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2 Challenges towards more sustainable land use
In past decades, several developments have been made towards more sustainable land use. For instance, since 1960, the intensification of agricultural input use and concentrated animal feed, modern crop varieties and better management practices have led to increased crop yields and livestock production in developed and developing countries (OECD, 2020[3]). This contributed to the tripling of agriculture production with only modest increase in cultivated land (around 10-15%) (OECD, 2020[3]) and important gains in reducing both poverty (OECD, 2011[4]) and malnourishment (TCI, 2020[5]). In addition, intensive agriculture decreases the need for land, and therefore lessens the intensity of impacts caused by forest conversion to agriculture such as greenhouse gas emissions and biodiversity loss (OECD, 2013[6]). This makes sustainable agricultural intensification an important response to global climate change (IPCC, 2019[1]). However, several challenges remain. This section reviews existing literature providing evidence of the following key impacts connected to unstainable land use: loss of biodiversity, climate change, zoonotic diseases and impacts of invasive alien species, impacts on water resources, food-related impacts and loss of livelihoods and lands of indigenous populations.
Loss of biodiversity Biodiversity on Earth is declining. The magnitude and speed at which the diversity of life on Earth is declining today is comparable to what happened during the five great extinction crises of geological time (Ceballos et al., 2015[7]). Around a million plant and animal species are now threatened with extinction (IPBES, 2019[2]). Wild vertebrate populations have declined by 68% in around 40 years (WWF, 2020[8]) and insect populations have been decreasing in a number of regions. For instance, Hallmann et al. (2017[9]) finds that 76% of flying insect biomass 1 have disappeared in 30 years in Germany in protected natural areas, and 67% in meadows in just ten years (Seibold et al., 2019[10]). However, this decline is not observed everywhere. In the United States for instance, a recent study reports no net insect abundance and diversity declines (Crossley et al., 2020[11]). The decline in insect population is particularly concerning given its impact on animal pollination on which more than 75 per cent of global food crop types relies 2, including key cash crops 3 like coffee, cocoa and almonds (IPBES, 2019[2]). Agriculture and urban development can contribute to biodiversity loss due to land conversion. Biodiversity loss in tropical and subtropical countries is mainly related to forest conversion to agriculture (FAO, 2020[12]). In Africa for instance, high population growth together with the use of small-scale agriculture are linked to a rate of deforestation that remains high (FAO, 2020[12]). In Southeast Asia, high1
the total weight of flying insects (regardless of species)
2
The rest of them rely on wind pollination.
3
a crop produced for its commercial value rather than for use by the grower
