In yet another attack on CNBC skeptic Joe Kernen, the Bad Astronomer (aka Phil Plait) writes at Slate:
That’s right, [Kernen] thinks CO2 isn’t a big deal because it’s a tiny fraction of the total content of our air. To people who understand reality, yes, 0.04% does sound like a lot, because we understand how the greenhouse effect works. If Kernen thinks 0.04% isn’t a lot, would he drink a glass of water that was 0.04% arsenic? I wouldn’t: That’s hundreds of times the minimum lethal dose. How about if that water contained 0.04% botulinum? A microgram of that protein is deadly. A level of 0.04% in a glass of water would be millions of times the lethal dose.
Dose makes the poison, as doctors say. It doesn’t matter what the amount sounds like. What matters is what it can do. In this case, CO2 makes it hotter, and it doesn’t take much in our air to do that. That is a fact.
Yes, it is the dose that makes the poison. Water with 0.04% arsenic may be lethal — but an atmosphere with 0.04% CO2 is… not an obvious problem despite tens of billions of dollars worth of investigation.
Phil’s comparison to arsenic is not a good one, and shows he is not a person who “understands reality.”
Here’s a better comparison: Imagine if tap water regularly had 0.03% arsenic, and this was not the least bit harmful. Would you dare drink a glass that had 0.04%? Mankind is not responsible for the 0.04% of CO2 in the atmosphere. Before industrialization, the atmosphere already had 0.03%. We only contributed 0.01%
I have news for Phil. Every glass of water he drinks has x% of some “toxin” in it. He still has to drink the water or he dies of dehydration. According to OSHA CO2 gets to be a problem at 3% so if the 3:0.04 ratio is applied to the lethal dose arsenic, he is probably drinking this everyday.
100% water in your lungs is lethal but a world without at least .02 CO2 is dead
I agree with kml, 0.04% arsenic(III) in a 250ml glass would may not be deadly. In fact if you were very health and incredibly stupid, you could most likely drink 2 glasses and live to tell the tale..
“Water with 0.04% arsenic MAY be Lethal” is right. An 8 ounce glass would probably–but not certainly–kill most people under 200 lbs. But 0.04 is certainly not “hundreds of times” the lethal dose.