Ian Bradford: The Importance of Carbon Dioxide

The US Clean Air Act of 1970 defined six Criteria Air Contaminants subject to regulation. They are: particulate matter, ground level ozone, sulphur dioxide, nitrogen dioxide, lead, and carbon monoxide. In 2007 the Supreme Court ruled that “greenhouse gases” were also pollutants. Among them of course was carbon dioxide. So the court ruled that carbon dioxide was a pollutant.

However, the Criteria Air Contaminants are subject to regulatory control because they cause problems depending on their concentrations. These problems may include odour and visibility, damage to plants, and at higher exposure levels, toxic effects in humans. On the other hand carbon dioxide is odourless and colourless, and has no toxic effects at reasonable ambient levels. Carbon dioxide is essential for plant growth through photosynthesis and higher levels encourage more vegetation.

Today’s air contains about 430 ppm (parts per million), of carbon dioxide. This is increasing at the rate of about 1.3ppm per year. A permissible exposure limit has been set by the US Occupational Safety and Health Administration of 5000 ppm over 8 hours. Research from 2002 found that schoolchildren from 120 randomly selected schools in Texas, experienced no ill health when peak carbon dioxide concentrations exceeded 1000 ppm in 88% of the classrooms and 3000 ppm in 21 % of the classrooms. A study from 2021 published in the peer reviewed journal Indoor Air examined the effect of greatly elevated carbon dioxide levels on a broad array of health indicators such as blood chemistry, heart rate, respiratory rate and cognitive ability. The level of Carbon dioxide was increased to 22,000 ppm. Blood pH decreased slightly, but generally, no significant changes were noted. It should be noted also that submariners in the Second World War often had to endure periods where carbon dioxide concentrations were 8,000 ppm.

The increasing amounts of carbon dioxide in the atmosphere promotes plant growth, so we have increasing yields in the agriculture sector. The increasing amounts of carbon dioxide enhances photosynthesis and improves the efficient use of water.

For many years now the Earth has been greening due to increased carbon dioxide. Greening refers to an increase of the Earth’s surface covered by plants. It is quantified by the Leaf Area Index (LAI). The Leaf Area Index is measured by satellite. Zhu et al, from 1982 to 2011 detected greening over 25-50% of the Earth against browning of only 4%. He attributed most of the greening to the increased carbon dioxide concentrations. Zeng et al 2017 noted that greening was mitigating warming.

The colour chart gives the change of leaf area. Dark green means a large change. Any green area means an increase.

Plant models do predict increased photosynthesis because of rising carbon dioxide. Haverd et al 2020, reported a carbon dioxide fertilisation rate much larger than model predictions. He found that carbon dioxide fertilisation had driven an increase in observed photosynthesis by 30% since 1900. This was against just 17% predicted by models. So global models have understated the benefits to crops and agriculture.

Slightly less acreage of grain has been planted in 2017 compared with 1926 but the yield has increased very significantly.

Plants build biomass through photosynthesis. Biomass is the material which the plant is made up of. Photosynthesis is the process that converts carbon dioxide, water and light into sugar.

6 CO2 + 6 H2O = C6H12O6 + 6O2

Carbon dioxide and water, plus sunlight, gives glucose and oxygen. We humans breathe in oxygen and that combines with the glucose in our blood to give us growth and energy. This is respiration. The glucose comes from the foods we eat. We exhale carbon dioxide and water vapour.

An enzyme called Rubisco for short, enables photosynthesis to take place. (An enzyme is a biological catalyst, nearly always a protein, that speeds up specific chemical reactions within living organisms. Enzymes work because they lower the activation energy for a reaction to begin and they can be reused as they are not consumed in the process.)

Photosynthesis takes place when carbon dioxide is available at the surface of the Rubisco enzyme. Here carbon dioxide is converted to a molecule with three carbon atoms and is then incorporated into plant mass. This is called a C3 process. Rubisco is estimated to have evolved about 3 billion years ago.

About 400 million years ago CO2 levels were somewhere between 2000 and 4000 ppm, and for much of the interval from 200 to 50 million years ago was at or above 1000 ppm. However, for the past 40 million years the level of atmospheric CO2 has been steadily declining, reaching as low as 170 ppm during glaciations. It seems plants and animals evolved under much higher levels of CO2 than at present.

Some plants responded to the low CO2 levels during glaciations. They evolved another photosynthesis pathway called C4. Among the C3 plants are wheat, soybeans, and most other crops. C4 plants include maize, sugar cane, millet, sorghum. Below 180 ppm the growth rates of many C3 species are reduced 40-60% or more compared with today’s carbon dioxide levels. Growth stops altogether under experimental conditions of 60-140 ppm. Some C4 plants are still able to grow at levels even as low as 10 ppm but very slowly.

Current levels of CO2 are about 430 ppm. The positive response of plants to extra CO2 is shown below.

The photo on the left is taken with carbon dioxide at the atmospheric level at that time ie 385 ppm. On the right the carbon dioxide concentration has been increased by 450 ppm to 835ppm.

The greening of the Sahel

THE SAHEL IS GREENING

The Sahel is a semi-arid strip bordering the Sahara Desert to the South of it. The area has suffered droughts and famines from the 1960’s through to about 1990. The decrease in rainfall was the problem. This led to droughts. Many residents left for the coast, rather than face famine. However, since about 1980, rainfall has increased. This has caused an increase in growth , which in turn causes more rain. What was barren land before with just rock and sand, is now growing plants. The southern border of the Sahara has been slowly retreating and this is making farming possible in what used to be a very arid region. All regions across the Sahel are greening. Vegetation has increased in Southern Mauritania, parts of Niger, central Chad, Sudan, and some of Eritrea in the past 15 years or so. In addition to the increase in rainfall, the increase in carbon dioxide has also played its part. More carbon dioxide means the stomata in the plants do not have to remain open for as long and so water loss from the plant is reduced. People are now returning to the area. Farming is now viable again.

In the map below the Sahel is shown in orange. The greening of the Sahel and the Sahara is not without precedent. During the Holocene Climate optimum between 9,000 and 4,000 BC temperatures in the optimum may have been somewhere between 2 and 5 degrees C warmer than at present. . The northern part of Africa received abundant rainfall. The Sahara desert was then covered in vegetation and lakes and rivers covered the area.

Studies over the past 60 years show overwhelmingly that plants, especially C3 plants benefit from extra CO2 The growth benefit comes from enhanced photosynthesis and increased water use efficiency.

Plants take in water through the stomata- tiny pores on the undersides of the leaves. When CO2 is scarce the stomata must be open for long periods allowing water to evaporate. Under enriched CO2 the stomata remain closed for longer, and so the plant retains water for a longer period. So water use efficiency is increased. Models predict that drylands would expand under climate warming but current data shows the opposite. Greening is happening even in arid areas. Global water use by plants has not increased even in spite of the increased biomass.

The IPCC has only barely discussed global greening and fertilisation of agricultural crops. They state they have low confidence in the magnitude of the trend towards greening. The Policymaker Summaries, Technical Summaries, and Synthesis Reports do not discuss the topic.

Removing carbon dioxide from the atmosphere- a huge mistake

The Intergovernmental Panel on Climate Change - the IPCC - asserts that limiting global warming to 1.5 Deg C could avert the most catastrophic effects of climate change. In its recent report, it laid out four means of achieving this - all of them rely on removing carbon dioxide from the atmosphere. This is because even if we cut most of our “carbon” emissions down the zero, emissions from agriculture and air travel would be difficult to eliminate altogether. And since carbon dioxide that’s already in the atmosphere can affect climate for hundreds to thousands of years, the IPCC maintains that carbon dioxide removal (CDR) technologies will be critical to get rid of 100 to 1000 gigatonnes of CO2 this century.

Apart from the huge cost of constructing this plant the actual running of the plant is also very expensive.

I have a list of 36 researchers whose research on carbon dioxide in the atmosphere give times between about 5 years to 10 years for carbon dioxide resident in the atmosphere. So on this basis carbon dioxide put into the air today does NOT affect climate for hundreds to thousands of years. It is totally false.

The actual figures for carbon dioxide concentration for the past 72 years give an increase of just 1.3ppm per year. At this rate by the year 2100 we would expect carbon dioxide concentrations to be about 511 ppm. , and by the year 2200 just 641 ppm. We can easily cope with this amount of carbon dioxide. If we start to enter another ice age then levels will drop. So the concentration of carbon dioxide in the atmosphere is not a problem for a very long time - if ever. So removal of carbon dioxide from the atmosphere must be going on because people in authority think humans are causing climate change. It is concerning that NZ is investigating ways to remove carbon dioxide from the air. Do those people really think they can surpass the amount of carbon dioxide that China and India put into the air? It’s all a total waste of money. Money that is needed for hospitals for example. You cannot stop natural processes, but what we need to do if climate is actually changing is adapt to those changes just like our forebears adapted to the ice ages.

Ian Bradford, a science graduate, is a former teacher, lawyer, farmer and keen sportsman, who is writing a book about the fraud of anthropogenic climate change.