Tuesday, July 24, 2012

A little exercise: when will we run out?

Following on from my recent post about the must-read Bill McKibben piece in Rolling Stone, here's a little exercise.

1. Take McKibben's 2nd number (565 Gt of CO2 as the global carbon budget to have 80% chance of staying under 2ºC) and let's call it the somewhat sane global carbon budget: SSGCB. It is only somewhat sane since a 2ºC rise is no walk in the park, but already represents straying into territory agreed by all world governments as representing "dangerous anthropogenic interference with the climate system".
By the way, 1 Gt equals one billion tonnes. Current global emissions are above 31 Gt each year - and rising. Also, remember that there is a difference between emissions and atmospheric concentrations.

2. In this list, find your country's current population and its proportion of global population.

3. Imagine that this percentage is your country's fair share of that total carbon budget. Admittedly, this ignores past emissions and so pretends that some countries haven't been hogging far more than their fair share for as long as we've known about this problem. But let's go with it for the moment to keep the picture from getting unmanageably complex and just remember that the results will be skewed in favour of those countries with a long history of fossil fuel use.

4. So multiply 565Gt CO2 by that percentage you found in step to find your country's actual share of the SSGCB. This is how many Gt of CO2 your country can emit between now and, well, pretty much forever, but let's just say 2050 for now, since that seems to be about as far ahead as any national government cares to think.

5. Now find your country's annual emissions in this list. It's a few years out of date, but it will do for the sake of this exercise. This is in thousands of tonnes (kt), so divide it by one million to convert to Gt. We're also going to assume, for the sake of simplicity, that national emissions are not changing (neither are populations). Since most countries' emissions (and populations) only change by a small percent each year, this isn't too much of a stretch for a ballpark exercise like this.

6. Now divide your country's actual share in the SSGCB (from step 4) by annual emissions (step 5) and see how many years it will take you to blow through your entire budget. After this point, all future emissions are stealing from everyone's else's right to emit.

For Australia, we'll be all done by late 2016.


byron smith said...

Of course, this particular exercise was already being suggested more than five years ago, and from that perspective, Australia's share has already expired.

byron smith said...

Conversation: Australia is not de-carbonising.

"We like to believe that technology can solve the problems we face without the need for serious social change. But we’ve made no progress in reducing CO₂ emissions since the first IPCC report more than two decades ago.

"Fossil fuels' share in global electricity production is now much higher than it was in 1995. In Australia it rose from 90.5% in 1995 to 92.4% in 2011. We’re re-carbonising, not de-carbonising."

Anonymous said...

Don't forget point 7.

7. France decided to move from oil-fired electricity to clean nuclear powered electricity and achieved that in just 20 years. France enjoys abundant affordable electricity at just 90grams of carbon per kwh, but Denmark remains at 650grams. Despite 20 years of deploying wind power.

In other words, the moral of this story is that it's nuclear power or it's climate change.

byron smith said...


Population: 65,350,000 on January 1, 2012 = 0.93% of global population.

0.93% x 565 Gt CO2 = 5.2545 Gt CO2

Annual emissions (2008) = 0.377 Gt CO2.

5.2545/0.377 = 13.94 years.

France, including their nuclear build, will run out of their share of emissions by 2026.


Population: 5,584,758 on April 1, 2012 = 0.079% of global population.

0.079% x 565 Gt CO2 = 0.44 Gt CO2

Annual emissions (2008) = 0.046 Gt CO2.

0.44/0.046 = 9.7 years.

Denmark, including their wind power, will run out of their share of emissions by 2022.

I'm sure France can feel very smug during those four years.

"it's nuclear power or it's climate change"
False dichotomy. It is most likely to be both. And that then raises the issue of running all these hundreds of extra nuclear plants in a much, much less geopolitically stable world.

Benjamin Ady said...

What's perhaps super interesting is that I did the exercise for the U.S., without thinking too much about it, and then realized that the Aus number actually more accurately "belongs" to me. The U.S. it going to hit that wall by 2017 or so.

There should be a list of nations by carbon emissions per capita on the web somewhere.

Is it possibly more useful to do on an individual basis? 565 GT/7 billion =565t/7=80t per person which means we can each use ~80 tons in our own lifetime (one way of looking at it) which means in most western nations we need to use only ~1 ton per year each. Which perhaps needs we need to move to Guatemala or Yemen

byron smith said...

Yes, per capita might be a more useful way of doing the exercise. Of course, you've got to remember that your allocation is to be shared between you and all your descendants.

Though that's oversimplifying somewhat, due to the complexities of the carbon cycle meaning that while cumulative emissions is a reasonable approximation, it does not actually capture the dynamics of the whole system, where some carbon is put back into long term storage through natural processes. So there is a small amount of "renewable" carbon quota each year.

But in any case, the bottom line comes out the same for us today. Most of us in the developed world blew through our emissions years ago (since the same exercise could well have been conducted a decade ago when we already had enough knowledge to know better), or, if we want to stay with the fiction of beginning our quota today, will blow the lot in a handful of years.

jaffa said...