The origin of mainstream Western agriculture lies in the ‘fertile crescent’ of the Middle East and, in this cradle of arable farming, dryland plants were domesticated that currently constitute some of our major cereal, legume and fibre crops. This ‘semi-desert’ agriculture installed the idea that productive land must be dry, a paradigm that ever since has been applied also to wet, organic soils. We deeply drain peatland to grow arid maize Zea mays in Germany, strongly water-demanding sugar cane Saccharum spp. in Florida and the desert species Aloe vera in Indonesia. Practices like this have made agriculture the main driver of global peatland loss (Joosten and Clarke 2002, Chapter 2) and drained peatlands are thus primarily found in regions that are climatically favourable for agriculture, i.e. in the temperate zone and the (sub)tropics (Chapter 2).
Peatland drainage causes inherent peatland degradation, a substantial financial and environmental burden and eventually the loss of the productive value of the peat soil (Joosten, Tapio-Biström and Tol 2012). These problems are increasingly being recognised: worldwide several thousands of square kilometres of drained agricultural peatlands have been rewetted in recent years for climate change mitigation, for biodiversity, or simply because maintaining drainage infrastructure had become too expensive. Rewetting has indeed re-established major regulating and cultural services of wet peatlands, including carbon storage, flood control, water purification, archive function and biodiversity (Theuerkauf et al. 2006; Limpens et al. 2008; Trepel 2010; Tanneberger and Wichtmann 2011; Joosten et al. 2015a; Chapter 6). The provisioning services of these formerly productive lands, however, were mostly lost as the rewetted areas were generally earmarked for nature conservation with the condition that they would no longer be used agriculturally.
On the other hand, the quest for productive land is rapidly growing worldwide. This demand will continue to increase, because of the inevitable growth of human population and the justified demands for food security and more welfare. The demand will also grow, because biomass from cultivated land will increasingly have to replace the resources that until now were obtained from the wilderness (wood, non-timber forest products, bushmeat) and the bedrock (coal, oil, gas, minerals). Both the persistent use of drained peatlands for agriculture and the conversion of agriculturally used peatlands to unused wetlands imply that we are losing productive land at a time when we need it most.