This Working Group focuses on the planetary boundary of Land-System Change.
The group is currently working to expand the below initial statement, which summarises the boundary and its relationship with AMR, into a longer policy brief.
This Working Group is open to new members – please email CLIMAR.Network@exeter.ac.uk to join.
While not exceeded to such an extent as some of the other planetary boundaries, Land-System Change is still a domain under stress. Land-system change impacts AMR through agricultural and urban land systems in complex entanglements. Urban conurbations cover only ~2-3% of Earth’s total land mass [1] but around half of Earth’s habitable land is used for agriculture (growing crops and grazing livestock) to feed increasingly urban populations, making urban and rural land areas impossible to consider in isolation. There have been concerns for decades that the world will run out of land to grow food unless the human population stops increasing at the current rate (0.85% pa), or populations move to a considerably more plant-based diet [2]. Agricultural processes push for increased yields on comparatively less land, enabled by artificial fertilizers and livestock intensification [3] that in turn impact soil biota [4]. Globally, 40% of arable soil is considered degraded and could increase to 95% by 2050 [5]. In addition, increased urbanisation can change catchment hydrology by altering the amounts of surface runoff, as well as contributing greater amounts of human sewage. Informal urban settlements pose a particular challenge [6], while the use of strong detergents containing products including parabens, triclosan, and ammonium compounds in more affluent, developed urban regions can also drive resistance, along with a host of other factors that suggest urban environments are an overlooked AMR challenge [7]. Land-system changes in intensive farming impact AMR through high antimicrobial use to address animal ill-health caused by overcrowding and poor welfare conditions, driven by increasing meat content of urban diets. As climate change challenges crop yields, particularly in areas of the world that are under the most climate stress such as India and the Middle East, increasing numbers of farmers move from crop farming into livestock with little understanding of how to manage animal health in intensive systems, creating a vicious circle of poor health and high antibiotic use. This has been observed in poultry, dairy cattle, and aquaculture [8, 9, 10, 11].