Meaning and proposal
The Anthropocene, from Greek anthropos (human) and -cene (new), denotes the idea that since the Holocene, which began about 11,700 years ago, humans have become a geological force reshaping the Earth system. The atmospheric chemist and Nobel laureate Paul Crutzen and the biologist Eugene Stoermer proposed the term in 2000 in the newsletter of the International Geosphere-Biosphere Programme, and Crutzen popularized it in his 2002 Nature commentary "Geology of mankind".
Evidence: the traces humans leave
- Climate: burning fossil fuels has pushed atmospheric carbon dioxide above the range of natural variation of hundreds of thousands of years.
- Biosphere: habitat loss and overexploitation have accelerated extinctions, and livestock and humans now make up most land-mammal biomass.
- Material cycles: nitrogen fertilizers have altered the nitrogen and phosphorus cycles, and novel materials such as plastics, concrete and aluminium accumulate in sediments.
- Radioactive markers: plutonium and other fallout from 1950s nuclear tests was deposited worldwide at the same time, making it a candidate boundary marker.
The start-date debate
Crutzen first placed the start at the late-eighteenth-century Industrial Revolution, around James Watt's improvement of the steam engine. Other proposals include the origins of agriculture and 1610, when carbon dioxide dipped after the conquest of the Americas. Steffen et al. (2015) showed the "Great Acceleration", a sharp post-1950 rise in population, GDP, energy use and Earth-system indicators, and argued that from an Earth-system-science perspective it is by far the most convincing start date.
Rejection as a formal epoch
The Anthropocene Working Group (AWG) proposed an epoch beginning in the 1950s, with Crawford Lake in Canada as its reference section, but in March 2024 the Subcommission on Quaternary Stratigraphy voted it down and the International Union of Geological Sciences (IUGS) upheld the decision. Critics argued that human impact appeared gradually and at different times in different places, and that some seventy years is too short for an epoch. The decision concerns only the stratigraphic definition; the Anthropocene remains a widely used concept in environmental science, the humanities and the arts for reflecting on the relationship between humans and nature.
Related concepts
A discussion that extends energy use and rising disorder to social problems is in the entropy law, and the basic principles of energy conservation and conversion are in the laws of thermodynamics.
References
- Crutzen, P. J., & Stoermer, E. F. (2000). The "Anthropocene". IGBP Global Change Newsletter, 41, 17–18.
- Crutzen, P. J. (2002). Geology of mankind. Nature, 415, 23.
- Steffen, W., Broadgate, W., Deutsch, L., Gaffney, O., & Ludwig, C. (2015). The trajectory of the Anthropocene: The Great Acceleration. The Anthropocene Review, 2(1), 81–98.