Ocean Optimism: A To-Do List of Possible Climate Solutions

September 27, 2019

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(Our Daily Planet) The IPCC Oceans report released on Wednesday painted a dire picture of the health of the ocean today. The ocean is a carbon sponge absorbing 93% of the carbon emitted thus far, and it is reaching a breaking point according to the IPCC. But another panel that was formed last year — the High Level Panel for a Sustainable Ocean Economy (HLP) made up of 14 serving heads of government — is committed to sparking “bold, pragmatic solutions for ocean health and wealth that support the Sustainable Development Goals (SDGs) and build a better future for people and the planet.” They also issued a report this week — and it provides a roadmap to reducing global GHG emissions by up to 4 billion tons of carbon dioxide in 2030 and by up to 11 billion tons in 2050, which would reduce emissions by as much as 21% of the emission reduction required in 2050 to limit warming to 1.5°C and 25% for a 2°C target. The authors provide:

“a ‘no-regrets to-do list’ of ocean-based climate actions that could be set in motion today. We highlight the report’s analysis of the mitigation potential and the required research, technology, and policy developments for five ocean-based mitigation areas of action: renewable energy; shipping and transport; protection and restoration of coastal and marine ecosystems; fisheries, aquaculture, and shifting diets; and carbon storage in the seabed (see the figure). Make no mistake: These actions are ambitious, but we argue that they are necessary, could pay major dividends toward closing the emissions gap in coming decades, and achieve other co-benefits along the way.”

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Here is a link to a blog about the Report, and a link to an article discussing it in the Journal Science.

To Go Deeper: You can download the entire report here.

The Ocean as a Solution to Climate Change: Five Opportunities for Action (World Resources Institute)

Ships Exploiting Regulatory Loophole to Emit SO2 Into the Ocean (Our Daily Planet)

Seaweed: The New Ethanol? (Popular Mechanics)

Excerpt from World Resources Institute: The energy intensity and the absolute GHG emissions of
ocean-based transport can be reduced in the following ways:

Technical and operational interventions to reduce energy consumption per tonne transported (reduced energy intensity).

Substitution of low- and zero-carbon fuels (e.g., hydrogen, ammonia, some biofuels) for diesel and bunker oil (reduced absolute emissions). The 50 percent GHG reduction target set by the IMO might be achievable with technical and operational measures alone. Achieving a greater level of reduction by 2050—or the full phaseout of GHG emissions from shipping, as called for in the Initial Strategy’s vision statement—will be possible only with the introduction of low- and zero-carbon fuels to replace fossil fuels. In practice, a rapid and cost-effective reduction in GHG emissions will require both technical and operational interventions and a swift transition to low- and zerocarbon fuels.

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Low/zero carbon synthetic or “e” fuels could replace fossil fuels. Examples include renewable hydrogen, hydrogen-based fuels such as ammonia, and fuels that have been post-processed with CO2 to make hydrocarbons. These fuels differ from synthetic fuels made from gas or coal. Biofuels could replace fossil fuels. However, it is commonly assumed that biofuels will have a limited role because of land and water constraints on sustainable supply and the fact that many biofuels are not, in fact, carbon-neutral (Searchinger et al. 2019).

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Projections of mitigation from seaweed farming could reach 0.05–0.29 GtCO2e/year by 2050. However, there are uncertainties in rates of expansion of the industry and the proportion of production that would be sequestered. Scaling up seaweed production via aquaculture offers different potential mitigation pathways:

Seaweed products might replace products with a higher CO2 footprint, thereby avoiding emissions (rather than directly contributing to sequestration) in fields such as food, feed, fertilisers, nutraceuticals, biofuels, and bioplastics (World Bank 2016; Lehahn et al. 2016; Duarte et al. 2017). The extent of this mitigation pathway is currently not known.

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Seaweed biomass
has potential as a source of various biofuels although it is evident that there are significant technological hurdles to be overcome before seaweed biofuel is viable in either energy or economic terms (Milledge et al. 2014). READ MORE