5 ms·

A number of problems with this method of study, and the headline is misleading. The real question is whether there will be more biomass and more photosynthesis

by nwah1 8y ago

A number of problems with this method of study, and the headline is misleading. The real question is whether there will be more biomass and more photosynthesis in response to more CO2, not whether individual trees grow more. The climate skeptics don't say tree trunks will get wider, they say there will be more plant biomass. And also this is adding in confounding variables and saying more CO2 could change precipitation in certain places, and thus cause lower growth. Other studies that show more growth with more CO2 are using greenhouses to control for confounding variables. And even if you are trying to answer the question in terms of a holistic analysis, you can't just study one forest in Canada and then make any kind of conclusion. You'd need to study trees from most of the major forests, and look at the density of the foliage in each.

amvalo 8y ago
> The climate skeptics don't say tree trunks will get wider, they say there will be more plant biomass. Speculating that plant biomass might help mitigate global warming doesn't really deserve the label "climate skeptic." It's already confirmed that rising CO2 affects crop growth rates.
- nwah1 8y ago
  What do you mean by mitigate global warming? I think what they argue is that there will be winners and losers, and it isn't some kind of black and white issue. For instance, the Saharan desert seems to be greening.
  - saalweachter 8y ago
    > For instance, the Saharan desert seems to be greening. I hadn't heard about that, and my first few Googles came back without any good, definitive articles; do you have more information?
    - mrpopo 8y ago
      It's not. It's a false claim from climate skeptics based on this study: https://www.nature.com/articles/s41467-018-04616-8 https://www.nature.com/articles/s41467-018-04616-8 The study is about sub saharan Africa, mostly the African savanna, and the identified drivers are human causes (decline in burned area, changes in herbivores density). They explicitly exclude CO2 levels increase as a driver.
      - nwah1 8y ago
        >Factorial simulations with multiple global ecosystem models suggest that CO2 fertilization effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (LCC) (4%). https://www.nature.com/articles/nclimate3004 https://www.nature.com/articles/nclimate3004
        mrpopo 8y ago
        I acknowledge that CO2 contributes to fertilisation. I was refuting the claim about the saharan desert. Your new link doesn't seem to contradict me : > CO2 fertilization effects explain most of the greening trends in the tropics
        nwah1 8y ago
        Yes, I accept your correction. I accept that the Saharan desert may be greening primarily for other reasons. It seems to have been on a long term trend towards greening irrespective of the Industrial Revolution, and there are other human activities that are greening it. Although, your link does leave open the possibility that rising CO2 explains up to 22% of the greening in the Sahara.
        saalweachter 8y ago
        Incidentally the second (earlier) paper is cited by the first (newer) paper, so hopefully they are not in contradiction (since it was merely referenced and not responded to).
  - Dylan16807 8y ago
    'mitigate' in this case means that some extra carbon gets captured, slowing whatever happens down. It's unrelated to the specific positives and negatives.
hinkley 8y ago
Several of the reports I've seen have said we will get more biomass, but most of it will be plants we generally refer to as weeds.
- nwah1 8y ago
  Makes sense, considering that most of the plants we have already match that description.
  - hinkley 8y ago
    Most of the plants in residential areas, sure (but only if you think grass is a weed). Not so much in reasonably well-run parks or woodlands.
- rawland 8y ago
  "It is estimated that between 50% and 85% of the world's oxygen is produced via phytoplankton photosynthesis." Most 'plants' are in the water. source: https://en.wikipedia.org/wiki/Phytoplankton https://en.wikipedia.org/wiki/Phytoplankton
porpoisely 8y ago
This is what I dislike about the politically driven climate "science" or any science corrupted by politics. So much of it is intentionally misleading and many times outright false. They manipulate data, cherrypick time frames or simply outright lie. The problem is exacerbated by the fact that special interest groups fund these misleading studies and are widely propagated by media with a particular interest.

by nwah1 8y ago

amvalo 8y ago

> The climate skeptics don't say tree trunks will get wider, they say there will be more plant biomass. Speculating that plant biomass might help mitigate global warming doesn't really deserve the label "climate skeptic." It's already confirmed that rising CO2 affects crop growth rates.

nwah1 8y ago
What do you mean by mitigate global warming? I think what they argue is that there will be winners and losers, and it isn't some kind of black and white issue. For instance, the Saharan desert seems to be greening.
- saalweachter 8y ago
  > For instance, the Saharan desert seems to be greening. I hadn't heard about that, and my first few Googles came back without any good, definitive articles; do you have more information?
  - mrpopo 8y ago
    It's not. It's a false claim from climate skeptics based on this study: https://www.nature.com/articles/s41467-018-04616-8 https://www.nature.com/articles/s41467-018-04616-8 The study is about sub saharan Africa, mostly the African savanna, and the identified drivers are human causes (decline in burned area, changes in herbivores density). They explicitly exclude CO2 levels increase as a driver.
    - nwah1 8y ago
      >Factorial simulations with multiple global ecosystem models suggest that CO2 fertilization effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (LCC) (4%). https://www.nature.com/articles/nclimate3004 https://www.nature.com/articles/nclimate3004
      - mrpopo 8y ago
        I acknowledge that CO2 contributes to fertilisation. I was refuting the claim about the saharan desert. Your new link doesn't seem to contradict me : > CO2 fertilization effects explain most of the greening trends in the tropics
        nwah1 8y ago
        Yes, I accept your correction. I accept that the Saharan desert may be greening primarily for other reasons. It seems to have been on a long term trend towards greening irrespective of the Industrial Revolution, and there are other human activities that are greening it. Although, your link does leave open the possibility that rising CO2 explains up to 22% of the greening in the Sahara.
        saalweachter 8y ago
        Incidentally the second (earlier) paper is cited by the first (newer) paper, so hopefully they are not in contradiction (since it was merely referenced and not responded to).
- Dylan16807 8y ago
  'mitigate' in this case means that some extra carbon gets captured, slowing whatever happens down. It's unrelated to the specific positives and negatives.

hinkley 8y ago

Several of the reports I've seen have said we will get more biomass, but most of it will be plants we generally refer to as weeds.

nwah1 8y ago
Makes sense, considering that most of the plants we have already match that description.
- hinkley 8y ago
  Most of the plants in residential areas, sure (but only if you think grass is a weed). Not so much in reasonably well-run parks or woodlands.
rawland 8y ago
"It is estimated that between 50% and 85% of the world's oxygen is produced via phytoplankton photosynthesis." Most 'plants' are in the water. source: https://en.wikipedia.org/wiki/Phytoplankton https://en.wikipedia.org/wiki/Phytoplankton

porpoisely 8y ago

This is what I dislike about the politically driven climate "science" or any science corrupted by politics. So much of it is intentionally misleading and many times outright false. They manipulate data, cherrypick time frames or simply outright lie. The problem is exacerbated by the fact that special interest groups fund these misleading studies and are widely propagated by media with a particular interest.