Just_a_fan wrote: ↑30 Jan 2020, 02:17
CO2 is needed for plant growth, yes. But it is not a case of "keep adding CO2 and keep getting better results". For one thing, you need to add other nutrients too. For crop species, nitrogen is supplied by fertiliser which of course makes the crop more expensive, but away from fields nitrogen is a limiting factor in plant growth because most plants grow in soils that don't have sufficient nitrogen anyway. These plants won't "benefit" from higher CO2 levels. Oh, and you need more water too, because in order for the CO2 to be used in plant growth, you need water along with the nitrogen (and other things).
Also, whilst crop species grow better with increased CO2, the level of human-required nutrients in those crops decreases to the point that people relying on those crops as a staple food will be malnourished. Protein levels are reduced (protein requires nitrogen and as already noted, nitrogen deficiency is a problem anyway). Essential minerals such as iron and zinc are also available in lower concentrations. In countries that already have high anaemia levels, the problem will be made worse by increased CO2 in the atmosphere. Over a billion people already suffer from anaemia - that number will increase.
The oh-so-simple argument that "plants need CO2 so it's all ok" really does fall apart when the science is looked at. Of course, that's the same for many things where overly simple "sound bites" are used as defence.
what a bunch of condescending and crooked greenist propaganda !
today's CO2 level keeps alive 2 billion people who otherwise wouldn't be here
yes farmers of course support it with nitrogenous growth driver that we call fertiliser and with water
but CO2 is the key growth driver in plants - and it is free to all worldwide
plant growth ie nutrition is the driver of human fertility ie population growth
water is a pressing issue - billions live on food grown using unsustainable water supplies pumped from below ground
btw
greenhouses use a CO2 level of 1100 ppm - production rising in proportion
CO2 level in some airliner cabins overnight higher still - they turn down aircon refresh rate to stretch range
the IAM at Farnborough told me that in some passengers this causes a disruption of their metabolism of alcohol