AbstractHuman impacts can induce ecosystems to cross tipping points and hence unexpected and sudden changes in ecosystem services that are difficult or impossible to reverse. The world´s oceans suffer from cumulative anthropogenic pressures like overexploitation and climate change and are especially vulnerable to such regime shifts. Yet an outstanding question is whether regime changes in marine ecosystems are irreversible. Here we first review the evidence for regime shifts in the North Sea ecosystem, one of the heaviest impacted and best studied marine ecosystems in the world. We then used catastrophe theory to show that fishing and warming have caused a previously undetected and potentially irreversible regime shift. Our study emphasizes the combined effects of local and global human impacts in driving significant ecosystem shifts and suggests that adaptation is likely the central avenue forward for maintaining services in the face of global climate change.