Land degradation severely threatens planetary boundaries

A significant new scientific report outlines an urgent need for a fundamental shift in how the world cultivates food and manages land to prevent irreversible damage to Earth’s capacity to support both human life and environmental health.

Produced under the leadership of Dr. Johan Rockström at the Potsdam Institute for Climate Impact Research (PIK) in collaboration with the UN Convention to Combat Desertification (UNCCD), the report is being launched as nearly 200 UNCCD member states begin their COP 16 summit in Riyadh, Saudi Arabia.

The role of land in Earth’s stability

Land serves as the foundation of Earth’s stability by regulating climate, preserving biodiversity, and maintaining freshwater systems. It provides essential resources, including food, water, and raw materials, as detailed in the Stepping back from the precipice: Transforming land management to stay within planetary boundaries report. 

Drawing on roughly 350 information sources, the report examines land degradation and opportunities for action from a planetary boundaries perspective.

However, deforestation, urbanization, and unsustainable farming practices are causing global land degradation at an unprecedented scale, threatening various Earth system components and human survival itself. 

The deterioration of forests and soils undermines Earth’s capacity to cope with climate and biodiversity crises, which in turn accelerate land degradation in a harmful cycle.

Alarming extent of land degradation

“If we fail to acknowledge the pivotal role of land and take appropriate action, the consequences will ripple through every aspect of life and extend well into the future, intensifying difficulties for future generations,” said UNCCD Executive Secretary Ibrahim Thiaw.

Currently, land degradation disrupts food security, drives migration, and fuels conflicts. The global area affected by land degradation – about 15 million square kilometers, which is more than the entire continent of Antarctica and nearly the size of Russia – is expanding each year by about a million square kilometers.

Planetary boundaries and land use

The report situates both problems and potential solutions related to land use within the scientific framework of planetary boundaries, which has quickly gained policy relevance since its emergence 15 years ago.

The planetary boundaries include nine critical thresholds which are essential for maintaining our planet’s stability. 

How humanity uses and abuses land directly impacts seven of these boundaries, including climate change, species loss and ecosystem viability, freshwater systems, and the circulation of elements such as nitrogen and phosphorus. Moreover, change in land use is also an important planetary boundary.

Transformative action or irreversible change

Alarmingly, six boundaries have already been breached until now, and two more are close to exceed their thresholds: ocean acidification and the concentration of aerosols in the atmosphere. Among the planetary boundaries, only stratospheric ozone – the object of a seminal 1989 treaty to reduce ozone-depleting chemicals – remains within its “safe operating space.”

“The aim of the planetary boundaries framework is to provide a measure for achieving human wellbeing within Earth’s ecological limits,” said Johan Rockström, lead author of the important study introducing the concept in 2009. 

“We stand at a precipice and must decide whether to step back and take transformative action, or continue on a path of irreversible environmental change.”

Decline of forests and ecosystem services

The benchmark for land use is the extent of the world’s forests before significant human impact. 

Maintaining more than 75% of original forest cover keeps us within safe bounds, but forest cover has already been reduced to only 60% of its original area, according to a recent update of the planetary boundaries framework by Katherine Richardson and colleagues.

Until recently, land ecosystems absorbed nearly one-third of human-caused CO₂ emissions, even as these emissions increased by half. Yet, during the last decade, deforestation and climate change have reduced the capacity of trees and soil to absorb excess CO₂ by 20%.

Unsustainable agriculture and its consequences

Conventional agriculture is the leading cause of land degradation, contributing to deforestation, soil erosion, and pollution. Unsustainable irrigation practices deplete freshwater resources, while excessive use of nitrogen- and phosphorus-based fertilizers destabilizes entire ecosystems.

Degraded soils result in lower crop yields and reduced nutritional quality, directly impacting the livelihoods of vulnerable populations. Secondary effects include increased dependency on chemical inputs and expanded land conversion for farming.

Today, land degradation hotspots stem from intensive agricultural production and high irrigation demands, particularly in dry regions such as South Asia, northern China, the US High Plains, California, and the Mediterranean.

At the same time, climate change (which has long since breached its own planetary boundary) accelerates land degradation through phenomena such as extreme weather events, prolonged droughts, and intensified floods. 

Moreover, melting mountain glaciers and disrupted water cycles heighten vulnerabilities, particularly in arid regions.

Human impact of land degradation

Rapid urbanization exacerbates these challenges, contributing to habitat destruction, pollution, and biodiversity loss. 

The impacts of land degradation disproportionately affect tropical and low-income countries due to lower resilience and concentrated impacts in tropical and arid regions. 

Women, youth, Indigenous peoples, and local communities bear the brunt of environmental decline. For instance, women struggle with increased workloads and health risks, while children suffer from malnutrition and major educational setbacks.

Government challenges and sustainability goals 

Weak governance and corruption worsen these challenges. Corruption, for instance, fosters illegal deforestation and exploitation of resources, thus perpetuating cycles of degradation and inequality. 

According to the Prindex initiative, almost one billion people lack secure land tenure, with the highest concentrations in North Africa (28%), sub-Saharan Africa (26%), and South and Southeast Asia. The continuous fear of losing one’s home or land frequently undermines efforts to promote sustainable practices.

Agricultural subsidies often incentivize harmful practices, leading to overuse of water and biogeochemical imbalances. Aligning these subsidies with sustainability goals is crucial for effective land management. 

From 2013 to 2018, over half a trillion dollars were spent on such subsidies in 88 countries, according to a report from 2021. From these, almost 90% went to inefficient, unfair practices that harmed the environment.

Reversing soil and land degradation 

Transformative action to combat land degradation is essential to return to the safe operating space for land-based planetary boundaries. Just as the planetary boundaries are strongly interconnected, so must be the actions taken to prevent or slow their transgression.

Principles of fairness and justice are highly important when designing and implementing transformative actions to stop land degradation, making sure that benefits and burdens are equitably distributed.

Reforming agriculture, protecting soil, managing water resources, implementing digital solutions, creating sustainable or “green” supply chains, ensuring equitable land governance, and protecting and restoring forests, grasslands, savannas, and peatlands are crucial for halting and reversing land and soil degradation.

Regenerative agriculture is defined by its outcomes, such as improved soil health, carbon sequestration, and biodiversity enhancement. Agroecology emphasizes holistic land management, integrating forestry, crops, and livestock management.

Practices such as woodland regeneration, no-till farming, nutrient management, improved grazing, water conservation and harvesting, efficient irrigation, intercropping, use of organic fertilizers, and enhanced use of compost and biochar can all increase soil carbon and boost crop yields.

Technological innovations and ecosystem protection

Savannas are under extreme threat from human-caused land degradation, yet are essential for human and ecological wellbeing. 

A major store of biodiversity and carbon, covering 20% of our planet’s land surface, savannas are increasingly being lost to cropland expansion and misguided afforestation practices.

The current rate of groundwater extraction exceeds replenishment in 47% of global aquifers, making more efficient irrigation crucial to reduce agricultural freshwater use.

According to the experts, the water sector must continue to shift from “grey” infrastructure (dams, reservoirs, channels, and treatment plants) to so-called “green” infrastructure, including practices such as reforestation, floodplain restoration, forest conservation, or recharging aquifers.

More efficient delivery of chemical fertilizers is also essential: currently, only 46% of nitrogen and 66% of phosphorus applied as fertilizer is absorbed by crops. The remainder runs off into freshwater bodies and coastal areas, with dire consequences for the environment.

New technologies to improve land use

Novel technologies coupled with big data and artificial intelligence have enabled innovations such as precision farming, remote sensing, and drones which can detect and combat land degradation in real time. 

Benefits also come from the precise application of water, nutrients, and pesticides, along with early pest and disease detection.

For instance, Plantix, a free app available in 18 languages, can detect almost 700 pests and diseases on over 80 different crops. 

Finally, improved solar cookstoves can offer households additional income sources and improve livelihoods while reducing the current reliance on forest resources.

Preventing further damage to Earth

Stronger regulatory measures, enhanced land governance, formalizing land tenure rights, and greater corporate accountability regarding environmental impacts are essential steps toward sustainable land management.

Although numerous multilateral agreements aimed at transforming land-use systems are in place, they have largely fallen short of their goals. 

For instance, the Glasgow Declaration, signed by 145 countries during the 2021 climate summit, committed to halting deforestation and land degradation by 2030. Yet, deforestation rates have continued to rise since its adoption.

Safeguarding undisturbed peatlands and restoring 60% of those already degraded could significantly reduce greenhouse gas emissions, transforming these areas into net carbon sinks by the end of the century. 

Currently, degraded peatlands contribute 4% to 5% of global greenhouse gas emissions, according to the International Union for Conservation of Nature (IUCN).

The report, which can be found here, underscores that humanity’s future – and the health of the planet – relies on immediate, collaborative action to reform how land is utilized and managed.

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