This study quantifies the potential effects of land restoration for soil, food, water, biodiversity and climate change at the global and regional levels, using three global land-use scenarios up to 2050.

https://www.pbl.nl/en/publications/the-global-potential-for-land-restoration-scenarios-for-the-global-land-outlook-2

https://www.pbl.nl/sites/default/files/downloads/pbl-2021-the-global-potential-for-land-restoration-glo2-3898.pdf

https://themasites.pbl.nl/nature-based-solutions/nature-based-solutions

Nature-based solutions and scenarios

Nature-based Solutions (BbS) are actions that enable the protection, sustainable management and restoration of natural and managed ecosystems, that can simultaneously provide human well-being an biodiversity benefits.

Nature-based solutions (NbS) include restoration, management, and rehabilitation measures, as well as conservation of ecosystems, that enhance nature’s contribution to people, such as agroforestry, conservation agriculture, assisted natural regeneration and urban green and blue spaces.

There is now increased attention on these solutions as they have the potential to address many global sustainable development challenges simultaneously, from environmental to socio-economic to health challenges.

NbS can help generate multiple benefits for society, such as food and water security, climate mitigation and adaptation, while addressing biodiversity loss. This is their unique selling point. NbS can therefore contribute towards the achievement of many of the UN Sustainable Development Goals (SDGs) simultaneously, including in particular, climate action (SDG 13), life on land (SDG 15), zero hunger (SDG2) and clean water and sanitation (SDG6), alongside many others.

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Nature-based solutions and their use in practice are becoming increasingly recognised in international policy discussions.

The rapid growth in policy interest for NbS has culminated in the UN Decade on Ecosystem Restoration (2021-2030), following on from recent restoration ambitions such as the Bonn Challenge, that aims to restore 350 million ha of degraded land by 2030. Nature-based solutions are central to the new CBD Global Biodiversity framework for 2021-2030, the implementation of the Paris Agreement, the EU Biodiversity Strategy, Land Degradation Neutrality Targets and multiple SDGs. Fortunately, many types of these solutions are already happening on the ground.

The need for action and impact on the ground is accelerating. Scenarios are a tool that can help to link global level policy frameworks to local level action and vice versa.

Scenarios are a tool that can help policymakers chart possible future pathways, to realise the potential of nature-based solutions and restoration for multiple societal and environmental benefits and contribute towards achieving multiple international goals, such as the SDGs.

Global perspective

Assessing potential future environmental changes helps policymakers decide where to take action and understand what the effects of policy can be. PBL uses scenarios and computer models to explore such future pathways.

Scenarios are storylines and assumptions on potential future developments, and models use these to project future developments. Projections are presented in maps and graphs.

Three scenarios are used to show the impact of future developments:

  • Business-as-usual: a baseline scenario that includes assumptions on future land degradation
  • Restoration: a scenario that includes restoration, improved land management measures, and protection of key ecosystems
  • “Sharing the Planet”: A broader portfolio of transformative action towards achieving the SDGs
  1. The problem: if current trends continue, global environmental problems will worsen with some regions being impacted more than others.

The pressure on land and ecosystems is growing in many regions of the world, especially in sub-Saharan Africa and South America. This is mainly due to the increasing demand for arable crops, meat and dairy products, bio-energy and timber, while land degradation and climate change impacts continue to accelerate. Such impacts have huge consequences for ecosystem functions, biodiversity, and the resilience of ecological and human systems.

  1. The problem: If current trends continue, global environmental problems will worsen with some regions being impacted more than others.

land use change: between 2015 and 2050, under the baseline scenario, land use is projected to continue to increase, with agriculture and pasture land expanding at the cost of remaining natural areas, especially in sub-Saharan Africa.
Indicator:

  • Deforestation and conversion of other natural land (% change per grid cell)
  • Reforestation and abandonment of agricultural to other natural land (% change per grid cell)

Land degradation: Land degradation is shown by long-term trends in the biomass productivity of ecosystems, through normalised difference vegetation index (2001-2018, corrected for climate change). NDVI is key indicator of land degradation in the Sustainable Development Goals.
Indicator:

  • Annual % change in Normalised Difference Vegetation Index (NDVI)

Climate change: Climate change affects land use and the condition of land and biodiversity, with the largest temperature changes (2015-2050) expected in northern regions.
Indicator:

  • Degrees Celsius

Main conclusions:
Projected increase in cropland and pastureland 430 million ha;
Land-use change in sub-Saharan Africa around 200 million ha;
Global land area with a long-term negative trend in productivity 7-10%

Exploring future changes in land use and land condition and the impacts on food, water, climate change and biodiversity Scenarios for the UNCCD Global Land Outlook
– Policy Report by PBL

  1. The restoration scenario: nature-based solutions can contribute to multiple Sustainable Developments Goals simultaneously.

Compared to the baseline scenario in 2050, an ambitious global implementation of solutions to restore natural land and rehabilitate agricultural land will benefit many SDGs, including those on climate action, food security, and land degradation. At the global level, there is a projected increase of around 9 percent in crop yield, an estimated 3 per cent of additional soil carbon sequestration, and reduction in biodiversity loss of up to 2 per cent MSA. Explore the global and regional potential benefits of restoration in the graph below.

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  1. The bigger picture: nature-based solutions are part of a wider portfilio of options to bend the trend for biodiversity and climate change, while avoiding increasing risks for food security.

Nature-based solutions can provide an important contribution to multiple SDGs simultaneously, such as safeguarding global food production, conserving biodiversity and mitigating climate change impacts. However, they are only a part of a wider palette of options required to bend the trend. Nature-based solutions (in terms of restoration and conservation) need to be combined with changes to production and consumption in order to further close the gap towards reaching many of the SDGs, such as plant rich diets, reducing the yield gap, reduction of waste and changes to the energy system. If all these solutions are combined into a broader “Sharing the Planet” scenario, the potential future impact they may have on food production, biodiversity conservation and global temperatures can be seen. The graphs show the current pathway, a pathway with just restoration and protection, and the broader scenario with all solutions combined.

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  1. The solutions: there are various solutions that are included under nature-based solutions, including restoration of natural and managed land-use systems and the conservation of key areas that provide important ecosystems functions.

Different solutions are applicable in different circumstances, land uses, climates and land conditions. Explore the 15 different solutions and where they can be applied across the world. The single restoration solution maps show only what is technically feasible. The combined map shows the optimum solution(s) regarding largest soil carbon gains, only on degraded land area.

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Solutions:

  • Agroforestry1
  • Assisted Natural Regeneration2
  • Conservation agriculture3
  • Conservation measures4
  • Cross-slope barriers5
  • Forest plantation6
  • Grassland improvement7
  • Grazing management8
  • Organic amendments9
  • Urban green and blue areas10

  1. Agroforestry is a method of agriculture which combines trees and crops, or trees and pastures, within the same plot. These systems are one of a wide range of restoration approaches used for restoring degraded forests and agricultural lands. ↩︎

  2. ‘Assisted Natural Regeneration’ (ANR) is a low-cost forest restoration method that can effectively restore forests on degraded lands and convert degraded vegetation into more productive forests. ANR techniques are flexible and allow for the integration of various values such as timber production, biodiversity recovery, and cultivation of crops, fruit trees, and non-timber forest products in the restored forest. ANR also allows for the integration of economic and social values in the restored forest. ↩︎

  3. The conservation agriculture (CA) approach is a system of managing agricultural lands based on certain farming practices e.g. minimising soil disruption and disturbance and increasing the retention of crop residues and crop diversification. ↩︎

  4. Conservation measures, according to IUCN (2016), include “the protection, care, management and maintenance of ecosystems, habitats, wildlife species and populations, within or outside of their natural environments, in order to safeguard the natural conditions for their long-term permanence”. Key ecosystems that are important to protect and manage include:
    Biodiversity hotspots: biogeographic regions with significant levels of biodiversity that are threatened by human habitation;
    High carbon forest areas: forest areas with high storage of carbon;
    High carbon wetlands: wetlands areas with high carbon storage such as peatlands;
    Water towers: areas considered important for maintaining water quantity and regulation in watersheds, functioning as sponges;
    Riparian zones: important for preventing soil erosion and the improve water purification function;
    Slopes: areas vulnerable to erosion, where protection of slopes is required. ↩︎

  5. Cross-slope barriers are soil and water conservation measures that are created on sloping lands in the form of earth or soil bunds, stone lines, and/or vegetative strips/barriers (usually grass). By reducing the steepness and/or the length of the slope, these techniques therefore contribute to soil, water, and nutrient conservation. ↩︎

  6. Plantation forests are one form of planted forests – typically monocultures that are composed of trees established through planting and/or deliberate seeding. They are established primarily for wood and fibre production as well as to stabilise slopes and watersheds. They are usually intensively managed and have relatively high growth rates and productivity. The establishment of forests on land where there were previously no forests before is called afforestation and the replanting of trees in an area where there was once a forest, and which has since been destroyed or damaged, is known as reforestation. ↩︎

  7. Grassland can be defined as ground covered by vegetation that is dominated by grasses, which has little or no tree cover. Grassland improvement is a restoration technique that introduces a selection of local or exotic grasses and legumes. It has been done experimentally in better-watered zones and is used by some commercial systems. Along with sown pasture, it is common in commercially mixed farming and more intensively managed grasslands. ↩︎

  8. Grazing management involves the planning, implementing, and monitoring of grazing. Through the reduction of overgrazing and the improvement of forage production, the aim of this restoration technique is to maintain healthy and productive pastures so that cattle can use the land for as long as possible during the year while staying within the limits of the ecosystem. ↩︎

  9. Organic amendments are substances that are added to the soil to improve its physical properties. Decline in soil organic matter under intensive farming systems is a major cause of soil fertility loss. Organic matter plays a critical role in soil ecosystem as it provides substrates for decomposing microbes (that in turn supply mineral nutrients to plants). Organic amendments improve soil structure and water holding capacity, permeability, water infiltration, drainage, aeration and structure. In addition, they also increase natural suppressiveness against soil-borne pathogens as well as reduce heavy metal toxicity. ↩︎

  10. Nature-based solutions (NbS) in urban areas involve maintaining, restoring and creating new green and blue spaces. Urban green and blue spaces are public and private open spaces located in urban areas, primarily covered by vegetation, or water. Urban NbS emerge as an effective tool in tackling multiple societal challenges in urban areas, such as addressing climate change impacts (e.g. heat, flooding), and human health issues, while also contributing to reducing the loss of biodiversity. Not only are they an important part of cities and urban spatial planning, but they also form part of the common services that are provided by a city, typically serving as a health-promoting setting for all members of the community. Urban NbS types range from individual small-scale NbS on buildings or along streets, to large-scale NbS such as urban forests or rivers across an urban areas, connecting to peri-urban areas and the wider landscape, including:
    Green and blue structures connected to grey structures: Green and blue structures attached to street, bicycle lane, pedestrian path, parking lots and drainage systems, such as street trees, raingardens, flowerbeds, roadside green and constructed wetlands;
    Parks and (semi-) natural green areas: mainly public or semi-public larger areas dominated by green features, such as parks, urban forests, greenways, botanical gardens and cemetery;
    Gardens: Mainly private areas managed for (at least some) food production, such as allotment gardens, courtyards and community gardens;
    Building greens: Green structures attached to a building, such as a green roof or green wall;
    Water bodies: (Semi-) natural water bodies such as lakes, rivers, canals and wetlands. ↩︎