"The International Panel on Climate Change (the IPCC) is in the middle of the long process of making public its Fifth Assessment Report, a massive compilation of research papers published since the previous report saw the light of day in 2007....The WGIII Summary for Policymakers (all that most people ever read) is due to be released on Sunday but, as usual, has been leaked. Interestingly, it talks of the possibility of the supposedly vital reductions in greenhouse gas emissions cuts not happening and the need therefore for a Plan B (World ‘needs Plan B on climate’ – IPCC report). At this stage, according to the authors, it may be necessary to remove carbon dioxide from the atmosphere and lock it away."  The Scientific Alliance questions whether it will work.

# Would Plan B work any better than Plan A? The International Panel on Climate Change (the IPCC) is in the middle of the long process of making public its Fifth Assessment Report, a massive compilation of research papers published since the previous report saw the light of day in 2007. The first part covers the physical science and concludes, to no-one’s great surprise, that the Earth is warming and that we are mainly to blame. The report from Working Group II analyses the likely impacts and, for once, talks about some of the positive impacts as well as the negative ones which make the headlines. Finally, we have the part covering what is called mitigation, more commonly dubbed the fight against climate change. The WGIII Summary for Policymakers (all that most people ever read) is due to be released on Sunday but, as usual, has been leaked. Interestingly, it talks of the possibility of the supposedly vital reductions in greenhouse gas emissions cuts not happening and the need therefore for a Plan B ([World ‘needs Plan B on climate’ – IPCC report](http://scientific-alliance.us2.list-manage1.com/track/click?u=f1e3eeb023e7d88eff0dda8a2&id=a91a3f7014&e=83bc8ff1ba)). At this stage, according to the authors, it may be necessary to remove carbon dioxide from the atmosphere and lock it away. According to Roger Harrabin’s report *“The final draft report to the Intergovernmental Panel on Climate Change (IPCC) adopts a new tone of realism in the face of repeated failures by governments to meet their rhetoric on climate change with action.”* The problem is that the IPCC’s proposed ‘safe’ limit for carbon dioxide of 450ppm (actually a range of 430-480ppm) is set to be exceeded by 2030. This limit has been set based on modelling which suggests it provides a 2:1 chance of keeping temperature rise below 2°C by 2100. There are, of course, a number of assumptions behind all this. The key ones are that a 2° rise in average temperatures would have a net negative impact; something about which there continues to be active debate. The second and more basic assumption is that additional carbon dioxide in the atmosphere not only tends to push average temperatures up modestly (the basic physical science argument which no-one seriously disputes) but that this effect is magnified by positive feedback mechanisms. The argument goes like this: additional CO₂ induces a temperature rise which increases the amount of water vapour in the air. Water vapour itself raises temperatures further and the warmer conditions also allow more carbon dioxide to be released from the vast reservoir of the oceans, which pushes temperatures up further… This is clearly not a runaway feedback mechanism such as a nuclear chain reaction, since the climate would have been highly unstable over quite short timescales (there have been very large changes over a geological timescale, but these are essentially shifts between different approximately steady states). Nevertheless, it means that CO₂ emissions should have both a short term effect and then a longer-term but indirect influence as temperatures continue to rise. The IPCC prescription for this – Plan A – is to radically reduce global emissions of carbon dioxide and other minor but potent greenhouse gases to keep below the notional safe limit. This is the plan to which the global community of nations, via the UN Global Convention on Climate Change, pays lip service. The reality, however, is rather different and, to their credit, the lead authors of the latest Assessment Report seem at last to be recognising the fact. While pointing out the obvious that a failure to meet emissions reduction targets in the short term will make the task harder later in the century, the draft report accepts that this also may fail, leaving the option of capturing and storing some of the excess CO₂ from the atmosphere. This is Plan B. The fact is that, although the EU is in the vanguard of mitigation policy, Europe alone will make little impact on global emissions. The USA never ratified the Kyoto protocol and has no internationally-binding emissions reduction targets. Nevertheless, its recent exploitation of shale gas has been a major factor in a significant reduction in American emissions, showing that there is no intrinsic barrier to such reductions if the economics is right. But beyond replacement of coal by gas there seems little chance of further steps towards major cuts. But it gets worse. For those committed to mitigation policy, the situation in large, rapidly-developing countries – particularly China for now but perhaps to be dominated by India in years to come – makes it inevitable that emissions will continue to rise for the next several decades. The high-profile failure of the Copenhagen summit in 2009 to reach a ‘vital’ international agreement was a major dose of realism for the climate change community. Next year’s Paris summit is in danger of being hyped almost as much as Copenhagen and the strong likelihood is of a further failure to come to a binding agreement which would reverse emissions growth. Plan A isn’t working, so a different approach is clearly needed to make any impact. But Plan B also has two major flaws. The first is that no carbon capture scheme has yet been demonstrated on a large enough scale to make any scrap of difference. There have been several attempts at EU-funded demonstration projects, all of which have ended with participants pulling out at an early stage. So, this is not simply a case of ramping up an existing technological solution. The second flaw is even more basic. Plan A is failing because it has simply not been possible to get all major economies to commit to costly rejigging of their energy systems. Even those that have, with EU Member States in the vanguard, are not finding the task easy, even at this relatively early stage in the process. Carbon capture and storage would have to be undertaken on a vast scale to have any effect, and it would be costly. It can only have any impact if undertaken across the globe. Experience has shown that, despite all the fine words, most countries are unwilling to prejudice the prosperity of their citizens for the sake of possible long-term gain unless all other countries share the pain. Plan B is no more credible than Plan A.