Thread by @geoengineering1

🚨𝐑𝐄𝐕𝐈𝐄𝐖 𝐏𝐀𝐏𝐄𝐑🚨

"The recent review article discusses the basic operation of the marine #CarbonCycle & 2 #mCDR methods that are "thought to offer the greatest potential in terms of #CDR mass:
🌊#OceanIronFertilization
&
🌊#OceanAlkalinityEnhancement."

🧵
1/14

Various conclusions were drawn in the review which are enlisted below:

1️⃣ "The alkalinity of the ocean creates a massive increase in the ocean’s capacity to #store #carbon, relative to a scenario without #OceanAlkalinity."
2/14

2️⃣ "Ocean warming causes decreases in both #CO2 #solubility and the Revelle factor (B), which make the ocean less efficient at #absorbing CO2."
3/14

3️⃣ "Surface-water production of CaCO3 drives an increase rather than a decrease in surface-water pCO2w, but carbonate-bearing productivity remains of interest for #CarbonDrawdown because the soft tissue pump (STP) component outperforms the carbonate pump component."
4/14

4️⃣ "Carbonate compensation (dissolution of sedimentary carbonate) is nature’s ultimate mechanism for “cleaning up” a major #CO2 #perturbation, but it requires many tens of thousands of years and cannot conceivably be accelerated to timescales relevant to society....."
5/14

Contd...
"Hence, research concentrates on #CarbonStorage
a) in the vast oceanic DIC reservoir with multi-centennial timescales,
b) through burial in sea-floor sediments with timescales up to millions of yr.
To achieve this, proposals focus on manipulation of the STP/OAE."
6/14

5️⃣ "Many uncertainties remain w.r.t. soft tissue pump manipulation (notably, through OIF). These include:
(a) feedbacks that offset the CO2 #sequestration gains, including production of N2O/CH4 that would quickly erode the net #GHG benefit of iron fertilization."
7/14

Contd...
(b) "the likelihood of toxic algal bloom development;
(c) the potential for water-column de-oxygenation;
(d) side-effects to critical ecosystem services over a wider spatial domain due to, for example, #NutrientRobbing."
8/14

6️⃣ "A key challenge in #OceanAlkalinityEnhancement is to develop the required mineral processing and distribution/dissolution mechanisms at volumes and timescales that are relevant to society...."
9/14

Contd...
"Estimates for the longevity (100s to 1000s of years) & potential mass (tens-more than a 100 GtC by 2100) of #CarbonSequestration through #OAE are highly relevant to the problem of anthropogenic #CDR, but many uncertainties remain about feedback processes..."
10/14

Contd...
"There is specific urgency in accelerating research into these feedbacks for #OceanAlkalinityEnhancement because it seems to be a feasible, largely safe, and potentially long-lasting method for CO2 #sequestration."
11/14

7️⃣ "Finally, given the broad scope & potentially large spatial scales of feedbacks & impacts, it is crucial that large-scale oceanic methods for #CDR, once executed, remain subject to ongoing & independent, multinational scientific monitoring, oversight & validation."
12/14

Read the pre-print review article entitled, "Marine methods for carbon dioxide removal: fundamentals and myth-busting for the wider community" here ⬇️
academic.oup.com/oocc/advance-a…

#mCDR
#CarbonDioxideRemoval
#OceanAlkalinityEnhancement
#OceanIronFertilization

13/14

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