Why The IPCC Is Wrong About Bio-Energy

So, the IPCC has released their report on climate change mitigation. Naturally various people are in spin-mode. Greenpeace’s “journalism” wing have “15 key findings from the IPCC mitigation report.” Unsurprisingly the findings that do not suit Greenpeace’s agenda are not key.

And some journalists are doing a woeful job in doing their job. Damian Carrington of the Guardian tells us that the IPCC have concluded that mitigating climate change is “eminently affordable.” Meanwhile in a separate story the Guardian reports the IPCC telling Mr. Carrington that they are not allowed to make such conclusions.

But instead of hectoring journalists and complaining about the inevitable platitudes doled out in response to this report, I will instead suggest that the IPCC needs a good kick up the arse.

Consider what they say about bio-energy in the summary for policy-makers.

The table on page 18 informs us that if we only use a “limited” amount of “modern” bio-energy then the costs of keeping things to 450 ppm CO2-equivalent will increase by 64%. This 64% is a median figure, the range is from 44-78%.

So, they are expressing reasonably high confidence that restricting ourselves to “limited” bio-energy will make things much more expensive.

However their definition of “limited” bio-energy is rather absurd, hence my suggestion that they need a kick up the arse.

What is limited? 100 EJ of “modern” bio-energy per year. For context we consume around 450 EJ of fossil fuels each year. So “limited” bio-energy means that we will get the equivalent of 20% of current global primary energy consumption from “modern” bio-energy.

This is not “limited” in any sense, and it is easy to see why.

100 EJ per year corresponds to an average power of around 3.2 TW, that is 3.2 trillion watts. How much land would we need for this to come from bio-energy? Well, a lot.

Typical bio-energy plantations provide a power density of less than 0.5 watts per square metre, and this is after significant fossil fuel inputs through nitrogen based fertilizers etc.

So to get 3.2 TW from bio-energy we will need something like 6 million square kilometres of land to be converted to bio-energy plantation. This is roughly two times larger than India. Of course with a bit of genetic engineering and good luck perhaps we could shove this down to 3 million square kilometres. But a land mass the size of India is not “limited” by any definition.

According to the FAO total global arable land is 14 million square kilometres, just over two times bigger than the land we might need to get “limited” amounts of energy from bio-energy. It already appears to be the case that existing biofuels have put vast pressures on land use, and are resulting in significant increases in food prices. Just imagine what a few million square kilometres of arable land being converted over to biofuel plantation might do.

Of course some of this bio-energy could come from forest plantations. The IPCC maybe have bio-coke in mind, so that we can continue making over a billion tonnes of primary steel each year without needing over half a billion tonnes of coal.

How much forest plantation do we currently have? In 2005 it was just over 1.4 million square kilometres. Converting all of this over to biomass plantation would provide us with around a quarter of this “limited” bio-energy. Perhaps we could just convert the whole of the Amazon rainforest over to biomass plantation, it is only 5.5 million square kilometres.

So if we want “cheaper” mitigation we will need to convert perhaps well in excess of 6 million square kilometres of land over to bio-energy plantation. Does the IPCC really believe this is credible?