Energy and Transport.pdf - Richmond School District No. 38

SeriesMillion vehicles400350300250200150100500Light commercial vehicleHeavy commercial vehicleThree-wheelerCar/sports utility vehicleMotorbike2005 2008 2015 2025 2035Figure 2: Vehicle populations forecast in China 7Million tonnes of carbon dioxide40003500300025002000150010005000IndiaChina2005 2008 2015 2025 2035Figure 3: Total carbon dioxide emissions (well to exhaust) from on-roadvehicles: India and China 7requires energy for construction and maintenance.Furthermore, transport facilitates changes in land use,enabling deforestation and thus reducing the earth’sability to absorb carbon dioxide.Although transport emissions are rising faster inlow-income and middle-income countries than in thosewith high income, there remain massive globalinequalities in transport energy use both between andwithin countries. In 2003, global average consumption ofpetrol and diesel was 283 L per person per year, rangingfrom about 12 L per person per year in Nepal, Bangladesh,and Ethiopia to 2135 L per person per year in the USA. 4Walking remains the main mode of transport for thepoor in most countries.Attention is increasingly focused on China, with a fifthof the global population and rapid economic growth, andwhere consumption of petrol for transport nearly doubledbetween 1990 and 2003. 5 Although still substantiallybelow per-head distances in high-income countries, totalmotorised passenger-km rose six-fold between 1980and 2003, and freight distance increased nearly five-fold. 6Rapid urbanisation and motorisation have seen roadspace for cycling curtailed. The number of cars andsports-utility vehicles in China could increase 15-foldover the next 30 years to over 190 million, with carbondioxide emissions from transport increasing more thanthree-fold (figure 2 and figure 3), 7 a situation that wouldbe environmentally unsustainable. However, expectinglower-income countries to change trajectory whiletransport emissions in rich countries continue to risefrom much higher levels is unreasonable.Aviation is increasing and has a large effect on climatechange. In 2001, the Intergovernmental Panel on ClimateChange (IPCC) estimated that aviation caused 3·5% ofhuman-induced global warming, which could rise to 15%by 2050. In 2003 there were 1·6 billion trips by passengersworldwide and, by 2010, this figure could exceed2·3 billion. The UK has the highest air travel per head inEurope, with a fifth of international flights passingthrough UK airports. According to the UK Civil AviationAuthority, passenger numbers at UK airports have beengrowing at about 6% per year since the mid-1970s—morethan twice the rate of economic growth—and show nosign of slowing. The UK Department of Transportestimates that aviation contributes about 5·5% of UKcarbon-dioxide emissions, but about 11% of the UK’stotal effect on climate change. The UK’s share iscalculated by allocating emissions from half the flights toand from UK airports to the UK, but more than half ofthese flights are by UK citizens. Therefore, at thehousehold level, the contribution of flying is higher andcould be greater than from driving. 8,9 Recent studiesestimate that by 2030 UK total aviation emissions ofcarbon dioxide will rise from 32 million tonnes in 2000 to65–85 million tonnes. 10 These predictions includeprobable gains in efficiency.Most of the increase in UK flights has come fromwealthier individuals flying more. Trips by those in thelower-income bands fell between 2000 and 2004. 10 Evenwith cheap flights, foreign holidays remain too expensivefor those on low incomes. The average household incomeof UK leisure passengers travelling through Stanstedairport was £51 000 in 2005, according to the CivilAviation Authority’s 2005 Passenger Survey Report, 11compared with an average household income of £31 000.A survey of emissions in the UK, including all transportmodes, found that the top 10% of emitters producedalmost 43% of emissions whereas the bottom10% produced only 0·1%. 9Aviation is believed to have a greater effect on climatechange than its carbon emissions alone. Additionalcontributors include nitrogen oxides, soot, sulphateparticulates, and water vapour, which lead to theformation of contrails and cirrus clouds at altitude. Cirruscloud formation is difficult to predict and model. Theeffects of nitrogen oxides and water vapour vary by2 www.thelancet.com Published online September 13, 2007 DOI:10.1016/S0140-6736(07)61254-9