Hi, I don’t tend to post here very often, but I had a query relating to a story I’m writing and since I can’t seem to find the answer I’m looking for via Google I thought I’d try people smarter, or at least more scientifically minded, than me
My hypothetical query relates to what would happen if photosynthesis ceased to work (for the sake of argument lets say aliens fire a beam at the earth that accomplishes this!).
Well, actually not so much a ‘what would happen’, as a ‘how long it would take’. I know we’d be screwed, plants would die meaning starvation, and worse they wouldn’t be pulling carbon dioxide out of the atmosphere and replacing it with oxygen so we’d all choke to death…my question is though, how long before the air became unbreathable?
Obviously the atmosphere still has a lot of oxygen, but how long before it dropped to levels where life could no longer function?
As I say the internet’s been a bit rubbish in answering this, I’ve seen estimates ranging from a few days or weeks (which seems a ridiculously short time) to several thousand years (which seems way too long).
Obviously I realise there won’t be a definitive answer (because a lot may depend on how we react. If we cull 90% of the population and stop pumping co2 into the air, it’ll last the survivors a lot longer than if we just carry on like nothing’s happened) I’m just looking for something that’s more than vaguely scientifically plausible.
Thanks in advance