Yesterday I was pointed in the direction of this post. It’s a fairly optimistic blog about the cost of solar panels. The thing that caught my eye though was the first paragraph about how much energy the sun delivered to the earth. On the face of it is sounds amazing – in 14.5 seconds it delivers all the energy humanity uses in a day. Sounds fantastic – we just need to capture it. I decided to have a play to see on our current infinite growth path how long we could continue assuming we moved to completely sustainable sources of energy. Would there be a point when we’d not have enough energy from the sun each day ?

The Infinite Growth Paradigm.

Depending on how widely you’ve read you may or may not have come across this term. It is however the underlying paradigm of virtually everything you hear by politicians, business men and the popular press. They never call it this but every time they tell you we need growth this is implicit in it. We have a recession – we need to spend our way out of it. In fact, the very definition of recession is lack of growth. Also, implicit is the fact it should keep continuing. If they believe at some stage it should stop then why not right now when there’s lots of evidence it’s unsustainable ? Since they don’t even consider this as a possibility I can only assume they think it will continue indefinitely and thus is infinite.

Now for a insanely optimistic scenario. Here’re my assumptions

1. There are no limit to resources other than energy. So we completely recycle, go to mars and mine whatever – no limits
2. We move to completely sustainable energy sources. The only truly sustainable way to use energy is by using that available from the sun. (uranium will run out and I’m not considering that cold fusion will somehow work for this experiment). For sustainability we need to on average use the suns energy at the rate it arrives. Burning oil, coal, natural gas is burning historic sunlight. Burning wood in a sustainable way is a way of storing current sunlight to be used later. All our energy ends up from capturing the suns energy eg: solar, wind, hydro, biofuels. [aside – tidal is another possibility which I’ve ignored – using this would merely add to the maximum limit we can’t exceed]
3. Many people state thats it’s efficiency that will allow us to continue to grow despite limited resources. I’ve included a 5% increase in energy efficiency every year forever !
4. I’ve done various scenarios giving a minimum that this efficiency will tend towards. It’s an optimistic scenario but not one where I can imagine that we will progress ever closer to zero energy per unit of economic activity. Current efficiency in the UK is about 6.5 megajoules per $1 of economic activity. My three scenarios are for an absolute limit of 50% (3.25 mj/$), 10% (0.65 mj/$) and 5% (0.325 mj/$)
5. I’ve assumed that when we capture sunlight we are 100% efficient (thus ignoring the laws of thermodynamics). However, I’ve assumed we’re sensible enough to not capture all of it otherwise there’d be none left for other animals, plants, heating the earth, creating wind etc… so I’ve assumed a hard limit of using 33% of the suns energy above which I’m pretty sure we’d create a whole lot of problems.

6.2% economic growth is assumed. This sees to be largely touted figure for a healthy economy.

I stuck this all into a spreadsheet and produced the graph at the top.

Zero Energy Efficiency Gains

This scenario is all the above but energy per economic output stays the same.

Years before we run out of energy (33% of sun):  384 years

GDP at this point: 1,967 x (Current GDP)

Efficiency Gains at 5% tending to a limit of double current efficiency

Years till we run out: 419 years

GDP: 4,013 x (Current GDP)

Efficiency Gains at 5% tending to a limit of 10 times current efficiency

Years till we run out: 500 years

GDP: 19,957 x (Current GDP)

Efficiency Gains at 5% tending to a limit of 20 times current efficiency

Years till we run out: 535 years

GDP: 39,911 x (Current GDP)

WOW ! You may have noticed how the increasing in efficiency progressively gains us less time. Doubling it in this final step only gave an extra 35 years !!

Growth will trump efficiency.

Now this was really just a bit of a giggle but has a very serious side. You may laugh at so many parts of it

• the idea of capturing 33% of all sunlight that hits the earth. That can be pulled apart on so many levels
• the idea that GDP will be 1,000s of times what it is currently.
• the idea that we’ll always have enough resources to manage this
• the idea that the impacts on the worlds ecosystem would not bring this to a halt.

Yes ! This is completely insane.

BUT – this is implicit in the Infinite Growth Paradigm. This is what is implicit every time you nod in agreement that what we need is growth. Even if we manage all the ridiculous assumptions I’ve made we still hit a limit which is the energy of the sun. In fact, in my first two scenarios it takes less than five hundred years to be needing to use 100% of the energy the sun delivers to the earths surface.

You also may point out “but thats hundreds of years in the future”. Well yes, we won’t be around but lets face it thats a selfish attitude. If you plan on having descendants then some will have to face it. You may assume that at some point we’ll address this paradigm. Well yes … so why not now ? The evidence is all around we are hitting limits you just have to look.

My analysis here is crude but hopefully illustrative. It was just a few hours work to make a point. However back in 1972 a report called “The Limits To Growth” was presented to the Club Of Rome in which scientists built very sophisticated models to test out various growth scenarios. Back then they predicted we need to act immediately to bring about a smooth transition to a sustainable civilisation. They did a 20 and 30 year update with the 40 year update due in 2012. The updates really confirmed their analysis and that the world was continuing to follow their reference scenario which culminated in Collapse. Considering their study in 1972 concluded we had to start acting immediately together with the fact we’ve done nothing and the passage of time has confirmed their analysis you can imagine the urgency of a complete paradigm shift in our thinking.

Limits to Growth, The 30-Year Update is well worth a read.