Almost nine out of 10 climate scientists do not believe political efforts to restrict global warming to 2C will succeed, a Guardian poll reveals today. An average rise of 4-5C by the end of this century is more likely, they say, given soaring carbon emissions and political constraints.

Such a change would disrupt food and water supplies, exterminate thousands of species of plants and animals and trigger massive sea level rises that would swamp the homes of hundreds of millions of people.

The poll of those who follow global warming most closely exposes a widening gulf between political rhetoric and scientific opinions on climate change. While policymakers and campaigners focus on the 2C target, 86% of the experts told the survey they did not think it would be achieved. A continued focus on an unrealistic 2C rise, which the EU defines as dangerous, could even undermine essential efforts to adapt to inevitable higher temperature rises in the coming decades, they warned.

The survey follows a scientific conference last month in Copenhagen, where a series of studies were presented that suggested global warming could strike harder and faster than realised.

The Guardian contacted all 1,756 people who registered to attend the conference and asked for their opinions on the likely course of global warming. Of 261 experts who responded, 200 were researchers in climate science and related fields. The rest were drawn from industry or worked in areas such as economics and social and political science.

The 261 respondents represented 26 countries and included dozens of senior figures, including laboratory directors, heads of university departments and authors of the 2007 report from the Intergovernmental Panel on Climate Change (IPCC).

The poll asked the experts whether the 2C target could still be achieved, and whether they thought that it would be met: 60% of respondents argued that, in theory, it was still technically and economically possible to meet the target, which represents an average global warming of 2C since the industrial revolution. The world has already warmed by about 0.8C since then, and another 0.5C or so is inevitable over coming decades given past greenhouse gas emissions. But 39% said the 2C target was impossible.

The poll comes as UN negotiations to agree a new global treaty to regulate carbon pollution gather pace in advance of a key meeting in Copenhagen in December. Officials will try to agree a successor to the Kyoto protocol, the first phase of which expires in 2012. The 2C target is unlikely to feature in a new treaty, but most of the carbon cuts proposed for rich countries are based on it. Bob Watson, chief scientist to Defra, told the Guardian last year that the world needed to focus on the 2C target, but should also prepare for a possible 4C rise.

Asked what temperature rise was most likely, 84 of the 182 specialists (46%) who answered the question said it would reach 3-4C by the end of the century; 47 (26%) suggested a rise of 2-3C, while a handful said 6C or more. While 24 experts predicted a catastrophic rise of 4-5C, just 18 thought it would stay at 2C or under.

Some of those surveyed who said the 2C target would be met confessed they did so more out of hope rather than belief. “As a mother of young children I choose to believe this, and work hard toward it,” one said.

“This optimism is not primarily due to scientific facts, but to hope,” said another. Some said they thought geoengineering measures, such as seeding the ocean with iron to encourage plankton growth, would help meet the target.

Many of the experts stressed that an inability to hit the 2C target did not mean that efforts to tackle global warming should be abandoned, but that the emphasis is now on damage limitation.

It’s simple: there should be no new coal burning without 100% carbon capture and storage (CCS) to bury carbon dioxide emissions underground where they cannot influence the climate.

This is a very different matter from Ed Miliband’s proposal in the House of Commons today that energy companies must “demonstrate CCS on a substantial proportion of any new coal-fired power station.” The figures he has just proposed (400MW of gross capacity) suggest that only around one-quarter to one-fifth of total emissions from a new plant will be captured.

These partly abated coal plants, in other words, would still be much worse than unabated gas plants.

Miliband went on to insist that “when the technology is proven [we will make a] commitment that CCS will be fitted on the entire plant.”

So the big “if” about CCS has magically been turned into a “when”.

If Miliband is sure that full-scale CCS is viable, two questions arise:

1. Why has he just announced four demonstration projects to test whether it is viable or not?

2. Why not go ahead with full CCS right now?

Of course, there is no “when”. As Alastair Darling told the House of Commons in May 2007:

“It is true to say that the technology to capture, transport and store the carbon exists, but it has not actually been joined up on a commercial basis yet … these things might never become available.”

It might work. It might not. As anyone seeking to develop and commercialise a new technology knows, it is likely to be beset by a host of unforeseeable difficulties, which will almost certainly delay it and possibly derail it.

As Miliband says:

“I have had representations that from day one there should be 100% CCS on new coal, but I believe that this does not appreciate the need that still exists to demonstrate the technology before full-scale commercial deployment is possible.”

So here’s the difficulty for the government. It will approve a new generation of coal-burning power stations, starting with Kingsnorth in Kent, on the basis that they will one day reduce their emissions by means of a technology that has not yet been demonstrated. What happens if the CCS demonstrations show that it doesn’t work on the scale Miliband envisages, or not, at least, when he predicts? The only means the government will then have of cutting emissions from the coal-burning plants it approves today is to shut them down, wholly or partially. Two factors mean that this is likely to be politically impossible:

1. The government has to decide now what our future energy mix will be. All large-scale electricity generation – whether from fossil fuel, nuclear or renewables – takes years to plan, develop and bring onstream. If, say, the government decides that in 2020 one-fifth of our power will come from coal, and then discovers in 2020 that coal emissions cannot be abated by CCS, it will not be able to shut those power stations down without massive consequences for electricity supply. The choice will be a stark one: either it will have to abandon its carbon targets or it will have to subject the country to electricity rationing and rolling black-outs. It’s not hard to guess which way it would jump.

2. Both Labour and the Conservatives have long colluded with the power generation industry. The Guardian’s new revelations about this relationship are just the latest in a long line. The power sector is a formidable industrial lobby group, which no government appears prepared to confront.

Miliband can make extravagant promises today about retrofitting 100% CCS to all new coal-burning power stations by 2020 and preventing them from operating without it. But he probably won’t be in office then, and almost certainly won’t be in his current role. Perhaps, as a private citizen, he intends to march into the Kingsnorth power plant and demand that it shuts down, but he can expect to be bludgeoned by the police if he does, just like the rest of us.

The government’s announcement, in other words, is cynical and meaningless. It cannot enforce the decision it has just made, and it knows that no one else will. If coal plants go ahead on the condition that their emissions will one day be abated through CCS, the emissions will be a certainty. The abatement will not.

monbiot.com