Ecological overshoot is the phenomenon which occurs when the demands made on a natural ecosystem exceed its regenerative capacity. Global ecological overshoot occurs when the demands made by humanity exceed what the biosphere of Earth can provide through its capacity for renewal. [1] [2]
To determine whether ecological overshoot is happening requires the collection of global and nation-specific data regarding the availability of natural resources, the capability of the ecosystems to renew any natural resources that were consumed, and the rate at which the resources are being consumed, usually assessed for each calendar year.
This data collection, and analysis is typically done by scientific and conservation organisations, such as the Global Footprint Network, which collects data to assess the ecological footprint of each country and the global community.
Ecological data collected so far reveals that the global community has been exceeding the regenerative capacity of the Earth since 1970, which was the year when the consumption capacity of humanity first exceeded the biocapacity the Earth. Each year since 1970 humanity has witnessed global ecological overshoot. [3]
This problem is highlighted each year on Earth Overshoot Day, an illustrative calendar date obtained through calculation, on which day humanity's resource consumption for the year is considered to have exceeded the Earth’s capacity to regenerate those resources for that year. [4]
This ecological debt is often referred to as our global 'ecological overshoot'. The data from the Global Footprint Network has been used to create the graph below, it shows that since the 1970s the global population is increasingly compromising the Earth's ecosystem. The red section of the graph indicates that the global population have been accruing a global ecological overshoot since 1970. This means that the rate at which we are using natural resources exceeds the time required by the ecosystems to regenerate the resources and absorb the waste products that are involved.
The continued over-exploitation of natural resources results in ever more severe damage to global ecosystems over time, this has destabilised many micro ecosystems causing increasing extinction rates and the macro ecosystems are coming under increasing pressure. In this way humans are currently exceeding the carrying capacity of Earth as we increase the ecological overshoot each year. The IPAT equation attempts to quantify the environmental impact ("I") of the human population ("P"), their affluence ("A") and technology ("T"). Furthermore the Jevons paradox warns us that increasing our efficiency using technology will usually result in increased ecological damage.
The majority of the world currently follow an economic paradigm that seeks to grow all three of the IPAT parameters: population size, affluence and use of technology. These behaviour patterns are causing escalating environmental damage and there is evidence for growing risk of ecological collapse. [5]
The outcomes from various possible human behaviour scenarios have been explored in a demographic model developed by Prof Chris Bystroff. [6] According to the Bystroff predictions, continuing with the growth economic paradigm will result in a rapid decrease in population numbers halving global population by 2040. The Bystroff predictions are echoed in further research by Dr William E. Rees, who originally developed the concept of Ecological Footprint. [7] This research states that to reduce ecological overshoot it is necessary to reduce economic consumption drastically to stop growing the economy and to repay the accrued ecological debt by restoration and rewilding back to the one planet level or less. A recent review of the World 3 demographic model by KPMG also concludes that humans need to rethink their pursuit of economic growth or anticipate collapse by 2040. [8] For countries that have already achieved social affluence, although their social performance and resource utilization levels are high, the ecological overshoot brought about by these developments is still maintaining a continuously increasing trend. On the other hand, many low-income countries tried increasing their per capita wealth through economic activities to improve their social shortfalls. However, their social development is slower than the resulting increase in ecological overshoot. In this case, the ecological environment will be more overwhelmed. [9]
It is important to bear in mind that the data collected by the Global Footprint Network (GFN) makes the assumption that the whole biocapacity of the Earth is entirely at the disposal of humanity. [10] However it is evident that we need biodiversity in order to survive, therefore unless we reserve some of the global biocapacity for other species we cannot survive. Several organisations argue that to reinstate biodiversity to levels comparable to those preceding the high extinction rates associated with the ongoing Holocene extinction event, at least 50% of the Earths biocapacity would need to be protected as nature reserve areas which are kept free from human intervention. This suggestion was presented in the book titled Half Earth. Global Footprint Network data shows that for over 50 years humanity has been stressing the ecosystems on the planet beyond their ability to recover. [10]
A crisis of human behaviour (the Human Behavioural Crisis) has been highlighted as the driver of anthropogenic ecological overshoot in a peer-reviewed World Scientists' Warning paper led by Joseph J. Merz and co-authored by William E. Rees, Phoebe Barnard et al. [11]
The most well known symptom of ecological overshoot is the rising extinction rate. Pandemics of zoonotic diseases, like COVID-19 also become increasingly likely with overpopulation and global travel because we encroach on wildlife habitats and accelerate the spread. [12] Biocapacity is measured by calculating the amount of biologically productive land and sea area available to provide the resources a population consumes and to absorb its wastes, given the prevailing technology and management practices. [13] Countries differ in the productivity of their ecosystems, and this is reflected in the National Footprint and Biocapacity Accounts kept by York University, FoDaFo and Global Footprint Network. A country has an ecological reserve if its Ecological footprint is smaller than its biocapacity; otherwise it is operating with an ecological overshoot. The former are often referred to as ecological creditors, and the latter as ecological debtors. Today, most countries, and the world as a whole, are in ecological overshoot. Over 85% of the world population lives in countries operating with an ecological overshoot.
The pursuit of growth economics relies on continual increase in our numbers and our consumption. Several economists have been challenging the wisdom of this prevailing discipline for many years. Those suggesting a new economic paradigm can be considered collectively as advocates for degrowth.[ citation needed ]
The carrying capacity of an environment is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the environment's maximal load, which in population ecology corresponds to the population equilibrium, when the number of deaths in a population equals the number of births. The effect of carrying capacity on population dynamics is modelled with a logistic function. Carrying capacity is applied to the maximum population an environment can support in ecology, agriculture and fisheries. The term carrying capacity has been applied to a few different processes in the past before finally being applied to population limits in the 1950s. The notion of carrying capacity for humans is covered by the notion of sustainable population.
The Limits to Growth is a 1972 report that discussed the possibility of exponential economic and population growth with finite supply of resources, studied by computer simulation. The study used the World3 computer model to simulate the consequence of interactions between the Earth and human systems. The model was based on the work of Jay Forrester of MIT, as described in his book World Dynamics.
I = (PAT) is the mathematical notation of a formula put forward to describe the impact of human activity on the environment.
Human ecology is an interdisciplinary and transdisciplinary study of the relationship between humans and their natural, social, and built environments. The philosophy and study of human ecology has a diffuse history with advancements in ecology, geography, sociology, psychology, anthropology, zoology, epidemiology, public health, and home economics, among others.
Overconsumption describes a situation where a consumer overuses their available goods and services to where they can't, or don't want to, replenish or reuse them. In microeconomics, this may be described as the point where the marginal cost of a consumer is greater than their marginal utility. The term overconsumption is quite controversial in use and does not necessarily have a single unifying definition. When used to refer to natural resources to the point where the environment is negatively affected, it is synonymous with the term overexploitation. However, when used in the broader economic sense, overconsumption can refer to all types of goods and services, including manmade ones, e.g. "the overconsumption of alcohol can lead to alcohol poisoning". Overconsumption is driven by several factors of the current global economy, including forces like consumerism, planned obsolescence, economic materialism, and other unsustainable business models and can be contrasted with sustainable consumption.
The ecological footprint measures human demand on natural capital, i.e. the quantity of nature it takes to support people and their economies. It tracks human demand on nature through an ecological accounting system. The accounts contrast the biologically productive area people use to satisfy their consumption to the biologically productive area available within a region, nation, or the world (biocapacity). Biocapacity is the productive area that can regenerate what people demand from nature. Therefore, the metric is a measure of human impact on the environment. As Ecological Footprint accounts measure to what extent human activities operate within the means of our planet, they are a central metric for sustainability.
Environmental degradation is the deterioration of the environment through depletion of resources such as quality of air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. It is defined as any change or disturbance to the environment perceived to be deleterious or undesirable.
The "World Scientists' Warning to Humanity" was a document written in 1992 by Henry W. Kendall and signed by about 1,700 leading scientists. Twenty-five years later, in November 2017, 15,364 scientists signed "World Scientists' Warning to Humanity: A Second Notice" written by William J. Ripple and seven co-authors calling for, among other things, human population planning, and drastically diminishing per capita consumption of fossil fuels, meat, and other resources. The second notice has more scientist cosigners and formal supporters than any other journal article ever published.
William Rees, FRSC, is Professor Emeritus at the University of British Columbia and former director of the School of Community and Regional Planning (SCARP) at UBC.
Human overpopulation describes a concern that human populations may become too large to be sustained by their environment or resources in the long term. The topic is usually discussed in the context of world population, though it may concern individual nations, regions, and cities.
The global hectare (gha) is a measurement unit for the ecological footprint of people or activities and the biocapacity of the Earth or its regions. One global hectare is the world's annual amount of biological production for human use and human waste assimilation, per hectare of biologically productive land and fisheries.
Mathis Wackernagel is a Swiss-born sustainability advocate. He is President of Global Footprint Network, an international sustainability think tank with offices in Oakland, California, and Geneva, Switzerland. The think-tank is a non-profit that focuses on developing and promoting metrics for sustainability.
In environmental science, a population "overshoots" its local carrying capacity — the capacity of the biome to feed and sustain that population — when that population has not only begun to outstrip its food supply in excess of regeneration, but actually shot past that point, setting up a potentially catastrophic crash of that feeder population once its food populations have been consumed completely. Overshoot can apply to human overpopulation as well as other animal populations: any life-form that consumes others to sustain itself.
Earth Overshoot Day (EOD) is the calculated illustrative calendar date on which humanity's resource consumption for the year exceeds Earth’s capacity to regenerate those resources that year. The term "overshoot" represents the level by which human population's demand overshoots the sustainable amount of biological resources regenerated on Earth. When viewed through an economic perspective, the annual EOD represents the day by which the planet's annual regenerative budget is spent, and humanity enters environmental deficit spending. EOD is calculated by dividing the world biocapacity, by the world ecological footprint, and multiplying by 365, the number of days in a year:
Environmental issues are disruptions in the usual function of ecosystems. Further, these issues can be caused by humans or they can be natural. These issues are considered serious when the ecosystem cannot recover in the present situation, and catastrophic if the ecosystem is projected to certainly collapse.
The Global Footprint Network was founded in 2003 and is an independent think tank originally based in the United States, Belgium and Switzerland. It was established as a charitable not-for-profit organization in each of those three countries. Its aim is to develop and promote tools for advancing sustainability, including the ecological footprint and biocapacity, which measure the amount of resources we use and how much we have. These tools aim at bringing ecological limits to the center of decision-making.
The biocapacity or biological capacity of an ecosystem is an estimate of its production of certain biological materials such as natural resources, and its absorption and filtering of other materials such as carbon dioxide from the atmosphere.
The Ten Million Club Foundation is a non-governmental organization based in the Netherlands which promotes global overpopulation awareness. For the Netherlands, it advocates to match the population size with the carrying capacity of the area. Initially, the foundation was calling for a shrinking population; later on the emphasis was also put on a reduction of the ecological footprint of the inhabitants of the Netherlands. The club was set up as a private foundation by the Dutch historian Paul Gerbrands in 1994.
Sustainable population refers to a proposed sustainable human population of Earth or a particular region of Earth, such as a nation or continent. Estimates vary widely, with estimates based on different figures ranging from 0.65 billion people to 9.8 billion, with 8 billion people being a typical estimate. Projections of population growth, evaluations of overconsumption and associated human pressures on the environment have led to some to advocate for what they consider a sustainable population. Proposed policy solutions vary, including sustainable development, female education, family planning and broad human population planning.
| External videos | |
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 How Earth's Population Exploded -Bloomberg Quicktake |