Without a functioning biosphere, what else really matters? A healthy biosphere is foundational to life itself, at the center of nearly everything. Yet today, the integrity of the biosphere is in severe decline, and we do not collectively reckon with this existential reality nearly enough. Doing so would require a fundamental reassessment of how we interact with nature, forcing us to confront our environmental footprint at every level from the spaces we inhabit, and the resources required to feed, house, clothe, and entertain ourselves.
As the biosphere erodes more rapidly and visibly, ignoring these fundamental relationships does not merely threaten human well-being; it threatens the continuation of complex life as we know it. This article examines the current state of the biosphere to provide a clear-eyed understanding of where we stand, before turning to the role agriculture plays in driving these changes and how it also offers the most direct pathway toward stewarding life for future generations.
In 2024, the World Wildlife Fund (WWF) released its Living Planet Report, finding an average 73 percent decline in monitored global wildlife populations between 1970 and 2020. While this does not mean total wildlife abundance has fallen by 73 percent everywhere (some populations have increased), this still represents a catastrophic global trend with profound ecological consequences.
These findings align with assessments from the International Union for Conservation of Nature (IUCN), which reports that over 48,600 species, or roughly 28 percent of those they assess, are threatened with extinction. The breakdown is sobering: 41 percent of amphibians, 26 percent of mammals, 11 percent of birds, 21 percent of reptiles, 34 percent of conifers, and 71 percent of cycads face the threat of extinction. Aquatic ecosystems show similarly severe declines, with shark and ray populations halved since 1970 and coral reef coverage reduced by roughly half since the 1950s, marking the likely crossing of earth’s first tipping point as of late 2025. Insects, which make up as much as 90 percent of all animal species, are harder to track comprehensively, but global reviews reveal widespread declines in common species across many regions.
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) estimates that more than one million species globally are threatened with extinction. No matter how biodiversity is measured, whether through declines in migratory bird and butterfly populations or more human-centered metrics like shrinking crop seed diversity and even changes in the human microbiome, the signs of systemic distress are unmistakable.
While these figures are alarming on their own, their significance becomes even clearer when placed within the planetary boundaries framework, which defines a safe operating space for earth’s life-support systems. To assess biosphere integrity, scientists have identified two key control variables: genetic diversity and functional integrity. Genetic diversity is measured by the rate at which species are going extinct, while functional integrity reflects how much energy humans extract from ecosystems through activities like harvesting, hunting, and fishing.
The scientific consensus holds that extinction rates should not exceed 10–100 species per million species per year, with the boundary placed at the lower end to remain precautionary. This threshold reflects the highest rate of species loss the earth system can tolerate while maintaining ecological resilience and the genetic foundations of ecosystem functioning. This boundary was crossed in the mid-to-late twentieth century, and today the extinction rates are well above the upper bound of 100 extinctions per million species per year.
Functional integrity is measured through human appropriation of net primary production, with a boundary set at 10 percent. In other words, to remain within a safe operating space, humans should appropriate no more than 10 percent of the biosphere’s natural productivity. This limit was likely exceeded in the early twentieth century. Today, humans appropriate roughly 30 percent of global net primary production.
Together, these transgressions represent some of the most severe violations of the identified planetary boundaries. As a result, many scientists now argue that earth has entered a sixth mass extinction event, unfolding over an extraordinarily short span of time. If you were born before 1970, this dramatic transformation of the biosphere has occurred within your lifetime.
UN scientists identify the global food system as the primary driver of biodiversity loss, with agriculture alone implicated as a threat to 86 percent of species at risk of extinction. This is largely due to large-scale land-use changes, which have eliminated and fragmented wildlife habitat worldwide. Agriculture has historically been, and remains, the dominant driver of deforestation, accounting for nearly 90 percent of forest loss today. Additionally, agriculture has contributed to the near-total destruction of wetlands, with roughly 85 percent drained between 1700 and 2000.
Yet not all forms of agriculture affect ecosystems equally. Different food systems carry vastly different land requirements and ecological impacts, particularly when comparing plant-based foods with livestock-based production.
Agriculture occupies nearly half of all habitable land on earth, and approximately 80 percent of that land is used for livestock production. Despite this enormous footprint, livestock provides just 17 percent of global calories. Put differently, more than 80 percent of global calories come from less than one-fifth of agricultural land, which is dedicated to plant-based foods. This inefficiency lies at the heart of agriculture’s outsized role in biodiversity loss.
The transformation of wild ecosystems into agricultural land is reflected in global biomass distributions. Humans now account for 36 percent of mammal biomass, livestock for 59 percent, and wild mammals for just 5 percent. Among birds, farmed poultry make up 71 percent of total biomass, while wild birds account for only 29 percent.
In effect, vast areas once hosting complex ecosystems have been converted into simplified landscapes supporting livestock production. The extraordinary diversity of life that once occupied these regions has been replaced by the more than 85 billion land animals farmed annually. This disproportionate land use is why the WWF estimates that meat-heavy diets account for roughly 60 percent of global biodiversity loss. Essentially, we have engineered ecosystems around animal consumption so aggressively that we are now destabilizing the very systems that sustain life.
Despite its central role in driving biodiversity loss (or perhaps because of it), agriculture also represents the clearest pathway to reversing it. By addressing the fundamental inefficiencies in land use, it is possible to restore habitat at scales large enough for biodiversity to recover.
A transition from livestock-based agriculture to plant-based food systems could reduce agricultural land use by 75 percent without any reductions to the global food supply. This would shrink the agricultural footprint from roughly 4 billion hectares to 1 billion hectares. The scale of this solution can be hard to appreciate. Not often do we think in terms of billions of hectares. Said another way, we could rewild and conserve an area larger than China, Australia, the European Union, and the continental United States—all without reducing the food supply. Returning this land to nature would allow ecosystems to regenerate, biodiversity to recover, and wildlife populations to rebound.
Our daily experiences often shield us from the realities of biodiversity loss, which frequently unfold far from where we live. Yet our choices ripple across the biosphere. While we tend to think of our land footprint in terms of housing and urban spaces, these pale in comparison to the land required to feed us. When it comes to life on earth, the choices we make with our forks are among the most consequential.
Yet, as humans, we possess a deep capacity for empathy and connection with the natural world. On some level, we all intuitively understand ourselves as a part of the larger web of life. The scale of biodiversity loss can evoke despair or shame, yet this same empathy offers a pathway toward intentional stewardship and care for life and the broader biosphere.
The first step is recognizing the problem for what it is: urgent, foundational, and solvable. In many ways, the simplicity of the solution is a gift. Relatively modest changes in what we consume can dramatically reduce pressure on the biosphere, opening space for conservation and regeneration. On the other hand, the scale of the problem requires a moonshot effort that demands total focus and clarity.
This may prove to be the defining challenge of our time. After mass extinction events, scientists estimate it takes around ten million years for complex life to recover. Life will persist in some form, but whether humanity remains part of that future depends on the choices we make now—choices deeply intertwined with how we feed ourselves and how we treat the living world that sustains us.
This article is part of the Planetary Boundaries and Food series. This series explores how the global food system has pushed humanity beyond seven of the nine planetary boundaries, including climate change, biosphere integrity, land-system change, ocean acidification, biogeochemical flows, novel entities, and freshwater use. Each article examines how food production and consumption have driven us past these critical limits, and how reimagining our food system can help bring human activity back within a safe operating space for life on earth. To follow the series and read more about Food for a Sustainable Future, subscribe to stay up to date with the latest articles.
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