09.8.2018

Global land change from 1982 to 2016

Abstract

Land change is a cause and consequence of global environmental change1,2. Changes in land use and land cover considerably alter the Earth’s energy balance and biogeochemical cycles, which contributes to climate change and—in turn—affects land surface properties and the provision of ecosystem services1,2,3,4. However, quantification of global land change is lacking. Here we analyse 35 years’ worth of satellite data and provide a comprehensive record of global land-change dynamics during the period 1982–2016. We show that—contrary to the prevailing view that forest area has declined globally5—tree cover has increased by 2.24 million km2 (+7.1% relative to the 1982 level). This overall net gain is the result of a net loss in the tropics being outweighed by a net gain in the extratropics. Global bare ground cover has decreased by 1.16 million km2 (−3.1%), most notably in agricultural regions in Asia. Of all land changes, 60% are associated with direct human activities and 40% with indirect drivers such as climate change. Land-use change exhibits regional dominance, including tropical deforestation and agricultural expansion, temperate reforestation or afforestation, cropland intensification and urbanization. Consistently across all climate domains, montane systems have gained tree cover and many arid and semi-arid ecosystems have lost vegetation cover. The mapped land changes and the driver attributions reflect a human-dominated Earth system. The dataset we developed may be used to improve the modelling of land-use changes, biogeochemical cycles and vegetation–climate interactions to advance our understanding of global environmental change1,2,3,4,6.

References

1. Turner, B. L. II, Lambin, E. F. & Reenberg, A. The emergence of land change science for global environmental change and sustainability. Proc. Natl Acad. Sci. USA 104, 20666–20671 (2007).
2.  Foley, J. A. et al. Global consequences of land use. Science 309, 570–574 (2005). 3. Le Quéré, C. et al. Global carbon budget 2016. Earth Syst. Sci. Data 8, 605–649 (2016). 4. Alkama, R. & Cescatti, A. Biophysical climate impacts of recent changes in global forest cover. Science 351, 600–604 (2016) 5. FAO. Global Forest Resources Assessment 2015 (UN Food and Agriculture Organization, Rome, 2015). This article appeared on the Nature website at https://www.nature.com/articles/s41586-018-0411-9
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