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What's perhaps more alarming in the original paper [0] is that earthworms were shown to increase nitrous oxide (N2O) emissions even more than they increased CO2

What's perhaps more alarming in the original paper [0] is that earthworms were shown to increase nitrous oxide (N2O) emissions even more than they increased CO2 emissions from soil (42% and 33%, respectively). In terms relevant to the greenhouse effect, N2O is 298 times more potent than CO2 in the atmosphere [1]. I wonder about how increasing the entire boreal forest's emissions of N2O by 42% would affect the current projections. Seems...bad. There's perhaps a silver lining here though: earthworms "unlock" stored nutrients in soils, making them easier for plants to access. This might spur growth, thereby storing atmospheric carbon in the process. [0]: https://www.nature.com/articles/nclimate1692 https://www.nature.com/articles/nclimate1692 [1]: https://www.epa.gov/ghgemissions/overview-greenhouse-gases https://www.epa.gov/ghgemissions/overview-greenhouse-gases

whatshisface 7y ago
According to this paper, about 10,000 times as much CO2 is emitted by the forest floor than N2O. So, even though N2O is more potent, the CO2 is a bigger deal (and changes in it are therefore a bigger deal as well). https://academic.oup.com/forestry/article/90/4/541/3064404 https://academic.oup.com/forestry/article/90/4/541/3064404 See table 4. Note that NO2 efflux is measured in mg and CO2 is measured in g.
- tony_cannistra 7y ago
  Hey, thanks for that reference. You're right, but the 300x potency of N2O vs CO2 and the sheer unknowns lurking in our understanding of the "earthworm problem" still make this worth investigation, in my opinion. Additionally, at the risk of being pedantic and because I'm a stuck-up academic, I want to point out that your reference is studying a temperate forest. This is relevant not only because species composition and climatic regimes present in temperate forests (decidious trees, high species diversity, high nutrient availabilty, moderate climates) differ markedly from those of boreal forests (coniferous trees, low species diversity, low nutrient availability, extreme climatic seasonality). There's good reason to believe that this difference has a corresponding shift in the GHG emission regimes of the respective forestlands, which you can see here [0]. Additionally, boreal forests are the earth's largest terrestrial ecosystem [1], which makes this potential difference quite relevant. Your point is well taken, though -- it's important to triage effort in facing a complicated global challenge. [0]: https://www.nrcresearchpress.com/doi/10.1139/X08-209#.XOLSAFNKjOY https://www.nrcresearchpress.com/doi/10.1139/X08-209#.XOLSAF... [1]: https://en.wikipedia.org/wiki/Taiga https://en.wikipedia.org/wiki/Taiga
seren 7y ago
It depends on how big is the base rate of emission of N2O for boreal forest, if it was negligible before an increase of 42% is certainly not good but might not be catastrophic.

whatshisface 7y ago

According to this paper, about 10,000 times as much CO2 is emitted by the forest floor than N2O. So, even though N2O is more potent, the CO2 is a bigger deal (and changes in it are therefore a bigger deal as well). https://academic.oup.com/forestry/article/90/4/541/3064404 https://academic.oup.com/forestry/article/90/4/541/3064404 See table 4. Note that NO2 efflux is measured in mg and CO2 is measured in g.

tony_cannistra 7y ago
Hey, thanks for that reference. You're right, but the 300x potency of N2O vs CO2 and the sheer unknowns lurking in our understanding of the "earthworm problem" still make this worth investigation, in my opinion. Additionally, at the risk of being pedantic and because I'm a stuck-up academic, I want to point out that your reference is studying a temperate forest. This is relevant not only because species composition and climatic regimes present in temperate forests (decidious trees, high species diversity, high nutrient availabilty, moderate climates) differ markedly from those of boreal forests (coniferous trees, low species diversity, low nutrient availability, extreme climatic seasonality). There's good reason to believe that this difference has a corresponding shift in the GHG emission regimes of the respective forestlands, which you can see here [0]. Additionally, boreal forests are the earth's largest terrestrial ecosystem [1], which makes this potential difference quite relevant. Your point is well taken, though -- it's important to triage effort in facing a complicated global challenge. [0]: https://www.nrcresearchpress.com/doi/10.1139/X08-209#.XOLSAFNKjOY https://www.nrcresearchpress.com/doi/10.1139/X08-209#.XOLSAF... [1]: https://en.wikipedia.org/wiki/Taiga https://en.wikipedia.org/wiki/Taiga

seren 7y ago

It depends on how big is the base rate of emission of N2O for boreal forest, if it was negligible before an increase of 42% is certainly not good but might not be catastrophic.