Cited by 106Soil erosion and sediment transportLand Use and Ecosystem ServicesWater and Land Management

The DOI matches its Crossref record; 151 of the 151 references it cites were found in a registry or an index; 111 of the 246 sources its claims cite were checked for support.

Restoring Degraded Lands

Open access

Abstract

Land degradation continues to be an enormous challenge to human societies, reducing food security, emitting greenhouse gases and aerosols, driving the loss of biodiversity, polluting water, and undermining a wide range of ecosystem services beyond food supply and water and climate regulation. Climate change will exacerbate several degradation processes. Investment in diverse restoration efforts, including sustainable agricultural and forest land management, as well as land set aside for conservation wherever possible, will generate co-benefits for climate change mitigation and adaptation and morebroadly for human and societal well-being and the economy. This review highlights the magnitude of the degradation problem and some of the key challenges for ecological restoration. There are biophysical as well as societal limits to restoration. Better integrating policies to jointly address poverty, land degradation, and greenhouse gas emissions and removals is fundamental to reducing many existing barriers and contributing to climate-resilient sustainable development.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

Land degradation is a widespread challenge driven mainly by socioeconomic factors, and climate change is expected to exacerbate it while degradation itself contributes to greenhouse gas emissions and biodiversity loss. Restoration and sustainable land management can deliver climate mitigation, adaptation, and broader co-benefits, but adoption barriers and hard ecological/social limits remain.

Key findings

  • Approximately 70–75% of the ice-free land area is affected by human use, nearly 50% intensively; degradation negatively impacts livelihoods in more than a quarter of the Earth’s ice-free land area, with possibly up to 3.2 (1.3–3.2) billion people affected globally, and about 500 (±120) million people live in or near desertification hotspots.
  • Since 1961, crop production increased about 3.5-fold and animal product production 2.5-fold, enabled by fertilizer inputs (+800%) and freshwater withdrawals (+100%); population rose from 3.0 to 7.8 billion by 2020, while per capita calorie intake increased 32%.
  • Restoration and sustainable land management can yield economic returns: case studies found each US$1 invested in land restoration could yield US$3–$6 in societal economic returns over 30 years; forest restoration increased biodiversity by 15–84% and vegetation structure by 36–77% above degraded ecosystems, though values remained below old-growth forests.
  • Risks exist: large-scale afforestation/reforestation or bioenergy can backfire through biodiversity loss, food-production trade-offs, and land-use displacement; the Bonn Challenge aims to restore 3.5 Mkm² of forested landscapes by 2030, while 2019 voluntary restoration commitments totaled 230 million hectares of forest.

Methods

  • This is a review/synthesis article; it draws on cited literature and IPCC/IPBES assessments and presents summary tables (Tables 1–2) and figures rather than primary data collection.
  • Data/sample: Not stated in the paper as a primary dataset; the article synthesizes global and regional estimates from referenced studies and assessments.
  • Main analysis: narrative synthesis of degradation drivers, climate interactions, restoration practices, governance, and policy, with no new empirical modeling or systematic review protocol reported.

Limitations

  • The paper states soft barriers (human, social, economic, institutional, technological) and hard limits to restoration, including species already committed to extinction, habitat loss from sea-level rise, and possible tipping points such as climate-driven desertification or permafrost collapse; return to pristine historical states may be difficult or impossible.
  • The paper states uncertainties and a lack of restoration scenarios, noting that attribution of climate change as a degradation driver is complicated by concurrent CO₂ increases and regional variability, and that measuring mitigation-adaptation co-benefits is technically complex, expensive, and may take years to decades.
  • Evident from the text: as a review, reported estimates depend on cited sources with differing definitions and methods (e.g., forest area, wetland extent), and no systematic search or quality appraisal is described.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1146/annurev-environ-012320-054809

Cites

151 of 151 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

67 Own interpretation · 61 Partly supported · 57 No full text of the sources · 31 Sources not found · 23 Supported · 14 No basis given · 9 Couldn’t confirm · 6 Supported so far · 4 Not checked yet · 3 Not supported · 1 Own result · accuracy not yet measured

  • It may state two separate claims as one. 86
  • Probably not a substantial claim. 58
122 of 122
  • The paper relies on this without support.

    These grasslands represent the key source of livelihoods for approximately 100 million to 200 million pastoralists around the world.

    “These grasslands represent the key source of livelihoods for approximately 100 million to 200 million pastoralists around the world.”
  • The paper relies on this without support.

    Grasslands provide essential supporting, regulating, and cultural ecosystem functions and services.

    “Grasslands also provide essential supporting, regulating, and cultural ecosystem functions and services.”
  • The paper relies on this without support.

    Tropical grassy ecosystems harbor approximately half of the vascular plant richness found in tropical forests, and species richness for mammals, birds, and amphibians is also high.

    “For instance, tropical grassy ecosystems harbor approximately half of the vascular plant richness found in tropical forests, and species richness for mammals, birds, and amphibians is also high.”
  • The paper relies on this without support.

    Grassland degradation is a widespread phenomenon, with overgrazing being a key driver, together with frequent wheel traffic, or overfertilization, all of which result in changes in sward composition, reduction in yields, and deterioration of soils.

    “Grassland degradation is a widespread phenomenon, with overgrazing being a key driver, together with frequent wheel traffic, or overfertilization, all of which result in changes in sward composition, reduction in yields, and deterioration of soils.”
  • The paper relies on this without support.

    Grasslands can act as carbon sinks, transferring carbon below-ground via their expansive root systems.

    “Grasslands can act as carbon sinks, transferring carbon below-ground via their expansive root systems.”
  • The paper relies on this without support.

    The global extent of land used for grazing is estimated to be 28–42 Mkm², with the range mainly determined by differences in definitions.

    “The global extent of land used for grazing is estimated to be 28-42 Mkm², the range being mainly determined by differences in definitions.”
  • The authors state this as an assumption.

    Grassland established after deforestation can be assumed to be under intensive management schemes.

    “and can be assumed to be under intensive management schemes.”
  • The paper relies on this without support.

    Grasslands are sources of ruminant methane (CH4) emissions and nitrous oxide (N2O) emissions from excreta or fertilized pastures.

    “grasslands are sources of ruminant methane (CH 4 ) emissions as well as nitrous oxide (N 2 O) emissions from excreta or fertilized pastures.”
  • The paper relies on this without support.

    Modern conventional agriculture is a driver of terrestrial and marine ecosystem degradation and emissions of greenhouse gases.

    “It is axiomatic that modern conventional agriculture is a driver of terrestrial and marine ecosystem degradation as well as emissions of greenhouse gases.”
  • The paper relies on this without support.

    Agricultural soils and practices are a major source of CH4 and N2O.

    “Agricultural soils and practices are also a major source of CH 4 and N 2 O.”
  • The paper relies on this without support.

    Within the agricultural and forestry sector, annual emissions of CH4 and N2O together are similar (in CO2-equivalents) to emissions of CO2 from net deforestation.

    “Within the agricultural and forestry sector, annual emissions of CH 4 and N 2 O together are similar (in CO 2 -equivalents) to emissions of CO 2 from net deforestation.”
  • The paper relies on this without support.

    Wetlands play a vital role for a range of ecosystem services, such as flood control, water purification, groundwater replenishment, and nutrient retention, and they are often hotspots of biodiversity.

    “Wetlands play a vital role for a range of ecosystem services, such as flood control, water purification, groundwater replenishment, and nutrient retention, and they are often hotspots of biodiversity.”
  • The paper relies on this without support.

    Wetlands are under severe stress and subject to degradation.

    “Despite their importance, wetlands are under severe stress and subject to degradation.”
  • The authors state this as an assumption.

    The intensification of the hydrological cycle is at least linearly linked to warming at a rate of 6-7% per degree K (the Clausius-Clapeyron response).

    “Theoretically, the intensification is assumed to be at least linearly linked to warming at a rate of 6-7% per degree K (the Clausius-Clapeyron response), but empirical evidence and model studies indicate a steeper increase in precipitation intensity, particularly in dry regions (82,83).”
  • The paper relies on this without support.

    Erosion from agricultural fields under conventional tillage is often 2-3 orders of magnitude larger than the rate of soil formation.

    “Erosion from agricultural fields under conventional tillage is often 2-3 orders of magnitude larger than the rate of soil formation.”
  • The paper relies on this without support.

    Unsustainable harvesting of fuelwood for domestic use is a major cause of land degradation, especially in tropical and dryland regions.

    “Unsustainable harvesting of fuelwood for domestic use is a major cause of land degradation, especially in tropical and dryland regions.”
  • The paper relies on this without support.

    Expansion of purpose-grown energy crops such as canola, soy, miscanthus, or oil palm causes loss of carbon stocks in biomass and soil, loss of soil fertility, and loss of biodiversity if it leads, directly or indirectly, to the conversion of grassland or natural forest to cropland or plantations and/or to further environmentally detrimental intensification of cropland management.

    “Expansion of purposegrown energy crops such as canola, soy, miscanthus, or oil palm causes loss of carbon stocks in biomass and soil, loss of soil fertility, and loss of biodiversity if it leads, directly or indirectly, to the conversion of grassland or natural forest to cropland or plantations and/or to further environmentally detrimental intensification of cropland management.”
  • The paper relies on this without support.

    Socioeconomic drivers of degradation such as population growth and increasing per capita demand for ecosystem services are projected to continue into the future.

    “Socioeconomic drivers of degradation such as population growth and increasing per capita demand for ecosystem services are projected to continue into the future.”
  • The paper relies on this without support.

    Reductions in net greenhouse gas emissions or atmospherically reactive precursors of climate forcers are in principle measurable, but these measurements are often technically complex and expensive and require large investment in human power and instrumental infrastructure.

    “For instance, reductions in net greenhouse gas emissions or atmospherically reactive precursors of climate forcers are in principle measurable, but these measurements are often technically complex and expensive and require large investment in human power and instrumental infrastructure.”
  • The paper relies on this without support.

    The effectiveness of measures may only become evident years or even decades after implementation.

    “In both cases, the effectiveness of measures may only become evident years or even decades after implementation, such as the carbon uptake of a restored forest (including the fate of wood products or carbon losses through fire or insects) or the net carbon budget (CO 2 versus CH 4 ) and catchment water balance in restored wetlands, which may take decades to centuries to semiequilibrate.”
  • The paper relies on this without support.

    Carbon sinks decline in all forests as they mature.

    “Carbon sinks decline in all forests as they mature.”
  • The paper relies on this without support.

    Biophysical surface exchange processes in tropical forests cause local cooling as a climate co-benefit.

    “Biophysical surface exchange processes in tropical forests, with often large evapotranspiration rates, cause local cooling as a climate co-benefit.”
  • The paper relies on this without support.

    Animals have carbon to nitrogen ratios lower than plant material.

    “And animals have carbon to nitrogen ratios that are lower than plant material; hence, the return of nutrients to soil in the form of animal feces has quite different decomposition rates than plant litter.”
  • The paper relies on this without support.

    The return of nutrients to soil in the form of animal feces has quite different decomposition rates than plant litter.

    “And animals have carbon to nitrogen ratios that are lower than plant material; hence, the return of nutrients to soil in the form of animal feces has quite different decomposition rates than plant litter.”
  • The paper relies on this without support.

    The presence or absence of large carnivores impacts type and density of prey animals, including the abundance of herbivores and the type and amount of consumed green leaf area.

    “Furthermore, the presence or absence of large carnivores impacts type and density of prey animals, including the abundance of herbivores and the type and amount of consumed green leaf area.”
  • The paper relies on this without support.

    Earthworms and termites are well known for their role in decomposition of litter and soil organic matter and nutrient turnover.

    ““Soil engineers” such as earthworms and termites are well known for their role in decomposition of litter and soil organic matter and nutrient turnover.”
  • The paper relies on this without support.

    Perennial woody or herbaceous energy crops are able to grow, albeit slowly, on low fertility soils.

    “Likewise, perennial woody or herbaceous energy crops (e.g., grasses such as switchgrass or Miscanthus species) can be grown where topsoil has been lost, as they are able to grow, albeit slowly, on low fertility soils.”
  • The paper relies on this without support.

    Wolves preying on moose in Northern American boreal forests enhance NPP and net ecosystem carbon uptake by up to 30% via increased growth of deciduous trees and enhanced tree leaf area index.

    “Wolves preying on moose in Northern American boreal forests were also estimated to enhance NPP and net ecosystem carbon uptake by up to 30% via increased growth of deciduous trees (which, as the preferred fodder of moose, are suppressed in their presence) and enhanced tree leaf area index.”
  • The paper relies on this without support.

    There are very few examples of large-scale scenarios of restoring degraded land.

    “Although scenario analysis is used widely across the environmental sciences, there are very few examples of large-scale scenarios of restoring degraded land.”
  • The paper relies on this without support.

    Restoration is part of the CBD's post-2020 biodiversity targets expected to be agreed at the next UN CBD COP in China in 2021.

    “Restoration is also part of the CBD's post-2020 biodiversity targets that are expected to be agreed upon at the next UN CBD Conference of the Parties (COP) in China (which will take place in 2021)”
  • The paper relies on this without support.

    At least 66% of Paris Agreement signatories include nature-based solutions in some form in their Nationally Determined Contributions (NDCs).

    “At least 66% of Paris Agreement signatories were found to include nature-based solutions in some form in their Nationally Determined Contributions (NDCs).”
  • The paper relies on this without support.

    An important share of the economic benefits of restoration is in the form of nonprovisioning ecosystem services, which benefit society as a whole, but individual land users cannot fully monetize these benefits.

    “Firstly, an important share of the economic benefits of restoration is in the form of nonprovisioning ecosystem services, which benefit society as a whole, but individual land users cannot fully monetize these benefits.”
  • The paper relies on this without support.

    Benefits of private goods may accrue only after a long period of time, while up-front costs may be prohibitively high, especially for the poor without access to credit.

    “Secondly, even when the value of private goods can be realized by land users, the benefits may accrue only after a long period of time, while up-front costs may be prohibitively high, especially for the poor without access to credit.”
  • The paper relies on this without support.

    Continuing institutional barriers such as land tenure insecurity and lack of access to rural advisory services pose formidable barriers to the wider adoption of SLM practices and technologies.

    “Furthermore, continuing institutional barriers such as land tenure insecurity and lack of access to rural advisory services, i.e., to the information and know-how about SLM and land restoration technologies, pose formidable barriers to the wider adoption of SLM practices and technologies.”
  • The paper relies on this without support.

    Many synergies exist between restoration and key international policy areas that relate to nature-based solutions for climate change mitigation and adaptation (UNFCCC), avoiding and reducing degradation and restoring degraded land (UNCCD), and the CBD and its Aichi Biodiversity Targets.

    “Many synergies exist between restoration and key international policy areas that relate to nature-based solutions for climate change mitigation and adaptation (UNFCCC), avoiding and reducing degradation and restoring degraded land (UNCCD), and the CBD and its Aichi Biodiversity Targets.”
  • The authors state this as an assumption.

    Large uncertainties about the future exist.

    “Given large uncertainties about the future (and a general lack of restoration scenarios) static goals and policies that aim to achieve restoration (and sustainable development more generally) are likely to fail.”
  • The authors state this as an assumption.

    There is a general lack of restoration scenarios.

    “Given large uncertainties about the future (and a general lack of restoration scenarios) static goals and policies that aim to achieve restoration (and sustainable development more generally) are likely to fail.”
  • The paper relies on this without support.

    The SSPs are currently widely used in the global environmental change research community.

    “The SSPs currently widely used in the global environmental change research community vary in their challenges to climate change adaptation and mitigation, but do not specify challenges to nature conservation, nor many of the critical drivers of ecosystem change.”
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Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

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Citations

Cites

Show all 136 references

Research works printed but not linked: 12

  1. IPBES (Intergov. Sci.-Policy Platf. Biodivers. Ecosyst. Serv.), 2019, The IPBES Global Assessment on Biodiversity and Ecosystem Services
  2. Olsson L, 2019, Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems, 345
  3. Mirzabaev A, 2019, Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems, 249
  4. FAO (United Nations Food Agric. Organ.), 2016, Trees, Forests and Land Use in Drylands: The First Global Assessment—Preliminary Findings
  5. Shin Y-J, 2019, The IPBES Global Assessment on Biodiversity and Ecosystem Services
  6. Prince S, 2018, The IPBES Assessment Report on Land Degradation and Restoration, 315
  7. Jia G, 2019, Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems, 131
  8. Hurlbert M, 2019, Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems, 673
  9. IPCC (Intergov. Panel Clim. Change), 2018, Global Warming of 1.5°C
  10. Montgomery DR., 2017, Growing a Revolution: Bringing Our Soil Back to Life
  11. De Stefano A, 2018, Agroforestry Syst, 92, 285
  12. Seddon N, 2019, Nature-Based Solutions in Nationally Determined Contributions: Synthesis and Recommendations for Enhancing Climate Ambition and Action by 2020

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Metadata

Authors
Arneth, A., Olsson, L., Cowie, A., Erb, K.-H., Hurlbert, M., Kurz, W. A., Mirzabaev, A., & Rounsevell, M. D. A.
Affiliations
  • Karlsruhe Institute of Technology (DE)
  • Lund University (SE)
  • Government of New South Wales (AU)
  • BOKU University (AT)
  • University of Regina (CA)
  • Canadian Forest Service (CA)
  • University of Bonn (DE)
Venue
Annual Review of Environment and Resources
Published
2021-10-18
Volume
46
Issue
1
Pages
569-599
ISSN
  • 1543-5938 (ISSN-L)
  • 1545-2050
OpenAlex
W3193845121
Cited by
106
References
136
Citations by year
2026: 17 · 2025: 31 · 2024: 26 · 2023: 13 · 2022: 15 · 2021: 3
FWCI
1.50
Type
journal article
Language
en
Open access
Locations
  • Annual Review of Environment and Resources (publishedVersion, cc-by)
  • Repository KITopen (Karlsruhe Institute of Technology) (submittedVersion, cc-by)
  • RUNE (Research UNE) (submittedVersion, cc-by)
  • Edinburgh Research Explorer (University of Edinburgh) (submittedVersion, cc-by)
  • Lund University Publications (Lund University) (submittedVersion)
  • KITopen (cc-by)
Funders
  • Canada Research Chairs
  • Vetenskapsrådet (2016-06300)
  • Horizon 2020 Framework Programme (773901, 757995)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil erosion and sediment transport
  • Physical Sciences › Environmental Science › Global and Planetary Change › Land Use and Ecosystem Services
  • Physical Sciences › Environmental Science › Management, Monitoring, Policy and Law › Water and Land Management
Keywords
land degradation, ecological restoration, climate change mitigation, climate change adaptation, greenhouse gas emissions, ecosystem services, sustainable agriculture, forest management, land conservation, poverty, sustainable development, food security, biodiversity loss

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