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Photosynthesis is a strange beast... You know the cliché that something designed by evolution, or "natural", is usually pretty efficient, sort-of "in sync" wit

Photosynthesis is a strange beast... You know the cliché that something designed by evolution, or "natural", is usually pretty efficient, sort-of "in sync" with its surroundings, etc. For many things this subjectively holds true, with things like Spider silk, flight of large birds, a diving penguin, etc. Photosynthesis, and the core protein, Rubisco, is anything but! It's the central protein of live on earth, and yet... it's a totally ridiculous machine. You ever wonder what the inside of a typical cell sounds? In a cartoon it would be a high-pitched whining, because that correlates well with the typical speed at which some protein does its business when busy. Rubisco is the fat guy lazily picking up the hammer every once in a while, balancing it in the air, slamming it down and...missing 2/3 the time. So this idea does have potential. Unfortunately, the plant biophysics have been well understood for a few decades, and the idea isn't new or anything. I'd say the even-odds of doubling the CO_2 fixation of some plant we can grow on a large scale is about 20%. It is completely irresponsible to let this, and other such schemes, inform policy wrt climate change right now. Invest in research, yes. But using it to put of necessary changes is just motivated reasoning an will end with nothern russia looking like Florida, and Florida looking like what's 30km east of Florida now.

chrisco255 7y ago
Sea levels are rising at 2-3mm a year. That's about a foot of sea level rise per century, assuming some combination of AMO negative phase, PDO negative phase, volcanic activity, geomagnetic reversal, increased cosmic rays and subsequent cloud cover due to increased nucleation and grand solar minimum due in the coming decades doesn't kick off a cooling trend that causes a mini ice age to set in and sea levels to fall, of course.
- Majestic121 7y ago
  I was surprised by your affirmation, as I had the (apparently wrong) assumption that sea levels would increase by at least a few meter in the century. However, the IPCC (UN group in charge of research for climate change) does predict an increase of ~0.2 to 0.5m (basically a foot) of the sea level in the next century. Here is the source for interested people : https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/faq-5-1.html https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/faq...
  - wh1t3n01s3 7y ago
    Subsidence of lands under glaciers limits sea level rising, but not equally on the earth surface
    - mantap 7y ago
      I don't understand how subsidence of land under glaciers limits sea level rise, could you explain it more?
      - yencabulator 7y ago
        Let's try this: If both sea level and ground level move, what their interaction is locally isn't the same as the difference of the global averages.
5efh456 7y ago
Remember when people believed that 90% of DNA is junk? Or that the human appendix is totally useless? Now we know better. So when photosynthesis is "inefficient" after billions years of evolution, surely we would be more careful with the conclusions. "Photosynthesis is only 1% efficient" sounds a bit like "we only use 10% of our brain" (according to some measurement). > Photorespiration wastes little energy and instead enhances nitrate assimilation, the process that converts nitrate from the soil into protein, according to a new study. > Most plants, contrary to popular belief, do not waste over 30% of their photosynthate in a futile cycle called photorespiration. Rather, the photorespiratory pathway generates additional malate in the chloroplast that empowers many energy-intensive chemical reactions, such as those involved in nitrate assimilation. Thus, the balance between carbon fixation and photorespiration determines the plant carbon–nitrogen balance and protein concentrations. https://www.nature.com/articles/s41477-018-0191-0 https://www.nature.com/articles/s41477-018-0191-0
- deleted 7y ago
  [deleted]
Gatsky 7y ago
Even with some more efficient scheme the problem is scalability. Deploying enough of this altered plant mass to meaningfully reduce CO2 is a real challenge. There is also likely to be huge opposition to injecting GMO plants into the biosphere. I make no judgement on this, just highlighting the issue.
- candiodari 7y ago
  The main limit on plant growth is exactly that: a shortage of CO2 in the atmosphere. Yes, shortage. Will this actually make a difference with the plants starved of CO2, as opposed to a CO2-enriched atmosphere in the lab ? (obviously I mean from the perspective of a plant that wants to grow faster, what matters from a global perspective can and probably will be different) e.g. https://www.forbes.com/sites/jamestaylor/2012/10/25/contrary-to-what-you-hear-global-warming-has-been-good-to-africa/#2fc5305627f6 https://www.forbes.com/sites/jamestaylor/2012/10/25/contrary...
  - 5efh456 7y ago
    If the main limit is CO2, why does adding fertilizer (nitrogen) to a field suddenly increases the yield 3 times?
    - candiodari 7y ago
      Because plants have chosen to specialize into nitrogen-eating and non-nitrogen eating. So in nature there isn't a problem because these plants mix. Grass puts Nitrogen into the soil. There are other plants, but grass is the most well-known. Things like corn or grain take nitrogen out, and use it. In nature these plants grow centimeters apart, so there is no problem. There's a nitrogen cycle. However if you want much denser grain, you can only have grain. So now we've got agriculture, and it requires density. Large plots of land where you've got nothing but grain. Nitrogen goes out, doesn't come back in. Grain grows for 2-3 years, then refuses. It dies, because it cannot use the nitrogen from the atmosphere. It can only get it from the soil. So we found a solution a very long time ago (it's in the bible, surprisingly, although we have figured out slight improvements since then). Do agriculture in a 7 year cycle: leave blank, grain, grass + animals, grain, grass, grain, grass + animals. There are many cycles used in various places, but they're all quite similar. Fertilizer shortcuts the process: so why does it increase the yield 3 times ? Because you can cut out the grass years and the blank years. Not because the plants grow faster, because you can grow 3x as many of them.
lm28469 7y ago
Maybe its inefficiency is necessary. After all earth is a global eco system, it's all about balance, everything is inter connected. What if Rubisco stopped missing 2/3 and never missed instead ? What about the global CO2 levels ? Oxygen ? More plants = more food for some animals &c. This sounds like the typical junior developer starting working on a 20 years old project saying 'Wait a minute, I can rewrite these 50k lines in 500 lines of _insert tech of the day_' while ignoring 20 years of side effects, special cases, well thought decisions, &c.
- eloff 7y ago
  On a long enough scale the carbon we added to the atmosphere will get sequestered again, and using more efficient plants everywhere would cause a swing the other way to a reduction in CO2 and global cooling. That's a much easier and slower problem to deal with though. That would be so far in the future though we can't even imagine what the earth would be like, or what we would be capable of, or what the population would be. Hopefully we decided it was important to leave large natural spaces on the planet.
- ben_w 7y ago
  > After all earth is a global eco system, it's all about balance, everything is inter connected. Unfortunately, evolution doesn’t do balance, but rather local gradient descent. Species reliant on one prey or one plant can and do over-consume their food into extinction and then go extinct themselves. Even the oxygen we breathe was a toxic waste product when the earth was young, and while evolution found a pathway to consuming it, there’s never any guarantee of that. Evolution has had a long time to find solutions, so it shouldn’t be ignored, but it’s also not a particularly smart system and it definitely isn’t directed with long-term goals in mind — evolution can create birds, but not birds which grow their own hypersonic ramjets.
  - beowulfey 7y ago
    Conversely, after the millions of years of evolution, it's not unreasonable to think that creating a more efficient Rubisco could have happened spontaneously in nature by mutation. Our logic suggests this would almost certainly provide some benefit; and yet, nearly all Rubisco enzymes show roughly the same level of efficiency. To me, this implies some other limiting factor that we don't understand.
derefr 7y ago
> will end with nothern russia looking like Florida, and Florida looking like what's 30km east of Florida now. You say that like that’s inherently a bad thing. IIRC (from some other commentor’s previous napkin math), such a change would actually be unlocking a lot more livable/arable land than would be desertified by it. Just counting the tundras in Northern Canada + Northern Russia + Antarctica + Greenland, that’s already more potential arable/livable landmass than the entirety of the US + Europe. What you should probably highlight, if you want to make an argument like this, is the time scale. If that change occurred over ~100,000 years, it’d probably be a great thing for human civilization, and, though it’d kill off a fair number of animal species, there’d also be time for many new adaptations to occur, so overall biosphere diversity wouldn’t be greatly impacted. The Earth would be different, but not necessarily worse. It’s the fact that said change has the potential to occur over only ~100 years, that screws the biosphere (including us) over.
- chimprich 7y ago
  > more potential arable/livable landmass than the entirety of the US + Europe. That's fine if you want to spend trillions moving the cities of Europe and US to Siberia. It would be much cheaper, and require far less political co-ordination, to avert the CO2 emissions leading to climate change in the first place. And even if you do take the incredibly drastic step of moving most of humanity to the Arctic circle, you still have the problem of runaway heating. What are you going to do when the climate changes for the places you have moved to? Besides, I rather like having a range of different biomes available on my planet.
  - pmontra 7y ago
    I'm definitely with you about prevention. > That's fine if you want to spend trillions moving the cities of Europe and US to Siberia. I don't even want to get into thinking why and if Russia [1] would let the people of Europe and the USA in, but that's only about 1 B people. There are many more out there. [1] The Nordic countries and Canada, and probably the south of Chile and especially Argentina, are similarly well positioned.
  - derefr 7y ago

chrisco255 7y ago

Sea levels are rising at 2-3mm a year. That's about a foot of sea level rise per century, assuming some combination of AMO negative phase, PDO negative phase, volcanic activity, geomagnetic reversal, increased cosmic rays and subsequent cloud cover due to increased nucleation and grand solar minimum due in the coming decades doesn't kick off a cooling trend that causes a mini ice age to set in and sea levels to fall, of course.

Majestic121 7y ago
I was surprised by your affirmation, as I had the (apparently wrong) assumption that sea levels would increase by at least a few meter in the century. However, the IPCC (UN group in charge of research for climate change) does predict an increase of ~0.2 to 0.5m (basically a foot) of the sea level in the next century. Here is the source for interested people : https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/faq-5-1.html https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/faq...
- wh1t3n01s3 7y ago
  Subsidence of lands under glaciers limits sea level rising, but not equally on the earth surface
  - mantap 7y ago
    I don't understand how subsidence of land under glaciers limits sea level rise, could you explain it more?
    - yencabulator 7y ago
      Let's try this: If both sea level and ground level move, what their interaction is locally isn't the same as the difference of the global averages.

5efh456 7y ago

Remember when people believed that 90% of DNA is junk? Or that the human appendix is totally useless? Now we know better. So when photosynthesis is "inefficient" after billions years of evolution, surely we would be more careful with the conclusions. "Photosynthesis is only 1% efficient" sounds a bit like "we only use 10% of our brain" (according to some measurement). > Photorespiration wastes little energy and instead enhances nitrate assimilation, the process that converts nitrate from the soil into protein, according to a new study. > Most plants, contrary to popular belief, do not waste over 30% of their photosynthate in a futile cycle called photorespiration. Rather, the photorespiratory pathway generates additional malate in the chloroplast that empowers many energy-intensive chemical reactions, such as those involved in nitrate assimilation. Thus, the balance between carbon fixation and photorespiration determines the plant carbon–nitrogen balance and protein concentrations. https://www.nature.com/articles/s41477-018-0191-0 https://www.nature.com/articles/s41477-018-0191-0

deleted 7y ago
[deleted]

Gatsky 7y ago

Even with some more efficient scheme the problem is scalability. Deploying enough of this altered plant mass to meaningfully reduce CO2 is a real challenge. There is also likely to be huge opposition to injecting GMO plants into the biosphere. I make no judgement on this, just highlighting the issue.

candiodari 7y ago
The main limit on plant growth is exactly that: a shortage of CO2 in the atmosphere. Yes, shortage. Will this actually make a difference with the plants starved of CO2, as opposed to a CO2-enriched atmosphere in the lab ? (obviously I mean from the perspective of a plant that wants to grow faster, what matters from a global perspective can and probably will be different) e.g. https://www.forbes.com/sites/jamestaylor/2012/10/25/contrary-to-what-you-hear-global-warming-has-been-good-to-africa/#2fc5305627f6 https://www.forbes.com/sites/jamestaylor/2012/10/25/contrary...
- 5efh456 7y ago
  If the main limit is CO2, why does adding fertilizer (nitrogen) to a field suddenly increases the yield 3 times?
  - candiodari 7y ago
    Because plants have chosen to specialize into nitrogen-eating and non-nitrogen eating. So in nature there isn't a problem because these plants mix. Grass puts Nitrogen into the soil. There are other plants, but grass is the most well-known. Things like corn or grain take nitrogen out, and use it. In nature these plants grow centimeters apart, so there is no problem. There's a nitrogen cycle. However if you want much denser grain, you can only have grain. So now we've got agriculture, and it requires density. Large plots of land where you've got nothing but grain. Nitrogen goes out, doesn't come back in. Grain grows for 2-3 years, then refuses. It dies, because it cannot use the nitrogen from the atmosphere. It can only get it from the soil. So we found a solution a very long time ago (it's in the bible, surprisingly, although we have figured out slight improvements since then). Do agriculture in a 7 year cycle: leave blank, grain, grass + animals, grain, grass, grain, grass + animals. There are many cycles used in various places, but they're all quite similar. Fertilizer shortcuts the process: so why does it increase the yield 3 times ? Because you can cut out the grass years and the blank years. Not because the plants grow faster, because you can grow 3x as many of them.

lm28469 7y ago

Maybe its inefficiency is necessary. After all earth is a global eco system, it's all about balance, everything is inter connected. What if Rubisco stopped missing 2/3 and never missed instead ? What about the global CO2 levels ? Oxygen ? More plants = more food for some animals &c. This sounds like the typical junior developer starting working on a 20 years old project saying 'Wait a minute, I can rewrite these 50k lines in 500 lines of _insert tech of the day_' while ignoring 20 years of side effects, special cases, well thought decisions, &c.

eloff 7y ago
On a long enough scale the carbon we added to the atmosphere will get sequestered again, and using more efficient plants everywhere would cause a swing the other way to a reduction in CO2 and global cooling. That's a much easier and slower problem to deal with though. That would be so far in the future though we can't even imagine what the earth would be like, or what we would be capable of, or what the population would be. Hopefully we decided it was important to leave large natural spaces on the planet.
ben_w 7y ago
> After all earth is a global eco system, it's all about balance, everything is inter connected. Unfortunately, evolution doesn’t do balance, but rather local gradient descent. Species reliant on one prey or one plant can and do over-consume their food into extinction and then go extinct themselves. Even the oxygen we breathe was a toxic waste product when the earth was young, and while evolution found a pathway to consuming it, there’s never any guarantee of that. Evolution has had a long time to find solutions, so it shouldn’t be ignored, but it’s also not a particularly smart system and it definitely isn’t directed with long-term goals in mind — evolution can create birds, but not birds which grow their own hypersonic ramjets.
- beowulfey 7y ago
  Conversely, after the millions of years of evolution, it's not unreasonable to think that creating a more efficient Rubisco could have happened spontaneously in nature by mutation. Our logic suggests this would almost certainly provide some benefit; and yet, nearly all Rubisco enzymes show roughly the same level of efficiency. To me, this implies some other limiting factor that we don't understand.

derefr 7y ago

> will end with nothern russia looking like Florida, and Florida looking like what's 30km east of Florida now. You say that like that’s inherently a bad thing. IIRC (from some other commentor’s previous napkin math), such a change would actually be unlocking a lot more livable/arable land than would be desertified by it. Just counting the tundras in Northern Canada + Northern Russia + Antarctica + Greenland, that’s already more potential arable/livable landmass than the entirety of the US + Europe. What you should probably highlight, if you want to make an argument like this, is the time scale. If that change occurred over ~100,000 years, it’d probably be a great thing for human civilization, and, though it’d kill off a fair number of animal species, there’d also be time for many new adaptations to occur, so overall biosphere diversity wouldn’t be greatly impacted. The Earth would be different, but not necessarily worse. It’s the fact that said change has the potential to occur over only ~100 years, that screws the biosphere (including us) over.

chimprich 7y ago
> more potential arable/livable landmass than the entirety of the US + Europe. That's fine if you want to spend trillions moving the cities of Europe and US to Siberia. It would be much cheaper, and require far less political co-ordination, to avert the CO2 emissions leading to climate change in the first place. And even if you do take the incredibly drastic step of moving most of humanity to the Arctic circle, you still have the problem of runaway heating. What are you going to do when the climate changes for the places you have moved to? Besides, I rather like having a range of different biomes available on my planet.
- pmontra 7y ago
  I'm definitely with you about prevention. > That's fine if you want to spend trillions moving the cities of Europe and US to Siberia. I don't even want to get into thinking why and if Russia [1] would let the people of Europe and the USA in, but that's only about 1 B people. There are many more out there. [1] The Nordic countries and Canada, and probably the south of Chile and especially Argentina, are similarly well positioned.
- derefr 7y ago