A captivating remedy

A crude division can be made between two sets of people who both want to fight climate change. One seeks a fundamental reconstruction of the way humans live, a sustainable revolution that would change many aspects of modern society. The other has smaller ambitions, hoping technology will provide a specific solution to climatic threats, leaving the rest of life intact. This latter camp includes Gordon Brown, who last week backed nuclear power and carbon capture in an article in the Guardian.

The prime minister's ambitions are reasonable, but bring with them a problem. Technology can only answer climate change if it works and is affordable. As yet, neither criterion is met. Nuclear power, if it returns to Britain on any scale, will take decades to replace carbon-based electricity, while carbon capture and storage (CCS) is still at an experimental stage. The idea of stripping pollution from fossil fuels is seductive - a quick fix to an overwhelming crisis. The danger is that policymakers have now talked so much about it, they believe it is already happening. They do not realise how much work must still be done, and how much money spent, before it will be possible. Imposing CCS on the world's power-generating system would be incredibly costly - although for countries that develop it there could also be big profits.

An unexpected scientific breakthrough might transform things. On Saturday, the Guardian reported that American scientists are developing plastic membranes that strip carbon from the ordinary atmosphere, not just power stations, and then shed it so that it can be stored. The technology is exciting, but there are prohibitive logistical problems with implementing it on any scale. The idea of a million giant scrubbers cleaning up a century's pollution by processing the air still belongs to science fiction. At best CCS will limit the future pollution from specific sources of carbon dioxide. Even in that context, the work going into it nowhere near matches the political rhetoric.

Delivering CCS involves two distinct challenges: first, to capture polluting gases, and then to put them somewhere they can do no harm. There are proven ways to take carbon dioxide from exhaust gases (or the fuel source) of coal power stations. But not all the carbon can be captured and the process takes energy, adding to inefficiency and meaning more fuel must be burned. Carbon capture will only ever make coal power stations, which will never be wholly clean, much less polluting. As for schemes to lock away carbon by injecting it into old oil wells, they are still being tested. The biggest, in the Sleiper field in Norway, is going well. But oilfields are often a long way from the places where power is produced. Even if carbon can be stored in quantity without leaking, it will have to be transported around the world first.

These hurdles could be jumped, but governments are not helping. A small CCS has just begun in Australia - which, as a huge coal producer, has an economic interest in making the technology work. But the US department of energy has recently cancelled funding for the FutureGen project, after costs doubled to well over $1bn. In Britain the government is enthusiastic. Late last year the prime minister launched a competition to find a firm able to develop an effective CCS plant by 2014. But money is very limited and some experts complain that the scheme is too restrictive.

Meanwhile, despite empty talk of new power stations being "capture ready", pressure is growing for new polluting plants, such as the one at Kingsnorth in Kent, just to keep the lights on. Britain's blackout last week confirmed that the existing infrastructure is strained. Electricity prices are soaring, even before the huge cost of carbon capture is factored in. The technology will work in the end, but someone will have to pay for it if carbon capture is ever to produce more than hot air.