Pull up sunken nutrients to create CO2-capturing plankton blooms, then push new organic carbon into ocean depths before it reverts to CO2.
A drawdown of atmospheric CO2 would address all three big issues--global overheating, ocean acidification, and methane burps--but it would need to be big, quick, and sure-fire.
How big? Aim at removing all 350 GtC emitted since 1750. That would cool things off and slow methane production.
How quickly? We must back out of the danger zone before being weakened by resource wars and economic collapse. During a 20 yr project period, another 250 GtC are likely be emitted from business-as-usual, so make that goal 600 GtC. That's 30 GtC/yr.
Once the drawdown is complete, half of the sequestration capacity might still be needed to continuously counter out-of-control emissions; the rest goes on standby for future emergencies such as a methane burp.
How secure? Our initiative needs to be sure-fire, since we must avoid the human population crash that a collapse of civilization would trigger.
Most candidates suitable for long-run improvements will be too small, too slow, or too iffy for this emergency. Even fertilizing the ocean surface enough to settle out 30 GtC/yr of the usual debris into the depths would require an unachievable 3x increase in ocean productivity worldwide.
The proposed push-pull pump plantations should need less than 1% of the ocean surface. Pump up nutrients from the depths to enhance plankton production (what winter winds do).
But also emulate natural downwellings. Pump down the carbon-enriched surface waters within a week, before the new organic carbon reverts to CO2. This also sinks the 240x larger amounts of organic carbon from feces and decomposition that are dissolved in surface waters and will never settle out.
Just as farmers grow a nitrogen-fixing crop of legumes and then plow it under, we would be growing a carbon-fixing crop of plankton and then pumping it under.
Charge the Second Manhattan Project to deploy something like this within four years. A decade later, the climate threat should be half gone.
Category of the action
What actions do you propose?
Who will take these actions?
Where will these actions be taken?
What are other key benefits?
Putting current and past CO2 emissions back into secure storage would reduce the global overheating, relieve deluge and drought, reverse ocean acidification, reverse the thermal expansion portion of sea level rise, slow the thaw of methane-generating tundra, and reduce the chance of abrupt climate shifts.
Because not all of the new plankton will be successfully captured and sunk, fertilization will stimulate the marine food chain locally. Most major fisheries have declined in recent decades and, even where sustainable harvesting is practiced, it still results in fish biomass 73% below unharvested levels. For fish of harvestable size, there is niche space going unused.
This push-pull pumps proposal has some unique advantages compared to current climate strategies: It is big, quick, and secure. It is impervious to drought and holdout governments. It does not compete for land, fresh water, fuel, or electricity. It runs on wind power, augmenting the natural up- and down-welling of oceans.
What are the proposal’s costs?
Capital Costs. If a pipe pump were to cost a thousand dollars in mass production (Kithil's estimate), even a million of them would cost no more than the billion dollars spent in a single month on dog food in the U.S. But given what is at stake, it would be best to aim for the thousand-fold-larger scale of an unbudgeted bank bailout.
Operating Costs. Wind and wave are free. Unlike fishing and farming, nothing about sink-on-the-spot plankton plantations will necessarily require handling, transport, or processing. Continuing costs would primarily be for maintenance and monitoring. With unit costs low, replacement could be an alternative to repair. Commercial fishing fees could provide significant income.
This is an initiative that qualifies as feasible. A single industrialized country could fund it with only minor economic impact, perhaps from existing defense budgets.
What climate-engineering initiatives might be feasible, especially to avoid methane feedbacks caused by global warming?