I asked this question about a year ago, but surprisingly for me, it did not generate any particular interest. Because of that and because of the fact that I consider it important, I am repeating it once again in the hope that this time the interest will be greater. Some researchers believe that approximately 0.045% by volume is the maximum more or less acceptable concentration of CO2 in the atmosphere. According to them, a concentration of CO2 above that level would be disastrous for living conditions on planet Earth. Knowing that without carbon dioxide, vegetation would die out in an extremely short time (along with animals and humans), the question is, what is the minimum necessary concentration of CO2 in the atmosphere?
Dear Risto,
just for the purpose of clarification: Are you inquiring about the minimum concentration of carbon dioxide in the atmosphere necessary to sustain life on Earth IN GENERAL or just about the amount of atmospheric CO2 needed for a minimal number of plants/a rudimentary vegetation cover to survive on this planet?
Best,
Julius
An experimental estimate is available that plants need a minimum of 150ppm of CO2 to grow. Ref: Dippery et al. (1995). "Effects of low and elevated CO2 on C3 and C4.". Oecologia, 101, 13-20, (1995), Springer-Verlag.
"Dippery et al. (1995) found the most extreme response, where low [CO2] (150 ppm) prevented reproduction in the modern C3 annual, A. theophrasti, as a result of the abortion of all flower buds that drove the fitness response to zero. This finding suggested that 150 ppm CO2 may be near the threshold for successful completion of the life cycle in some C3 species (not necessarily C4 species)".
The more CO2 they get the less water they need and vice versa.
Commercial greenhouses sometimes up the amount of CO2 in the greenhouse to 1,000 – 2,000 ppm for optimal plant growth.
In: "The Case for Increasing Atmospheric CO2" by Robert Fagan, https://www.dr-robert-fagan.com/posted-articles
Dear Julius Riese,
Thanks, a very important note. Actually, both. However, I am primarily interested, at least, in what is the minimum concentration of carbon dioxide in the atmosphere that is sufficient to sustain life in the form at least approximately as we know it today.
The minimum co2 concentration at the surface to support photosynthesis is 150-200 ppm. Goals of "Climate Scientists" to reduce co2 by half is ecological suicide. Co2 is the source of all life through endothermic photosynthesis and increasing it is the key to sustainability by increasing food production through endothermic photosynthesis. Warming and droughts are due to reduced plant life due to development and pollution, mainly as a result of reduced transpiration (water evaporation and evaporative cooling from land by plant life). See https://www.coatsengineering.com/climate.htm for a number of white papers on these subjects and references to discussions in which it is heavily censored by the fraudulent.
Beyond that, incident and reflected solar at the surface is about 55% infrared radiation, which very simply disproves the greenhouse gas global warming theory. Solar is not all visible light that is transformed by surface absorption and then cooling by blackbody emission of infrared radiation that is then increasingly trapped in the atmosphere by increasing co2! The earth's surface cools by conduction to the atmosphere and then convection within it, not blackbody emission. Every process engineer on earth knows that.
There are many more obvious proofs that co2 emissions are not causing warming. Look at the infrared absorbance spectra of water vapor (at lab conditions saturated water concentration is around 2%) and see how the fields of atmospheric and climate science compare it to measured co2 absorbance at a concentration of 33%, as shown by the NIST spectra in our national database (see my paper on atmospheric infrared absorption and references given on the climate web page). Beer's law says that the co2 absorbance must be scaled down by the ratio of atmospheric to sample concentration, about .0004/.33 = 1/825. Methane is even more insignificant in the troposphere where water exists. It's absorbance is overrepresented in the literature by about 40,000. Co2 and Methane are very dilute and harmless trace gases in the atmosphere. That should be obvious to any compentent person from its atmospheric concentration alone, about 2 ppm. Obviously, a component with 0 concentration has 0 affect on any fluid property or behavior.
Dear Risto,
many thanks for the clarification. I was just wondering: Is your query related to astrobiological research you are conducting? The question of a minimum atmospheric CO2 concentration required to sustain biota - or life more generally - as we know it, clearly is highly relevant in exobiological research, such as in investigating the atmospheres of exoplanets in search for potential "biosignatures". Just interested...
Best,
Julius
The current level is 0.04%, it has risen from 0.03% over the last few decades. At below 0.02%, plant life begins to die. The solution to the world's ills is a drastic reduction in consumption, not carbon taxation. Polluter pays does not work because the costs of fines are just passed on to the consumer, because this is how capitalism works. The central banking cabal is getting nice and rich off carbon trading though, so at least we can console ourselves with that.
- Badges
- Science topic
- Similar topics
- Geoscience
- Atmospheric Sciences
- Atmosphere