How humans became a global force changing climate, biodiversity, and geology
Definition of the Anthropocene
The term "Anthropocene" (from Greek anthropos – "human") refers to the proposed epoch in which human activity has a global impact on geological and ecosystem processes. Although official approval from the International Commission on Stratigraphy is still awaited, this concept is widely used both in scientific fields (geology, ecology, climate studies) and in the public sphere. It suggests that humanity's overall impact—fossil fuel burning, industrial agriculture, deforestation, mass species introduction, nuclear technologies, etc.—leaves long-lasting traces in Earth's layers and life, likely comparable in scale to previous geological events.
Key markers of the Anthropocene:
- Global climate change driven by greenhouse gas emissions.
- Altered biogeochemical cycles, especially carbon and nitrogen cycles.
- Widespread biodiversity loss and biotic homogenization (mass extinctions, invasive species).
- Geological traces, such as plastic pollution or layers of nuclear fallout.
Following these changes, scientists increasingly argue that the Holocene epoch—beginning about 11,700 years ago after the last Ice Age—has transitioned into a qualitatively new "Anthropocene" stage dominated by human forces.
2. Historical context: humanity's impact accumulates over millennia
2.1 Early agriculture and land use
Human impact on landscapes began with the Neolithic Revolution (~10,000–8,000 BCE), when in many regions nomadic food gathering was replaced by farming and animal husbandry. Deforestation for fields, irrigation projects, and domestication of plants and animals reshaped ecosystems, promoted sediment erosion, and altered local soils. Although these changes were significant, they mostly occurred at local or regional scales.
2.2 Industrial Revolution: exponential growth
Since the late 18th century, the use of fossil fuels (coal, oil, natural gas) has driven industrial production, mechanized agriculture, and global transport networks. This Industrial Revolution accelerated greenhouse gas emissions, intensified resource extraction, and promoted global trade. The human population grew dramatically, as did demands for land, water, mineral resources, and energy, transforming Earth's changes from local or regional scales to an almost planetary scale [1].
2.3 The Great Acceleration (mid-20th century)
After World War II, the so-called "Great Acceleration" in social and economic indicators (population, GDP, resource consumption, chemical production, etc.) and Earth system indicators (atmospheric CO2 concentration, biodiversity loss, etc.) increased sharply. Humanity's footprint expanded in terms of infrastructure, technology, and waste volume, giving rise to phenomena such as nuclear fallout (visible as a global geological marker), a rapid increase in synthetic chemical use, and elevated greenhouse gas concentrations.
3. Climate change: a key feature of the Anthropocene
3.1 Greenhouse gas emissions and warming
Anthropogenic emissions of carbon dioxide, methane, nitrous oxide, and other greenhouse gases have increased sharply since the Industrial Revolution. Observations show:
- CO2 concentration in the atmosphere has exceeded the pre-industrial level (280 parts per million) and today already surpasses 420 parts per million (and continues to grow).
- Average global surface temperature has risen more than 1 °C since the late 19th century, and this rise has accelerated further over the past 50 years.
- Arctic sea ice, glaciers, and ice sheets are noticeably melting, causing sea level rise [2], [3].
Such rapid warming is unprecedented at least in the past several thousand years and coincides with the Intergovernmental Panel on Climate Change (IPCC) conclusion that human activity is the main cause. The consequences of climate change—extreme weather, ocean acidification, changing precipitation patterns—further alter terrestrial and marine ecosystems.
3.2 Feedback loops
Rising temperatures can trigger positive feedback loops, for example, thawing permafrost releases methane, reduced ice albedo intensifies warming, and warming oceans lose their ability to absorb CO2. These phenomena show how relatively small initial greenhouse gas changes caused by humans can lead to huge and often unpredictable regional or global consequences. Models increasingly indicate that certain tipping points (e.g., drying of the Amazon rainforest or collapse of large ice sheets) can trigger abrupt shifts in Earth's system regimes.
4. Biodiversity crisis: mass extinction or biotic homogenization?
4.1 Species extinction and the sixth mass extinction
Many scientists consider the current loss of biodiversity as a possible "sixth mass extinction", the first caused by a single species. The global rate of species extinction is tens or hundreds of times higher than the natural background level. Ecosystem destruction (deforestation, wetland drainage), excessive resource use (hunting, fishing), pollution, and the introduction of invasive species are the main causes [4].
- IUCN Red List: about 1 million species face extinction in the coming decades.
- Global vertebrate populations have declined on average by ~68% from 1970 to 2016 (WWF Living Planet Report).
- Coral reefs, critically important marine biodiversity hotspots, are experiencing decay due to ocean warming and acidification.
Although the Earth has recovered over long geological periods after mass extinctions, the recovery time spans millions of years—a time interval far longer than the scale of humanity.
4.2 Biotic homogenization and invasive species
Another important feature of the Anthropocene is biotic homogenization: humans transport species between continents (intentionally or accidentally), and sometimes invasive species displace native flora and fauna. This reduces regional endemism, and once distinct ecosystems become increasingly similar, dominated by a few "cosmopolitan" species (e.g., rats, pigeons, invasive plants). Such homogenization can diminish evolutionary potential, degrade ecosystem services, and disrupt cultural connections with local biodiversity.
5. Geological traces of humanity
5.1 Technofossils: plastic, concrete, and more
The term "technofossils" describes human-made materials leaving a durable trace in stratigraphic layers. Examples:
- Plastic: micro-particles are found in oceans, beaches, lake sediments, even polar ice. Future geologists may discover clearly defined plastic horizons.
- Concrete and metal alloys: cities, roads, reinforced structures will likely become anthropogenic "fossil" records.
- Electronic waste and high-tech ceramics: rare metals from electronics, nuclear waste from reactors, etc. can form recognizable layers or concentrations.
These materials show that modern industrial products will remain in the Earth's crust and may overshadow natural layers for future geologists [5].
5.2 Nuclear markers
Atmospheric nuclear weapons testing peaked in the mid-20th century, spreading radioisotopes (e.g. 137Cs, 239Pu) worldwide. These isotopic changes can become a precise "Golden Spike" marking the start of the Anthropocene in the mid-20th century. Traces of these nuclear isotopes in sediments, ice cores, or tree rings highlight how a single technological phenomenon can create a global geochemical marker.
5.3 Land Use Changes
Almost all continents have plowed land, urban expansion, and infrastructure altering soil and topography. Sediment flows in rivers, deltas, and coasts have greatly increased due to deforestation and agriculture. Some call this "anthropogeomorphology", emphasizing how human engineering works, dams, and mining surpass many natural processes shaping Earth's surface. This is also reflected in oxygen-depleted "dead zones" at river mouths (e.g., the Gulf of Mexico), formed due to nutrient excess.
6. Discussions on the Anthropocene and Formal Definition
6.1 Stratigraphic Criteria
To declare a new epoch, geologists look for a clear global boundary layer—similar to the K–Pg boundary iridium anomaly. Proposed Anthropocene markers include:
- Radioactive nuclide peak from nuclear tests around 1950–1960.
- Plastic layers in sediment cores from the mid-20th century.
- Carbon isotope shifts due to fossil fuel combustion.
Anthropocene Working Group in the International Commission on Stratigraphy (ICS) investigates these signals in various potential reference sites (e.g., lake sediments or glaciers), searching for an official "Golden Spike."
6.2 Debates on Start Dates
Some researchers propose an "early Anthropocene" starting thousands of years ago with agriculture. Others highlight the 18th-century Industrial Revolution or the 1950s "Great Acceleration" as sharper, clearer markers. ICS generally requires a global synchronous marker. For many, the mid-20th century peak of nuclear test fallout and rapid economic boom is the most suitable, but final decisions have not yet been made [6].
7. Challenges of the Anthropocene: Sustainability and Adaptation
7.1 Planetary Boundaries
Scientists emphasize "planetary boundaries" related to processes such as climate regulation, biosphere integrity, and biogeochemical cycles. Crossing these boundaries risks destabilizing Earth's systems. The Anthropocene shows how close or even beyond these safe operating spaces we may be. Continued greenhouse gas emissions, nitrogen excess, ocean acidification, and deforestation threaten global systems with unpredictable states.
7.2 Socioeconomic Inequality and Environmental Justice
The impacts of the Anthropocene are unevenly distributed. Highly industrialized regions have historically contributed more to emissions, but climate change vulnerabilities (rising sea levels, droughts) often affect less developed countries the most. This gives rise to the concept of climate justice: the need to balance urgent emission reductions with equitable development. Addressing anthropogenic challenges requires cooperation across different social and economic strata – an ethical test for global governance.
7.3 Mitigation Measures and Future Directions
Possible ways to mitigate the threats posed by the Anthropocene may include the following:
- Energy decarbonization (renewable sources, nuclear energy, carbon capture).
- Sustainable agriculture, reducing deforestation, excessive chemical use, and protecting biodiversity refuges.
- Circular economy, which would drastically reduce plastic and toxic waste.
- Geoengineering proposals (solar radiation management, carbon dioxide removal), although controversial and unpredictable.
Implementing these strategies requires political will, technological leaps, and fundamental cultural shifts. The question remains whether the global community can transition in time to sustainable and long-term Earth system management.
8. Conclusion
The Anthropocene reveals a fundamental reality: humanity has reached a planetary scale of influence. From climate change to biodiversity loss, from plastic-saturated oceans to radioisotope traces in geology – the scale of our species' collective activity now shapes Earth's trajectory as profoundly as natural forces once did. Whether this epoch is officially recognized or not, The Anthropocene emphasizes our responsibility and vulnerability – reminding us that with great power to alter nature comes the risk of ecological crisis if abused.
By recognizing the Anthropocene, we understand the fragile balance between technological progress and ecological disruption. The path forward requires scientific knowledge, ethical governance, and global collaboration on innovation – a huge challenge that could determine humanity's future if we continue to exploit resources short-sightedly. Understanding that we are geological agents, we must rethink the human-Earth relationship to preserve the richness and diversity of life for future generations.
Links and further reading
- Crutzen, P. J., & Stoermer, E. F. (2000). “The ‘Anthropocene’.” Global Change Newsletter, 41, 17–18.
- IPCC (2014). Climate Change 2014: Synthesis Report. Cambridge University Press.
- Steffen, W., et al. (2011). “The Anthropocene: conceptual and historical perspectives.” Philosophical Transactions of the Royal Society A, 369, 842–867.
- Ceballos, G., Ehrlich, P. R., & Dirzo, R. (2017). “Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines.” Proceedings of the National Academy of Sciences, 114, E6089–E6096.
- Zalasiewicz, J., et al. (2014). “The technofossil record of humans.” Anthropocene Review, 1, 34–43.
- Waters, C. N., et al. (2016). “The Anthropocene is functionally and stratigraphically distinct from the Holocene.” Science, 351, aad2622.