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I don't see what there is to figure out about what we should do with the carbon we sequester from the atmosphere. It seems to me that the only thing we can do i

I don't see what there is to figure out about what we should do with the carbon we sequester from the atmosphere. It seems to me that the only thing we can do is dump it into the ground (maybe as plastic?). That's where the carbon we've put into the atmosphere came from, and that is exactly where we should put it back. Planting forests, using it as fuel, using it for plastic goods, putting it into the oceans are all temporary measures. The carbon from that will enter the cycle again rather quickly. Of course this will be energy intensive. We essentially need to put the energy back into carbon that we got from burning those carbon fuels over the last two centuries. That is obviously a tremendous amount of energy. There probably is no way around this. >we will probably need to be removing about 10 billion tonnes of carbon dioxide from the air each year by 2050, and double that by 2100. >They’re hoping to use these gadgets to make carbonated water for soft drinks—or create greenhouses that have lots of carbon dioxide in the air, for tastier vegetables. This sounds very exciting … until you learn that currently their method of getting carbon dioxide costs about $500 per ton. The numbers don't even look as bad as I thought they would. They at least seem achievable if we really wanted it. $500 per ton for 10 billion tons comes out at $5 trillion. The world's GDP is around $80 trillion. From a numbers perspective it seems like this is at least possible. Whether this solution will work politically is another matter though. My own suspicion is that politicking and corruption will make this a much more difficult and expensive process than it should be. This article makes the future look less bleak to me than what I hear on the news.

galangalalgol 7y ago
Or we could spend $1B seeding the ocean with iron sulphate to create algal blooms that reflect sunlight well. Harvest the excess salmon to balance the ecosystem, and repeat whenever we need to dump some heat. As the co2 continues to climb buffer the oceans with a cheap base to counter acidification. Which will sequester that carbon as a salt.
- sveme 7y ago
  Oh, how I love these handwaving arguments. You don't think that a huge algal bloom in our oceans, a prime protein source for billions of people, will not have an effect on the life in the ocean? Just one of a plethora of inadvertent effects that would need to be thoroughly studied...
  - dr_dshiv 7y ago
    Studied by testing the effects, I assume? A large contingent don't want this research done because it may point to a technological solution, reducing political pressure of reducing emissions.
    - Buttons840 7y ago
      "Good news! We found out how to have far greater control of the environment. This will allow us to fix the environment we already had control of and completely ruined!" They have a point I think.
    - imtringued 7y ago
      If humans are willing to damage the climate for a profit they are also willing to damage other things for a profit.
  - dr_dshiv 7y ago
    Here is a recent article on the topic: https://www.independent.co.uk/environment/climate-change-ocean-iron-aerosols-fertilise-science-david-king-a8988241.html https://www.independent.co.uk/environment/climate-change-oce...
    - galangalalgol 7y ago
      They talk about how little carbon is actually sequestered. I assumed it was actually none. The goal was actually to make large swaths of ocean reflective. At IR algae mats are almost as white as snow.
- herogreen 7y ago
  This seems impossible to undo, so extremely risky.
  - galangalalgol 7y ago
    It is temporary in nature. I envision it as a bandaid to bridge us until we finish burning anything we can dig up that is cheaper than carbon neutral energy sources. That is unless you used too much and the ice sheets expanded too far locking us in a snowball earth. Napkin math puts that at around $1.5B
- gumby 7y ago
  Back in the 1990s Jeff Shrager (then at the Carnegie institute at Stanford) built a library of algae strains that thrived at different concentrations of O2 and CO2 as a last ditch hedge against climate change. Then he lost funding and the library was discarded.
kragen 7y ago
Some forms of sequestered carbon, like compressed CO2 injected back into salt domes and magnesite, are much lower energy than the hydrocarbons and coal the humans burned. So it isn't necessary to put the energy back, necessarily. Just the carbon. Even if it is, though, the Earth receives about 1000 years of world marketed energy consumption in the form of sunlight every year. So even energy-intensive carbon sequestration approaches like algal photosynthesis (promoted with iron sulfate, say) may be feasible.
- ryanmercer 7y ago
  > So even energy-intensive carbon sequestration approaches like algal photosynthesis (promoted with iron sulfate, say) may be feasible. They aren't though, algae is more than carbon and pure water. They still need various minerals which you have to input into the system somehow. To do this at any scale it means mining massive amounts and feeding the system, that's just one of the reasons why YC's own idea to turn to Sahara into a bunch of shallow algae pools [1] is absurd. [1] http://carbon.ycombinator.com/desert-flooding/ http://carbon.ycombinator.com/desert-flooding/
  - kragen 7y ago
    > They aren't though, algae is more than carbon and pure water. They still need various minerals which you have to input into the system somehow Yes, that's why iron fertilization is so effective. > To do this at any scale it means mining massive amounts and feeding the system Actually not. In conditions where iron is the limiting nutrient, each kg of iron fixes 83 tonnes of carbon, 304 tonnes of CO2. So sequestering a billion tonnes a year would require 3 million tonnes of iron per year. That probably sounds like a “massive amount” to somebody like you, but it's about 16 tankships full. The humans currently mine some 2.3 billion tonnes of iron ore per year, so we're talking about increasing iron mining by about 0.2%. The Sahara idea might be better, I don't know. Certainly there are a lot more minerals in the Sahara than in the middle of the ocean surface. The mass of water you'd have to transport (and desalinate!) is clearly much larger than the amount of iron, and they call that out as the major cost. It wouldn't be limited by the iron-poor regions of the ocean, though, but ironically, it might create more of them. The US$50b cost estimate seems higher than other sequestration approaches.
Buttons840 7y ago
The carbon cycle you mention was an important realization to me, one I learned rather late compared to many I think. We pull carbon out of the ground with no way to ever (relative to human life spans) put it back, and it doesn't just "dissolve into nothing" like so much of what we do seems too, it stays in various forms on the surface "forever". We also pull so much oil from the ground that running out world wide is a concern we give some thought too. It's going to have an effect. If I seem stuck on first base, it's because I regularly deal with people who don't believe in climate change.

galangalalgol 7y ago

Or we could spend $1B seeding the ocean with iron sulphate to create algal blooms that reflect sunlight well. Harvest the excess salmon to balance the ecosystem, and repeat whenever we need to dump some heat. As the co2 continues to climb buffer the oceans with a cheap base to counter acidification. Which will sequester that carbon as a salt.

sveme 7y ago
Oh, how I love these handwaving arguments. You don't think that a huge algal bloom in our oceans, a prime protein source for billions of people, will not have an effect on the life in the ocean? Just one of a plethora of inadvertent effects that would need to be thoroughly studied...
- dr_dshiv 7y ago
  Studied by testing the effects, I assume? A large contingent don't want this research done because it may point to a technological solution, reducing political pressure of reducing emissions.
  - Buttons840 7y ago
    "Good news! We found out how to have far greater control of the environment. This will allow us to fix the environment we already had control of and completely ruined!" They have a point I think.
  - imtringued 7y ago
    If humans are willing to damage the climate for a profit they are also willing to damage other things for a profit.
- dr_dshiv 7y ago
  Here is a recent article on the topic: https://www.independent.co.uk/environment/climate-change-ocean-iron-aerosols-fertilise-science-david-king-a8988241.html https://www.independent.co.uk/environment/climate-change-oce...
  - galangalalgol 7y ago
    They talk about how little carbon is actually sequestered. I assumed it was actually none. The goal was actually to make large swaths of ocean reflective. At IR algae mats are almost as white as snow.
herogreen 7y ago
This seems impossible to undo, so extremely risky.
- galangalalgol 7y ago
  It is temporary in nature. I envision it as a bandaid to bridge us until we finish burning anything we can dig up that is cheaper than carbon neutral energy sources. That is unless you used too much and the ice sheets expanded too far locking us in a snowball earth. Napkin math puts that at around $1.5B
gumby 7y ago
Back in the 1990s Jeff Shrager (then at the Carnegie institute at Stanford) built a library of algae strains that thrived at different concentrations of O2 and CO2 as a last ditch hedge against climate change. Then he lost funding and the library was discarded.

kragen 7y ago

Some forms of sequestered carbon, like compressed CO2 injected back into salt domes and magnesite, are much lower energy than the hydrocarbons and coal the humans burned. So it isn't necessary to put the energy back, necessarily. Just the carbon. Even if it is, though, the Earth receives about 1000 years of world marketed energy consumption in the form of sunlight every year. So even energy-intensive carbon sequestration approaches like algal photosynthesis (promoted with iron sulfate, say) may be feasible.

ryanmercer 7y ago
> So even energy-intensive carbon sequestration approaches like algal photosynthesis (promoted with iron sulfate, say) may be feasible. They aren't though, algae is more than carbon and pure water. They still need various minerals which you have to input into the system somehow. To do this at any scale it means mining massive amounts and feeding the system, that's just one of the reasons why YC's own idea to turn to Sahara into a bunch of shallow algae pools [1] is absurd. [1] http://carbon.ycombinator.com/desert-flooding/ http://carbon.ycombinator.com/desert-flooding/
- kragen 7y ago
  > They aren't though, algae is more than carbon and pure water. They still need various minerals which you have to input into the system somehow Yes, that's why iron fertilization is so effective. > To do this at any scale it means mining massive amounts and feeding the system Actually not. In conditions where iron is the limiting nutrient, each kg of iron fixes 83 tonnes of carbon, 304 tonnes of CO2. So sequestering a billion tonnes a year would require 3 million tonnes of iron per year. That probably sounds like a “massive amount” to somebody like you, but it's about 16 tankships full. The humans currently mine some 2.3 billion tonnes of iron ore per year, so we're talking about increasing iron mining by about 0.2%. The Sahara idea might be better, I don't know. Certainly there are a lot more minerals in the Sahara than in the middle of the ocean surface. The mass of water you'd have to transport (and desalinate!) is clearly much larger than the amount of iron, and they call that out as the major cost. It wouldn't be limited by the iron-poor regions of the ocean, though, but ironically, it might create more of them. The US$50b cost estimate seems higher than other sequestration approaches.

Buttons840 7y ago

The carbon cycle you mention was an important realization to me, one I learned rather late compared to many I think. We pull carbon out of the ground with no way to ever (relative to human life spans) put it back, and it doesn't just "dissolve into nothing" like so much of what we do seems too, it stays in various forms on the surface "forever". We also pull so much oil from the ground that running out world wide is a concern we give some thought too. It's going to have an effect. If I seem stuck on first base, it's because I regularly deal with people who don't believe in climate change.