0.04%: Small Does Not = Immaterial

If you follow me on Twitter , you're probably familiar with the onslaught of nonsense from the anti-science crowd.

I'm fine with respectful, reasoned responses, but many of the arguments are insulting, childish or conspiratorial.

I know, if I were trying to win these people over I shouldn't belittle them. But I'm not trying to win them over. There's plenty of objective data showing why they're wrong, but they choose to believe their feelings and political loudmouths instead of science. Nothing I do will change their minds. So I continue to make my observations about the world - take it or leave it.

Frankly, I don't understand how these people have the time to scour Twitter for posts outside their world view. This brigade of deniers with nothing better to do has clearly gone through the same training program. They make the same points and share the same charts. Often, their 'rebuttal' has nothing to do with the original tweet. It's like they're blindly copy-pasting from their "how to be a science-denier" guidebook.

I usually ignore (or block) these comments, but once in a while something drives me nuts.

One argument I've heard on repeat recently is that CO2 is only 0.04% of the atmosphere, therefore it cannot affect the climate.

I'm being kind when I say this is a simplistic argument.

Small does not = immaterial.

To prove my point, here are 10 things that are deadly at levels far below 0.04% concentration:

1. Botulinum toxin: It can be lethal at about 1 nanogram per kilogram of body weight. This equates to incredibly minute concentrations, roughly 0.0000000001% in the body.
2. Ricin: A dose of about 22 micrograms per kilogram of body weight can be lethal. This is also a very low concentration, about 0.0000022%.
3. Mercury: Chronic exposure to mercury vapor at concentrations as low as 0.025 milligrams per cubic meter of air can cause neurological and behavioral disorders. This converts to about 0.0000025%.
4. Arsenic: Safe exposure limit in drinking water is 10 micrograms per liter, which equates to 0.000001%.
5. Dioxin: Typically considered safe at levels in the parts per trillion range, approximately 0.0000000001%.
6. Polonium-210: A few micrograms can be fatal if ingested or inhaled, but specific percentage concentrations in the body are difficult to quantify due to its extreme radioactivity.
7. Cyanide: Lethal at approximately 1-2 milligrams per kilogram of body weight; around 0.0001% of body mass.
8. Tetrodotoxin: Fatal at about 1 milligram per person. In body weight terms, this would be around 0.000001% for an average adult.
9. VX nerve agent: Lethal from skin exposure at about 10 milligrams per person, roughly 0.000001% by body weight.
10. Sarin: Fatal from exposure to about 0.5 milligrams per kilogram of body weight, equating to 0.00005% by body weight.