Climate-change-driven changes in ocean characteristics and the frequency and intensity of extreme events  increase the risk of persistent, rapid and abrupt ecosystem change , often referred to as ecosystem collapses or regime shifts . Such abrupt changes include altering ecosystem structure, function and biodiversity outside the range of natural fluctuations . They can involve mass-mortality events and 'tipping points' or 'critical transitions', where strong positive feedbacks within an ecosystem lead to self-sustaining change . Abrupt ecosystem shifts have been observed in both large open-ocean ecosystems and coastal ecosystems , with dramatic social consequences through significant loss of diverse ecosystem services  . A summary of previous assessments of abrupt ecosystem shifts and extreme events is provided in Table 3.21.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report