Warming world, changing ocean: mitigation and adaptation to support resilient marine systems

Abstract

Proactive and coordinated action to mitigate and adapt to climate change will be essential for achieving the healthy, resilient, safe, sustainably harvested and biodiverse ocean that the UN Decade of Ocean Science and sustainable development goals (SDGs) seek. Ocean-based mitigation actions could contribute 12% of the emissions reductions required by 2030 to keep warming to less than 1.5ºC but, because substantial warming is already locked in, extensive adaptation action is also needed. Here, as part of the Future Seas project, we use a "foresighting/hindcasting" technique to describe two scenarios for 2030 in the context of climate change mitigation and adaptation for ocean systems. The "business-as-usual" future is expected if current trends continue, while an alternative future could be realised if we were to effectively use available data and knowledge to push as far as possible towards achieving the UN SDGs. We identify three drivers that differentiate between these alternative futures: (i) appetite for climate action, (ii) handling extreme events and (iii) climate interventions. Actions that could navigate towards the optimistic, sustainable and technically achievable future include:

Developing achievable alternate futures for key challenges during the UN Decade of Ocean Science for Sustainable Development

“…The Indigenous and Traditional Knowledge team followed a distinct approach to developing their paper and futures, which are detailed in Fischer et al ( 2020 ). This team also co-authored, reviewed and/or provided critical input for the other Key Challenges (Bax et al 2020 ; Farmery et al 2020 ; Haas et al 2020 ; Kelly et al 2020 ; Melbourne-Thomas et al 2020 ; Nash et al 2020 ; Novaglio et al 2020 ; Smith et al 2020 ; Trebilco et al 2020 ; Ward et al 2020 ; Willis et al 2020 ), based on their chosen preferences and interests, and initiated and elected to draft a preface for the special issue as a whole (Mustonen et al unpublished).…”

Deep aspirations: towards a sustainable offshore Blue Economy

“…We gave less consideration to SDGs that are more relevant to other papers of this special issue (e.g. Farmery et al 2020 focusing on SDG Zero Hunger, Alexander et al submitted to this species issue and considering equity as per SDG 10, and Trebilco et al 2020 discussing climate actions).

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“…2 and Table 1 for a description of the alternative futures in relation to drivers and SDGs; see Table S1 for more details). The offshore Blue Economy also plays a key role in meeting SDG 2 (Zero Hunger), SDG 10 (Reduced Inequalities) and SDG 15 (Climate Actions), but see Farmery et al 2020 , Trebilco et al 2020 and Alexander et al submitted to this special issue for a thorough consideration of these topics in the context of the Future Seas special issues.…”

“…Innovation also aims for zero waste generation and carbon neutral (or even negative) footprints (Rockström et al 2017 ) and provides support for regenerative practices, such as waste removal or habitat restoration in areas impacted by past damaging activities (Duarte et al 2020 ). Increased production and uptake of offshore renewables, innovation in energy storage systems, and co-location of renewable production with other sectors (Rockström et al 2017 ) achieves decarbonisation (see also Trebilco et al 2020 ). By 2030 offshore aquaculture is a major carbon sequestration industry (Buck et al 2017 ; Sondak et al 2017 ) and source of bioenergy (Roesijadi et al 2008 ).…”

“…The growth in offshore economic activity brings additional environmental risks, including further exacerbating climate change, pollution (e.g. plastics and chemicals) and habitat degradation (Halpern et al 2019 ; Pörtner et al 2019 ; Egger et al 2020 ; see also Trebilco et al 2020 , Melbourne-Thomas et al 2020 and Willis et al 2020 , part of this special issue). Marine ecosystems are inter-connected, and the full cumulative implication of emerging offshore developments is uncertain (Halpern et al 2019 ).…”