I was reading Flat Earth News by Nick Davies this morning. Flat Earth News is all those misconceptions and false stories that flood the media. It seems to me that the potential for Flat Earth news is greatest where the flaws of the scientific process slam headlong into the flaws of the mainstream media. Especially when numeric arguments are involved, because, of course, journos don’t have to be numerate.
Biofuels is a case in point.
I was at a talk last night about Wicken Fen near Cambridge. Apparently the idea (the “Wicken Vision”) is, over time, to expand the existing wetland reserve to an area of 50 sq kms. The National Trust is snapping up farmland in the designated area as fast as it can. It hopes to own the whole area in 100 years.
There was a lot of discussion of peat. Much of the whole area east of Cambridge – north towards the Wash, south through Essex – much, much bigger than 50 sq kms – was covered in peat, metres deep, up to a few centuries ago. Now, this is what got me scribbling during the talk. Get this, just this 50 sq km area would once, the speaker claimed, have held 27Mt** of carbon.
Now 27Mt over 50 sq km is 5000 tonnes of carbon per hectare [for any journos reading, there are 100 hectares (100m x 100m) in a sq km (1000m x 1000m). 27 000 000 tonnes (i.e. 27Mt) divided by 5000 hectares is about 5000 tonnes/hectare, rounding down.].
[Is this feasible? Yes. 5000 tonnes/hectare is 500 kg/sq m (100×100=10000 sq m in a hectare), i.e. 5 kg per 10cm x 10cm area. I choose this area because at the density of water 10cmx10cmx10cm (1 litre) is 1kg. So could we have 5kg of carbon in 10cm x 10cm x (say) 3m (300 cm) of peat? Yes, I would have thought so.* This is just a sanity check – all I’m doing is re-engineering the calculation that gave us the 27Mt/hect, which would have been based on empirical measurements of the average amount of carbon actually stored per sq m of peat.].
Virtually all this 5000 tonnes/hectare has been emitted to the atmosphere as a result of farming the land.
Now, remember we have established that crops grown to produce biofuels in Europe can displace at best 2 tonnes of carbon emissions (before allowing for fertilizers and energy inputs and so on) per hectare per year.
And remember that devoting even existing farmland to biofuels will inevitably cause further human encroachment into the world’s remaining wilderness areas.
Let’s say we look ahead for the next century. If we grow biofuels continually we may “save” 100 x 2 = 200 tonnes of carbon emissions per hectare of land devoted to biofuel crops (it needn’t be the same land every year).
What would the odds of food production being displaced onto wetland somewhere in the world have to be for us to justify diverting existing farmland in the UK (or anywhere else in the world) to the production of biofuel feedstocks?
Let’s do some division: Carbon cost of 5000 tonnes/hectare divided by “saving” of 200 tonnes/hectare = 25.
Conclusion (1): Even if there is as little as a 1 in 25 chance that devoting land in the UK to growing biofuels displaces other activities (such as growing food) onto wetland somewhere in the world, it’s not worth growing the biofuels. Remember, this argument applies to the one reason alone of loss of wetland and takes no account of all the other arguments against and costs of producing biofuels.
Now, it might be worth bearing in mind that one area of the world where farming is likely to be displaced into if we increase the human ecological footprint is – as the world warms – further north than is farmed at present in Canada, Russia, Scandinavia etc. Because these areas are cold, there is a lot of wetland, and peat, even if much of it is frozen a lot of the time right now. (Much of the tundra is, of course, frozen peat, and – since it seems it stores something of the order of 5000 tonnes of carbon/hectare – it might be a good idea not to warm it up at all!). Of course, tropical wetlands exist also and are already being drained – some for biofuels – in Indonesia, for example.
I’d say the chance – if we divert a hectare of farmland to biofuels here in Europe, and instead import a hectare’s worth more food from elsewhere in the world – that this will lead to a hectare more wetland being drained and turned into farmland somewhere in the world, than would otherwise be the case, is a lot higher than 1 in 25. Wouldn’t you?
We can look at this on the small scale as well. The Fen peat, last night’s speaker said, was laid down over the period from 7000 to 2500 years ago. That is, over about 5,000 years (rounding up). That is, at the rate of about 1 tonne carbon/hectare/year. Now, in this argument I can’t make the generous assumption that growing biofuels will displace 2 tonnes of carbon per hectare. We have to look a little deeper at the cost of producing biofuel. To justify growing biofuel on land to the east of Cambridge, taking account only of the slow process of laying down peat (i.e. ignoring all the trees etc. that would also grow on the less boggy bits of the land) that could otherwise be allowed to revert to wetland (with all manner of co-benefits) we’d have to be convinced that cultivating biofuels would result on a sustained long-term basis in the displacement of at least 1 tonne/hectare of carbon. And, even using UK Government figures, such a claim cannot be justified (e.g. see my paper on Biofuel Payback Periods).
Further conclusion (2): We’d be better off letting farmland near Cambridge return to its natural wetland state than we would growing biofuels on it. We don’t even have to plant trees, or worry about them burning down.
Final conclusion (3): It is not worth devoting land to growing biofuels. It only conceivably makes sense to use crop residues to produce biofuels, so that no land additional to existing farmland is required to produce biofuels.
Methinks it might well turn out that it would be better to leave crop residues in the soil (e.g. to reduce the need to use fertilizer) than turn them into biofuels with clever GM bacteria.
But, even if we don’t look too closely at the pros and cons of using crop residues to produce biofuels, let’s just ask if it is a sensible policy to subsidise biofuels and force everyone to use them through targets such as the UK’s RTFO, from April 15th 2008.
We don’t have to look far. We need to know how to turn crop residues into biofuels. Do we, perchance, actually know how to do this? That is, do we know how to make biofuels from cellulose?
This is what Scientific American (April 2008 ) has to say: “…no company has yet demonstrated a cost-competitive industrial process for making cellulosic biofuels. … ‘The oil companies say that it takes 10 years to fully commercialize an industrial processing route’ warns [the expert]…”
So in the meantime we only have first generation biofuels – produced from food rather than “waste” (though I have my doubts whether this term is valid) such as stalks. Remember this the next time someone says “not all biofuels are bad”. What they are in fact talking about are things that do not yet exist.
Yet I find in my Inbox this morning, courtesy of Biofuelwatch, the information that the Gallagher Review of “The Indirect Effects of Biofuels” starts from the assumption that: “Biofuels have the potential to deliver significant environmental benefits,…” (the start of the terms of reference). No, no, no! This is what we’re trying to establish. The fact that the Gallagher Review has been set up is great news, but it’s important that it starts with a clean sheet of paper.
And it’s shocking that the RTFO has not been suspended pending the Gallagher Review. Instead, it will come into force on 15th April – Biofools Day.
So if anyone can make it please go to the demonstration in London against the RTFO at 6pm on 15th April.
*Postscript: a study on Indonesia (pdf) suggests between 45 and 90kgC/m3 of peat – here I’ve derived a value of about 165 kgC/m3 (5kg in 3/100 m3), but then the UK’s temperate climate and Indonesia’s tropical one are likely to produce peat with different characteristics, and my estimate of peat depth was a guesstimate – there’s therefore no reason to disbelieve the estimate from the National Trust.
**Postscript (2): The 27Mt is from the notes I took at last night’s meeting. The link supplied gives 1.5 times the annual emissions of the UK’s cars. The total UK road transport emissions in 2006 were about 32MtC (based on DEFRA data), so the 27Mt figure tallies, as 18MtC/year from cars is compatible with 32MtC/year for all road transport (I don’t know where to find a breakdown).