Worsening land degradation caused by human activities is undermining the well-being of two fifths of humanity, driving species extinctions and intensifying climate change. It is also a major contributor to mass human migration and increased conflict, according to the world’s first comprehensive evidence-based assessment of land degradation and restoration.
The dangers of land degradation, which cost the equivalent of about 10% of the world’s annual gross product in 2010 through the loss of biodiversity and ecosystem services, are detailed for policymakers, together with a catalogue of corrective options, in the three-year assessment report by more than 100 leading experts from 45 countries, launched on Monday, March 26, 2018.
Produced by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the report was approved at the 6th session of the IPBES Plenary in Medellín, Colombia. IPBES has 129 State Members.
Providing evidence for policymakers to make better-informed decisions, the report draws on more than 3,000 scientific, government, indigenous and local knowledge sources. Extensively peer-reviewed, it was improved by more than 7,300 comments, received from over 200 external reviewers.
Serious Danger to Human Well-being
Rapid expansion and unsustainable management of croplands and grazing lands is the most extensive global direct driver of land degradation, causing significant loss of biodiversity and ecosystem services – food security, water purification, the provision of energy and other contributions of nature essential to people. This has reached “critical” levels in many parts of the world, the report says.
“With negative impacts on the well-being of at least 3.2 billion people, the degradation of the Earth’s land surface through human activities is pushing the planet towards a sixth mass species extinction,” said Prof. Robert Scholes (South Africa), co-chair of the assessment with Dr. Luca Montanarella (Italy). “Avoiding, reducing and reversing this problem, and restoring degraded land, is an urgent priority to protect the biodiversity and ecosystem services vital to all life on Earth and to ensure human well-being.”
“Wetlands have been particularly hard hit,” said Dr. Montanarella. “We have seen losses of 87% in wetland areas since the start of the modern era – with 54% lost since 1900.”
According to the authors, land degradation manifests in many ways: land abandonment, declining populations of wild species, loss of soil and soil health, rangelands and fresh water, as well as deforestation.
Underlying drivers of land degradation, says the report, are the high-consumption lifestyles in the most developed economies, combined with rising consumption in developing and emerging economies. High and rising per capita consumption, amplified by continued population growth in many parts of the world, can drive unsustainable levels of agricultural expansion, natural resource and mineral extraction, and urbanisation – typically leading to greater levels of land degradation.
By 2014, more than 1.5 billion hectares of natural ecosystems had been converted to croplands. Less than 25% of the Earth’s land surface has escaped substantial impacts of human activity – and by 2050, the IPBES experts estimate this will have fallen to less than 10%.
Crop and grazing lands now cover more than one third of the Earth´s land surface, with recent clearance of native habitats, including forests, grasslands and wetlands, being concentrated in some of the most species-rich ecosystems on the planet.
The report says increasing demand for food and biofuels will likely lead to continued increase in nutrient and chemical inputs and a shift towards industrialised livestock production systems, with pesticide and fertiliser use expected to double by 2050.
Avoidance of further agricultural expansion into native habitats can be achieved through yield increases on the existing farmlands, shifts towards less land degrading diets, such as those with more plant-based foods and less animal protein from unsustainable sources, and reductions in food loss and waste.
Strong Links to Climate Change
“Through this report, the global community of experts has delivered a frank and urgent warning, with clear options to address dire environmental damage,” said Sir Robert Watson, Chair of IPBES.
“Land degradation, biodiversity loss and climate change are three different faces of the same central challenge: the increasingly dangerous impact of our choices on the health of our natural environment. We cannot afford to tackle any one of these three threats in isolation – they each deserve the highest policy priority and must be addressed together.”
The IPBES report finds that land degradation is a major contributor to climate change, with deforestation alone contributing about 10% of all human-induced greenhouse gas emissions. Another major driver of the changing climate has been the release of carbon previously stored in the soil, with land degradation between 2000 and 2009 responsible for annual global emissions of up to 4.4 billion tonnes of CO2.
Given the importance of soil’s carbon absorption and storage functions, the avoidance, reduction and reversal of land degradation could provide more than a third of the most cost-effective greenhouse gas mitigation activities needed by 2030 to keep global warming under the 2°C threshold targeted in the Paris Agreement on climate change, increase food and water security, and contribute to the avoidance of conflict and migration.
Projections to 2050
“In just over three decades from now, an estimated four billion people will live in drylands,” said Prof. Scholes. “By then it is likely that land degradation, together with the closely related problems of climate change, will have forced 50-700 million people to migrate. Decreasing land productivity also makes societies more vulnerable to social instability – particularly in dryland areas, where years with extremely low rainfall have been associated with an increase of up to 45% in violent conflict.”
Dr. Montanarella added: “By 2050, the combination of land degradation and climate change is predicted to reduce global crop yields by an average of 10%, and by up to 50% in some regions. In the future, most degradation will occur in Central and South America, sub-Saharan Africa and Asia – the areas with the most land still remaining that is suitable for agriculture.”
The report also underlines the challenges that land degradation poses, and the importance of restoration, for key international development objectives, including the United Nations Sustainable Development Goals and the Aichi Biodiversity Targets. “The greatest value of the assessment is the evidence that it provides to decision makers in Government, business, academia and even at the level of local communities,” said Dr. Anne Larigauderie, Executive Secretary of IPBES. “With better information, backed by the consensus of the world’s leading experts, we can all make better choices for more effective action.”
Options for Land Restoration
The report notes that successful examples of land restoration are found in every ecosystem, and that many well-tested practices and techniques, both traditional and modern, can avoid or reverse degradation.
In croplands, for instance, some of these include reducing soil loss and improving soil health, the use of salt tolerant crops, conservation agriculture and integrated crop, livestock and forestry systems.
In rangelands with traditional grazing, maintenance of appropriate fire regimes, and the reinstatement or development of local livestock management practices and institutions have proven effective.
Successful responses in wetlands have included control over pollution sources, managing the wetlands as part of the landscape, and reflooding wetlands damaged by draining.
In urban areas, urban spatial planning, replanting with native species, the development of ‘green infrastructure’ such as parks and riverways, remediation of contaminated and sealed soils (e.g. under asphalt), wastewater treatment and river channel restoration are identified as key options for action.
Opportunities to accelerate action identified in the report include:
- Improving monitoring, verification systems and baseline data;
- Coordinating policy between different ministries to simultaneously encourage more sustainable production and consumption practices of land-based commodities;
- Eliminating “perverse incentives” that promote land degradation and promoting positive incentives that reward sustainable land management; and
- Integrating the agricultural, forestry, energy, water, infrastructure and service agendas.
Making the point that existing multilateral environmental agreements provide a good platform for action to avoid, reduce and reverse land degradation and promote restoration, the authors observe, however, that greater commitment and more effective cooperation is needed at the national and local levels to achieve the goals of zero net land degradation, no loss of biodiversity and improved human well-being.
Knowledge Gaps
Among the areas identified by the report as opportunities for further research are:
- The consequences of land degradation on freshwater and coastal ecosystems, physical and mental health and spiritual well-being, and infectious disease prevalence and transmission;
- The potential for land degradation to exacerbate climate change, and land restoration to help both mitigation and adaptation;
- The linkages between land degradation and restoration and social, economic and political processes in far-off places; and
- Interactions among land degradation, poverty, climate change, and the risk of conflict and of involuntary migration.
Environmental and Economic Sense
The report found that higher employment and other benefits of land restoration often exceed by far the costs involved. On average, the benefits of restoration are 10 times higher than the costs (estimated across nine different biomes), and, for regions like Asia and Africa, the cost of inaction in the face of land degradation is at least three times higher than the cost of action.
“Fully deploying the toolbox of proven ways to stop and reverse land degradation is not only vital to ensure food security, reduce climate change and protect biodiversity,” said Dr. Montanarella, “It’s also economically prudent and increasingly urgent.”
Echoing this message, Sir Robert Watson, said: “Of the many valuable messages in the report, this ranks among the most important: implementing the right actions to combat land degradation can transform the lives of millions of people across the planet, but this will become more difficult and more costly the longer we take to act.”
