The Homines Fossilization: Brief Review of Anthropocene

This article is an insight into our lifetime and the enduring capacity of the planet—especially regarding water and space, in face of the Homines population growth. This is and will be recorded in the geological time: once preserved as human fossils, we will be part of a chapter in Earth’s history. A brief taphonomic chronology is presented, from the emergence of humans to the domination of the environment and supremacy over other species, and also a concern on how much planet Earth can bear Homines neglects. The objective of this review is to show that the strata that contain human fossils change during the Anthropocene not only the human body but also its tools, resulting from its development. Four stages were identified as taphonomic phases: the first wave, when organic Homines fossils were preserved only with materials in natura, including natural artefacts. The second fossilization phase has occurred and still occurs with the urban Homines, a product of the proliferation of cities, including anthropogenic waste and diseases. The technology that we master today also belongs to our taphonomy: hydrocarbons, metals, plastic, radioactive elements—all fossilize together with the industrial Homines, representing the third fossilization phase, which is very close to the fourth fossilization phase, where our enlightened intelligence buries the technological Homines together with his world of digital waste and new viruses. How will we fossilize the future? This question makes us think about the behavior we assume today—who or what will go to the grave with us, which geological/environmental response will stop superpopulation, which extinction event will hold human proliferation? Which will be the mineral, human and waste components of our subsequent strata? How much water and space can we still use without causing a global environmental collapse?

Plant conservation in the Anthropocene-Challenges and future prospects

Despite the massive efforts that have been made to conserve plant diversity across the world during the past few decades, it is becoming increasingly evident that our current strategies are not sufficiently effective to prevent the continuing decline in biodiversity. As a recent report by the CBD indicates,current progress and commitments are insufficient to achieve the Aichi Biodiversity Targets by 2020.Threatened species lists continue to grow while the world's governments fail to meet biodiversity conservation goals. Clearly, we are failing in our attempts to conserve biodiversity on a sufficient scale.The reasons for this situation are complex, including scientific, technical, sociological, economic and political factors. The conservation community is divided about how to respond. Some believe that saving all existing biodiversity is still an achievable goal. On the other hand, there are those who believe that we need to accept that biodiversity will inevitably continue to be lost, despite all our conservation actions and that we must focus on what to save, why and where. It has also been suggested that we need a new approach to conservation in the face of the challenges posed by the Anthropocene biosphere which we now inhabit. Whatever view one holds on the above issues, it is dear that we need to review the effectiveness of our current conservation strategies, identify the limiting factors that are preventing the Aichi goals being met and at the same time take whatever steps are necessary to make our conservation protocols more explicit, operational and efficient so as to achieve the maximum conservation effect. This paper addresses the key issues that underlie our failure to meet agreed targets and discusses the necessary changes to our conservation approaches. While we can justifiably be proud of our many achievements and successes in plant conservation in the past 30 years, which have helped slow the rate of loss, unless we devise a more coherent, consistent and integrated global strategy in which both the effectiveness and limitations of our current policies, action plans and procedures are recognized, and reflect this in national strategies, and then embark on a much bolder and ambitious set of actions,progress will be limited and plant diversity will continue to decline.

Geography in the Anthropocene:Transforming our world for sustainable development

The world is changing at an accelerating pace due to increased human exploitation of the earth’s resources and the consequent climate change and biodiversity loss crises.As a transdisciplinary discipline studying the coupled human and nature systems and their interactions,Geography has natural advantages to promote sustainable development.With the aim of stimulating sustainable development in the Anthropocene,the International Geography and Sustainability Workshop 2021 was held virtually during 23-24 November 2021.This editorial briefly reviews the development history of Geography,summarizes the presentations of keynote speakers,outlines the overall research framework,and discusses the future directions by which the discipline of Geography can be harnessed to advance sustainable development.The key outcomes are as follows:(1)The research paradigms of Geography are shifting from basic knowledge acquisition to understanding of coupling patterns and processes,and to the simulation and prediction of complex human-earth systems;(2)Landscape sustainability science and the metacoupling concept are emerging as new comprehensive research perspectives,and the framework of“Pattern—Process—Service—Sustainability”can be used as a basis to underpin Geography’s role in sustainability;(3)Geography can support sustainable development in many ways,such as in agricultural development,disaster and risk monitoring and early warning,global climate change mitigation,and in helping to achieve the Sustainable Development Goals(SDGs).Future research directions include:integrated geographical research on climate change and sustainable resource utilization;integrated geographical research on social and economic sustainable development;sustainable cascades of ecosystem structure,functions,services,and human well-being;metacoupling for sustainability;safe and justice space boundaries;the classification-coordination-collaboration approach;and geographical education for sustainable development.

Aerosol transmission of human pathogens:From miasmata to modern viral pandemics and their preservation potential in the Anthropocene record

Ongoing uncertainty over the relative importance of aerosol transmission of COVID-19 is in part rooted in the history of medical science and our understanding of how epidemic diseases can spread through human populations. Ancient Greek medical theory held that such illnesses are transmitted by airborne pathogenic emanations containing particulate matter(“miasmata”). Notable Roman and medieval scholars such as Varro, Ibn al-Khatib and Fracastoro developed these ideas, combining them with early germ theory and the concept of contagion. A widely held but vaguely defined belief in toxic miasmatic mists as a dominant causative agent in disease propagation was overtaken by the science of 19th century microbiology and epidemiology, especially in the study of cholera, which was proven to be mainly transmitted by contaminated water. Airborne disease transmission came to be viewed as burdened by a dubious historical reputation and difficult to demonstrate convincingly. A breakthrough came with the classic mid-20th century work of Wells, Riley and Mills who proved how expiratory aerosols(their “droplet nuclei”)could transport still-infectious tuberculosis bacteria through ventilation systems. The topic of aerosol transmission of pathogenic respiratory diseases assumed a new dimension with the mid-late 20th century “Great Acceleration” of an increasingly hypermobile human population repeatedly infected by different strains of zoonotic viruses, and has taken centre stage this century in response to outbreaks of new respiratory infections that include coronaviruses. From a geoscience perspective, the consequences of pandemic-status diseases such as COVID-19, produced by viral pathogens utilising aerosols to infect a human population currently approaching 8 billion, are far-reaching and unprecedented. The obvious and sudden impacts on for example waste plastic production, water and air quality and atmospheric chemistry are accelerating human awareness of current environmental challenges. As such, the “anthropause”lockdown enforced by COVID-19 may come to be seen as a harbinger of change great enough to be preserved in the Anthropocene stratal record.

Relationship between environmental evolution and human activities in the northeastern Qinghai-Xizang Plateau throughout the past millennium and its implications for the onset of the Anthropocene

In current research on the Anthropocene, assessing the impact of human activities via stratigraphic records of sediments and demarcating the Anthropocene epoch globally are critical scientific issues that urgently need to be addressed. The northeastern Qinghai-Xizang Plateau(QXP), where humans first settled permanently in large numbers in the QXP, has varying sedimentary environments that are extremely sensitive to human activities. In contrast to other regions of the QXP, the northeastern sector boasts a richer array of climatic and environmental reconstruction sequences. This distinctive feature renders it an exemplary locale for investigating the stratigraphic boundary of the Anthropocene. Through in-depth analysis and integration of existing paleoclimate and paleoenvironment sequences in the northeastern QXP, we draw the following conclusions:(1) Throughout the past millennium, the impact of human activities on the environment of the northeastern QXP has become increasingly significant, especially in the past 200–300 years, gradually overshadowing climatic factors.(2) Since AD 1950,multiple physicochemical indicators related to human activities in the northeastern QXP have shown exponential growth,forming a distinct peak within the past millennium and clearly depicting the global “Great Acceleration” phenomenon and its development process.(3) Intensified human activities have driven swift environmental shifts and “decoupled” the interplay between climatic variations and the ecological environment, propelling the northeastern QXP into the “Early Anthropocene”from the “Late Holocene”. On the basis of the above findings, we construct a model suitable for identifying the stratigraphic boundary of the Anthropocene in the northeastern QXP and note that since the ecological environment in the northeastern QXP has entered the “Early Anthropocene”, the climate signals of certain physicochemical indicators in sediments are gradually becoming weaker, whereas the signals of human activities are becoming stronger.

Dust storms in northern China and their significance for the concept of the Anthropocene

A key scientific issue in the study of the Anthropocene is the determination of the corresponding stratigraphic marker in geological archives.The arid and semi-arid regions of Asia are the second largest dust source on Earth,and their release,transport and deposition of dust affect global climate change,as well as marine and terrestrial biogeochemical cycles.Over the past~2000 years,human activity has outpaced natural climatic variability as the dominant control of dust storms in northern China.Thus,exploring the potential of anthropogenic Asian dust as a marker of the Anthropocene and its impacts on lake ecosystems may contribute to an improved definition of the characteristics and timing of the Anthropocene.In this context,we measured spectrally-inferred chlorophyll a from the sediments of an undisturbed alpine lake in northern China,and compared the results with dust storm data from the same cores and with regional climatic records.Asian dust is a widely distributed,globally significant signal of human activity,and it is also well preserved in various geological archives;hence,we propose anthropogenic dust can be considered as a potential marker of the Anthropocene.Anthropogenic dust signals in stratigraphic records during the past~2000 years differ substantially from those during the early and middle Holocene,which demonstrates that,at least since~2000 years ago,human activity has exceeded the natural forcing of dust transport in northern China.We therefore propose that there are spatial and temporal differences in the onset of the Anthropocene,as defined by anthropogenic dust deposition,which is therefore time-transgressive.Our spectrally-inferred chlorophyll a record is consistent with dust storm activity over the past~2000 years(except since the 1950s),suggesting that anthropogenic dust storms were the dominant control on lake primary production.Prior to the 1950s the interactions of the East Asian summer monsoon(EASM),human activity,dust storms and lake ecosystems resulted in a shift from a pattern in which“human activity outpaced the EASM as the dominant control on the Earth surface system”to one in which,after the 1950s,“human activity became the dominant factor influencing the EASM and the Earth surface system”.In the future this pattern may trend towards one in which there is the“sustainable development of humans and the environment”.We suggest that,in order to better understand the interactions of human activity,climate and environment,future research on the Anthropocene should focus on its time-transgressive characteristics and regional differences,in addition to the“Great Acceleration”

Paleoclimatic proxies from global closed basins and the possible beginning of Anthropocene

Global closed basins,occupying almost one fifth of the world's land area,spatially coincide with arid and semiarid areas.Paleoclimatic proxies can indicate basin-wide environmental change and human activity.However,previous studies have not approached the use of proxies in the same way to reconstruct natural and anthropogenic processes at regional and global scales.Here we present a regional study to investigate the basic processes of paleoclimatic proxies,from a typical closed-basin system in arid China.We use multiple paleoclimatic proxies of surface samples and sediments,as well as groundwater and sediment ages to study environmental change and human activity.We then establish a dataset for paleoclimatic proxies from global closed basins and do a numerical analysis on it.Regional studies verify that human activity greatly impacts paleoclimatic proxies,especially with regard to surface samples,as well as groundwater age,but Holocene sediments are less affected.Results from global studies indicate that the major changing trend of the wet/dry status of closed basins is associated with the movement of the westerly jet streams controlled by long-term changes in winter insolation.There is an abrupt change between 1800 AD and 1900 AD,according to a numerical synthesis of paleoclimatic proxies from global closed basins,which can be linked to human impact.We suggest this time period can be considered as a start point for the Anthropocene based on the sedimentary evidence of closed basins,globally.

Joining the Transformation of Nature-The Post-Natural and Confucian Perspective on Earth Stewardship in the Anthropocene

The emergence of the Anthropocene creates a new set of conditions for understanding the relationship between human power and the natural world.These conditions include an increasingly humanized and de-natured natural world,and greater responsibilities of stewardship for human beings.In current literature,there are diverse views on the meaning of the Anthropocene and the role of modem technology in future earth stewardship.Post-natural thought regards the Anthropocene as representing the end of nature,and thus appeals to disenchantment with respect to the idea that nature is an external moral norm.Although this approach correctly addresses the significance of locality and the mutuality between humans and the environment,it fails to provide us with adequate normative boundaries for preventing the endless artificialization of nature.Alternatively,this article defends the position that Confucianism is a more plausible philosophical ground for earth stewardship in the context of the Anthropocene.The Confucian approach is an inclusive humanism which is established on the cosmological ideal of realising the virtue of shengsheng生生(life generation)in all beings.Moreover,Confucian ethics draw much attention to the self-regulation of human beings as virtuous persons.This is indeed what is needed in the age of the Anthropocene.

Watershed systems science—A new paradigm to understand and govern the impact of human activities on the earth's surface in the Anthropocene

Recent scholars’work in Vol 58 Issue 1（2015）and Cheng and Li’s paper in Vol 58 Issue 7（2015）in Science China Earth Sciences propose development of＂Watershed science＂by＂Bridging new advances in hydrological science with good management of river basins＂.

Modern Heritage, the Other, and the Anthropocene

The 2020^(th) century was modernism’s century;a comparatively fleeting moment in which the human race’s transition to an urbanised species created an entirely new geological epoch:the Anthropocene.The existen­tial challenge for our species in the 21st century will be to transform the modern city into a site of truly sustainable human habitation.This challenge requires us to engage critically with the past in a way that serves the needs of the future,globally and permanently.The Historic Urban Landscapes(HUL)approach,together with the UN’s Sustain­able Development Goals and UN Habitat’s New Urban Agenda,offers a framework for meeting this challenge and,critically,to change our relationship with both the past and the future.

A Five-stage Evolution of Earth's Phosphorus Cycle

Phosphorus(P)is a key biological nutrient and probably the ultimate limiter of marine productivity during Earth history.In recent years,a wealth of new knowledge has revolutionized our understanding of the global P cycle,yet its longterm evolution remains incompletely documented.In this paper,we review the effects of three major controlling factors on the long-term evolution of the global P cycle,i.e.,tectonics,marine redox conditions,and bio-evolution,on the basis of which a five-stage model is proposed:StageⅠ(>~2.4 Ga),tectonic-lithogenic-controlled P cycling;StageⅡ(~2.4 Ga to 635Ma),low-efficiency biotic P cycling;StageⅢ(~635 Ma to 380 Ma),transitional biotic P cycling;StageⅣ(~380 Ma to near-modern),high-efficiency biotic P cycling;and Stage V(Anthropocene),human-influenced P cycling.This model implies that the earlier-proposed Ediacaran reorganization of the marine P cycle may represent only the start of a-250-Myr-long transition of the Earth's P cycle(StageⅢ)between the low-efficiency biotic mode of the Proterozoic(StageⅡ)and the high-efficiency biotic mode of the Phanerozoic(StageⅣ).The development of biologically-driven,high-efficiency P cycling may have been a key factor for the increasing frequency and volume of phosphorite deposits since the late Neoproterozoic.

Safeguarding our future by protecting biodiversity

The Anthropocene is marked by twin crises:climate change and biodiversity loss.Climate change has tended to dominate the headlines,reflecting,in part,the greater complexity of the biodiversity crisis.Biodiversity itself is a difficult concept.Land plants dominate the global biomass and terrestrial arthropods probably dominate in terms of numbers of species,but most of the Tree of Life consists of single-celled eukaryotes,bacteria,and archaea.Wild plants provide a huge variety of products and services to people,ranging from those that are species-specific,such as food,medicine,and genetic resources,to many which are partly interchangeable,such as timber and forage for domestic animals,and others which depend on the whole community,but not on individual species,such as regulation of water supply and carbon sequestration.The use of information from remote sensing has encouraged a simplified view of the values of nature's contributions to people,but this does not match the way most people value nature.We can currently estimate the proportion of species threatened by human impacts only for a few well-assessed groups,for which it ranges from 14%(birds)to 63%(cycads).Less than 8%of land plants have been assessed,but it has been estimated that 30e44%are threatened,although there are still few(0.2%)well-documented extinctions.Priorities for improving protection of biodiversity include:improving the inventory,with surveys focused on geographical areas and taxonomic groups which are under-collected;expanding the protected area system and its representativeness;controlling overexploitation;managing invasive species;conserving threatened species ex situ;restoring degraded ecosystems;and controlling climate change.The Convention on Biological Diversity(CBD)COP15 and the United Nations Framework Convention on Climate Change(UNFCCC)COP26 meetings,both postponed to 2021,will provide an opportunity to address both crises,but success will require high ambition from all participants.

Identifying interlinkages between urbanization and Sustainable Development Goals

Urbanization and Sustainable Development Goals(SDGs)are important global issues in the current“Anthropocene”.Climate change and the COVID-19 pandemic have exacerbated global urban problems and hindered the ability to meet SDGs on time,while the broad interlinkages between urbanization and the SDGs remain poorly understood.This study shows that among the interlinkages of urbanization with 17 SDGs,synergies are observed with 151 targets(89%),among which 67(40%)have stronger synergies,and trade-offs are observed with 66 targets(39%),among which 31(18%)have stronger trade-offs.Furthermore,the synergies and trade-offs between urbanization and the achievement of SDGs are specifically analyzed based on four fundamental interaction fields:(a)public health and social welfare equality;(b)energy consumption and economic growth;(c)natural resource use and ecological/environmental impacts;and(d)international cooperation for development.Finally,based on these analyses,we propose four recommendations for sustainable urbanization,including(a)shared well-being and spatial justice for urban and rural residents;(b)guiding green and low-carbon urban development;(c)building resilient cities;and(d)promoting multilateral cooperation in cities,which can contribute to the achievement of SDGs by 2030.

Geography Education for Sustainable Development

Increased pressure on the earth’s resources has led to what is increasingly referred to as the climate crisis.While a whole range of environmental parameters have been transformed through such pressures,the effect of human activities on the climate is symbolic of the nature of the human footprint upon our planet and makes the lack of any coherent political leadership in most countries even more alarming.The discipline of Geography has a distinct advantage in developing a more holistic understanding of global environmental challenges in that it reaches across all the sciences(including social sciences and humanities).Geographical education therefore represents an important vehicle for citizens of all ages to help them understand the complexity of the sustainability goal and what can(and should)be done to achieve a more sustainable future.In this essay,I reflect on three approaches that are available to individuals and communities towards taking the steps to sustainability.The philosophy embodied by the International Year of Global Understanding(IYGU)is suggested as a particularly valuable tool for geography educators.The activities of the International Geographical Union(IGU)offer important opportunities for geographers to learn from each other and promote best practice in geographical education.As‘the science for sustainability’,Geography has an increasingly important role to play in developing the knowledge and the skills to equip future generations with the tools to adapt to and mitigate potentially catastrophic global environmental change.

The research priorities of Resources and Environmental Sciences

The great challenges of sustainable development highlight an urgent need to systematically understand the mech-anisms linking humans and nature.Resources and Environmental Sciences are a broad and practical discipline focused on coupled human and natural systems.They aim to study the formation and evolution of resources in the earth system,the drivers of various environmental problems,processes and relationships between resources and the environment,particularly under the combined impacts of natural conditions and human activities.The major resources and environmental problems drive the discipline development;international science programmes guide the direction of the discipline;interdisciplinary and transdisciplinary integration promotes new branches of the discipline;and technological progress results in a research paradigm shift.Facing the critical research re-quirements of strengthening trans-and interdisciplinarity,breaking through the key technology,targeting major environmental and disaster issues,and supporting sustainable development,nine critical scientific issues should be focused on climate change impact and adaptation,petroleum and mineral resources,water cycle and water re-sources,soil and land resources,ecosystems,remote sensing and geographic information science,environmental science and technology,disaster risk,and global and regional sustainable development.Suggestions to enhancing funding systems,improve talent cultivation,develop scientific platforms,and strength international cooperation are provided in this study to support scientific policymaking.The promotion of Resources and Environmental Sci-ences enables a more comprehensive and in-depth understanding of economic development and environmental changes relevant to assure a more sustainable global development.

The Natural History Approach to Maintaining Ecological Balance

The present ecological imbalance is due to human beings' unrestrained desires and their actions of developing multifarious strong forces in order to conquer nature. Present science and technology and institutional arrangement still follow the old-fashioned premises. According to Tao Te Ching, nature and the natural process are sacred. The concept of Anthropocene and the idea of unpredictability from complexity science remind us that it is necessary to revive the old tradition of natural history, which is interesting enough and helps to maintain the ecological balance.

Relentless Resilience

The paper observes that one of the most significant changes experienced by global cities in their growth is that(fortunately)they keep a Relentless Resilience of some of their urban components.These are clearly perceived as configuring territorial fragmentations,either in extra-or intra-urban location,caused by the obsolescence of uses non-aligned to contemporary life;and territorial discontinuities interspersed along the conurbation.It is precisely in these fragments that good opportunities for the smart growth of a global city can be detected.They represent a trend towards a curtailment of the undesired sprawl and the creation of new places that will somehow act as“gluing”the fractures.Indeed,one of the most striking features of contemporary cities has been the strong tendency to value their old memories through redeveloping their heritage assets.The newest trend is to reuse them under the generical denomination of“Cultural and Creative Parks”,in line with the ideas of the“creative economy”and the revitalization of brownfields.

An Analysis of The Road from the Perspective of Community Theory

As one of the representatives of Anthropocene fiction, Cormac McCarthy’s The Road focuses on the protagonists’ looking for hope for living. It can be inferred when analyzed with Tönnies’ theory that a community is constructed within the relationship between father and son, together with other characters that are involved in the narration. Accordingly, the changing process of community is demonstrated in a progressive sequence of blood-geopolitics-spirit, revealing a sense of progression in an Anthropocene context. This paper analyzes and explores the process of evolution in three dimensions reflected in the novel: construction, crisis, and the reconstruction of community. It is considered that The Road conveys powerful calls of the yearn for the survival of the individual, which can be regarded as a reflection of the human condition in reality. Meanwhile, its distinct and full-scale evolution of community process expressed in the novel also presents a referentiality to the age of Anthropocene.

Reimagining large river management using the Resist-Accept-Direct(RAD)framework in the Upper Mississippi River

Background Large-river decision-makers are charged with maintaining diverse ecosystem services through unprec-edented social-ecological transformations as climate change and other global stressors intensify.The interconnected,dendritic habitats of rivers,which often demarcate jurisdictional boundaries,generate complex management chal-lenges.Here,we explore how the Resist–Accept–Direct(RAD)framework may enhance large-river management by promoting coordinated and deliberate responses to social-ecological trajectories of change.The RAD frame-work identifies the full decision space of potential management approaches,wherein managers may resist change to maintain historical conditions,accept change toward different conditions,or direct change to a specified future with novel conditions.In the Upper Mississippi River System,managers are facing social-ecological transformations from more frequent and extreme high-water events.We illustrate how RAD-informed basin-,reach-,and site-scale decisions could:(1)provide cross-spatial scale framing;(2)open the entire decision space of potential management approaches;and(3)enhance coordinated inter-jurisdictional management in response to the trajectory of the Upper Mississippi River hydrograph.Results The RAD framework helps identify plausible long-term trajectories in different reaches(or subbasins)of the river and how the associated social-ecological transformations could be managed by altering site-scale conditions.Strategic reach-scale objectives may reprioritize how,where,and when site conditions could be altered to contribute to the basin goal,given the basin’s plausible trajectories of change(e.g.,by coordinating action across sites to alter habitat connectivity,diversity,and redundancy in the river mosaic).Conclusions When faced with long-term systemic transformations(e.g.,>50 years),the RAD framework helps explicitly consider whether or when the basin vision or goals may no longer be achievable,and direct options may open yet unconsidered potential for the basin.Embedding the RAD framework in hierarchical decision-making clarifies that the selection of actions in space and time should be derived from basin-wide goals and reach-scale objectives to ensure that site-scale actions contribute effectively to the larger river habitat mosaic.Embedding the RAD framework in large-river decisions can provide the necessary conduit to link flexibility and innovation at the site scale with stability at larger scales for adaptive governance of changing social-ecological systems.

The oxygen cycle and a habitable Earth

As an important contributor to the habitability of our planet, the oxygen cycle is interconnected with the emergence and evolution of complex life and is also the basis to establish Earth system science. Investigating the global oxygen cycle provides valuable information on the evolution of the Earth system, the habitability of our planet in the geologic past, and the future of human life. Numerous investigations have expanded our knowledge of the oxygen cycle in the fields of geology,geochemistry, geobiology, and atmospheric science. However, these studies were conducted separately, which has led to onesided understandings of this critical scientific issue and an incomplete synthesis of the interactions between the different spheres of the Earth system. This review presents a five-sphere coupled model of the Earth system and clarifies the core position of the oxygen cycle in Earth system science. Based on previous research, this review comprehensively summarizes the evolution of the oxygen cycle in geological time, with a special focus on the Great Oxidation Event(GOE) and the mass extinctions, as well as the possible connections between the oxygen content and biological evolution. The possible links between the oxygen cycle and biodiversity in geologic history have profound implications for exploring the habitability of Earth in history and guiding the future of humanity. Since the Anthropocene, anthropogenic activities have gradually steered the Earth system away from its established trajectory and had a powerful impact on the oxygen cycle. The human-induced disturbance of the global oxygen cycle, if not controlled, could greatly reduce the habitability of our planet.