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So just how much carbon have we got left?
Thread started on 30/9/2009 19:40

shane

shane

carbon allowance

I know that’s a bit of a silly question and that there’s huge unkowns with feedbacks etc but if we could envisage a carbon limit as a finite amount, what would it be?
Kevin Anderson says we’ve got about 1400 to 2100 giga tonnes until we hit 450ppm. So that seems like a reasonable cut off point, given that a lower peak in atmospheric emissions would likely be unachievable. But when i divey this up between our global population (and a little bit of growth), i’m not sure if i’ve got my maths wrong but it doesn’t seem to add up? “giga” is a prefix used to indicate “billion” or 10 to the 9. So with say 8 billion people (including some increase of the next 10 to 20 years. That would mean we have about 175 tonnes each before hitting 450. It just seems like quite a lot. I suppose 20 to 25% of this is from deforestation, what else am i missing? where have i gone wrong?
thanks
Shane

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UK CO2 emissions from 2000 to 2050

written on 30/9/2009 22:22

john ackers

john ackers

I think that the 1400 to 2100 GtCO2 refers to UK emissions between 2000 and 2050. At least it does in this presentation to the Royal Society.

 
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Hi John, Definitely

written on 1/10/2009 19:09

shane

shane

Hi John, Definitely global!! i’ve got the slides from this presentation http://www.youtube.com/watch?v=5do9K8NSbHw and the relevant slide reads;

“For 450ppmv CO2e emission estimates for
2000-2100 range from:

~ 1400 to 2200 GtCO2e
(i.e. the global carbon budget)”

 
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how safe is safe?

written on 4/11/2009 01:10

dsorsby

> The question in my mind with all of this is ‘safe level for who?’
>
> 450 ppm of co2 probably means we won’t all die in the developed world
> – not immediately anyway. but would you feel ‘safe’ if you were living in
> bangladesh in the ganges delta at this level, given that far lower levels
> seem to have started causing serious melting of the polar ice caps over
> thirty years ago? i wouldn’t.
>
> I can’t help thinking that any sensible safe level would be one that
> stabilised the ice caps. the arctic ice was first observed to start
> melting in the late 1970s, when CO2 in the atmosphere was around 350 ppm. isn’t
> somewhere under this point the only level we can rationally call a
> ‘safe’ limit?

 
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point of clarity

written on 6/11/2009 21:54

shane

shane

@dsorsby,
the idea being a 450ppm plateau and then returning to a safer level (300/350 http://climatesafety.org/). there’s little chance that we will be able to stabalise emissions before 450ppm. My question is more directed towards how much carbon do we have left before we cross the 450ppm threshold.

 
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