Thursday, 14 January 2010

More on Global Warming

As anticipated the world agreed to limit global warming at Copenhagen but could not agree who should do it and who should get how much money from whom. Perhaps the politicians will be more open to new approaches now that their single-minded pursuit of cap and trade with offsets has got them nowhere.

Among people polled there is strong support for the alternative scheme detailed in my previous blog in November. In a recent Times Online live debate 85% voted that "Fossil fuel companies should be obliged to sequester an increasing fraction of the carbon content of the products they sell to avoid dangerous climate change"

This motion was proposed by Myles Allen, head of the Climate Dynamics Group at the University of Oxford. Darren Johnson who is Chair of the London Assembly and a Green Party councillor also voted in favour because energy conservation and renewables will be much more attractive if we have to pay for sequestration when using fuel. He saw the proposal as a transitional measure in the move to a renewables/efficiency led programme but I see it as a long-term way of growing our affluent industrial society without stressing the planet.

Ed Miliband, Secretary of State for Energy and Climate Change, has failed to even acknowledge my emails on the proposed scheme but Norman Baker my local Liberal Democrat MP has offered to chase him for a response and I will shortly ask him to do so.

The International Energy Agency (an intergovernmental organisation) say that stabilising the climate in 2050 would cost at least 70% more without carbon capture.

Myles Allen pointed me to a paper which shows how very slowly atmospheric carbon dioxide concentration would decline even if emissions stopped. The ocean currently absorbs 2.2 billion tonnes/year of carbon (as noted in my November blog) but as described in the paper, uptake would fall to about a quarter of that value (ie only 6% of current emissions) if atmospheric carbon dioxide concentration stopped rising today.

The arctic ocean downwelling flow corresponding to the ongoing carbon uptake of 0.54 billion tonnes/year predicted in the paper gives an ocean turnover time of 2500 years. The 0.54 billion tonnes/year also implies that only about 1.4 billion tonnes/year of carbon in dead organisms sinks far enough to contribute to the measured increase in dissolved inorganic carbon in the cold downwelled polar water that fills the ocean below about 500 metres depth. Most of the often quoted 10 billion tonnes/year of sinking solid organic matter must decompose in the shallower water and leave the dissolved carbon there.

The observed 2 ppm per year increase in atmospheric carbon dioxide concentration would explain the other three quarters of the current 2.2 billion tonnes/ year of oceanic carbon uptake if the top 350 metres of the ocean were well mixed.

The ongoing ocean carbon uptake would be higher if the atmospheric carbon dioxide concentration were higher, because more carbon would dissolve in the icy water downwelling to the deep ocean. But even if the atmospheric concentration were allowed to level out above 500 ppm (compared to today’s 388 ppm) the ocean would only continue to absorb at the rate of 10% of today’s emissions.

A reduction to that level will be difficult but not impossible to achieve without sacrificing worldwide growth or our living standards. Recovery efficiency for carbon capture will need to approach 100% but no doubt this will be possible with the right financial incentive. Overseas holidays and year-round exotic perishable produce have become a key part of our standard of living, but planes need fuel and cannot easily capture carbon. Aviation already accounts for 2% of carbon emissions and this will probably rise as incomes rise substantially in China and India. Biofuel use on such a scale may not be politically acceptable as pressure grows to feed an expanding population without increasing the area under cultivation. There will also be a residual fuel requirement for transport, heating etc. in remote locations without the possibility of a mains electricity supply.

But for sure every year that we delay cutting back on our emissions we are squandering at least ten years of our children’s meagre ration. They will not thank us for going round the same old loop over and over again ignoring the obvious option of obliging fuel producers to pay for the capture of the carbon dioxide their fuels produce.


  1. You wrote: "every year that we delay cutting back on our emissions we are squandering at least ten years of our children’s meagre ration."

    Most quotes I've read from the coal industry indicate that carbon capture won't be ready on a large scale for at least a decade or more. That represents a significant delay in cutting our emissions.
    Government investment is limited. Every billion spent on carbon capture is a billion that could have been spent on existing, proven carbon reduction methods, such as efficiency projects, solar, wind, and even shutting down older coal plants while making more frequent use of existing natural gas plants. To me, carbon capture looks like a risky distraction that will squander the future.

  2. Will,
    You raise a key point about the readiness of carbon capture technology that I have mentioned in my latest blog, so can I refer you to that.

    You also say that government investment is limited, which is true, but I am not proposing any government investment. My proposal will motivate the free market to make carbon capture happen. It will also drive all the other low carbon alternatives including not only energy saving and renewables but also in the short term gas. This is because for a given heat release potential, gas producers will only have to pay for about half as much carbon capture as coal producers, regardless of what fuel is used on the facility where the carbon is captured.