We breathe in about 21 lbs. of air each day. This is much more than we eat each day! Important thing to think about in terms of how clean that air is.

A related fun fact is that you generally lose weight by exhaling, generally while you sleep. Sweating, defecating, etc. is all temporary. If you're trying to lose weight, make sure you're sleeping enough!

edit: see my followup comment, didn't mean to mislead here. I'm not a scientist and sleep and food science is both pretty hard to trust.

I love how he ends it with “thinking about space habitats” as I immediately thought: “well, if you can trap it and compress it, you’ll have enough briquettes for a weekly bbq”.

He obviously knows this too. Dealing with human waste/by-product is a real challenge. Far more so in space than on an ocean or in an RV.

We humans need to learn to use everything and not let anything go to waste. Else we have nothing left to waste.

Does anyone know how to reduce this? I’m worried about creating climate change.

without javascript: https://xcancel.com/ID_AA_Carmack/status/1945948569246027934

And plants love it!

For comparison, a small ICE car produces around 100g of CO2/km, so with the same carbon budget you could drive 10km.

Similarly, burning a gallon of gasoline emits about 20 pounds of CO2. (2.3 kg/l). So daily human exhalations are equivalent to driving a couple of miles or so.

I wrote about this some time ago ... the calculations are here:

https://www.solipsys.co.uk/new/CountingCarbonCalories.html?y...

I'll submit that as a separate item ...

Here: https://news.ycombinator.com/item?id=44605555

A couple weeks ago mosquitos were at their peak in my yard. I started thinking about adult mosquito traps, but I don't love the idea of using propane as a CO2 source like most commercial solutions do. I casually looked into solar powered direct air capture of CO2, but that would not scale down. Then I realized maybe I could just capture my own exhalations for 30 minutes a day to use in a trap. Not sure I'll ever actually implement it.

At standard temperature and pressure 1 kg of CO2 has a volume of around 500 l.

Exhaled air contains about 4% CO2, so you would have to exhale 12500 l of air to put out 500 l of CO2.

At 0.5 l per exhalation that's 25,000 breaths, which seems rather on the high side: 17 breaths per minute, round the clock.

It seems like a bit of a high estimate; could be true for people who are very physically active during parts of every 24 h period.

> “thinking about space habitats”

I think Carmack is a genius and admire his work ethic, but I can't understand what interests smart people like him about human space travel.

Might be able to get more people excited about maintaining our amazing ecosystem if we talked about "Spaceship Earth" more.