In this chapter, we briefly discuss the effects of the expansion of new, intensive irrigated agriculture on the desertification processes in the Mediterranean. First, we examine how the intensification in the new irrigated lands leads to desertification, while at the same time, the process itself “hides” its own consequences. We then present how the in situ degradation processes work. However, while locally the degradation is hidden by the intensification, we show how the ongoing desertification processes are indirectly reflected in larger-scale water dynamics, both on surface hydrology and on groundwater, sometimes with paradoxical effects. This mechanism is illustrated with three paradigmatic case studies from South Spain, Doñana National Park, Tablas de Daimiel National Park and Mar Menor Lagoon. Finally, we discuss why the desertification debate is easily distorted by the hidden effects behind “greening fields” and how land degradation induced by new irrigated lands can be addressed.