[–] lemon11 0 points 2 points (+2|-0) ago  (edited ago)

http://infogalactic.com/info/Carbon_dioxide#Toxicity

CO2 is an asphyxiant gas and not classified as toxic or harmful [...]. In concentrations up to 1% (10,000 ppm), it will make some people feel drowsy and give the lungs a stuffy feeling. Concentrations of 7% to 10% (70,000 to 100,000 ppm) may cause suffocation, even in the presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour. [...]

Because it is heavier than air, in locations where the gas seeps from the ground (due to sub-surface volcanic or geothermal activity) in relatively high concentrations, without the dispersing effects of wind, it can collect in sheltered/pocketed locations below average ground level, causing animals located therein to be suffocated.

Summary: yes, especially for the short.

Edit: By the way, this is why you don't want those "Climate Change" CO2 sequestration tanks anywhere, especially on land in cities like they have been suggested. They are deadly.

[–] KingChem 0 points 2 points (+2|-0) ago 

Because CO2 is has a higher density a 10% by mass would likely be enough to be a simple asphyxiant. Fortunately we measure CO2 in ppb.

[–] SyriansAreTerrorists 0 points 4 points (+4|-0) ago 

Yeah 10% CO2 in the air is more than the percentage in venous blood. There would be no way to transfer CO2 out of the body since the lungs work through diffusion rather than an active pump. Breathing would accomplish nothing

[–] SyriansAreTerrorists 0 points 1 points (+1|-0) ago  (edited ago)

It would fuck us up. Many of the body's responses are related to CO2 levels. For instance when you hold your breath, its not the low O2 that tells your brain to breathe, it's the increase in bicarbonate. Our lungs are already not super efficient at transferring gases (at least not compared to bird lungs), and in addition if CO2 was as high as 10% the gradient in the alveoli would be reversed.

I'd say you wouldn't last 5 minutes with 10% CO2. You'd get dizzy and nautious almost immediately