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There's a few "plant trees" or "terraform the sahara" comments in here. For some context, if we planted trees wherever we could around the world we can only un

• BartBoch 5y ago
  Not a solution, but still - check "Oxytree". It's a tree "farmed" in Europe, that was created in Spain. Within 6 years it grows to 16 meters. You can cut it almost completely, and it will regrow. You cut it then every 4 years. It will regrow multiple times. The tree as far as I know cannot re-plant itself (so its not invasive), and it absorbs up to 10 times more CO2 than regular trees. It's still young project, but more and more countries create plantations of it (also as a way of CO2 recapture).
• tekstar 5y ago
  Also, planting trees sequesters co2 into the biosphere. That is not good enough, we need to be sequestering co2 into the geosphere if we want to remove it from the equation
  • detritus 5y ago
    I'm sure it's been mentioned elsewhere here already by someone, but I've always thought that converting felled 'sequestration stock' to bio-char and making terra preta out of it would be win-win-win, as it could then be used to improve desertified land. As much as CO2 emissions befear me, so too does increasingly poor topsoil, globally. - ed I'm not even sure we'd need to wait for trees to mature either - we just need work with whatever plant absorbs the most CO2. Perhaps algae, even?
    • simon_000666 5y ago
      So I’m thinking the same. Soil + Terra preta(charcoal + food waste) is the best way. There needs to be some kind of inverse Bitcoin - something where we incentivize large number of people to claim areas of land and terra Preta it up. The reward is some kind of token that can be exchanged for value. We can maybe use satellite imagery to identify which land has been converted. Someone has to be forming a team on this for the prize.
    • kmtrowbr 5y ago
      This is definitely a thing: https://en.wikipedia.org/wiki/Bioenergy_with_carbon_capture_and_storage https://en.wikipedia.org/wiki/Bioenergy_with_carbon_capture_... In theory it's energy positive: burning the crop can produce energy.
  • kisamoto 5y ago
    Naturally (without human influence) a combination of biosphere (decades) and geosphere (millenia) would keep CO₂ levels in check. We (humans) have accelerated emissions (by burning, thus reversing, geosphere capture via oil) and destroyed the biosphere through deforestation. This has also been accelerated as raising temperatures thaw permafrost & destroy ocean life (among others). Anything we can do to reverse this is beneficial.
  • mrfusion 5y ago
    Has anyone checked if earths total biomass has increased as co2 increases?
    • ralusek 5y ago
      There is more greenery/forestation, and likely more biomass downstream, but I would expect other effects to cancel those effects beyond certain thresholds. For example, even though plankton and algae might benefit from additional carbon and heat, acidification of the ocean might lead to a net decrease in both.
      • mrfusion 5y ago
        I guess it would be impossible to actually measure. Heat could also increase biomass since there would be a longer growing season and higher latitudes opening up. But like you say, it’s a trade off so hard to predict.
    • hedora 5y ago
      We’ve pumped a lot of nitrogen into the biosphere. I wonder how much that’s increased the total biomass.
  • BurningFrog 5y ago
    That assumes a lot about the world in 50-100 years when trees planned today are full grown!
• songzme 5y ago
  Trees do much more than remove carbon from the air. Carbon removal machine could potentially create c02 deficit regions, creating hostile environments for trees. We can't possibly build a machine for every function a tree does.
  • deleted 5y ago
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  • kisamoto 5y ago
    Are there any sources of this? As I understand it the air carrying the CO₂ is constantly moving and will not create any deficit regions? Besides, with the large over concentration of carbon dioxide we have at the moment I think increasing temperatures have a higher chance of creating hostile environments.
  • p_j_w 5y ago
    I think the point GP was making was that just planting trees is not enough, not that we shouldn't be doing it. If all we do is plant trees, we're still running full bore up shit creek.
    • kisamoto 5y ago
      Yes thank you - trees are part of the solution, not _the_ solution.
  • usefulcat 5y ago
    > Carbon removal machine could potentially create c02 deficit regions, creating hostile environments for trees. If we could remove so much CO2 from the air that it prevented plants from growing (even if the effect were highly localized, which is pretty much a certainty), then we might actually have a shot at being able to remove CO2 in a reasonable amount of time. So this definitely sounds like a good problem to have. Personally I think that's pretty unlikely though.
    • Robotbeat 5y ago
      CO2 is pretty well-mixed and it takes a lot of energy to pull CO2 out so it is unlikely to be the primary method of address Climate change. Also at this point we are substantially above the pre-industrial level of CO2 so there’s essentially no chance of having CO2 poor regions.
• Zababa 5y ago
  I've heard that planting trees in the Sahara would be worse because since they're darker they would absorb way more heat.
  • kisamoto 5y ago
    Actually yes, planting trees (especially the wrong trees) is not always a good thing. Darker leaves will attract more heat (imagine if it was possible to turn the polar regions into trees - this would have a very negative effect). Also mono cultures and replacing natural vegetation with man-made forestation can actually be more limited to the amount of carbon they can capture long term. Source: https://spiral.imperial.ac.uk:8443/bitstream/10044/1/80271/6/What%20role%20can%20forests%20play%20in%20tackling%20climate%20change.pdf https://spiral.imperial.ac.uk:8443/bitstream/10044/1/80271/6...
• hitpointdrew 5y ago
  >For some context, if we planted trees wherever we could around the world we can only undo a decades worth of emissions[0]. Not even, say you could transform the Sahara to rain forest, awesome right? I mean it would be an incredible feat, but it would give you exactly 0 with reducing carbon. Contrary to popular belief the Amazon rain forest aren't the "lungs" of the planet, the Amazon rain forest is basically net 0. Why? Because the rain forest also has a tremendous amount of life/animals, those animals use the oxygen and produce carbon. The real "lungs" of the planet are in the ocean.
  • otterley 5y ago
    Wait a minute. Are you saying that the animals in the Amazonian rain forest produce more CO2 than the plants within it consume? Do you have any data that shows this?
    • hitpointdrew 5y ago
      This is cited in the documentary "One Strange Rock". That is the only data I have. I am trusting that the documentary is accurate, I have not fact checked the documentary. EDIT: You might find this PBS article interesting as well, https://www.pbs.org/newshour/science/no-the-amazon-fires-wont-deplete-the-earths-oxygen-supply-heres-why https://www.pbs.org/newshour/science/no-the-amazon-fires-won... "Forest plants produce lots of oxygen, and forest microbes consume a lot of oxygen. As a result, net production of oxygen by forests – and indeed, all land plants – is very close to zero."
      • otterley 5y ago
        Saying net production of oxygen is zero is not identical to saying net sequestration of carbon dioxide is zero. Photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2 You can see here that there's glucose (a carbohydrate) being produced in addition to oxygen.
  • eloff 5y ago
    The Amazon rain forest is not net zero because of animals. It's net zero (actually net negative last I heard) because humans are burning it to make way for agriculture. Trees sequester carbon. They also return that carbon to the atmosphere eventually, but as long as they're replaced by new trees, that's fine. That's not what's happening in the Amazon. From a carbon perspective forests for timber are even better because then we keep several generations of trees worth of carbon locked up in our structures. It's also an easier sell because that has real economic value. From a biodiversity perspective it's not as good to have monoculture crops of any kind, including trees.
• mbgerring 5y ago
  There's no reason not to plant trees in addition to everything else we'll need to do to fix this problem. The advantage of planting trees is that we know it works, it's cheap, and we can do it right now. So some people should be doing that, and others should be doing R&D on other means of carbon removal. No need to pit one against the other.
  • kisamoto 5y ago
    I totally agree and I'm sorry if I gave the impression that trees should not be part of a solution. Trees (and other nature based methods) should definitely not be neglected. I merely wanted to try and raise some awareness to those who question the need for technological removal methods as there is a bit of a toxic "trees will save us" attitude when things like this get mentioned.
    • elevaet 5y ago
      This kind of civil discourse is what makes HN such a gem on the internet.
      • foota 5y ago
        You're sure it's not comments like these? https://news.ycombinator.com/item?id=27826277 https://news.ycombinator.com/item?id=27826277 I thought it was funny to see similar sentiments back to back :)
      • flingo 5y ago
        Meta-warning; I'm more into the juxtapositions of interactions between idiots vs experts, specialists vs generalists, startup-billionaire vs unemployed-drug-addict-hacker, and the level of insight that can be gained from these conversations. I believe that the civility, and desire for unfettered conversation (avoiding ad-hominem, flame-wars. etc···) are more of an instrumental-goal of this process, than the true goal. I don't really know why the comments on hn are the way they are, and I doubt anyone ever will. But that's what keeps me coming back here. It's the only place on the internet I can get this kind of thing, whatever it is. I do have to say, there's something special and unique here. Like the userbases of wikipedia, stack overflow, 4chan, or twitter, there's something here that's impossible to recreate and worth preserving.
• brightball 5y ago
  Depends on the tree. Empress seems to be the ideal candidate. https://www.bloomberg.com/news/features/2019-08-02/we-already-have-the-world-s-most-efficient-carbon-capture-technology https://www.bloomberg.com/news/features/2019-08-02/we-alread...
  • aaronblohowiak 5y ago
    Planting a monoculture would be a disaster, as we've seen when a billion poplars died in china's green wall.
• rcpt 5y ago
  It does seem unlikely that we'd be able to control temperatures without resorting to sulfur dioxide. It'll probably start a war, but once natural resources start getting scarce I fully expect the affected nation to deploy SO2.
  • burgessaccount 5y ago
    Calcium carbonate is a better fit - see Gates’s experiments. Likely to still be disastrous, but better than sulfur dioxide
    • bamboozled 5y ago
      Grammar tip, if someone name ends in s, you can just write Gates’ experiment.
    • rcpt 5y ago
      Interesting thanks. Why disasterous?
      • burgessaccount 5y ago
        Particulate matter in the air causes precipitation. Spraying large amounts of particulate matter into the sky is likely to drastically change global rainfall patterns - so you might get a ton of rain in the Sahara, where it’s useless, and none at all in the American Midwest. The result could be drastic food shortages and famines. Major volcanic eruptions have been associated with droughts and famines. I think geoengineering on this scale may be necessary, but it is a terrible option and an absolute last resort
        • rootusrootus 5y ago
          Isn't the upside of this kind of geoengineering the reversibility? If we inject SO2, and we don't like the effect, we stop. IIRC it doesn't hang around that long.
          • 5y ago
• lvs 5y ago
  > we can only undo a decades worth of emissions Sounds like dramatic progress to me. It uses a technology we already have against a problem that is only getting worse by the second. The side effect of fostering sustainable natural resources would be an unquestionable good as well.
• foobarian 5y ago
  Do trees actually help? AFAIK once a forest reaches equilibrium it puts out as much CO2 as it takes in through various decomposition processes.
  • jpalomaki 5y ago
    Using more wood as construction material helps to tie the CO2 for longer period.
    • Robotbeat 5y ago
      This. Early trees sequestered a whole bunch of carbon in their structure (and there wasn’t efficient methods of breaking down lignin at the time, so the carbon stayed in the ground instead of rotting and returning to the sky). If we build long-lived structures out of wood or other carbon bearing materials whose carbon source is the atmosphere, we’ll be doing the same thing as trees but with human civilization as the organism.
    • schiffern 5y ago
      Sounds like the real question is, how does 1 hectare of stick frame buildings compare to 1 hectare of mature forest? What stores more carbon-per-hectare, and how many years does the building actually lock up that carbon? While a hectare of forest may be "only" CO2-neutral, a hectare of buildings are typically net CO2 emitters.
  • BurningFrog 5y ago
    Yes, but that takes 50 years at least. In the 2070s things will be very different.
  • inlikealamb 5y ago
    We already have all the pieces needed, they just need to be connected in a better way. Forests need to be managed to optimize for sequestration; log the right parts at the right time, replant. Also need to invest more in controlling forest fires (hell, use the military if that's the only way to get the budget). At the other end we need to reduce burning wood for fuel through other renewables and put more lumber into building.
• Arete314159 5y ago
  A decade sounds like a pretty good start. If we could combine that with transitioning away from lawns and towards gardens / orchards (like even on highway medians!), imagine the savings in terms of shipping food.
  • bognition 5y ago
    Highway medians are lawn for safety reasons. Planting an orchard between two lanes of traffic going 75 mph would result in a ton of fatalities
    • schiffern 5y ago
      Seems like you'd intentionally plant many small/short trees that will act as nice crash barriers, not large strong trees that act like brick walls. Orchards tend to be short trees anyway. Hitting the tree equivalent of those sand-filled barrels sounds a lot better than dissipating that same energy by either A) flipping, or B) colliding with oncoming traffic. It would be interesting to see the videos of "crash testing" various types of orchards!
      • BurningFrog 5y ago
        Sure, but small trees contain little carbon.
        • schiffern 5y ago
          Grass contains even less carbon, and it doesn't produce anything of economic value. As I wrote elsewhere in the thread, it's all about maximizing the total carbon stored per hectare. That means more trees in the median, more trees in our suburbs, more trees in the city, and (most importantly) more trees in agriculture. There's a small set of "farmer's trees" (eg black locust) that coexist with crops right up to the trunk, drop copious mulch, have deep tap roots that bring up minerals, and make nutritious pods that are good fodder for animals. Planting 15-20 of these trees per hectare will actually increase the crop yield beneath. Tons more carbon stored, better crop yield, cuts down wind erosion, and free fodder too. The cost is that the farmer has to drive around the trees. It's a non-zero cost yes, but it's a much easier switch than transitioning to full-on agroforestry.
• burgessaccount 5y ago
  A few other problems - 1) trees take a lot of water to grow, and 2) all the carbon they sequester can go right back into the atmosphere in a forest fire. Some very scrupulous carbon-offset companies (like YC co terraformation!) are careful to plant diverse, native species in a way that rebuilds habitat and fits local water supplies. But there are a huge number of irresponsible tree-planting orgs that plant monoculture trees in places they don’t belong. For instance, eucalyptus trees in California - an invasive species that sucks water out of the ground, then burns up like an oil rag
  • macawfish 5y ago
    Trees take a lot of water to grow but they also hold water and share it through the air and ground with other plants and with other creatures in the form of transpired water vapor.
    • burgessaccount 5y ago
      Definitely true! I am a huge fan of trees. But the wrong tree in the wrong place is a bad thing. I try to advocate for responsible and thoughtful reforestation - which is, unfortunately, a lot more expensive than people want it to be.
      • jbay808 5y ago
        Where can I learn more about the costs and challenges of thoughtful reforestation, and the key differences between the responsible and irresponsible sort? (Just popping in to ask because it seems like you might know). I'm interested in doing some work in this space but don't have any background.
        • burgessaccount 5y ago
          Hmm… can’t point to one specific book, but there are lots of links. You can google “reforestation monoculture” and “reforestation native species.” This article is a great place to start: https://e360.yale.edu/features/why-green-pledges-will-not-create-the-natural-forests-we-need https://e360.yale.edu/features/why-green-pledges-will-not-cr... It doesn’t get into the granularity of the costs, but highlights that the basic issue is countries are still hoping to make a profit off these “carbon sinks” by planting easily usable timber - aka monoculture - which greatly diminishes the benefits of forests and leaves them vulnerable to blights and other disasters.
• insulanus 5y ago
  We need technology, but more important is business and government. We have all the data on what is causing the problem, but we are not making value judgements, and taking action based on those judgements. Until our technology catches up and provides net carbon-neutral energy, we have to pollute less. And that may be and doing less, and "consuming" less. And that will require force. Public pressure, social pressure, and regulation. No business will do it voluntarily, and no government will make itself unpopular voluntarily. Long term we need green energy technology. Short term, we need technology is to help force change in our habits. Do all the other stuff too, sure, but it seems like most of the pollution currently comes from Industry, Agriculture and transport. Things that enhance human quality of life. We need to decide which enhancements are most essential, and cut back. https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data https://www.epa.gov/ghgemissions/global-greenhouse-gas-emiss...
• bgroat 5y ago
  I'm working on agri-forestry and biochar reactors on a hobby farm. Hybrid poplars mature within a decade, and a biochar reactor is a net-energy producing reaction that produces soil improving char as a byproduct. It won't save the world on it's own, but trees can be leveraged in powerful ways.
  • simon_000666 5y ago
    Can you think of anyway we could measure individuals doing this? I’m thinking reverse Bitcoin - provide a kit for people to start generating terra preta and deploying it and then give them coins for the amount of carbon they store.
  • phire 5y ago
    Hang on. That sounds carbon-neutral at best. Great for replacing fossil fuels, but not a carbon sequestration technique.
    • bgroat 5y ago
      You can bury the char or plow it into fields as a soil ameliorant. Or if you wanted you could literally just bury it. Then it becomes a coal plant in reverse
• dqpb 5y ago
  A lot can happen in decades.
• napier 5y ago
  It’s not just about carbon equations. Appropriately selected, well planted trees reduce local environment temperatures, regulate rainfall and soak up excess water in a positive feedback loop. The urban heat island effect will make lived experience even more challenging than it already does as the planet warms; turning cities into agro-forestry reserves would counteract this.
  • adrianN 5y ago
    Planting more trees in cities makes a lot of sense, but it doesn't do much for CO2 levels in the air.
• reader_mode 5y ago
  >Our use of technology threw nature out of balance and we need to use technology to get the balance back again. The notion being that nature or even the climate is balanced/stable ? I think the focus should be on increasing resiliency not hoping everything is going to be alright "if we just undo this one thing". Having said that I'm all for reverting CO2 emissions, just dislike this implicit notion that nature is harmonious by default and humans fucked it up - there's speculation about weather related disasters pre industrial era, so even very recently in human context. Or the disruptions we have with relatively minor volcanic activity. So many natural thing could screw us way worse than global warming and for the first time in history we're getting technologically advanced enough to protect against it.