Abstract: Water scarcity is an escalating environmental challenge, particularly in semi-arid regions like Spain, where balancing human and ecosystem needs is critical for sustainable development. Freshwater ecosystems are vital for biodiversity, water security, and economic systems, but often lose protection during droughts. Spain, largely under a Mediterranean climate, shows strong interdependence between ecological and socioeconomic systems, with agriculture, tourism, and energy sectors heavily reliant on scarce water resources. Spain's economy has thrived on water-dependent activities yet increasing droughts and infrastructure limits are pushing ecosystems toward collapse, with severe biodiversity loss and irreversible damage. Furthermore, investments aimed at increasing water-use efficiency often backfire, leading to expanded irrigation without real water savings. Climate change, urbanization, and pollution exacerbate these tensions, posing risks to public health and economic stability. Transformative strategies are urgently needed: protecting and restoring ecosystems, promoting conservation agriculture, regulating water-intensive industries, and planning collective responses to illegal water use. Simply increasing supply or reacting to crises without systemic change of water demands will not ensure future water security. Spain's experience highlights the urgent need for integrated management of natural and human systems to preserve freshwater resources, biodiversity, and economic resilience.
