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It's a cool idea but I don't see how this is a viable long term solution, even if done at a large scale. Global oil production is on the order of 90M barrels/ye

It's a cool idea but I don't see how this is a viable long term solution, even if done at a large scale. Global oil production is on the order of 90M barrels/year, each barrel contains about 300 lbs of oil, so we're currently producing something like 27B lbs (~12B kg) of oil per year. I'm not sure how much of this ends up as CO2 in the atmosphere versus e.g. plastics, but I think it's safe to say we're probably emitting at least 1B lbs/kg carbon into the atmosphere per year just based on these numbers. Seaweed grows quickly, but it's almost entirely water by mass, and this strategy will really only work in coastal regions. If this strategy was adopted at a wide scale globally how much time does this really buy us? And this isn't even considering things like the unknown ecological effects of the plan.

bobthepanda 3y ago
I’m wondering what pitfalls we’ll fall into here. Twenty years ago algae hyped up many of the same benefits and that didn’t really pan out.
gdudeman 3y ago
I like this back-of-the-envelope estimate, but it's even worse than that. The carbon in oil is lightweight relative to the two oxygens it combines with (atomic weights 12 and 16 respectively) from the air, so 1kg of oil emits about 3kg of CO2! Punchline: we emit around 34 gigatons of CO2 per year.
- _fizz_buzz_ 3y ago
  But wouldn't it be a carbon chain again in the seaweed without oxygen? So, we can ignore the weight of the oxygen? Still, the numbers are huge. But I think at this point we have try everything at once.
- thechao 3y ago
  My argument is that we're probably going to kill the Gulf of Mexico, anyways, with global warming; so, let's go ahead and dump 34 gigatons/year of serpentine in it. That'll 0-out the CO2 we're releasing, at the cost of dramatically changing the Gulf's ecosystem. At this point, I really do think we (humanity) are going to have to make some pretty hard trade-offs.
  - selimthegrim 3y ago
    What changes do you anticipate?
    - thechao 3y ago
      I don't know — I'd just assume that if we began dumping, say, 35 billion tons of serpentine into the Gulf per year, it might changes things?
- euroderf 3y ago
  This is the part that car drivers don't get cos neither they nor any journalist does the math. Maybe visualisation would help. Consider: One gallon of gas. [rest of world: liter] 1) How much CO2 does its combustion generate ? 2) How much does that CO2 weigh ? 3) At 100% concentration and sea level atmospheric pressure, how many Olympic-sized swimming pools (or football stadiums) would that CO2 fill ? 4) At current ambient concentrations (CO2 ppm), what volume does it fill ?
baq 3y ago
Yeah last time it happened (on a scale which is hard to imagine we could achieve) it took a 800k years to reduce CO2 ppm by ~2850, this is a leisurely rate of 3.56ppm/1k years. https://en.wikipedia.org/wiki/Azolla_event https://en.wikipedia.org/wiki/Azolla_event
jorgen123 3y ago
Here is a calculation done by project Drawdown. Potentially 2.5 to 4.72 gigatons CO2e reduced/sequestered over a 30 year period: https://drawdown.org/solutions/seaweed-farming https://drawdown.org/solutions/seaweed-farming It is one of many viable solutions and humanity is working on many or most of them. We need them all. Seaweed would be great as cattle feed is one of the pathways this highlights.
- actionfromafar 3y ago
  Yeah that brings me to another problem. We have too much cattle already. Also, they emit methane.
- roboticmind 3y ago
  It doesn't do as much as you think for cattle feed as most the high % numbers you see touted are only looking at feedlot emissions - which are only 11% of overall cattle emissions. Actual reductions are pretty small >What’s more, feeding cattle algae is really only practical where it’s least needed: on feedlots. This is where most cattle are crowded in the final months of their 1.5- to 2-year lives to rapidly put on weight before slaughter. There, algae feed additives can be churned into the cows’ grain and soy feed. But on feedlots, cattle already belch less methane—only 11 percent of their lifetime output [...] >Unfortunately, adding the algae to diets on the pasture, where it’s most needed, isn’t a feasible option either. Out on grazing lands, it’s difficult to get cows to eat additives because they don’t like the taste of red algae unless it’s diluted into feed. And even if we did find ways to sneak algae in somehow, there’s a good chance their gut microbes would adapt and adjust, bringing their belches’ methane right back to high levels. [...] > All told, if we accept the most promising claims of the algae boosters, we’re talking about an 80 percent reduction of methane among only 11 percent of all burps—roughly an 8.8 percent reduction total https://www.wired.com/story/carbon-neutral-cows-algae/ https://www.wired.com/story/carbon-neutral-cows-algae/
  - Springtime 3y ago
    The authors' argument about the 8.8% reduction hinges on both their assumption that it wouldn't be feasible to add to cows' diets on pastures and the uncertain possibility their guts would adapt and mitigate the effectiveness. Yet the articles they cite (which both quote the same study) describe that on a diet of 0.75% seaweed (0.25% more than the research I saw years prior) only some cattle didn't like the taste and there was an unspecified reduction in feed intake, which hardly seems the foregone conclusion the Wired authors make it out to be. While the aspect about cows' gut reactions long term is also unknown, though one of their links mentions both a 72 and 90 day trial which showed no gut adaption or reduction in effectiveness which is said to be hopeful since 'most adaptations happen within a few weeks'. Ironically the On Pasture link Wired cites for their argument against is more neutral/optimistic and also mentions that two other more common types of seaweed reduce methane output by 20% and encouraged experimenting with for cattle diets.
oezi 3y ago
Looking at the technology trajectories of PV and wind it is pretty clear that within the next 5 to 15 years many countries will start seeing substantial extra electricity being generated by the build out of renewables. Because countries will aim to cover most electricity by renewables and thus overprovision them for dark windless winters, it is likely that there will be massive amounts of energy available during the summer and windy times in spring/autumn. At this point the technology which is best in converting surplus electricity in something which counteracts climate change is most likely to become relevant.
- euroderf 3y ago
  So, how do you apply this to carbon sequestration in seaweed ?
  - oezi 3y ago
    I don't think there is an easy way, so that's why I think this is will not be one of the key things to solve the climate crisis.
mullingitover 3y ago
> Global oil production is on the order of 90M barrels/year It's much worse, this is off by a factor of ~365: that production of ~90M barrels is per day[1]. Global carbon emissions are up to 36 billion tons annually as of 2022[2]. [1] https://www.statista.com/statistics/265203/global-oil-production-in-barrels-per-day https://www.statista.com/statistics/265203/global-oil-produc... [2] https://www.iea.org/reports/co2-emissions-in-2022 https://www.iea.org/reports/co2-emissions-in-2022

bobthepanda 3y ago

I’m wondering what pitfalls we’ll fall into here. Twenty years ago algae hyped up many of the same benefits and that didn’t really pan out.

gdudeman 3y ago

I like this back-of-the-envelope estimate, but it's even worse than that. The carbon in oil is lightweight relative to the two oxygens it combines with (atomic weights 12 and 16 respectively) from the air, so 1kg of oil emits about 3kg of CO2! Punchline: we emit around 34 gigatons of CO2 per year.

_fizz_buzz_ 3y ago
But wouldn't it be a carbon chain again in the seaweed without oxygen? So, we can ignore the weight of the oxygen? Still, the numbers are huge. But I think at this point we have try everything at once.
thechao 3y ago
My argument is that we're probably going to kill the Gulf of Mexico, anyways, with global warming; so, let's go ahead and dump 34 gigatons/year of serpentine in it. That'll 0-out the CO2 we're releasing, at the cost of dramatically changing the Gulf's ecosystem. At this point, I really do think we (humanity) are going to have to make some pretty hard trade-offs.
- selimthegrim 3y ago
  What changes do you anticipate?
  - thechao 3y ago
    I don't know — I'd just assume that if we began dumping, say, 35 billion tons of serpentine into the Gulf per year, it might changes things?
euroderf 3y ago
This is the part that car drivers don't get cos neither they nor any journalist does the math. Maybe visualisation would help. Consider: One gallon of gas. [rest of world: liter] 1) How much CO2 does its combustion generate ? 2) How much does that CO2 weigh ? 3) At 100% concentration and sea level atmospheric pressure, how many Olympic-sized swimming pools (or football stadiums) would that CO2 fill ? 4) At current ambient concentrations (CO2 ppm), what volume does it fill ?

baq 3y ago

Yeah last time it happened (on a scale which is hard to imagine we could achieve) it took a 800k years to reduce CO2 ppm by ~2850, this is a leisurely rate of 3.56ppm/1k years. https://en.wikipedia.org/wiki/Azolla_event https://en.wikipedia.org/wiki/Azolla_event

jorgen123 3y ago

Here is a calculation done by project Drawdown. Potentially 2.5 to 4.72 gigatons CO2e reduced/sequestered over a 30 year period: https://drawdown.org/solutions/seaweed-farming https://drawdown.org/solutions/seaweed-farming It is one of many viable solutions and humanity is working on many or most of them. We need them all. Seaweed would be great as cattle feed is one of the pathways this highlights.

actionfromafar 3y ago
Yeah that brings me to another problem. We have too much cattle already. Also, they emit methane.
roboticmind 3y ago
It doesn't do as much as you think for cattle feed as most the high % numbers you see touted are only looking at feedlot emissions - which are only 11% of overall cattle emissions. Actual reductions are pretty small >What’s more, feeding cattle algae is really only practical where it’s least needed: on feedlots. This is where most cattle are crowded in the final months of their 1.5- to 2-year lives to rapidly put on weight before slaughter. There, algae feed additives can be churned into the cows’ grain and soy feed. But on feedlots, cattle already belch less methane—only 11 percent of their lifetime output [...] >Unfortunately, adding the algae to diets on the pasture, where it’s most needed, isn’t a feasible option either. Out on grazing lands, it’s difficult to get cows to eat additives because they don’t like the taste of red algae unless it’s diluted into feed. And even if we did find ways to sneak algae in somehow, there’s a good chance their gut microbes would adapt and adjust, bringing their belches’ methane right back to high levels. [...] > All told, if we accept the most promising claims of the algae boosters, we’re talking about an 80 percent reduction of methane among only 11 percent of all burps—roughly an 8.8 percent reduction total https://www.wired.com/story/carbon-neutral-cows-algae/ https://www.wired.com/story/carbon-neutral-cows-algae/
- Springtime 3y ago
  The authors' argument about the 8.8% reduction hinges on both their assumption that it wouldn't be feasible to add to cows' diets on pastures and the uncertain possibility their guts would adapt and mitigate the effectiveness. Yet the articles they cite (which both quote the same study) describe that on a diet of 0.75% seaweed (0.25% more than the research I saw years prior) only some cattle didn't like the taste and there was an unspecified reduction in feed intake, which hardly seems the foregone conclusion the Wired authors make it out to be. While the aspect about cows' gut reactions long term is also unknown, though one of their links mentions both a 72 and 90 day trial which showed no gut adaption or reduction in effectiveness which is said to be hopeful since 'most adaptations happen within a few weeks'. Ironically the On Pasture link Wired cites for their argument against is more neutral/optimistic and also mentions that two other more common types of seaweed reduce methane output by 20% and encouraged experimenting with for cattle diets.

oezi 3y ago

Looking at the technology trajectories of PV and wind it is pretty clear that within the next 5 to 15 years many countries will start seeing substantial extra electricity being generated by the build out of renewables. Because countries will aim to cover most electricity by renewables and thus overprovision them for dark windless winters, it is likely that there will be massive amounts of energy available during the summer and windy times in spring/autumn. At this point the technology which is best in converting surplus electricity in something which counteracts climate change is most likely to become relevant.

euroderf 3y ago
So, how do you apply this to carbon sequestration in seaweed ?
- oezi 3y ago
  I don't think there is an easy way, so that's why I think this is will not be one of the key things to solve the climate crisis.

mullingitover 3y ago

> Global oil production is on the order of 90M barrels/year It's much worse, this is off by a factor of ~365: that production of ~90M barrels is per day[1]. Global carbon emissions are up to 36 billion tons annually as of 2022[2]. [1] https://www.statista.com/statistics/265203/global-oil-production-in-barrels-per-day https://www.statista.com/statistics/265203/global-oil-produc... [2] https://www.iea.org/reports/co2-emissions-in-2022 https://www.iea.org/reports/co2-emissions-in-2022