- A new scientific report lays bare the stark impacts of land-system change and land degradation on planetary health, while also offering solutions to these problems. The report was published on the eve of the 16th session of the UN Convention to Combat Desertification, running Dec. 2-13 in Riyadh, Saudi Arabia.
- Seven of nine planetary boundaries are now adversely impacted by unsustainable land use and other land practices, the report finds. Six of those boundaries are already transgressed, having moved beyond their safe operating space for humanity and into the high-risk zone.
- Scientists warn that the seriously degraded land use boundary, interacting with the other transgressed planetary boundaries, could result in a domino-effect that may rapidly push Earth systems past dangerous and irreversible tipping points, threatening life as we know it.
- Unsustainable agricultural practices are a leading driver of land use degradation globally, responsible for vast amounts of greenhouse gas emissions, the majority of deforestation and freshwater use. Urgent measures are needed to restore ecosystems, shift to sustainable agriculture, and prevent further degradation.
Swift action must be taken to address human-caused land-system change and land degradation, which is now having wide ranging impacts on planetary health and human health, according to a first of its kind report linking the way land is being managed to negative impacts on seven of nine planetary boundaries.
Crucially, sustainable land management could prove pivotal in reversing an increasingly concerning trend that is pushing the Earth beyond it’s “safe operating space for humanity,” says the scientific report.
Unsustainable agriculture, urbanization and deforestation are key driving forces behind climate change, biodiversity loss, and pollution, the authors state. Those activities have already led to approximately 15 million km² of degraded land globally — an area larger in size than Antarctica. That figure is expanding by around one million km2 annually, according to the report.
The researchers reviewed 350 scientific papers and data sources to assess how land use change and land degradation impacts and interacts with seven “land-based” planetary boundaries. The planetary boundaries framework sets “safe operating limits” crucial to Earth system functioning and human wellbeing.
“The aim of the planetary boundaries framework is to provide a measure for achieving human wellbeing within Earth’s ecological limits,” said Johan Rockström, an author of the report and director of the Potsdam Institute for Climate Impact Research. He led the development of the framework 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.”
Disrupted Earth systems can interact like falling dominos
The report underlines how current land use, management and governance is not only transgressing the safe limits of the land-system change planetary boundary, but also contributing to the freshwater, biogeochemical flows, novel entities, climate change, biosphere integrity, and aerosol loading boundary transgressions — pushing them “into an increasingly dangerous zone.” All these boundaries, with the exception of aerosol loading, are already transgressed, according to the latest planetary boundary assessment issued in 2023.
“Land is absolutely central to environmental and human well-being for our generation, but also for the generations to come,” Julia Tomalka, a lead author on the report with the Potsdam Institute for Climate Impact Research, told Mongabay in an interview. “Land is threatened by the way that we use and manage it all over the world, and human activities are the main driver behind land degradation.”
Conducted by the Potsdam Institute for Climate Impact Research in collaboration with the UN Convention to Combat Desertification (UNCCD), the new report was published on the eve of UNCCD’s COP 16 in Saudia Arabia that will bring together representatives from member states worldwide. The summit runs from Dec. 2-13 in Riyadh, Saudi Arabia.
“Land degradation and drought are multidimensional crises with profound implications for climate stability, biodiversity and socio-economic resilience. The report underlines the urgency of transformative sustainable land management practices,” Barron Joseph Orr, chief scientist at UNCCD, wrote in an email. “COP16 is more than a critical milestone; it is an opportunity to raise global ambition and accelerate action on land restoration and drought resilience through a people-centred approach.”
The wide reach of land degradation
Humanity passed the safe limit for the land-system change planetary boundary in the 1990s, a shift driven primarily by deforestation for agriculture land. The safe boundary is calculated as a proportion of the original forest cover that existed before human activity occurred, with the safe limit set at 75%; currently the global figure has fallen far below that, and sits today at 60%.
While land use change, degradation and management are most noticeable at the local and regional level, their consequences can reverberate across landscapes and entire Earth systems, the report states. Land-system change is closely linked to both the climate change and biosphere integrity boundaries, notes Tomalka, which are both considered “core” as they link to and influence all the others.
Clearing forest for agriculture, for example, directly contributes to biodiversity loss and can diminish vital carbon sinks, further fueling the climate crisis. Food production is also a core driver of greenhouse gas emissions, especially via methane releases from livestock and rice production. Industrial agricultural practices particularly worsen these effects.
The use of agrochemicals — including petrochemical-based fertilizers and synthetic pesticides — can pollute land and aquatic ecosystems, resulting in nitrogen and phosphorus nutrient overload, along with the release of novel entities, which include chemical toxins harmful to wildlife and humans. Nearly 60% of atmospheric aerosol emissions, can be linked back to the current food system, primarily through land-use change and crop residue burning.
These examples offer just a few snapshots of the complex web of interactions between land system change and the destabilization of multiple planetary boundaries. With six boundaries already exceeding their safe operating limits, moving even further into the “high risk zone” could result in “irreversible environmental damage,” says Tomalka, impacting human health, food security, and even regional and national security.
“The status of these land-based planetary boundaries is quite concerning,” she says. “The report comes at a time of different crises that are closely linked to land degradation,” she notes, citing the example of drought and famine in the Horn of Africa, driven by a combination of land degradation, climate change and freshwater depletion.
“We have to do everything to get back to the safe operating space for those boundaries that have been crossed, and avoid transgression of those boundaries that have not been crossed,” Tomalka says. Without an over-arching land perspective and the reform of current practices, that won’t be possible.
Transforming the land, rolling back degradation
The report is the first to assess land’s relation to multiple planetary boundaries, offering a sweeping but in-depth perspective on the issue’s complexity, while also addressing how to begin resolving the problem.
Importantly, while the worsening of land degradation practices can directly and indirectly stress several planetary boundaries at once, sustainable land management practices can lead to greater resilience and drive wide-ranging positive change across multiple boundaries, the authors state.
“Many transformative actions exist that can be used to combat land degradation, but also other environmental challenges like climate change or biodiversity loss or freshwater depletion,” says Tomalka. “If we managed land sustainably, we would also be able to contribute to avoiding the transgression of these planetary boundaries, or coming back to the safe operating space.”
Agroforestry is one example she emphasizes. If implemented appropriately, it can be beneficial for the environment, helping soil recover, while aiding biodiversity. That could positively contribute to several global boundaries, including land-system change, climate, and biosphere integrity, while simultaneously supporting farmers at the local and regional level, she adds.
The report highlights a raft of “transformative action” to prevent land degradation, restore ecosystems and increase land resilience. These include not only a singular focus on forests and farmland, but on the restoration and conservation of savannas, drylands and grasslands. These biomes are vital for biodiversity and ecosystem functioning, and play an important, yet poorly understood role, in Earth’s climate system.
Consequently, there is a “need for immediate, coordinated and synergistic efforts” at the policy level, the report authors state, especially addressing land governance and corruption. Also, instead of solely embracing a top-down approach, these efforts need to include women, youth and Indigenous groups as decision making partners, as they can be particularly impacted by land degradation. These policy shifts need to be backed and driven by scientific research with the ultimate goal of achieving sustainable land use.
Lan Wang-Erlandsson, a researcher at the Stockholm Resilience Centre at Stockholm University who was not involved in the report, describes it as a “must-read” for COP 16 attendees and land use decision-makers. “The report also nicely highlights the importance of enabling [mechanisms], such as the importance of finance, land tenure issues, policy coherence, capacity building, collaborations and inclusivity and more,” she wrote in an email.
“Our hope is that the international community will recognize that land is central to solving these challenges, and that land is also closely connected to other environmental problems, like climate change and biodiversity loss,” Tomalka says.
“Actions such as ecological restoration of grasslands and peatlands not only combat degradation, but also enhance biodiversity, climate resilience and water efficiency,” Orr adds. “These solutions are critical as we [engage in] COP16, where bold, collective action is needed to address these interconnected challenges.”
Banner image: Unsustainable agriculture, urbanization and deforestation are key driving forces behind climate change, biodiversity loss, and pollution. Image by Fabian Köhler via Pexels (Public domain).
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Citation:
Tomalka, J., Hunecke, C., Murken, L., Heckmann, T., Cronauer, C., Becker, R., Collignon, Q., Collins-Sowah, P., Crawford, M., Gloy, N., Hampf, A., Lotze-Campen, H., Malevolti, G., Maskell, G., Müller, C., Popp, A., Vodounhessi, M., Gornott, C., Rockström, J. (2024). Stepping back from the precipice: Transforming land management to stay within planetary boundaries. Potsdam, Germany: Potsdam Institute for Climate Impact Research. DOI: https://doi.org/10.48485/pik.2024.018.
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