Pervasive human-driven decline of life on Earth points to the need for transformative change

Taking stock of the fabric of life

The challenges of mitigating and adapting to climate change while achieving food, water, energy, and health security, and overcoming the unequal burdens of environmental deterioration and biodiversity loss, all rest on a common foundation: living nature. Specifically, we consider the fabric of life on Earth that has been “woven” by natural processes over many millions of years and in conjunction with people for many thousands of years. The vital contributions made by living nature to humanity, referred to as nature’s contributions to people (4), affect virtually all aspects of human existence and contribute to achieving all the Sustainable Development Goals identified by the United Nations (5, 6). These various contributions are now widely recognized in the scientific literature, but governmental policies and market transactions typically do not reflect their full value (7).

Human actions are causing the fabric of life to unravel, posing serious risks for the quality of life of people. Over the past 50 years, the capacity of nature to support quality of life has declined for 14 of the 18 categories of nature’s contributions to people considered by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) (Fig. 1). Nature’s capacity to provide beneficial regulation of environmental processes—such as modulating air and water quality, sequestering carbon, building healthy soils, pollinating crops, and providing coastal protection from hazards such as storms and storm surges—has decreased globally, although for some benefits, trends vary by region (Fig. 1, third column) (8). For the 100 million to 300 million people who live in coastal areas below the 100-year flood level (9), the loss of coastal habitats has increased the risk of flooding and storm damage. Loss of animal pollinators affects more than 75% of global food crop types, risking US$235 billion to 577 billion of global crop output annually (10). The potential of nature to contribute in nonmaterial ways to human quality of life—through learning and inspiration, physical and psychological experiences, and supporting identities and sense of place—has also declined (Fig. 1). Exceptions to the downward trend of nature’s contributions to people come from an increase in many of the material goods provided by nature, including food, energy, timber, and other materials (Fig. 1). For example, the harvest of commercial timber (11) and fish have both increased by almost 50% since 1970, and the value of agricultural crop production ($2.6 trillion in 2016) has increased approximately threefold. However, even within material contributions, some indicators show a strong decline, such as the abundance of marine fish stocks (12). In addition, the benefits of these increases have not been evenly distributed: Although the prevalence (percentage) of undernourishment has decreased globally in the past two decades, more than 800 million people still face chronic food deprivation (11).

The increase in the global production of consumer goods and the decline in almost all other contributions are directly related. The world is increasingly managed to accelerate the flow of material contributions from nature to keep up with rising demand. Since 1970, global population has doubled (13), per capita consumption has increased by 45%, the value of global economic activity as measured in gross domestic product (GDP) has increased by >300% (14), global trade has increased by ~900% (15), and the extraction of living materials from nature has increased by >200% (16).

The results of this unprecedented appropriation of nature can now be seen much more clearly than even 15 years ago (17), thanks to rapid advances in data and tools for observation, analysis, synthesis, and modeling of marine, freshwater, and especially terrestrial nature. These new data reveal that human actions have directly altered at least 70% of land surface (18, 19); 66% of ocean surface is experiencing increasing cumulative impacts (20); around 85% of wetland area has been lost since the 1700s (21), and 77% of rivers longer than 1000 km no longer flow freely from source to sea (22). Coastal ecosystems show some of the largest and most rapid recent declines. Live coral cover on reefs has nearly halved in the past 150 years and is projected to virtually disappear this century unless there is strong climate change mitigation (23). Seagrass extent is decreasing by more than 10% per decade, while kelp forests have declined in 38% of their biogeographic regions (24).

The biomass of the world’s vegetation (25) has halved over human history, and forests now span only 68% of their preindustrial extent (26). Although the rate of forest loss has slowed globally since the 1980s, it is still rapid in many tropical regions (27), and the increased extent of temperate and boreal forests (28) has been accompanied by increased fragmentation and changes in function [such as carbon storage (29)].

As a result of human impacts, terrestrial ecological communities worldwide are estimated to have lost more than 20% of their original biodiversity on average (30). In the ocean, animal populations and habitat extent have declined in the 20th century (31), with more than 20 described marine species having gone extinct (32). The status of marine fish populations has worsened globally, with one-third of the stocks being currently overfished (12). Illegal, unreported, and unregulated exploitation of fisheries undermine the effectiveness of stock management measures, especially in developing countries, contributing to conflicts (33, 34). Many species that are large, slow-growing, habitat specialist, or carnivorous—such as large cats (35), large sharks (36), primates (37), reef-building corals (38), and woody plants (39)—are declining rapidly in, and being lost from, many places. On average, large terrestrial mammals have been extirpated from 75% of their natural ranges (40), while marine mammals have shown marked declines in abundance in recent centuries, many to near extinction (41, 42). Endemic species have typically seen larger-than-average changes to their habitats and show faster-than-average population declines. By contrast, ecological generalists and disturbance-adapted species have tended to become more abundant, and some have spread quickly around the world (43). In 21 countries with detailed records, for example, the numbers of invasive alien species have risen by an average of 70% since 1970 (44). This combination of declining endemic species and the spread of already widespread species as humans purposefully or unwittingly transport species around the world drives “biotic homogenization” (45, 46), a convergence of biological communities across regions that blurs the patterns on life’s rich tapestry.

The number of species currently threatened with extinction is unprecedented in human history: an estimated 1 million species of animals and plants. This figure is derived from assessments for many terrestrial, freshwater, and marine vertebrate, invertebrate, and plant groups that have applied the International Union for the Conservation of Nature (IUCN) Red List categories and criteria (the global standard for assessing the relative extinction risk of each species) (47). On average across these groups, ~25% of species are threatened (classified as Critically Endangered, Endangered, or Vulnerable), although for insects—by far the most species-rich group—the proportion might be as low as 10% (Fig. 2) (48, 49). Uncertainties in the numbers of animal and plant species and the percentage of them (particularly insects) that are threatened make any estimate necessarily approximate (50, 51). Moving from species to populations, wild animal populations are continuing to decline on land and in the sea. The global biomass of wild mammals is now less than 25% of that before the late Pleistocene megafaunal extinction—and less than 10% that of the world’s current human population (52). The global biomass of large predatory fish targeted by fisheries has fallen by two-thirds over the past 100 years (53). The outlook is worsening rapidly, with extinction risk increasing for all groups with known trends (5). A total of 705 vertebrate species are confirmed or presumed to have been driven extinct since 1500 (54), as have 571 plant species (39)—evidence that human actions have increased the global rate of species extinction by at least tens to hundreds of times over background rates before human intervention (39, 55, 56).

Domesticated species and varieties are also being lost. Fewer varieties of plants and animals are being maintained because of changes and standardization in farming practices, market preferences, large-scale trade, and loss of indigenous and local knowledge. Around 560 (~10%) of domesticated breeds of mammals had gone extinct by 2016, and at least 1000 more are threatened (57). Many hotspots of agrobiodiversity and of crop wild relatives are also under threat or lack formal protection (58), jeopardizing the pool of genetic variation that underpins the long-term resilience of agricultural production and food systems in the face of environmental change (59).

Declining trends are also documented in a worldwide evaluation of 321 indicators of nature important for quality of life developed by Indigenous Peoples and local communities. Although the decline in nature is lower in areas managed by Indigenous Peoples than in other lands (60), ~72% of the indicators assessed show deterioration (51).

In addition, rapid evolutionary responses to human drivers are now seen in all major taxonomic groups (61). This includes the evolution of resistance to pesticides and herbicides in insects and plants (62), smaller size and earlier maturation in marine fishes and invertebrates subject to fishing and global warming (63), changes in freeze tolerance in urban plants (64), and phenological shifts in a wide range of taxa in response to climate change (65).

Direct and indirect drivers of change

The direct causes of changes observed in the fabric of life are (in decreasing order of relative impact worldwide) land and sea use change, exploitation of organisms, climate change, pollution, and invasive alien species (Fig. 3). Within terrestrial and freshwater ecosystems, the driver with the highest relative impact is land use change, mainly land conversion for cultivation, livestock raising, and plantations. The main driver in the ocean is direct exploitation through biomass extraction (mostly fishing). Although climate change is already a substantial driver of changes to nature and its contributions to people in many places (Fig. 3), even causing extinction in some cases [for example, (66)], it is not yet globally the most important.

The vast area of the world managed by Indigenous Peoples (at least 25 to 28% of land surface) (Fig. 4) under various property regimes is no exception to these trends. Because of their large extent, the fact that nature is overall better preserved within them (60), and because of the diverse stewardship practices carried within them around the world (Fig. 4, A to I), the fate of nature in these lands has important consequences for wider society as well as for local livelihoods, health, and knowledge transmission (67).

Indirect drivers of change—including demographic, economic, political, and institutional arrangements, and underpinned by societal values—underlie the observed direct drivers (Fig. 3). Indirect drivers interact with one another; for example, economic development choices could cause less deterioration in the presence of environmental policy, whereas the lack of publicly enforced rights could undermine resource management and conservation practices by Indigenous Peoples and local communities (68).

Over the past five decades, global socioeconomic trends have followed highly divergent pathways for countries with contrasting levels of income (Fig. 5) (69). With the dramatic increase in global trade, and more generally economic and social globalization, nature is ever more influenced by distant consumers (70). Trade has shifted where goods are produced and used, contributing to new economic opportunities but also generating or exacerbating inequities in both economic development and environmental burdens. The demand for material goods is predominantly from higher- and middle-income countries, and it is often satisfied by production in middle- and lower-income countries (Fig. 5, A, B, and C). For example, the European Union, the United States, and Japan together accounted for ~64% of the world imports of fish products in value, whereas developing countries accounted for 59% of the total volume of traded fish (12). These exchanges are often negotiated between actors and institutions of unequal power, which affects the distribution of the benefits and long-term social and ecological costs (Fig. 5F). A handful of transnational corporations control large (>50%) shares of supply chains in agriculture, fishing, logging, and mining (71, 72), whereas funds channeled through tax havens support most illegal, unreported, and unregulated fishing (71, 73), creating governance challenges. Many economic incentives are harmful to nature, including direct and indirect subsidies to fisheries (74), agriculture (including fertilizers and pesticides) (75), livestock raising, forestry, mining, and energy production (including fossil fuels and biofuels) (76). However, conservation policies (including incentives) could also play out unequally. For example, higher-income countries might contribute to the financing of environmental protection in lower-income countries but only to secure global benefits—such as the preservation of particular species and ecosystems, or carbon storage—whereas such policies can sometimes lower welfare locally (77, 78).

Progress toward internationally agreed goals

In view of the trends summarized above, it is not surprising that progress in meeting internationally agreed goals has been generally poor. Progress toward the 20 “Aichi Targets” in the Strategic Plan on Biodiversity 2011–2020 of the Convention on Biological Diversity has been mixed (Fig. 6A). Of the 54 elements comprising the 20 targets, good progress has been made toward five (9%), moderate progress toward 19 (35%), and poor progress or movement away from the target for 21 (39%). Progress is unknown for nine elements (17%). Overall, it is clear that the majority of Aichi Targets will not be met. More progress has been made in adopting and/or implementing policy responses and actions to conserve and use nature more sustainably than has been achieved in addressing the drivers of biodiversity loss. The strongest progress has been toward increasing protected area coverage (Target 11) and developing national biodiversity strategy and action plans (Target 17). However, although protected areas now cover 14.9% of terrestrial and freshwater environments and 7.44% of the marine realm, they only partly cover areas of importance for biodiversity and are not yet fully ecologically representative, well-connected, and effectively and equitably managed. Although some species have been brought back from the brink of extinction (contributing toward Target 12 on preventing extinctions), the species in taxonomic groups with quantified trends are moving toward extinction at an increasing rate, meaning that this Target will not be met. Few data are available to quantify what the trends would have been in the absence of conservation action and policy responses to the Aichi Targets, although species’ extinction risk trends would have been worse (79), and many island ecosystems that are recovering after eradications of invasive mammals would not have done so (80).

Nature and its contributions to people were found to underpin the achievement of all the United Nations Sustainable Development Goals (SDGs), either directly for goals on water, climate, oceans, and biodiversity (SDGs 6, 13, 14, and 15, respectively) or through more complex interactions for goals on poverty, hunger, health, cities, education, gender equality, reduced inequalities, and peace (SDGs 1, 2, 3, 4, 5, 10, 11, and 16, respectively). For SDGs on energy, economic growth, industry and infrastructure, and consumption and production (SDGs 7, 8, 9, and 12, respectively), important feedbacks between these goals and nature and its contributions to people were found with consequences for the achievement of all SDGs.

Declines in nature and its contributions to people therefore compromise our ability to meet the SDGs. At the target level, progress to 35 SDG targets that could be quantitatively assessed—on poverty, hunger, health, water, cities, climate, and biodiversity (SDGs 1, 2, 3, 6, 11, 13, 14, and 15 , respectively)—are being undermined by current trends in aspects of nature and its contributions to people relevant to these targets (Fig. 6B). However, current goal and target articulation omit or obscure the links to nature, preventing an assessment of other targets under these goals as well as targets in other goals linked to education, gender equality, reduced inequalities, and peace.

Possible futures

We comprehensively reviewed both exploratory and target-seeking scenarios (81) of future change in direct and indirect drivers. These scenarios resulted in starkly different impacts on nature and its contributions to people and, in combination, enabled synthetic conclusions about the need for transformative change. We considered a wide range of exploratory scenarios on the basis of future plausible changes in direct and indirect drivers. A subset of the scenarios was based on Shared Socioeconomic Pathway (SSP) scenarios and Representative greenhouse gas Concentration Pathways (RCPs) developed in support of Intergovernmental Panel on Climate Change assessments (82). These combined scenarios ranged from “Global sustainability” [combining proactive environmental policy and sustainable production and consumption with low greenhouse gas emissions (SSP1 and RCP2.6)] to “Regional competition” [combining strong trade and other barriers and a growing gap between rich and poor with high emissions (SSP3 and RCP6.0)] to “Economic optimism” [combining rapid economic growth and low environmental regulation with very high greenhouse emissions (SSP5 and RCP8.5)]. Scenarios of a world with increased regional political and trade barriers tend to result in the greatest divergence across regions, scenarios that emphasize liberal financial markets result in intermediate levels of disparity, whereas scenarios that integrate actions toward sustainable development result in more modest differences between regions (83). Under business-as-usual future scenarios—meaning that drivers of change do not deviate from the current socioeconomic and governance trajectory—nature in terrestrial, freshwater, and marine realms and most of its contributions to people will continue to decline sharply. Recent modeling of natural regulation of water quality, reduction of coastal risk, and crop pollination worldwide (84) found convergent conclusions.

Direct drivers of change that have predominated in the past 50 years (Fig. 3) will continue to play an important role (19, 83, 85), with climate change increasingly driving further biodiversity and ecosystem decline (19, 83, 86). These projections come with important uncertainties as to the degree of change or to the geographical differentiation of the impacts, depending on the underlying socioeconomic scenario. Given the interconnectedness of the world regions, future scenarios need to better address the impacts of telecouplings [socioeconomic and environmental interactions over distances (70)], such as trade, foreign direct investment, migrations, biological invasions, and pollutant flows (87). Projections also omit interconnections among species, which may cause domino effects that amplify the loss of diversity (88).

A different picture emerges from “target-seeking” scenarios (81), which start with a desirable target set in the future and then evaluate different pathways allowing to achieve it, including the innovations and policy interventions that are needed to reach such a target. Our analysis suggests that it is possible to achieve many of the global biodiversity targets and sustainability goals related to food, energy, climate, and water at local and global scales. The complexity of the challenges calls for an integrative (nexus) approach (89) that simultaneously examines interactions among multiple sectors along with synergies and tradeoffs among goals. An example of a key nexus are the simultaneous needs to mitigate climate change, arrest biodiversity loss, and ensure that all people have adequate nutrition on one hand, and the potentially negative consequences of large-scale land-based climate change mitigation on the other. Even moderate warming will likely be detrimental for biodiversity (90) and associated benefits to people (91). However, most scenarios projected to limit warming to 1.5°C or 2°C by the end of the 21st century rely on large-scale mitigation measures on land, in the form of bioenergy crops, reforestation, and/or afforestation, negatively affecting biodiversity and also food production and water demand (19, 92). At the same time, expanding the amount of land devoted to agriculture to ensure that all people have adequate nutrition would negatively affect biodiversity as well (93) and would further exacerbate climate change (19, 92). Both land-based climate change mitigation and agricultural expansion, when deployed at the large scale, can undermine local livelihoods, create access problems, and intensify social conflict (94). A suite of possible actions could be effective in navigating these tradeoffs (19, 95)—for example, focusing on regeneration and restoration of high-carbon ecosystems (as well as reducing waste and overconsumption) rather than massive bioenergy monoculture plantations—to achieve climate change mitigation (19, 96, 97). Similarly, the increasing demands for food could be met without expanding agriculture’s footprint by sustainably increasing yields, changing dietary choices, and reducing waste, among other measures (19, 98, 99).

More generally, solutions are needed that simultaneously address a nexus of relevant goals, such as feeding humanity, resourcing growing cities, mitigating climate change, protecting nature on land and at sea, maintaining freshwater, and ensuring animal welfare (Fig. 7). The futures that successfully address this suite of sustainability goals require rapid transition toward clean energy, a continued ramping up of biological conservation, large-scale restoration of degraded ecosystems, and transformation of supply chains to reduce resource extraction and environmental impacts. However, such comprehensive changes to direct drivers also require reform of indirect drivers, including innovations in economic and political structures and societal norms.

Levers and leverage points for transformative change

Our assessment—the most comprehensive carried out to date, including the nexus analysis of scenarios and an expert input process with literature reviews—revealed clearly that reversing nature’s ongoing decline (100) while also addressing inequality will require transformative change, namely a fundamental, system-wide reorganization across technological, economic, and social factors, making sustainability the norm rather than the altruistic exception. Achieving such a transformation for the broader current and future public good will have to overcome resistance from vested interests, including some powerful actors (101). One important avenue to transformation is the improved implementation and enforcement of existing environmental policies and regulations and the removal and reform of harmful policies, such as subsidies for energy use or resource harvest (102). Another important step involves reforming global financial and economic systems, steering away from the current limited paradigm of economic growth to reward sustainability and penalize actions, resulting in the deterioration of the fabric of life (103, 104). Such transformative change can be enabled, strengthened, and accelerated with the collaborative application of priority interventions (levers) to key points of intervention (leverage points) through innovative governance approaches (Fig. 7).

A comprehensive set of five levers (95) for this transformative change emerged from our unprecedentedly broad and rigorous analysis of the many possible levers that have been proposed previously: (i) developing incentives and widespread capacity for environmental responsibility and eliminating perverse incentives; (ii) reforming sectoral and segmented decision-making to promote integration across sectors and jurisdictions; (iii) taking preemptive and precautionary actions in regulatory and management institutions and businesses to avoid, mitigate, and remedy the deterioration of nature, and monitoring their outcomes; (iv) managing for resilient social and ecological systems in the face of uncertainty and complexity to deliver decisions that are robust in a wide range of scenarios; and (v) strengthening environmental laws and policies and their implementation, and the rule of law more generally.

The scenarios analysis and expert-input process further found that efforts focused on the following eight leverage points yield disproportionately large effects: (i) enabling visions of a good quality of life that do not entail ever-increasing material consumption; (ii) lowering total consumption and waste, including by addressing both population growth and per capita consumption differently in different contexts; (iii) unleashing existing, widely held values of responsibility to effect new social norms for sustainability, especially by extending notions of responsibility to include the impacts associated with consumption; (iv) addressing inequalities, especially regarding income and gender, that undermine the capacity for sustainability; (v) ensuring inclusive decision-making and the fair and equitable sharing of benefits arising from the use of and adherence to human rights in conservation decisions; (vi) accounting for nature’s deterioration from both local economic activities and telecouplings (70), including, for example, international trade; (vii) ensuring environmentally friendly technological and social innovation, taking into account potential rebound effects and investment regimes; and (viii) promoting education, knowledge generation, and the maintenance of different knowledge systems, including in the sciences and indigenous and local knowledge, especially regarding nature, conservation, and nature’s sustainable use. Although change at some of these levers and leverage points may encounter resistance individually, action at other levers and leverage points can enable such changes.

The review also revealed that innovative governance approaches that are integrative, inclusive, informed, and adaptive (105, 106) are needed to effectively apply these levers to leverage points. Integrative approaches focus on the relationships between sectors and policies and ensure policy coherence and effectiveness, and inclusive approaches, including rights-based ones, reflect a plurality of values and thus promote equity. Informed governance entails new strategies for knowledge production and coproduction that are inclusive of diverse values and knowledge systems. Last, adaptive approaches—including learning, monitoring and feedback loops—help coping with inevitable uncertainties and complexities.