“say, doesn’t co2 kill plants??????”

While I have been taking a look at Aspergers, and describing some of my experiences and coping methods that worked for me, I have neglected a number of other very important topics. 

For example, I have promised to post on the topic of the climate.  And I promised that I would provide some solid information about why I hold the views I do.  Thus, I was preparing something on this. 

Alas, it is difficult to assess the information one is provided if one is not familiar with the underlying science behind the words.  More and more of what I have been reading from non-scientific (that is, MSM (main stream media) and many blogs, debating sites etc. – you know, all them places that have replaced the ‘watercooler chat’) has convinced me that before I can hope to provide useful information, it will be necessary to log in some explanations first.

As if to convince me that I ought to do this, in a coment on this post on a dime a dozen blog , somebody asked the following question: 

“say, doesn’t co2 kill plants??????”

I thought this question needed to be addressed, the sooner the better.  Here is my (somewhat expanded) answer:

No.  CO2 does NOT kill plants.  Nor is it pollution!  It is plant food, and what plants use to make food for us.

There are 2 basic ‘gas exchange’ processes that occur in plants:  breathing (respiration) and photosynthesis.


Why breathe?  What is the purposeENERGY!!! 

To carry out the process of living, all cells need energy.  That is why we – and plants – need to breathe 24 hours a day.  So how do we get energy by breathing in oxygen?

An oxygen molecule is made up of two oxygen atoms  (hence O2 – the 2 means the molecule is made up of 2 oxygen atoms).  These two atoms are held together by a ‘bond’ – breaking this bond releases energy.  But an oxygen atom by itself has a strong ‘need’ to bond to something (we rate it a level 2 need).  If left in this state, it would harm the surrounding cells (it is called a ‘free radical’). 

Organisms ‘solve’ the problem by taking a carbon atom (C) which has an even higher ‘need’ to bond (level 4).  Two oxygen atoms (with a ‘2’ each) are bonded to the one carbon atom (to add up to the carbon’s ‘4’).  (Yes, this is a major simplification – but the underlying principles are accurately described).  The resulting molecule is CO2 – or one carbon and two oxygen atoms.  All of its ‘needs’ for ‘bonds’ are met, so it is not harmful to the surrounding tissues.

Yes, it does require energy to bind the oxygen atoms to the carbon one.  However, because carbon has such a high ‘need’ for bonds, it takes less enegry to bind the oxygen atoms to it than was released by breaking the bonds between the two oxygen atoms.  In other words, when one breaks the molecular bonds between the two oxygen atoms in O2, then take a part of that energy and uses it to bind the two oxygen atoms to a carbon atom, one has some energy left over.  I stress again, this is a major simplification – there are many steps and other ‘bits’ (like glucose, which is where the carbon molecules for the reaction come from) are essential!!!  However, the underlying principle is correct.  If you would like to read more about this, here and here and here are good starting spots.

This energy difference is what cells use to carry out ‘living’.  We call this process aerobic respiration, both in plants and animals.  And though other molecules may be used in its place, oxygen is by far the most efficient one.  (Respiration in the absence of oxygen is called anaerobic respiration.)


During respiration, living cells get energy by breaking ‘bond’ betwen two oxygen atoms in an oxygen molecule (O2), and then use carbon atoms from glucose (simple sugar, made up of carbon, hydrogen and oxygen atoms) molecules to stop the resulting oxygen atoms (free radicals) from harming the cell itself.  So, where does the glucose come from?

Glucose is produced by photosynthesis.

Plants have special organelles called chloroplasts.  These are specialized organelles (sub-section of a cell with a specialized function) in the plant cells which contain the green pigment chlorophyl.  Their function is to take IN carbon dioxide (CO2) form the air, and combine it with hydrous oxyde (H2O – water). 

The C (carbon) from the CO2 is combined with the OH group from H2O.  OK, I am simplifying again:  you need several molecules of CO2 and H2O to make it work, because the result of combining the carbons and oxygens and hydrogens together is the simple sugar, glucose:  and it has 6 carbon atoms in it. 

It is, in fact, pretty much the reverse of the chemical reaction during respiration.  But the reason for respiration is to release energy.  So, this process of photosynthesis needs energy from the outside to happen – and this is the reason why it occurs in the chloroplasts, which contain the green pigment chlorophyll, which is very good at absorbing light energy from the sun.  It then uses this energy to drive the chemical reaction of binding carbon atoms (from CO2 in the air) to water molecules to produce the simple carbohydrate, glucose.

This process is called photosynthesis because it uses the enegy from light (photo) to build (synthesise) glucose, a simple sugar.  Glucos molecules can, in turn, be joined up into long chains so they can be stored efficiently.  The end product, the carbohydrate chain, is called starch.

Plants can then use the stored up starch in order to breathe.  And animals, unable to make starch themselves, eat plants in order to get it.  Thus, energy from sun gets stored by plants (using carbon dioxide and water) as carbohydrates. The byproduct of this process in the oxygen molecule. Plants and animals use these carbohydrates and oxygen from the air to use this stored solar energy to ‘drive’ their cells.  The byproduct of this is carbon dioxide.  This is the basic energy cycle of our current lifeforms.

The more complex the plant, the more CO2 it requires to grow and thrive.  For example, the ‘Great Plains’ in the US used to be mostly covered by trees – until the carbon dioxide levels became too low to support them.  Then, they reverted to grassplains, because grass is a less complex plant and requires (and uses)less CO2 in the air.

If you love trees, as I do, you cannot but object to anything that will reduce the CO2 levels available for them to grow.  I am a self-admitted tree hugger – and a scientist.  I thought the ‘global warming’ thing sounded good when it was first proposed, so I have ‘looked into’ it (extensively – though this is NOT my field of expertise!!!  I do not wish to mislead!).  The evidence has convinced me that this is not dangerous.  To the contrary.  Incerases in CO2 levels are higly advantageous to lifeforms on Earth because historically, they raise food availability and are accompanied by greater species differentiation and increase in overall lifeforms supported.  And despite some claims, hard datea shows that we are nowhere near historically high levels of CO2 in the atmosphere.

So, why the hype?

I don’t know.  In situations where things get as murky as this is, I like to use a very simple ‘rule of thumb’:  “cui bono?” 

Or, in other words, ‘Follow the money, honey!’ 

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