kb/data/en.wikipedia.org/wiki/Carrying_capacity-4.md

title	chunk	source	category	tags	date_saved	instance
Carrying capacity	5/5	https://en.wikipedia.org/wiki/Carrying_capacity	reference	science, encyclopedia	2026-05-05T07:17:32.393840+00:00	kb-cron

=== Ecological footprint accounting === Ecological footprint accounting measures the demands people make on nature and compares them to available supplies, for both individual countries and the world as a whole. Developed originally by Mathis Wackernagel and William Rees, it has been refined and applied in a variety of contexts over the years by Global Footprint Network (GFN). On the demand side, the ecological footprint measures how fast a population uses resources and generates wastes, with a focus on five main areas: carbon emissions (or carbon footprint); land devoted to direct settlement; timber and paper use; food and fiber use; and seafood consumption. It converts these into per capita or total hectares used. On the supply side, national or global biocapacity represents the productivity of ecological assets in a particular nation or the world as a whole; this includes "cropland, grazing land, forest land, fishing grounds, and built-up land." Again the various metrics to capture biocapacity are translated into the single term of hectares of available land. As Global Footprint Network (GFN) states:Each city, state or nation's Ecological Footprint can be compared to its biocapacity, or that of the world. If a population's Ecological Footprint exceeds the region's biocapacity, that region runs a biocapacity deficit. Its demand for the goods and services that its land and seas can provide—fruits and vegetables, meat, fish, wood, cotton for clothing, and carbon dioxide absorption—exceeds what the region's ecosystems can regenerate. In more popular communications, this is called "an ecological deficit." A region in ecological deficit meets demand by importing, liquidating its own ecological assets (such as overfishing), and/or emitting carbon dioxide into the atmosphere. If a region's biocapacity exceeds its Ecological Footprint, it has a biocapacity reserve.According to the GFN's calculations, humanity has been using resources and generating wastes in excess of sustainability since approximately 1970: currently humanity use Earth's resources at approximately 170% of capacity. This implies that humanity is well over Earth's human carrying capacity for our current levels of affluence and technology use. According to Global Footprint Network:In 2024, [Earth Overshoot Day] fell on August 1. Earth Overshoot Day marks the date when humanity has exhausted nature's budget for the year. For the rest of the year, we are maintaining our ecological deficit by drawing down local resource stocks and accumulating carbon dioxide in the atmosphere. We are operating in overshoot.The concept of 'ecological overshoot' can be seen as equivalent to exceeding human carrying capacity. According to the most recent calculations from Global Footprint Network, most of the world's residents live in countries in ecological overshoot (see the map on the right).
This includes countries with dense populations (such as China, India, and the Philippines), countries with high per capita consumption and resource use (France, Germany, and Saudi Arabia), and countries with both high per capita consumption and large numbers of people (Japan, the United Kingdom, and the United States).

=== Planetary boundaries framework === According to its developers, the planetary boundaries framework defines "a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system." Human civilization has evolved in the relative stability of the Holocene epoch; thus crossing planetary boundaries for safe levels of atmospheric carbon, ocean acidity, or one of the other stated boundaries could send the global ecosystem spiraling into novel conditions that are less hospitable to life—possibly reducing global human carrying capacity. This framework, developed in an article published in 2009 in Nature and then updated in two articles published in 2015 in Science and in 2018 in PNAS, identifies nine stressors of planetary support systems that need to stay within critical limits to preserve stable and safe biospheric conditions (see figure below). Climate change and biodiversity loss are seen as especially crucial, since on their own, they could push the Earth system out of the Holocene state: "transitions between time periods in Earth history have often been delineated by substantial shifts in climate, the biosphere, or both."

The scientific consensus is that humanity has exceeded three to five of the nine planetary boundaries for safe use of the biosphere and is pressing hard on several more. By itself, crossing one of the planetary boundaries does not prove humanity has exceeded Earth's human carrying capacity; perhaps technological improvements or clever management might reduce this stressor and bring us back within the biosphere's safe operating space. But when several boundaries are crossed, it becomes harder to argue that carrying capacity has not been breached. Because fewer people helps reduce all nine planetary stressors, the more boundaries are crossed, the clearer it appears that reducing human numbers is part of what is needed to get back within a safe operating space. Population growth regularly tops the list of causes of humanity's increasing impact on the natural environment in Earth system science literature. Recently, planetary boundaries developer Will Steffen and co-authors ranked global population change as the leading indicator of the influence of socio-economic trends on the functioning of the Earth system in the modern era, post-1750.

== See also == Biocapacity – Estimate of an ecosystem's production of certain biological materials Ecological footprint – Individual's or a group's human demand on nature Ecological overshoot – Demands on ecosystem exceeding regeneration Earth Overshoot Day – Calculated calendar date when humanity's yearly consumption exceeds Earth's replenishment Overpopulation – When a population of a species exceeds the carrying capacity of its environment Overshoot (population) – Phenomenon in which populations temporarily exceed carrying capacity of environment Planetary boundaries – Limits not to be exceeded if humanity is to survive in a safe ecosystem Population bottleneck – Sharp reduction in the size of a population Population ecology – Field of ecology Population growth – Increase in the number of individuals in a population r/K selection theory – Ecological theory concerning the selection of life history traits

== Further reading == Kin, Cheng Sok, et al. "Predicting Earth's Carrying Capacity of Human Population as the Predator and the Natural Resources as the Prey in the Modified Lotka-Volterra Equations with Time-dependent Parameters." arXiv preprint arXiv:1904.05002 (2019).

== References ==