Renewables and nuclear no substitute for carbon dioxide disposal, argues leading climate physicist

April 5, 2016, University of Oxford

In a paper published in Nature Climate Change, leading climate physicist Professor Myles Allen, from the Oxford Martin Programme on Resource Stewardship, argues that investment in technologies to capture and dispose of carbon dioxide is vital to stabilise climate, especially at temperatures 'well below 2 degrees Celsius', as called for in Paris, and that 'spare no expense' approaches to cutting emissions in the short term may even be counterproductive.

Professor Allen, Professor of Geosystem Science in Oxford's School of Geography and the Environment and Department of Physics, argues that there are only two things we can affect with policies today that will really matter for peak warming: reducing the cost of large-scale capture and disposal of , and maximising the average rate of economic growth we achieve for a given rate of emission in the meantime.

Combining standard macro-economic tools with more recent insights into how the climate system responds to , Professor Allen found that that, unless we can get the cost of carbon capture and disposal below $200/tonne of carbon dioxide, then stabilising temperatures below 2 degrees Celsius will require 'truly heroic levels of self-sacrifice by future generations'.

The implication, says Professor Allen, is clear: 'Early investment in carbon dioxide disposal is critical, because most of the cheapest options, like underground storage, will take decades to develop and gain public acceptance. Currently, of the billions being spent on combating climate change, only a tiny fraction is remotely relevant to these vital "backstop" technologies.'

Professor Allen goes on to argue that we need a new framework for assessing investments in renewable and nuclear energy. He recommends focussing on the 'carbon intensity of growth', or maximising the rate of economic growth we achieve for a given rate of emission. 'Sacrificing economic growth to reduce could even be counterproductive,' he notes, 'if it impairs the willingness and ability of future generations to reduce emissions to zero.'

Professor Allen makes the point that countries with relatively high per capita emissions and sluggish (which would include the UK and most of Europe) have a particular responsibility to invest in carbon dioxide disposal. Right now, these countries are 'like a broke student at the bar: continuing to contribute to the problem without contributing to the prosperity required to pay for the solution'. This is true even if their emissions are declining. 'It's not enough to promise to drink slower,' he says.

He concludes: 'A policy that relies exclusively on substitution requires a mindboggling assumption of "irrational selflessness" on the part of when they run out of the easy stuff to substitute. It is time to divert some of our less productive subsidies into carbon dioxide disposal.'

Explore further: Research highlights urgency of reducing carbon dioxide emissions

More information: Myles R. Allen. Drivers of peak warming in a consumption-maximizing world, Nature Climate Change (2016). DOI: 10.1038/nclimate2977

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5 / 5 (7) Apr 05, 2016
Pyrolytic distillation of biomass and sequestering the resulting solid carbon is an effective means of CO2 disposal that is also net-positive in energy from the syngas which can be converted to biofuels and chemicals. The resulting charcoal is also a fertilizer and a soil improving agent for agriculture, which makes it valuable in itself and solves the problem of where to sequester it - plow it in the ground and grow food on it.

It pays for itself. It's like a student who comes to the pub with his own case of beer and pays the bartender to open it.
2.3 / 5 (3) Apr 05, 2016
it's the hangover after the out of control student party, not self-sacrifice.
Da Schneib
4 / 5 (4) Apr 05, 2016
This is a pretty interesting argument, but I see a possible flaw. There have been some carbon capture and sequestration technologies mooted but none I've seen have been properly researched and added to the scholarly literature. Most are grandiose fantasies by technophiles but a few might actually be workable. The problem with them is that the necessary investment probably exceeds the damage limited warming will do. Another recent article on this site estimates the economic damage as being on the close order of a couple trillion dollars; one could easily blow twice or even ten times that trying to capture carbon from the atmosphere and sequester it.

The article:

Da Schneib
4 / 5 (4) Apr 05, 2016
@Eikka, what's the cost of setting up enough pyrolytic distillation plants to make a serious dent in the atmospheric CO₂ concentration, enough say to get us down under 2°C of warming after Paris? And how much would that cost be offset by selling charcoal fertilizer?

Remember also that if it's used as biofuels it is returned to the atmosphere, though a closed cycle is better than an open cycle with fossil fuels; and how much of the chemicals produced will wind up back in the atmosphere too?

A serious analysis is invited; I'd like this to work. But I'm skeptical.
5 / 5 (5) Apr 06, 2016
@Eikka, what's the cost of setting up enough pyrolytic distillation plants to make a serious dent in the atmospheric CO₂ concentration, enough say to get us down under 2°C of warming after Paris?

Considering that it's a net positive technology that produces more value than it consumes, the cost is below zero. You burn biomass, then sell the solid charcoal as fertilizer, get improved yield from the fields, and sell the gaseous components for energy and other chemicals.

Whether it's scalable enough to solve the whole issue alone, likely not, but it still makes sense.

how much of the chemicals produced will wind up back in the atmosphere too?

What comes out of the pyrolytic distillation is CO, methane and hydrogen. Most of the carbon is left behind as solids. Whether the resulting stuff gets burned doesn't matter, because it's already carbon neutral, and more carbon is put in the ground with the solid fraction.
5 / 5 (5) Apr 06, 2016
For a cost-benefit analysis:


According to Collins, an increase of the soil pH from 4.5 to 6.0-6.5 requires an application rate of 76.53 MT of biochar per ha. The wheat yield under pH 4.5 is estimated at 3924.44kg/ha, under pH 6.0 – 6219.44 kg/ha, that is the biochar application results in a 58% yield increase. Using the prices of the Union Elevator (2008) at $0.28/kg of wheat, the revenues will go up from $1098.84/ha to $1741/ha as a result of biochar application.

The cost of biochar application with a broadcast-and-disk method is $71.6–741.3/ha

Plowing the charcoal into marginal lands yields tremendous increases in production by soil improvement, which basically translates to less land required to produce food, lower food prices, and more land available to produce biofuels, which in turn reduces the need for fossil fuels.
5 / 5 (5) Apr 06, 2016
At the application rate of 76.53 tons of biochar the broadcast-and-disk method will cost $485/ha; the trench-and-fill method will cost $523.57/ha.

CO2 sequestration value: low end - $37/ton; high end – $200/ton;
preferred estimate - $124/ton.

So basically the CO2 value per hectare at 76.53 tons can be around $10k depending on how we value the emission reduction.
5 / 5 (3) Apr 06, 2016
The cheapest option is storage on continental surface or in near-surface ocean water, as discussed briefly at http://www.infere...46.shtml and at length at http://www.innova...ge23.pdf .

It takes advantage of the fact that on Earth, carbon dioxide capture is thermodynamically favoured.
Da Schneib
3.7 / 5 (3) Apr 06, 2016
Thanks, Eikka.
3 / 5 (4) Apr 10, 2016
Tinkering with the balance of nature has always proven to have unintended dire consequences. Scientists and activists regularly underestimate the the power of equilibrium in nature.

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