Reference:- The topic of atmospheric CO2 percentage was once again raised by Alan Jones. He can't understand how a gas that represents only .04% percent of the atmosphere could influence the climate .

Reference :-  This old chestnut is so overcooked that the staff at The Sky Reply advised the editor against correcting  Alan Jones, yet again   .   Sigh...... but here it is .

Jonesie, with all due respect , when it comes to atmospheric CO2 levels ,  you have no idea what you are talking about . This is the last time we will point this out . I implore you to stop making a fool of yourself by discussing the issue .  When you reveal that you know stuff all about climate change , it leads one to irrationally conclude that you no stuff all about anything , which does you no favours .
I am sure there are a few things you do know something about , so don't feel disheartened . 

 My son , Ken junior , who does quite well in science at the local state school, couldn't stop laughing at you and Ms Credlin .   His best friends , Monte , and Gabbo ( the aborigine)  started a contest in which they tried to outdo each other at mocking you with jokes based on the " avalanche "  effect .  You appear not to have heard of the  "avalanche effect "  .  This is a popular term for the observation that a very small change in part of a system can often precipitate massive changes in the system as a whole.

Monte started the game  .  He pretended he had been pulled over on his motorcycle and was being breath tested by the local copper .   "  But officer "  he protested  "  How could a blood alcohol level of only  .08 % effect my riding ?   That is less than one part in one thousand ? ".   He then pretended to fall off his bike and scream as the exhaust barbequed his leg   .

 Ken junior pretended to be an old bull about to be shot between the eyes with a Lee-Enfield 303 .    " Ha ha "  he laughed  "  How could a little piece of lead that weighs  .001 % of my body weight hurt me ? " .    He then shouted  "bang '' , and collapsed faster than a deregulated financial sector .

 But young Gabbo  ( the aborigine )  came up with the best one by far .   He pretended to be Maxwell Smart , agent 86 , who had just been given a suicide pill to use in case he was captured by the enemy.  He held the pill between his fingers , and said . "  But chief , how can this cyanide tablet kill anybody  ?  It only contains  a dose of .00000001 %  of average  body weight ? "    He then scrutinised the pill warily , and added . 
" And another thing chief , how do I get them to swallow the pill ? "

Jonesie , your knowledge  of chemistry would embarrass a caterpillar , and how Peta Credlin can keep a straight face as you waffle on astounds me .   I guess a saving grace might be that with your disdain for the potency of small concentrations ,you probably do concur that homeopaths are a bunch of lying quacks .   Anyway , lets never speak of percentages again .  I promise not to if you don't   .  

Your comrade , Ken