By Professor Michael Stephenson
In a now famous article in the journal Science in 2004, Pacala and Socolow introduced the scientific world to the concept of stabilization wedges. These are units by which we might measure the amount of effort we'll need to tackle global warming - while still keeping the lights on. Several of these wedges are needed to get from the ruinous 'business as usual' high-CO2 emissions scenario to one where we might reduce global warming to a manageable level.
One of Pacala and Socolow's wedges consisted of converting coal power plants to gas - in other words to make gas the provider of electricity baseload, rather than coal. This saves carbon because burning gas in power stations is about half as CO2-polluting as burning coal. Another suggested wedge was to introduce widespread carbon capture and storage (CCS) on gas and coal power stations. This is where the CO2 from the power stations is buried out of harm's way deep in geological formations. CCS has been taken up as Government policy in several countries (for example in Britain), though no large-scale CCS yet operates here.
In my talk tonight, as part of an event organised by Intelligence Squared with Shell, I'll discuss geological aspects of gas and CCS and how they affect the likelihood of these 'wedges of effort' being achieved. I'll also look at the overall feasibility of an expansion in the use of gas (particularly shale gas) and of widespread CCS relates to investor and public confidence.
At the moment confidence is not particularly high in shale gas and CCS in much of the world. Ordinary people worry about the same things in relation to both technologies: will gas (methane or CO2) leak out of the ground? Will there be earthquakes? Will water supplies be contaminated? Even 'conventional' gas is being accused of surface infrastructure leakage of methane (so called fugitive emissions), a potent greenhouse gas.
Also the overall carbon footprint of unconventional gas compared with the conventional variety isn't accurately known. But if these wedge technologies aren't seen as feasible it will be harder and more expensive to achieve the emissions targets we've set - and other 'wedges' will have to take the strain. We may also lose technologies that could act as bridges to a low carbon future.
Most geologists and technologists are confident that shale gas and CCS can be done safely, and the weight of scientific evidence in these new areas backs these views up. Cleaning up surface infrastructure above conventional and unconventional gas fields is also feasible and sensible.
However this doesn't mean that the public or the investors are convinced about the science. The science needs to be seen to be independent and peer-reviewed and it needs to be communicated! Scientists are not naive enough to believe that the results of scientific experiments enter the public consciousness, but their conclusions can, by slow diffusion, improve the quality of public and policy debate so that the right decisions can be made. The public and policy makers need to know that science can be rather a slow process, that single studies may yield ambiguous results - and that disagreement and argument amongst scientists is a sign of progress, not a basis to distrust them.
Having the public (and investor community) on the side of low carbon technologies (gas-CCS and coal-CCS; gas rather than coal) will help to keep our technology options open. Improving the quality of public debate is helped by doing the right science at the right time, keeping it independent, and communicating it well. This will help to keep the lights on while also meeting emissions targets and keeping global warming at bay.
Professor Michael Stephenson is Head of Science and Energy at the British Geological Survey.
Watch Stephenson live online tonight from 7.15pm, along with four other world experts, speaking at Intelligence Squared's 'A Natural Gas Revolution: Hot Air or Dose of Sanity. An Evening of Debate'. The event is part of the Switched On series of live debates and discussions in partnership with Shell.