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This isnt completely true. The biggest greenhouse gas CO2 is not a pollutant in any conventional sense. The gas is actually pumped into greenhouses to help pl

This isnt completely true. The biggest greenhouse gas CO2 is not a pollutant in any conventional sense. The gas is actually pumped into greenhouses to help plants grow faster, and helps plants grow in more arid environments, and reduces water consumption by plants. So efforts to reduce CO2 might not bear environmental benefits beyond fighting global warming.

jandrese 4y ago
It's pumped into greenhouses because they have to be sealed to prevent heat from escaping. In nature plants aren't CO2 limited, typically they are either nutrient, light, or usually water limited; and the warming planet is exacerbating water distribution issues. Increasing CO2 does little to increase plant growth because the bottleneck is elsewhere.
- HardlyCurious 4y ago
  Plants lose less water to the environment when CO2 concentrations are higher because they don't have to open their pores as much to effectively breath. That is why CO2 helps plants grow in more arid environments. And CO2 is definitely not pumped into greenhouses to help them stay warm. CO2 is a very weak greenhouse gas, and the tens of vertical feet in a greenhouse couldn't possibly trap any measurable amount of heat from heightened CO2 concentrations. The glass of a greenhouse is responsible for the 'greenhouse' effect, not CO2.
  - jandrese 4y ago
    Heat lost due to convection. Let in cold air and the greenhouse cools off.
    - HardlyCurious 4y ago
      Just to be sure I understand your point. Are you saying they CO2 in as an alternative to having the greenhouse ventilate to the atmosphere? I guess the reason being that the plants would convert all the CO2 to O2 in the greenhouse and then suffocate without the vent or pumped CO2. Is that the most economical way to keep the greenhouse warm enough? There are heat exchangers which are passive devices you can attached to an intake and exhaust to reclaim heat.
      - jandrese 4y ago
        Yes, exactly: https://www.dutchgreenhouses.com/en/technology/co2-enrichment/ https://www.dutchgreenhouses.com/en/technology/co2-enrichmen... Burning gas in the enclosed space not only enriches the CO2, but also warms up the greenhouse even more.
        HardlyCurious 4y ago
        You made it sound like adding CO2 was only a byproduct of an attempt to keep the greenhouse warm, not part of the intention. Yet your source says " The supply of extra carbon dioxide is an often applied method to increase the yield of greenhouse crops." So I'm not sure what your point is.
        jandrese 4y ago
        The point is that adding CO2 is necessary to solve a problem that greenhouses create, the enclosed plants deplete the available CO2 and stop growing. It's not applicable to the world at large. In an open atmosphere plants aren't limited by available CO2, they are limited by sunlight, temperature, soil nutrients, or usually water availability. Adding more CO2 has little to no benefit for the plants.
        HardlyCurious 4y ago
        "Has plant growth increased alongside rising levels of carbon dioxide in the atmosphere? It turns out the answer is Yes – in a big way. A new study published in the April 6 edition of the journal Nature concludes that as emissions of carbon dioxide from burning fossil fuels have increased since the start of the 20th century, plants around the world are utilizing 30 percent more carbon dioxide (CO2), spurring plant growth." - https://www.noaa.gov/news/study-global-plant-growth-surging-alongside-carbon-dioxide https://www.noaa.gov/news/study-global-plant-growth-surging-...
        saalweachter 4y ago
- OrvalWintermute 4y ago
  > In nature plants aren't CO2 limited, typically they are either nutrient, light, or usually water limited; and the warming planet is exacerbating water distribution issues Plants actually require extra water when CO2 levels are low, such as they are currently, which is why we see so much desertification of the planet. High CO2 levels reduce plants need for water, reducing desertification
ben_w 4y ago
OTOH, increased atmospheric CO2 impairs human cognition measurably.
- HardlyCurious 4y ago
  Increased CO2 concentrations do impare human cognition, but that is more about relatively sealed spaces with lots of people like a classroom where CO2 concentrations can be 3 times atmospheric levels or more.
  - ben_w 4y ago
    From what I’ve read, there is enough fossil carbon to raise normal CO2 levels that much. https://phys.org/news/2016-05-fossil-fuels-earth.html https://phys.org/news/2016-05-fossil-fuels-earth.html I expect we don’t go near that number for many reasons, but it is worth including in the cost/benefit calculations.
micromacrofoot 4y ago
Sorry, I should have specified improve the environment for us. Plants have been here before us and will be here after us, they'll be fine.
collyw 4y ago
Water vapor is the biggest greenhouse gas, not C02.
- HardlyCurious 4y ago
  Yes, but we can't do anything about that. So co2 is the most significant that is due to human activities.

jandrese 4y ago

It's pumped into greenhouses because they have to be sealed to prevent heat from escaping. In nature plants aren't CO2 limited, typically they are either nutrient, light, or usually water limited; and the warming planet is exacerbating water distribution issues. Increasing CO2 does little to increase plant growth because the bottleneck is elsewhere.

HardlyCurious 4y ago
Plants lose less water to the environment when CO2 concentrations are higher because they don't have to open their pores as much to effectively breath. That is why CO2 helps plants grow in more arid environments. And CO2 is definitely not pumped into greenhouses to help them stay warm. CO2 is a very weak greenhouse gas, and the tens of vertical feet in a greenhouse couldn't possibly trap any measurable amount of heat from heightened CO2 concentrations. The glass of a greenhouse is responsible for the 'greenhouse' effect, not CO2.
- jandrese 4y ago
  Heat lost due to convection. Let in cold air and the greenhouse cools off.
  - HardlyCurious 4y ago
    Just to be sure I understand your point. Are you saying they CO2 in as an alternative to having the greenhouse ventilate to the atmosphere? I guess the reason being that the plants would convert all the CO2 to O2 in the greenhouse and then suffocate without the vent or pumped CO2. Is that the most economical way to keep the greenhouse warm enough? There are heat exchangers which are passive devices you can attached to an intake and exhaust to reclaim heat.
    - jandrese 4y ago
      Yes, exactly: https://www.dutchgreenhouses.com/en/technology/co2-enrichment/ https://www.dutchgreenhouses.com/en/technology/co2-enrichmen... Burning gas in the enclosed space not only enriches the CO2, but also warms up the greenhouse even more.
      - HardlyCurious 4y ago
        You made it sound like adding CO2 was only a byproduct of an attempt to keep the greenhouse warm, not part of the intention. Yet your source says " The supply of extra carbon dioxide is an often applied method to increase the yield of greenhouse crops." So I'm not sure what your point is.
        jandrese 4y ago
        The point is that adding CO2 is necessary to solve a problem that greenhouses create, the enclosed plants deplete the available CO2 and stop growing. It's not applicable to the world at large. In an open atmosphere plants aren't limited by available CO2, they are limited by sunlight, temperature, soil nutrients, or usually water availability. Adding more CO2 has little to no benefit for the plants.
        HardlyCurious 4y ago
        "Has plant growth increased alongside rising levels of carbon dioxide in the atmosphere? It turns out the answer is Yes – in a big way. A new study published in the April 6 edition of the journal Nature concludes that as emissions of carbon dioxide from burning fossil fuels have increased since the start of the 20th century, plants around the world are utilizing 30 percent more carbon dioxide (CO2), spurring plant growth." - https://www.noaa.gov/news/study-global-plant-growth-surging-alongside-carbon-dioxide https://www.noaa.gov/news/study-global-plant-growth-surging-...
        saalweachter 4y ago
OrvalWintermute 4y ago
> In nature plants aren't CO2 limited, typically they are either nutrient, light, or usually water limited; and the warming planet is exacerbating water distribution issues Plants actually require extra water when CO2 levels are low, such as they are currently, which is why we see so much desertification of the planet. High CO2 levels reduce plants need for water, reducing desertification

ben_w 4y ago

OTOH, increased atmospheric CO2 impairs human cognition measurably.

HardlyCurious 4y ago
Increased CO2 concentrations do impare human cognition, but that is more about relatively sealed spaces with lots of people like a classroom where CO2 concentrations can be 3 times atmospheric levels or more.
- ben_w 4y ago
  From what I’ve read, there is enough fossil carbon to raise normal CO2 levels that much. https://phys.org/news/2016-05-fossil-fuels-earth.html https://phys.org/news/2016-05-fossil-fuels-earth.html I expect we don’t go near that number for many reasons, but it is worth including in the cost/benefit calculations.

micromacrofoot 4y ago

Sorry, I should have specified improve the environment for us. Plants have been here before us and will be here after us, they'll be fine.

collyw 4y ago

Water vapor is the biggest greenhouse gas, not C02.

HardlyCurious 4y ago
Yes, but we can't do anything about that. So co2 is the most significant that is due to human activities.