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.
Worsening worldwide land degradation is undermining the well-being of 3.2 billion people and is the main cause of species loss, according to a new report out today.
The landmark 3-year assessment by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) says land degradation cost the equivalent of 10 percent of the world’s annual gross product in 2010 through the loss of biodiversity and ecosystem services. Its authors say it has also been a major contributor to mass human migration and increased conflict.
Rapid expansion and unsustainable management of croplands and grazing lands is the most extensive global direct driver of land degradation, according to the report.
It causes significant loss of biodiversity and ecosystem services – food security, water purification, the provision of energy and other contributions of nature essential to people. The authors say this has now reached ‘critical’ levels in many parts of the world.
Professor Robert Scholes, co-chair of the assessment, said: “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.
“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."
Dr Luca Montanarella, co-chair of the assessment, said: “Wetlands have been particularly hard hit. We have seen losses of 87 percent in wetland areas since the start of the modern era – with 54 percent 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 percent 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 percent.
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.
Sir Robert Watson, Chair of IPBES, said: “Through this report, the global community of experts has delivered a frank and urgent warning, with clear options to address dire environmental damage.
“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.”
Contributor to climate change
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.
The report says 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. It could also increase food and water security, and contribute to the avoidance of conflict and migration.
Prof. Scholes added: “In just over three decades from now, an estimated 4 billion people will live in drylands. 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.”
Making better choices
Dr. Montanarella said: “By 2050, the combination of land degradation and climate change is predicted to reduce global crop yields by an average of 10 percent, and by up to 50 percent 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.
Dr. Anne Larigauderie, Executive Secretary of IPBES, said: “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.
“With better information, backed by the consensus of the world’s leading experts, we can all make better choices for more effective action.”
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.
Options for action
Opportunities to accelerate action identified in the report include: improving monitoring, verification systems and baseline data; coordinating policy between different ministries; eliminating incentives that promote land degradation; 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 , 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.
Among the areas identified by the report as opportunities for further research include: the consequences of land degradation on freshwater and coastal ecosystems; physical and mental health and spiritual well-being; the potential for land degradation to exacerbate climate change ; 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.
The report also found that higher employment and other benefits of land restoration often exceed 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.
Dr. Montanarella concluded: “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, it’s also economically prudent and increasingly urgent.”
Echoing this message, Sir Robert Watson, added: “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.”
Catherine Harte is a contributing editor to The Ecologist. This story is based on a release from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).