Marine carbon dioxide removal | European Marine Board

[Michael Hayes]

"Marine carbon dioxide removal

Reliable monitoring, reporting and verification (MRV) of marine carbon dioxide removal (mCDR) approaches will require accurate quantification of the amount of CO2 removed from the atmosphere, the durability of that removal, and non-carbon impacts on the marine environment. Given the vastness of the Ocean, the slow gas exchange across the sea surface, and the difficulty of defining baselines under ongoing environmental change, accurate estimates are challenging and need to include reliable uncertainty estimates. However, the required measurements, their integration with numerical models and the transparent provision of useful information are critical."

https://www.marineboard.eu/marine-carbon-dioxide-removal 

MH] Many precautionary factors are listed, yet no mention is given to questions about synergies, such as:

1) Can any mCDR systems provide renewable energy or fuels, thus addressing, to some extent, CO2 drawdown needs and reduction in emissions needs? Can any mCDR method store grid energy as an additional value?

2) Can any mCDR method utilize treated municipal waste, thus reducing the need for releasing such waste into rivers and coastal waters? Also, can some forms of plastic trash be utilized by any mCDR method?

3) Can any mCDR technique provide food/feed, fertilizer, Biochar etc., thus reducing pressure on land resources for such critical commodities? 

4) Can any mCDR tech produce freshwater or filtered freshwater?

5) Can any mCDR method, or combination of methods, earn money to allow financial self-sufficiency beyond C credits?

Looking on the bright of side of technologies, or a a synergistic views of the different mCDR options, has it's place in system of systems thinking.

[Bhaskar M V]

The most important questions about mCDR are:

1. What is the total natural Carbon sequestration in Oceans?

Is it ~400,000 GtC?

2. What is the impact of mCDR on fisheries?

If fish grow as a result of a mCDR solution, it would be extremely beneficial in supplementing food production on land.

3. What is the theoretical maximum fish biomass that the Oceans can sustain?

Fish biomass in Oceans is estimated to be very low, 3 to 15 GtC.

Why is it so low, can it be increased, if so what is the maximum limit?

4. Can the nutrients in wastewater and fertilizer runoff be used for mCDR?
At present nutrients in wastewater and fertilizers are 'polluting' oceans, and 

causing eutrophication, algal blooms, mass fish kills, hypoxia, etc.
Can we instead use the nutrients for a beneficial purpose - growing fish, producing O2, mCDR, etc. ?

Regards

Bhaskar