Overconsumption

Overconsumption describes a situation where consumers overuse their available goods and services to where they cannot, or do not want to, replenish or reuse them. In microeconomics, this is the point where the marginal cost of a consumer is greater than their marginal utility. The term overconsumption is quite controversial 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 artificial 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.

Defining the amount of a natural resource required to be consumed for it to count as "overconsumption" is challenging because defining a sustainable capacity of the system requires accounting for many variables. A system's total capacity occurs at regional and worldwide levels, which means that specific regions may have higher consumption levels of certain resources than others due to greater resources without overconsuming a resource. A long-term pattern of overconsumption in any region or ecological system can cause a reduction in natural resources, often resulting in environmental degradation. However, this is only when applying the word to environmental impacts. When used in an economic sense, this point is defined as when the marginal cost of a consumer is equal to their marginal utility. Gossen's law of diminishing utility states that at this point, the consumer realizes the cost of consuming/purchasing another item/good is not worth the amount of utility (also known as happiness or satisfaction from the good) they had received, and therefore is not conducive to the consumer's wellbeing.

When used in the environmental sense, the discussion of overconsumption often parallels population size, growth, and human development: more people demanding a higher quality of living requires greater extraction of resources, which causes subsequent environmental degradation, such as climate change and biodiversity loss. Currently, the inhabitants of high-wealth, "developed" nations consume resources at a rate almost 32 times greater than those of the developing world, making up most of the human population (7.9 billion people). However, the developing world is a growing consumer market. These nations are quickly gaining more purchasing power. The Global South, which includes cities in Asia, America, and Africa, is expected to account for 56% of consumption growth by 2030, meaning that if current trends continue, relative consumption rates will shift more into these developing countries, whereas developed countries would start to plateau. Sustainable Development Goal 12, "responsible consumption and production", is the main international policy tool with goals to abate the impact of overconsumption.

If everyone consumed resources at the US level, you will need another four or five Earths.

Economic growth is sometimes seen as a driver for overconsumption due to a growing economy requiring compounding amounts of resource input to sustain the growth. China is an example where this phenomenon has been observed readily. China's GDP increased massively from 1978, and energy consumption has increased by 6-fold. By 1983, China's consumption surpassed the biocapacity of their natural resources, leading to overconsumption. In the last 30–40 years, China has seen significant increases in its pollution, land degradation, and non-renewable resource depletion, which aligns with its considerable economic growth. It is unknown if other rapidly developing nations will see similar trends in resource overconsumption.

The Worldwatch Institute said China and India, with their booming economies, along with the United States, are the three planetary forces that are shaping the global biosphere. The State of the World 2005 report said the two countries' high economic growth exposed the reality of severe pollution. The report states that

The world's ecological capacity is simply insufficient to satisfy the ambitions of China, India, Japan, Europe, and the United States as well as the aspirations of the rest of the world in a sustainable way.

In 2019, a warning on the climate crisis signed by 11,000 scientists from over 150 nations said economic growth is the driving force behind the "excessive extraction of materials and overexploitation of ecosystems" and that this "must be quickly curtailed to maintain long-term sustainability of the biosphere". Also in 2019, the Global Assessment Report on Biodiversity and Ecosystem Services published by the United Nations' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, which found that up to one million species of plants and animals are at risk of extinction from human activity, asserted that