28.03.2018 |

Land degradation threatens human well-being and biodiversity, UN report

Land degradation reduces crop yields (Photo: CC0)

Land degradation is threatening the well-being of 3.2 billion people worldwide, pushing the planet towards a sixth mass species extinction, a major UN-backed report has warned. By 2050, land degradation and climate change together are predicted to reduce crop yields by an average of 10% globally and could force up to 700 million people to migrate. According to the comprehensive global IPBES assessment adopted on March 26 by the 129 member governments of the independent intergovernmental body, the main drivers of land degradation are human activities, mainly agriculture. “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,” IPBES said in a press release. Land degradation cost the equivalent of about 10% of the world’s annual GDP in 2010 through the loss of biodiversity and ecosystem services, the authors found.

The report, written by more than 100 leading experts from 45 countries in three years of work, was adopted in Medellín, Colombia. It draws on over 3,000 scientific, government, indigenous and local knowledge sources and was extensively peer-reviewed. According to the authors, the underlying drivers of land degradation 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 urbanization – typically leading to greater levels of land degradation,” IPBES warns. 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. 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 activities. The IPBES experts project that this figure will have fallen to less than 10% by 2050. “Wetlands have been particularly hard hit,” said Dr Luca Montanarella, co-chair of the assessment. “We have seen losses of 87% in wetland areas since the start of the modern era – with 54% lost since 1900.”

The report found that land degradation is a major driver of climate change, with deforestation alone contributing about 10% of all human-induced greenhouse gas emissions. Another factor 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. However, soils could contribute to mitigating climate change due to their carbon absorption and storage functions. The authors say that 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. “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,” said Sir Robert Watson, Chair of IPBES and Director of the World Agriculture Report (IAASTD) released in 2009. “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.” He added that “the evidence also shows that we know how to protect and partially restore our vital natural assets”.

To stop and reverse land degradation, the authors call for coordinated policies between different ministries in order to encourage more sustainable production and consumption practices of land-based commodities. They recommend eliminating ‘perverse incentives’ that promote land degradation and promoting positive incentives that reward sustainable land management. 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, options include reducing soil loss and improving soil health, the use of salt tolerant crops, conservation agriculture and integrated crop, livestock and forestry systems. Options on the consumer side to avoid further agricultural expansion into native habitats are 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. “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.” (ab)

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