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Are you aware of how CO2 is used by plants? that's a "hidden" benefit of the large-scale use of fossil fuels. At current CO2 levels plants are starved for CO2.
by mkempe 9y ago
Are you aware of how CO2 is used by plants? that's a "hidden" benefit of the large-scale use of fossil fuels.
At current CO2 levels plants are starved for CO2. At 150 ppm there would be a massive extinction of land-based plant life.
- QasimK 9y agoIs this some kind of a joke? Global warming, full stop. Plants are not starved, they were ubiquitous until we chopped “most” of them down.
- mkempe 9y agoIt's science. Land-based plants evolved when CO2 levels were much higher than today. [1] In fact levels have been steadily declining from 3000 ppm 150 million years ago; the current, holocene rise is a relatively minor bump. [2] [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692178/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692178/ [2] http://caos.iisc.ernet.in/faculty/pghosh/content/Publications/19.pdf http://caos.iisc.ernet.in/faculty/pghosh/content/Publication...
- mkempe 9y agoAnd by the way global temperature 150 million years ago was the same as today, +/- 2deg C.
- chiefalchemist 9y agoCould be. But the bio-make up of the planet was different then, yes?
- 24gttghh 9y agoI don't think plants are "starved" for CO2, and increasing levels of CO2 most likely do not linearly increase productivity of plants [0]. There's also the other ramifications of increased CO2 concentration like: ocean acidification, warmer overall climate globally and increased incidences of severe weather, rising seas resulting from the warmer temperatures, and not all plants will enjoy the higher temperatures (or the droughts, hailstorms, strong winds, too much rain all at once), especially those in the tropics which already get quite warm. >Our results suggest that future climate change will push this ecosystem away from conditions that maximize NPP, but with large year-to-year variability [0]http://www.pnas.org/content/pnas/early/2016/08/30/1606734113.full.pdf http://www.pnas.org/content/pnas/early/2016/08/30/1606734113... edit: less blunt.
- mkempe 9y agoIf you reject the fact that the vast majority of plants are currently starving for CO2, you reject science. Here is one of many scientific papers on the subject: "Carbon dioxide starvation, the development of C4 ecosystems, and mammalian evolution" [1] [1] http://rstb.royalsocietypublishing.org/content/353/1365/159 http://rstb.royalsocietypublishing.org/content/353/1365/159
- 24gttghh 9y agoI don't think you are reading the studies you are sharing. >Global expansion of C4 biomass is recorded in the diets of mammals from Asia, Africa, North America, and South America during the interval from about 8 to 5 Ma. That's a 3 million year period, ending 5ma. You say CO2 starvation is down to 150ppm, but atmospheric CO2 levels have fluctuated between 180-200 (ice ages) to 300ppm (warm periods) for the past half million years or so.[1] Meanwhile C3 plants (those supposedly which suffered during your linked expansion of C4 biomass) are around 95% of plant biomass currently. Doesn't seem like plants on the whole are starving for CO2 at this time. [1]https://climate.nasa.gov/climate_resources/24/ https://climate.nasa.gov/climate_resources/24/
- mkempe 9y ago> I don't think you are reading the studies you are sharing. I'm impressed by your method of argumentation.
- 24gttghh 9y agoWhat I mean to say is there is more to the data than any single paper, and with a bigger picture in mind there seems to be no shortage of CO2 for 95% of plants on earth(C3 carbon fixation, evolved earlier), and for the other 5% (C4 carbon fixation, evolved more recently) they can be fine in a much greater range of CO2 concentrations.
- mkempe 9y ago
- chiefalchemist 9y agoPerhaps that's true. I appreciate the insight. However it doesn't really address my point, as it was directed at another comment.