The Significance of Carbon Dioxide CO2

All plant life and thus the whole biosphere is dependent on atmospheric CO2. At 400 ppmv, (400/1,000,000), CO2 is still a trace gas. It is at a very low concentration when compared with the geologic past. A widely accepted diagram of global temperature and CO2 concentration in the geologic past 600 million years is shown below. Screen Shot 2014-09-17 at 13.42.47 Plants evolved about 500 million years ago, when the CO2 levels were much higher. Increased CO2 levels markedly improve plant growth and reduce their water requirements for transpiration, as plants need fewer and smaller, water releasing, stomata to ingest their essential CO2. Plants cannot survive at CO2 levels of less than ~200 ppmv and are stressed by low CO2 levels. Horticulturalists deliberately add extra CO2 to their greenhouses up to a level of some 1200 ppmv to enhance plant growth and fertility. It is estimated that the CO2 increases since 1850 have already enhanced all planetary plant growth and promoted greening of deserts by ~15%. In the past the world has seen much higher CO2 levels that were not necessarily associated with higher temperatures.

Whatever politicians and Global Warming advocates may think, promote with extreme alarm and may be convinced of, atmospheric CO2 is “clean”, essential to life and is anything but “a pollutant”.

So atmospheric CO2 is the essential plant food and is thus fundamental for all life on the planet.

That is the real stuff of life. Global Warming advocates who deny that also negate the ability of the world’s entire biosphere to exist on planet earth.

Photosynthesis in plants consists of chemical reactions that use atmospheric carbon dioxide (CO2) and water (H2O), catalysed by chlorophyll to store the sun’s output as chemical energy, initially in the form of sugars. This chemical reaction then leads onto all the other organic compounds within the biosphere. The Oxygen (O2) essential for animal life is a by-product of photosynthesis and is released into the atmosphere. The following equation summarizes photosynthesis:  

                           sun light                                                           


                          6 CO2 + 6 H2O    =  6 (CH2O) + 6 O2


                          sugars, thus leading to all other organic molecules

This amazing, almost miraculous, photosynthetic process has been working for half of the existence of the Earth, about 2.5 billion years. Land plants however have only existed for about a half billion years.

Photosynthesis is quite inefficient. Plants only absorb and convert about ½% to ¼% of the sun’s energy falling on their leaves. Geologic processes have created fossils fuels over many millions of years, and concentrated the energy from that inefficient photosynthetic process and stored it in accessible forms gas, oil, coal, etc.

But it is as if many western politicians, much of the scientific establishment, and all Green Global Warming advocates have all collectively and conveniently forgotten all their elementary school biology about photosynthesis and the carbon cycle. As a result of the failure to appreciate the elementary biology, the Western world has been forced into a massive guilt trip with endless predictions of impending global overheating catastrophes from the over-production of CO2 by mankind.

In reality any added atmospheric CO2 is just essential and increasingly useful food for plants.

Mankind’s use of fossil fuels simply releases the very diffuse and intermittent energy derived from sunlight by plants in previous eons. The release of CO2 back into the biosphere now is to the benefit of all plant life and thus to the livelihood of the planet. With the increase from ~300ppmv to ~400ppmv it has been assessed that planetary plant life has already increased by >10% worldwide. As an aside, this means that:

  • Carbon Capture and Storage, CCS, is a chemically difficult and very costly way to try to trap and to throw away comparatively miniscule quantities of useful plant food.
  • as opposed to taking the simplistic view that the fuel itself is for free, it is not evident that renewable energy technologies (solar or wind power) are necessarily that “clean”, non polluting and produce less CO2 for the equivalent energy output, when compared to fossil fuel use and viewed in the round.

Geophysical Research Letters Volume 40, Issue 12, Article first published online: 19 JUN 2013


One thought on “The Significance of Carbon Dioxide CO2

  1. Pingback: Ed Hoskins – a series of articles worth reading | Scottish Sceptic

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