Globally, collapse of ecosystems—potentially irreversible change to ecosystem structure, composition and function—imperils biodiversity, human health and well‐being. We examine the current state and recent trajectories of 19 ecosystems, spanning 58° of latitude across 7.7 M km2, from Australia's coral reefs to terrestrial Antarctica. Pressures from global climate change and regional human impacts, occurring as chronic ‘presses’ and/or acute ‘pulses’, drive ecosystem collapse. Ecosystem responses to 5–17 pressures were categorised as four collapse profiles—abrupt, smooth, stepped and fluctuating. The manifestation of widespread ecosystem collapse is a stark warning of the necessity to take action. We present a three‐step assessment and management framework (3As Pathway Awareness, Anticipation and Action) to aid strategic and effective mitigation to alleviate further degradation to help secure our future.

The concentration of human population along coastlines has far-reaching effects on ocean and societal health. The oceans provide benefits to humans such as food, coastal protection and improved mental well-being, but can also impact negatively via natural disasters. At the same time, humans influence ocean health, for example, via coastal development or through environmental stewardship. Given the strong feedbacks between ocean and human health there is a need to promote desirable interactions, while minimising undesirable interactions. To this end, we articulate two scenarios for 2030. First, Business-as-Usual, named 'Command & (Out of ) Control ', focuses on the anticipated future based on our current trajectory. Second, a more sustainable scenario called 'Living & Connecting ', emphasises the development of interactions between oceans and society consistent with achieving the Sustainable Development Goals. We describe a potential pathway to achieving the 'Living & Connecting' scenario, centred on improving marine citizenship, achieving a more equitable distribution of power among stakeholders, and more equitable access to resources and opportunities. The constituent actions of this pathway can be categorised into four groups: (i) improved approaches to science and health communication that account for society's diverse values, beliefs and worldviews, (ii) a shift towards more trusted relationships among stakeholders to enable two-way knowledge exchange, (iii) economic incentives that encourage behavioural changes necessary for achieving desired sustainability outcomes, and (iv) stronger regulations that simultaneously focus on ocean and human health. We contend that these changes will provide improved outcomes for both oceans and society over the UN Decade of Ocean Science.

Graphic abstract The concentration of human population along coastlines has far-reaching effects on ocean and societal health. The oceans provide benefits to humans such as food, coastal protection and improved mental well-being, but can also impact negatively via natural disasters. At the same time, humans influence ocean health, for example, via coastal development or through environmental stewardship. Given the strong feedbacks between ocean and human health there is a need to promote desirable interactions, while minimising undesirable interactions. To this end, we articulate two scenarios for 2030. First, Business-as-Usual, named ‘ Command and (out of) Control ’, focuses on the anticipated future based on our current trajectory. Second, a more sustainable scenario called ‘ Living and Connecting ’, emphasises the development of interactions between oceans and society consistent with achieving the Sustainable Development Goals. We describe a potential pathway to achieving the ‘ Living and Connecting ’ scenario, centred on improving marine citizenship, achieving a more equitable distribution of power among stakeholders, and more equitable access to resources and opportunities. The constituent actions of this pathway can be categorised into four groups: (i) improved approaches to science and health communication that account for society’s diverse values, beliefs and worldviews, (ii) a shift towards more trusted relationships among stakeholders to enable two-way knowledge exchange, (iii) economic incentives that encourage behavioural changes necessary for achieving desired sustainability outcomes, and (iv) stronger regulations that simultaneously focus on ocean and human health. We contend that these changes will provide improved outcomes for both oceans and society over the United Nations Decade of Ocean Science. Supplementary Information The online version contains supplementary material available at 10.1007/s11160-021-09669-5.

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