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.
10 comments:
The last paragraph should be in bold lettering! The money that is spent on trying to adapt nature to suit human habitation, pure folly.
Another great article, Ian. Sadly, Luxon will not read it.
It seems incredible, but I suspect our ‘leaders’ actually know all this. The attack on carbon dioxide simply follows the same pattern of the attacks on all other aspects of our civilisation. The perpetrators must be very certain of a safe bolt-hole somewhere.
I Totally agree the Carbon con it should be known as is a gip, better to adapt and harden the grid incase of solar flare or magnetic field changes
Further evidence that the ignorant continue continue to ignore!
And of course Trump has been vilified in the press for saying climate change is a big con job. Possibly should have said "climate alarmism" instead of climate change
No carbon dioxide, we all die. Baldrick, I have a cunning plan....
Ian, re the list of researchers and your 5 year C02 retention period, I thought was framed to illustrate why loading more and more C02 into the air would be highly beneficial and 'does not affect climate for hundreds to thousands of years.' Therefore, (but depending on whether or not you were aware of this) a classic DDBO appears evident here. You are correct that a single CO2 molecule may only last that long, but the other side is that there is a clear consensus that human induced emissions have been largely instrumental in raising atmospheric C02, from 280ppm in the pristinocene - just 350yo to 430 today (50% increase).
Via the carbon cycle, about a third of our total CO2 has been absorbed into sea (and fresh) water and to a depth of some 600m. And incidentally, ocean acidity is now becoming a huge problem especially since a tipping point was reached this year (not reported by the media of course).
And here is an equally serious question: if all pollution was stopped today, how many years would it take for the atmospheric CO2 to return to 280ppm (the naturally evolved concentration)? Variously the answer is from 1000 to 4 - 10000yr. Modern Humans have amassed about 400 generations so far, but after just 350 years what have we done that will affect the next 400?
Jon
Reply to Jon: suppose we are filling a container with water. The inflow pipe is 100mm diam. and there is an outflow pipe of 50mm diameter. Water is leaving the container through the 50 mm pipe but the tub will continue to fill as the 100mm pipe overwhelms the 50mm pipe. Same in the atmosphere. the amount of CO2 leaving the atmosphere is overwhelmed by the amount entering the atmosphere. so carbon dioxide will build up in the atmosphere even though some leaks out after five years. Yes, more CO2 is beneficial. Carbon dioxide does not cause climate change. Even in next thousand years it will not cause climate change. You use the word consensus. Consensus isn't science and science isn't consensus. That's been said a thousand times.
not sure where you got the figure of 1/3 from. The fact is about 60% of all carbon dioxide is in the oceans. The oceans have been alkaline for some 600 million years and warmer water holds LESS carbon dioxide so the present spate of carbon dioxide is coming out of the oceans . They are still alkaline. The IPCC stated that since the industrial revolution the pH of the oceans has fallen from 8.3 to 8.2. I presume you understand pH. That is a 1% reduction in alkalinity. It is NOT an increase in acidity! Ocean acidity is NOT a problem. How many years do you think it will take to pass the 7 pH mark for the oceans, if the fall in about 170 years is only 1%?
Finally. "If all pollution was stopped today" Carbon dioxide is NOT a pollutant. A gaseous pollutant is one which does harm to humans, animals, and plants. Carbon dioxide does no harm to any of those. Why would you want to return to 280ppm? We need more CO2 for extra plant growth to feed the growing world population. Life thrived in the past with carbon dioxide as high as 7000ppm.
Response to Ian
1) Re consensus I was of course meaning 'Scientific' not public opinion.
2) My '30%' of total human emissions absorbed by the oceans was a bit high, its actually 25 - 30%.
3) Yes I am very familiar with pH and acidity, but I'm unsure if you are?:
a) pH is a linear scale from 0 to 6.999 (being increasingly less acidic), 7 is neutral (neither acidic or nor alkaline) and with 7.001 to 14 being increasingly alkaline. It stands for potential Hydrogen (H+) meaning that H protons in the form of Hydronium (H3+) at pH 7 (neutral) are balanced with the same number of hydroxyl ions. Acidity begins when Hydronium ions predominate (decreased hydroxyl ions) and alkalinity, when hydroxyl ions predominate and hydronium ions are decreased. So pH is entirely dependent on the number/ratio of hydronium/hydroxal ion concentrations and because this scale is exponential, pH must first be converted to these units before a decreased percentage in alkalinity or increase in acidity can be determined. The difference between preindustrial ocean pH of 8.2 (not 8.3) and down to 8.04 in 2024 (2% reduction) is actually equivalent to an acidity increase of almost 45%.
4) Alkalinity is simply the opposite of acidity i.e. above or below pH 7 - they are inextricably connected and so increasing ocean acidity is the elephant in the room. Every organism has its own (fixed - as it was in the pristinocene) pH requirement. It plays a vital role in shellfish health relating to their ability to form strong calcium containing shells. Ocean Acidity IS the main problem.
5) The above signals just why we need to engineer a return to 'pristine' levels of atmospheric CO2 because it is this excess, caused by Humans over just 350 years, that are acidifying our oceans and freshwater resources (by the turn of the century ocean pH is predicted to fall to 7.7).
The question is: At '7000 ppm' atmospheric CO2, plant growth may well be enhanced but at such a high acidity, that few species as we know them today, would survive and our present food chain could be irrecoverably doomed.
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