Full of hot air

BOOKS & ARTS Clean, green flying machines DOES FLYING COST THE EARTH? Science Museum, London. Until 15 November 2008. Aircraft emissions show little sign of abating as the development of climate-friendly technologies struggles to keep pace with booming passenger numbers. Behemoths of the fossil fuel era greet visitors to London’s Science Museum. Just inside the entrance, in Energy Hall, stands Thomas Newcomen’s hulking steam engine, which started the industrial revolution and ran on coal. Two galleries in, hanging between nineteenth-century locomotives and a vertical stack of six classic cars, one of the world’s first commercial airliners glowers from the ceiling. It is a powerful symbol of modernity — its iconic status surely one reason the mere mention of slashing emissions from air travel draws so much anxiety. Aviation was the first economic sector to have its greenhouse emissions and promised technological innovations scrutinized in a special report of the Intergovernmental Panel on Climate Change (IPCC). Now the Science Museum takes up the same subject for one of the earliest in a series of climate change-related exhibitions. So how bad is aviation for the planet? The show, Does Flying Cost the Earth?, starts by highlighting the importance of perspective in addressing this question. Three pie charts present the case. Concerned that your carbon consumption is out of control? Then worry about air travel: taking about two flights a year costs the average Briton 12 per cent of her individual carbon pie. Or worried about how governments propose to cut national and global emissions? Planes spew 6 per cent of the UK’s carbon dioxide, but only 2 per cent of the world’s. By 2050, that 2 per cent is expected to creep up to about 3 per cent. This is where the exhibit first makes an inevitable compromise on thoroughness. Captions fail to make it clear that the pies show carbon dioxide 91 only and omit other greenhouse gases. But partly because of those other gases and their intensified effects at high altitude, the IPCC estimated in 1999 that air travel accounted for roughly 3.5 per cent of the human-caused greenhouse effect in 1992, a figure predicted to climb to 5 per cent by 2050, though with large uncertainty. More recently, the UK’s Royal Commission on Environmental Pollution suggested the 5 per cent should be revised to 6–10 per cent. The 1935 Lockheed Electra (left), an early commercial airliner featuring a then-cutting-edge aluminium-alloy skin, overlooks the entrance to the Science Museum’s exhibition of green aviation technology for the twenty-first century. Highly aerodynamic ‘blended-wing’ plane designs (right) may be seen on runways in 25 years. (Image credit: Left, Science Museum; Right, Jennie Hills/Science Museum. ) The impact of aircraft on our future climate will be determined by, among other factors, the combined warming effects of all greenhouse gases. Quoting percentages of carbon dioxide alone makes the numbers more digestible, perhaps — it’s the count most familiar to eco-conscious apportioners of pie slices — but far less meaningful. Stronger set-pieces follow. After an explanation of the greenhouse effect comes an excellent computer presentation on research into the impacts of aircraft emissions, which leads to a walk-through display of the green technology that could power future planes. Both have a high gee-whiz factor: I was delighted to learn that scientists at Lancaster University have recruited a network of condensation-trail spotters who gather data by staring at the sky daily, and to inspect models of nifty futuristic jets. In exploring such technologies, the exhibition makes inspired use of facts and figures. Each innovation, from lightweight composite materials to hydrogen fuel, is rated in five categories: emission cuts, timescale to deployment, cost, effort required, and effect on passenger experience. Removing rivets from plane surfaces, for example, can be done immediately at low cost but hardly cuts emissions. A new open-rotor engine yields deeper cuts but makes flights unpleasantly noisy and slow. Like those of baseball cards or characters in role-playing games, the statistics — listed on cards that can be picked up and passed around — are addictive to compare and analyze. Two important possible advances fall outside the scope of this green-tech survey, however: better air traffic control to cut emissions, and supersonic jets that would greatly worsen aviation’s impacts. A rudimentary video game near the exhibition’s end sums up the situation at a visceral level. As air traffic increases in the future, players try to keep emissions down by installing green technologies in the hordes of planes multiplying on a touch-screen sky — an upgrade carried out by poking the icons to change their color and shape. The difficulty of the task lends a crude but memorable caveat to the exhibit’s technological optimism. Finally, the exhibition ventures into activism, inviting visitors to pledge to nature reports climate change | VOL 2 | JULY 2008 | www.nature.com/reports/climatechange BOOKS & ARTS do their share against aviation emissions by supporting green policy, taking fewer flights or buying carbon offsets. A video display shows how many have taken each pledge, a great way to make people feel part of a concerned community. But the feel-good message that “collectively ... we can all make a difference” is undermined by the incomplete treatment of impacts earlier on. Make a difference between what — 2 and 3 per cent of global emissions? By its end, the exhibit has offered some engaging glimpses of aviation’s vanguard for climate science and engineering, but it hasn’t satisfyingly answered the question in its title. It has the excuse that scientists and engineers are still working out that answer. Published online: 12 June 2008 doi:10.1038/climate.2008.58 Anna Barnett Anna Barnett is assistant editor and copy editor of Nature Reports Climate Change. e-mail: Full of hot air AN APPEAL TO REASON: A COOL LOOK AT GLOBAL WARMING by Nigel Lawson Duckworth Overlook: April 2008. 149pp. £9.99 Far from being cool and rational, Nigel Lawson’s offering on climate change is largely one of misleading messages. Although there remains uncertainty in many aspects of climate science, as in all science, over the past few years an overwhelming and well-founded acceptance has emerged, not only in the scientific community, but among the general public and in political arenas, that human activity, and in particular the burning of fossil fuels, is warming the planet. Far from the debate being over, with this awareness the discourse on climate change has largely moved from one of questioning the science to disputing what ought to be done about the problem. Into this arena enters An Appeal to Reason by Nigel Lawson, former Chancellor of the UK Exchequer, who makes a call for “a cool look at global warming”. Journeying through the science, politics, economics an (...truncated)