth's total mass, calculated from Newtonian gravitational parameters and spacecraft observations, stands at 5.9722 × 10^{24} kg. Its mean density of 5.513 g/cm³, combined with seismic profiles and the planet's moment of inertia factor (0.3307), reveals a differentiated structure: a dense iron-rich core (about 32% of mass), silicate mantle (67%), and thin crust (0.4%).[40] These properties constrain bulk elemental abundances through integration of cosmochemical ratios (e.g., from meteorites) and high-pressure experiments. The resulting composition by mass emphasizes abundant, low-unit-value elements: iron (32%), oxygen (30%), silicon (15%), and magnesium (14%), with trace amounts of higher-value metals like nickel (1.8%). To compute value, the mass of each component multiplies by prevailing bulk commodity prices, typically for ores or industrial grades rather than refined forms. This yields nominal "scrap" valuations, though such figures are artifacts of extrapolation—market prices reflect scarcity and processing at surface scales, not planetary disassembly, which would require energy inputs rivaling the Sun's output and collapse prices via infinite supply. Illustrative values for major elements, using 2024-2025 average prices, are shown below (prices fluctuate; iron ore averaged ~1.50/kg, magnesium ~$2.50/kg; oxygen lacks a bulk market price as it is abundant in atmosphere and compounds):| Element | Mass Fraction (%) | Mass (kg) | Price per kg (USD) | Nominal Value (USD) |
|---|---|---|---|---|
| Iron | 32 | 1.91 × 10^{24} | 0.10 | 1.91 × 10^{23} |
| Silicon | 15 | 8.96 × 10^{23} | 1.50 | 1.34 × 10^{24} |
| Magnesium | 14 | 8.36 × 10^{23} | 2.50 | 2.09 × 10^{24} |
| Nickel (trace) | 1.8 | 1.07 × 10^{23} | 15.00 | 1.61 × 10^{24} |
Integrated Global Asset Assessments
Integrated global asset assessments synthesize valuations of diverse planetary assets, including human capital, produced capital, natural capital, and net foreign assets, to derive a comprehensive measure of Earth's total wealth. These assessments, exemplified by the World Bank's Changing Wealth of Nations series, extend beyond market-based metrics to incorporate the economic value of human productivity, manufactured infrastructure, renewable and nonrenewable resources, and international claims. By framing wealth as the present value of future income streams from these assets, such models enable cross-country and temporal comparisons of sustainability, revealing how resource depletion offsets gains in other categories.[42] The methodology relies on standardized accounting frameworks, where human capital—estimated as the discounted lifetime earnings of the working-age population adjusted for education and health—is the dominant component, comprising approximately 60% of global wealth in 2020. Produced capital, encompassing infrastructure, machinery, and urban land, accounts for about 20%, while natural capital (forests, minerals, fisheries, and subsoil assets) represents the balance, with nonrenewable resources like oil and gas valued at extraction costs plus rents. Net foreign assets adjust for cross-border holdings. This integration highlights causal trade-offs: for instance, global per capita natural capital declined by 1% from 1995 to 2020, driven by a 28% drop in timber stocks and over 25% in marine fish biomass, equivalent to a $70 billion loss in chained 2019 USD terms.[43][44] Despite growth in total real wealth per capita by 21% over the same period, primarily from human and produced capital accumulation, these assessments underscore systemic vulnerabilities. High-income countries hold over two-thirds of global wealth, with natural capital depletion concentrated in low- and middle-income nations reliant on resource exports. Updates in the 2024 report refine valuations using chained Törnqvist indices for volume changes and incorporate expanded data on hydroelectric assets ($3.5 trillion globally in 2020) and land sectors, where agricultural land per capita fell 24%. Such models inform policy by quantifying how overreliance on nonrenewables erodes intergenerational equity, though critics note uncertainties in discounting future flows and incomplete coverage of intangible assets like biodiversity.[43][45]| Asset Type | Approximate Global Share (2020) | Key Trends (1995–2020) |
|---|---|---|
| Human Capital | 60% | Primary driver of wealth growth; education/health investments key.[43] |
| Produced Capital | ~20% | Steady accumulation via infrastructure; offsets some natural declines.[43] |
| Natural Capital (Renewable & Nonrenewable) | ~20% | Per capita decline; renewables (e.g., fisheries) down >25%, nonrenewables stable but finite.[43] |
| Net Foreign Assets | Variable (netted in totals) | Adjusts for imbalances; minimal global net impact.[42] |