Climate Change

My Lords, I start with a bit of history. The Thames Barrier was conceived in the 1960s and completed in the early 1980s. It was a pioneering example of a major investment, more than £1 billion in today’s money, as an insurance policy against a very unlikely event—the flooding of London—which would have an economic impact many times larger. The debate that led to the barrier was a micro and localised version of the global issue confronting us today. The far-sighted committee that advocated the barrier was chaired by Sir Hermann Bondi. He seemed an odd choice for the task; he was an academic in my own field—a cosmologist. I do not dissent from anything that the noble Lord, Lord Broers, said about engineering, but I draw some comfort from this precedent when venturing into a topic far from my area of expertise. The politics of climate change are far more intractable than the science. It is clear that broad and sustained consent in many nations is a prerequisite for any effective action on climate change—as the noble Lord, Lord Giddens, has emphasised. Indeed, the noble Lord has spelt that out in a forthcoming book which he was too self-effacing to mention in his speech. However, there is zero chance of political consensus unless the public are confident that the scientific basis for the policies is firm. Some things in science are uncontroversial. There is no significant doubt that CO2 is a greenhouse gas—indeed, Sir John Tyndall first recognised that 150 years ago. It is also uncontroversial that the CO2 concentration has been rising for the past 50 years and that if you pursue business as usual it will reach twice the pre-industrial level by 2050 and more than three times that by the end of the century. The higher its concentration the greater the warming and, more important still, the greater the chance of triggering something grave and irreversible, such as rising sea levels due to the melting of the Greenland ice-cap, runaway release of methane in the tundra, and so forth. It is still substantially uncertain just how sensitive the climate is to the CO2 level and what regions of the world will be affected most. It is the ““high-energy tail”” of the uncertain probability distribution that should worry us most—the small probability of a really drastic climatic shift—just as for the Thames Barrier the main justification was ““insurance”” against the rarest and most extreme tidal surges. Global warming involves long time lags. It takes decades for the oceans to adjust to a new equilibrium and centuries for ice-sheets to melt completely; so the main downsides of global warming lie a century or more in the future. Therefore, as in the context of the Thames Barrier, we have to ask what discount rate we should apply. Should we commit substantial resources now to pre-empt much greater costs in future decades? There is a second feature of the climate change problem, and it is very different from the Thames Barrier. The effect is non-localised: the CO2 emissions from this country have no more effect here than they do in Australia, and vice-versa. Indeed, the worst effects are likely to be in Africa, Bangladesh and other places that have contributed least to the problem. That means that any credible regime where the polluter pays has to be broadly international. To ensure a better-than-evens chance of avoiding a potentially dangerous tipping point, it is widely agreed that global CO2 emissions must by 2050 be brought down to half the 1990 level. That is the target espoused by the G8 and the EU. It corresponds to two tonnes of CO2 per year from each person on the planet. For comparison, the current European level is about 10 and the Chinese level is already over four. To achieve the 2050 target without stifling economic growth is a huge challenge. For us in the UK, the 80 percent cut is enshrined in the Climate Change Act. In the years beyond 2050, the world may indeed have shifted to a low-carbon economy based on new technology and drastically changed lifestyles. But that is not soon enough. Unless the year-by-year rise in annual emissions can be turned around by 2020, the atmospheric concentration will irrevocably reach a threatening level. That is the real problem. Even optimists over the prospects in solar energy, advanced biofuels, fusion and other renewables have to acknowledge that it will be at least 30 years before those can fully take over. Coal, oil and gas seem set to dominate the world's ever-growing energy needs for at least that long. That is why an immediate priority has to be to develop carbon capture and storage—CCS. Carbon must be captured from power stations before it escapes into the atmosphere and then, somehow, it must be stored underground. To jump-start CCS technologies and implement a co-ordinated plan to build the 20-plus plants needed to test all the options might require $10 billion a year of public funding worldwide. That expenditure would be a small price to pay for bringing forward, by five years or more, the time when CCS could be widely adopted and the now rising graph of CO2 emissions turned round. Without CCS there is no prospect of avoiding a rise in CO2 above 500 parts per million, which is getting in the danger zone. Current R&D in the entire energy sector worldwide is far less than the scale and urgency demand. There is a glaring contrast here with health and medicine, where the worldwide R&D expenditures, both public and private, are disproportionately higher than those for energy. Surely this imbalance should be corrected. The Obama Administration have pledged an expanded effort, and in this country energy R&D has been cited as one way of stimulating the high-tech economy, although far more needs to be done. Indeed, I cannot think of anything that could do more to attract the brightest and best into engineering than a strongly proclaimed commitment by this country and by the US and Europe, to provide clean and sustainable energy for the developing and the developed world. What is the role of nuclear power in all this? I am in favour of the UK and the US having at least a replacement generation of power stations. However, proliferation concerns make us worry about this happening worldwide until we have some kind of fuel bank and leasing arrangement. Countries such as the UK can progress some of the way towards our targets by measures that actually save money. But globally, as my noble friend Lord Stern and others have emphasised, the costs will fall on the fast-developing nations; but they will have to be transferred to the developed West. My noble friend Lord Turner and others have estimated those costs as 1 or 2 percent of our GNP. That seems manageable and has been widely presented as such. However, I admit to some pessimism. To take another example, we are aware of the underfunding of overseas aid, which has not reached the 0.7 percent target despite the clear humanitarian imperative. That perhaps augurs badly for the actual implementation of the measures needed to meet the 2050 carbon emission targets, where the payoff is less immediately apparent than it is in overseas aid. Perhaps that is an over-pessimistic comparison, because there are extra shorter-term and less-altruistic motives for doing what is needed—energy security and diversity in particular. Some pessimists argue that, as a fallback against not reaching the 2050 targets, the international community should contemplate a plan B: to be fatalistic about the rise in CO2 but somehow intervene globally to combat its warming effects, for example by putting aerosols in the upper atmosphere or even huge sunshades in space. Such geo-engineering would not solve climate change but would at best buy time, probably at inordinate cost. Indeed, it is by no means clear that any such scheme is feasible. The political problems may be overwhelming. Any effective adaptation policy depends on being able to anticipate not just the mean global temperature rise but also the actual regional impacts. Even more confidence in those predictions will be needed before venturing actively to change the climate. The Royal Society has embarked on a study of geo-engineering. We think that it is at least worth while to clarify what makes sense and what does not. Our study may well put a damper on some enthusiasms and reveal why there is no realistic alternative to mitigation efforts. Finally, I add my voice to other speakers in emphasising that 2009 is an especially crucial year. Political decisions made this year at the G20 and in Copenhagen will resonate decades ahead. That is why today’s debate is timely as well as important, and why we should be grateful to the noble Lord, Lord Browne, for initiating it. The UK is only 2 per cent of the problem—that is our projected share of global emissions. But we can surely contribute far more than 2 per cent to the solution, both through our scientific and technical expertise and through our political influence in international fora.