About 3.6 - 4% of CO2 is present in exhaled air, however, these may be offsets by huge numbers of plants (70% of forest cover (land) in Bhutan) undergoing photosynthesis.

You are right of course Razieh-Mirsafaei, in a way, I taught the same analogy to my students, but that is a existential fact, there is no other way. At the same time what bothers that, the human derived systems in the name of science as vehicles, space craft, air conditioners and many many non-biodegradable materials add more fuel to it, at the same time we destroyed the natures' recycle mechanisms too as deforestation, nearly more than 11%. What we need to question ourselves is that whether we are really compassionate and grateful to this existential fact. We need to build a new Science which will protect, because science without love is blind and it will ruin society. When we learn science with love and compassion, the nature will bring more showers.It is a high time we need to change our direction of science.

Razieh Mirsafaei

This is a very interesting question that most of us seem to have ignored. According to an article in Science Focus the CO2 we produce through breathing comes from the carbohydrates that plants manufacture from CO2 that they absorb from the atmosphere. That means we are not adding any extra CO2.

For more details please see https://www.sciencefocus.com/planet-earth/how-much-does-human-breathing-contribute-to-climate-change/

The carbon dioxide we exhale does not contribute to global warming for the simple reason that we also take up an equivalent amount of carbon dioxide from the air, albeit indirectly. Everything we eat can be traced back to photosynthesis, the process by which plants take up carbon dioxide from the air and use it to produce the vast array of organic compounds needed for life. Our bodies can be regarded as living engines that require fuel and oxygen to produce the energy needed to sustain life. In that sense, we are not all that different from a car. Both for us and for the car, the source of oxygen is the air, roughly 20 per cent of which is made up of oxygen. An internal combustion engine burns gasoline and spews out water, carbon dioxide and a few combustion byproducts. We, instead of gasoline, burn the carbohydrates, fats and proteins in food. Like gasoline, these organic compounds are converted to carbon dioxide and water, which we then exhale.

How is it, then, that we don’t worry about the massive amounts of carbon dioxide that are released with every breath taken by the billions and billions of people and animals that inhabit the world? Because every atom of carbon in the exhaled carbon dioxide comes from food that was recently produced by photosynthesis. Everything we eat, save for a few inorganic components like salt, was in some way produced by photosynthesis. This is obvious when we eat plant products such as grains, fruits and vegetables, but of course it is also the case for meat. The animals we eat were raised on plant products. Indeed, a growing animal is basically a machine that converts plants into flesh. So, since all the carbon dioxide we exhale originated in carbon dioxide captured by plants during photosynthesis, we are not disturbing the carbon dioxide content of the atmosphere by breathing.

On the other hand, when we burn fossil fuels such as gasoline, we are releasing carbon dioxide that forms from carbon atoms that had been removed from the atmosphere millions and millions of years ago by photosynthesis and had then been sequestered in the coal, petroleum and natural gas that forms when plants and animals die and decay. By burning these commodities, we are increasing the current levels of carbon dioxide. Clearly, then, by living and breathing we are not contributing to global warming through the release of carbon dioxide. But can we help reduce global warming by dying? Probably. We no longer exhale carbon dioxide and it will be a long time before the carbon atoms in our body eventually make it back to the atmosphere as carbon dioxide. Of course, there are always plenty of new babies who start to respire as we expire.

Dear Razieh,

Very interesting discussion! If we want to remove CO2 from the atmosphere, organisms, which all depend on CO2, which is needed for carbohydrates, fatty acids, amino acids, nucleo acids and so on, must be completely removed from the biosphere, which can by done by storing dead plants or animals deeply in the earth crust, causing carbon C formation due to the disintegration of organic matter:

Organics -> Peat -> lignite (brown coal) -> bituminous -> anthracite

Thus, under the impact of pressure and temperature, water is removed and thus carbon C remains, while this process most effectively reduced the CO2 concentration of Earth's atmosphere in the carbon age. It is assumed that in this period large amount of plants were deposited in swamps, which also caused the increase of the O2 concentration.

Thus from my point of view, we need to plant trees or should try to enhance the global biomass, while we should allow that a fraction of the biomass after end of life (e.g. our dead bodies) is deposited deeply under the ground where CO2 release is hampered while carbon C formation is promoted.

All the best,

Thomas

it appears that as the population has increased over the years so has the CO2 LEVEL. THE AVERAGE PERSONS TEMPERATURE IS 36.5C compared to average temperatures of 25C. Surely this can explain increasing "warming".

Also there are 74 billion trees increasing at the rate of 180 per year per person. Could this help with decreasing CO2 LEVELS AND IF NOT WHY NOT?

The important calculation that has not been made is the fossil fuel CO2 production in manufacturing the "different" sources ENERGY of wind and solar machines, as well as their maintenance and replacement! How and with what do you lubricate wind turbines!

We need an ENERGY COST BENEFIT ANALYSIS. WE NEED BASE ENERGY TO START MANUFACTURE.

THE SIMPLE FORMULA IS

BASE ENERGY< ENERGY PRODUCED BY "ALTERNATIVES"

IF THIS IS SO THERE IS LITTLE TO DISCUSS.

Dear Dr M.J.Cross, while thinking of population we unknowingly neglect many living beings those were extinct now, There could be balance between the ecosystems in total, however I am quite unaware of ecosystems.