Question: if all the trees were cut down how long would the oxygen last and would everyone need a inhaylers

Andrew Scott answered on 25 Jun 2015:

I really didn’t know the answer to this question, so I googled it and it turns out that a very similar question was answered (really well!) in a previous year of this competition.

You can see the answer here:
http://microa13.imascientist.org.au/2013/09/05/if-there-was-one-tree-left-on-earth-and-you-were-2-m-away-from-it-how-long-could-you-survive-on-that-little-oxygen/

It turns out that the oxygen produced by one tree is only enough for us to survive for about 1 hour. A quick google search suggests that there are 61 trees per person in the world!

Hang on, it’s more complicated than the previous question!
1. Animals, cars, burning anything also uses oxygen.
2. There’s some oxygen in the atmosphere already that would need to get used up (but we need a certain level to operate).
3. The amount of carbon dioxide we produce might kill us before we run out of oxygen.
4. There’s plankton in the ocean taking in carbon dioxide and making oxygen.

Woah, this is complicated… I don’t know the proper answer. The other problem might be that the trees absorb a lot of sunlight and if they weren’t there, the earth would start to heat up. We’d also loose all of things we make from trees.

If the oxygen ran out, we’d all need to breathe oxygen from tanks or cylinders. Inhalers are used to give medicine that’s absorbed through the lungs. The problem with the oxygen tanks is that we’d have to get the oxygen from somewhere. We could get it from water, but we’d need electricity for that and to make electricity we need to burn something in air.

So, it’s complicated, but it’s clear that cutting all the trees down is a bad idea!