Failing to limit our emissions of carbon dioxide will have severe consequences for the world’s oceans. This report contends that the marine environment is doubly affected: continuing warming and ongoing acidification both pose threats. Accordingly, proactive and resolute action is needed in order to ensure that the oceans do not overstep critical system limits. The document makes recommendations in the following areas:Climate mitigation for marine conservation:global greenhouse emissions must be halved by 2050 from 1990 levelslimiting the rise in air temperature to a maximum of 2 degrees celcius relative to the pre-industrial value while also limiting the rate of temperature change to a maximum of 0.2 degrees celcius per decade.Bolstering the resilience of marine ecosystems: to preserve marine biodiversity and strengthen the resilience of marine ecosystems, at least 20–30 per cent of the area of marine ecosystems should be designated and managed as Protected Areasmarine resource management should follow the "ecosystem approach"our understanding of linkages between human action, biodiversity and marine ecosystems must be improved with intensive monitoring.Limiting sea-level rise and reorienting coastal zone management strategies:absolute sea-level rise should not exceed 1m in the long term, and the rate of rise should remain below 5cm per decade at all timesstrategies need to be developed for protection and accommodation, but also for a managed retreat from endangered areasthere is a need to improve the linking of nature conservation with coastal protection.Adopting innovative instruments of international law for refugees from sea-level rise:there is a need for agreements on the reception of refugees from coastal areas and on the apportionment of the associated coststo help inform policymaking, studies should be undertaken in the fields of law and social sciences.Halting ocean acidification in time: in order to prevent disruption of the calcification of marine organisms and the alteration of marine food webs, the pH of surface waters should not drop more than 0.2 units below the pre-industrial average value.Regulating carbon dioxide storage:the precautionary principle indicates that introducing CO2 into seawater should be prohibited, because the risk of ecological damage cannot be assessed and the retention period in the oceans is too shortstoring carbon dioxide in geological formations under the sea floor can only be an "emergency" solution for a transitional period.Imposing strict conditions upon methane hydrate mining: because of the potential instabilities of deposits, it is important to ensure even now that methane hydrate mining in the oceans is only permitted under very strict conditions. Existing regulatory systems governing ocean mining should be amended and adjusted accordingly.Complementing the existing financing mechanisms:fisheries subsidies must be removed in order to avoid providing misplaced incentives for overfishingthe establishment of microinsurance systems to protect individual assets should be supported as a component of a more comprehensive precautionary strategysome of the official development assistance resources presently deployed to provide emergency relief worldwide should be diverted into preventive measures.