The Economist - 19_25 April 2014

The Economist April 19th 2014 Science and technology 652 changer,” he says. “When the laserwas firstinvented, no one had any idea what itmight be used for. Today they’re everywhere.We’re still at that early stage withcheap rockets.”Perhaps. But although SpaceX is a commercialfirm, simple profitability is not itsonly goal. Mr Musk has been perfectlyfrank about his long-term aim: “to die onMars, preferably not on impact.” After theFalcon 9, the firm plans a beefier versioncalled the Falcon Heavy. That, in turn,would be a dress rehearsal for somethingcalled the Mars Colonial Transporter.Mr Musk wants to build a machine thatwould let him offer prospective colonists a(one-way) trip to the Martian surface forabout $500,000—or, as he puts it, roughlythe cost of a nice house in California. Perfectingreusabilityis essential forachievingthat dream.If you build it, will they come?Hard-headed commentators may roll theireyes at such ambition. And history suggestsreusability is difficult to do properly.The shuttle itself, for instance, was intendedto fly every week. In the end, it madeonly 135 trips over the course of 30 years.There is a credible case that it proved moreexpensive, in the long run, than old-fashionedthrowaway rockets would havedone. Yet SpaceXhas already shaken up anindustry once mired in stifling conservatism.A successful fully reusable rocketwould just be the latest example in a longtradition ofit confounding its critics. 7Eggs-actlyGlobal warmingAnother week,another reportOptions forlimiting climate change arenarrowingTHE Intergovernmental Panel on ClimateChange (IPCC), a gathering of scientistswho advise governments, describesitself as “policy-relevant and yetpolicy-neutral”. Its latest report, the third insix months, ignores that fine distinction.Pressure from governments forced it tostrip out of its deliberations a table showingthelinkbetween greenhouse gases andnational income, presumably because thismade clear that middle-income countriessuch as China are the biggest contributorsto new emissions. It also got rid of referencesto historical contributions, whichshow that rich countries bear a disproportionateresponsibility. That seems morelike policy-based evidence than evidencebasedpolicy and bodes ill for talks on anew climate-change treaty, planned to takeplace in Paris next year.The new report is intended to measurehowfargovernmentshave mettheirpromises,formalised in 2010, to keep the globalrise in mean surface temperatures comparedwith pre-industrial times to less than2°C. It says they are miles from achievingthat goal and are falling further behind.This picture is part of a scientific Easter-egg hunt. “Egglab” tries to recapitulate theevolution of crypsis in nightjar eggs by asking the public to act as predators and play“spot the egg” in photos of places where these ground-nesting birds might lay theirclutches. A computer generates the initial eggs (oval shapes whose colours and patternsare chosen at random and superimposed on the image) and the player has to find them.Those it takes longest to find are then mutated slightly and crossbred to create a newgeneration. After ten generations the result can, as the picture shows, be quite cryptic(spot the one artificial egg). Martin Stevens of Exeter University, in Britain, who devisedthe game, hopes to use it to study selection pressures on real eggs. Readers who wish toplay should go to nightjar.exeter.ac.uk/egglab/Between 2000 and 2010, it says, greenhouse-gasemissions grew at 2.2% a year—almost twice as fast as in the previous 30years—as more and more fossil fuels wereburned (especially coal, see page 51). Indeed,for the first time since the early 1970s,the amount ofcarbon dioxide released perunit of energy consumed actually rose. Atthis rate, the report says, the world willpassa 2°Ctemperature rise by2030 and theincrease will reach 3.7-4.8°C by 2100, a levelat which damage, in the form ofinundatedcoastal cities, lost species and crop failures,becomes catastrophic.The report looks at what would beneeded to rein back the rise in temperatures,so that it would not exceed 2°C. This,it says, would mean cutting greenhousegasemissions in 2050 to between 30% and60% of their levels in 2010. Unfortunately,emissionsare still risingand are likely to increaseby around 10% by 2030, at whichpoint, the IPCC suggests, there will be onlya 33-66% chance ofhitting the 2°C target. By2100, moreover, the burning of fossil fuelwould have to cease altogether unless allthe carbon dioxide thus generated is capturedand stored.The panel puts enormous weight oncarbon capture and storage (CCS): in someversions of its calculations, doing withoutit raises the cost of reducing greenhousegasemissions by between 30% and 300%.But CCS remains unproven at a large scale.The IPCC still thinksitmightbe possibleto hit the emissions target by tripling, to80%, the share of low-carbon energysources, such as solar, wind and nuclearpower, used in electricity generation. Itreckons this would require investment insuch energy to go up by $147 billion a yearuntil 2030 (and for investment in conventionalcarbon-producing power generationto be cut by $30 billion a year). In total,the panel says, the world could keep carbonconcentrations to the requisite level byactions that would reduce annual economicgrowth by a mere 0.06 percentagepoints in 2100.These numbers lookpreposterous. Germanyand Spain have gone further thanmost in using public subsidies to boost theshare of renewable energy (though tonothing like 80%) and their bills have beenenormous: 0.6% ofGDP a year in Germanyand 0.8% in Spain. The costs of emissionreductionmeasures have routinely provedmuch higher than expected.Moreover, the assumptions used to calculatelong-term costs in the models are, asRobert Pindyck of the National Bureau ofEconomic Research, in Cambridge, Massachusetts,put it, “completely made up”. Insuch circumstances, estimates of the costsand benefits of climate change in 2100 arenext to useless. Of the IPCC’s three recentreports, the firsttwo (on the natural scienceand on adapting to global warming) werevaluable. This one isn’t. 7