Editing IPCC:AR6/SRCCL/Chapter-1 (section)

==== 1.2.1.1 Future trends in the global land system ====

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Human population is projected to increase to nearly 9.8 (± 1) billion people by 2050 and 11.2 billion by 2100 (United Nations 2018 <sup>[[#fn:r241|241]]</sup> ). More people, a growing global middle class (Crist et al. 2017 <sup>[[#fn:r242|242]]</sup> ), economic growth, and continued urbanisation (Jiang and O’Neill 2017 <sup>[[#fn:r243|243]]</sup> ) increase the pressures on expanding crop and pasture area and intensifying land management. Changes in diets, efficiency and technology could reduce these pressures (Billen et al. 2015 <sup>[[#fn:r244|244]]</sup> ; Popp et al. 2016 <sup>[[#fn:r245|245]]</sup> ; Muller et al. 2017 <sup>[[#fn:r246|246]]</sup> ; Alexander et al. 2015 <sup>[[#fn:r247|247]]</sup> ; Springmann et al. 2018 <sup>[[#fn:r248|248]]</sup> ; Myers et al. 2017 <sup>[[#fn:r249|249]]</sup> ; Erb et al. 2016c <sup>[[#fn:r250|250]]</sup> ; FAO 2018b <sup>[[#fn:r251|251]]</sup> ) (Sections 5.3 and 6.2.2).

Given the large uncertainties underlying the many drivers of land use, as well as their complex relation to climate change and other biophysical constraints, future trends in the global land system are explored in scenarios and models that seek to span across these uncertainties (Cross-Chapter Box 1 in Chapter 1). Generally, these scenarios indicate a continued increase in global food demand, owing to population growth and increasing wealth. The associated land area needs are a key uncertainty, a function of the interplay between production, consumption, yields, and production efficiency (in particular for livestock and waste) (FAO 2018b; van Vuuren et al. 2017 <sup>[[#fn:r252|252]]</sup> ; Springmann et al. 2018 <sup>[[#fn:r253|253]]</sup> ; Riahi et al. 2017 <sup>[[#fn:r254|254]]</sup> ; Prestele et al. 2016 <sup>[[#fn:r255|255]]</sup> ; Ramankutty et al. 2018 <sup>[[#fn:r256|256]]</sup> ; Erb et al. 2016b <sup>[[#fn:r257|257]]</sup> ; Popp et al. 2016 <sup>[[#fn:r258|258]]</sup> ) (Section 1.3 and Cross-Chapter Box 1 in Chapter 1). Many factors, such as climate change, local contexts, education, human and social capital, policy-making, economic framework conditions, energy availability, degradation, and many more, affect this interplay, as discussed in all chapters of this report.

Global telecouplings in the land system, the distal connections and multidirectional flows between regions and land systems, are expected to increase, due to urbanisation (Seto et al. 2012 <sup>[[#fn:r259|259]]</sup> ; van Vliet et al. 2017 <sup>[[#fn:r260|260]]</sup> ; Jiang and O’Neill 2017 <sup>[[#fn:r261|261]]</sup> ; Friis et al. 2016 <sup>[[#fn:r262|262]]</sup> ), and international trade (Konar et al. 2016 <sup>[[#fn:r263|263]]</sup> ; Erb et al. 2016b; Billen et al. 2015 <sup>[[#fn:r264|264]]</sup> ; Lassaletta et al. 2016 <sup>[[#fn:r265|265]]</sup> ). Telecoupling can support efficiency gains in production, but can also lead to complex cause–effect chains and indirect effects such as land competition or leakage (displacement of the environmental impacts; see Glossary), with governance challenges (Baldos and Hertel 2015 <sup>[[#fn:r266|266]]</sup> ; Kastner et al. 2014 <sup>[[#fn:r267|267]]</sup> ; Liu et al. 2013 <sup>[[#fn:r268|268]]</sup> ; Wood et al. 2018 <sup>[[#fn:r269|269]]</sup> ; Schröter et al. 2018 <sup>[[#fn:r270|270]]</sup> ; Lapola et al. 2010 <sup>[[#fn:r271|271]]</sup> ; Jadin et al. 2016 <sup>[[#fn:r272|272]]</sup> ; Erb et al. 2016b; Billen et al. 2015 <sup>[[#fn:r273|273]]</sup> ; Chaudhary and Kastner 2016 <sup>[[#fn:r274|274]]</sup> ; Marques et al. 2019 <sup>[[#fn:r275|275]]</sup> ; Seto and Ramankutty 2016 <sup>[[#fn:r276|276]]</sup> ) (Section 1.2.1.5). Furthermore, urban growth is anticipated to occur at the expense of fertile (crop)land, posing a food security challenge, in particular in regions of high population density and agrarian-dominated economies, with limited capacity to compensate for these losses (Seto et al. 2012 <sup>[[#fn:r277|277]]</sup> ; Güneralp et al. 2013 <sup>[[#fn:r278|278]]</sup> ; Aronson et al. 2014 <sup>[[#fn:r279|279]]</sup> ; Martellozzo et al. 2015 <sup>[[#fn:r280|280]]</sup> ; Bren d’Amour et al. 2016 <sup>[[#fn:r281|281]]</sup> ; Seto and Ramankutty 2016 <sup>[[#fn:r282|282]]</sup> ; van Vliet et al. 2017 <sup>[[#fn:r283|283]]</sup> ).

Future climate change and increasing atmospheric CO <sub>2</sub> concentration are expected to accentuate existing challenges by, for example, shifting biomes or affecting crop yields (Baldos and Hertel 2015 <sup>[[#fn:r284|284]]</sup> ; Schlenker and Lobell 2010 <sup>[[#fn:r285|285]]</sup> ; Lipper et al. 2014 <sup>[[#fn:r286|286]]</sup> ; Challinor et al. 2014 <sup>[[#fn:r287|287]]</sup> ; Myers et al. 2017 <sup>[[#fn:r288|288]]</sup> ) (Section 5.2.2), as well as through land-based climate change mitigation. There is ''high confidence'' that large-scale implementation of bioenergy or afforestation can further exacerbate existing challenges (Smith et al. 2016 <sup>[[#fn:r289|289]]</sup> ) (Section 1.3.1 and Cross-Chapter Box 7 in Chapter 6).

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