( CNN ) -- High-Speed Rail ( HSR ) has been around been around for decades , but it 's back in the transport spotlight amid a surge of interest from the United States and China . Despite cuts to President Obama 's original plan to spend $ 53 billion on HSR over the next 25 years , an ambitious scheme for HSR to connect U.S. cities is still on the agenda . China has built more than 8,000 kilometers of high-speed rail lines in recent years and plans to spend over $ 400 billion on its program in the next five years , while the United Kingdom is contemplating plans to extend its more modest HSR network . Supporters of HSR often list environmental sustainability among its virtues . Some argue it 's a greener alternative to car and air travel and see it as an easy win in weaning people of fossil fuels . But just how green is HSR ? Two experts with different views give their opinions . Dr. Anthony Perl is Professor of Urban Studies and Political Science at Simon Fraser University in Vancouver , British Columbia , Canada , where he directs the Urban Studies Program . His latest book , co-authored with Richard Gilbert , is `` Transport Revolutions : Moving People and Freight Without Oil . '' Any debate about the future of high-speed rail must consider where this mobility option fits into the 'big picture ' of how transportation systems meet looming economic , energy and environmental challenges . In a world where 95 % of motorized mobility is currently fueled by oil , high-speed rail offers a proven means of reducing dependence on this increasingly problematic energy source . This value of using proven electric propulsion technology should not be underestimated when both the time and money to deploy energy alternatives are in short supply . In our recent book Transport Revolutions , Richard Gilbert and I documented the economic , environmental and political dividends to be gained from replacing the internal combustion engines powering today 's aircraft , cars , and motor vehicles with traction motors that can be powered by multiple energy sources delivered through the electric grid . Since electricity is an energy carrier , it can be generated from a mix of sources that incorporate the growing share of geothermal , hydro , solar , and wind energy that will be produced in the years ahead . And because electric motors are three to four times more efficient than internal combustion engines , an immediate improvement will precede introducing renewable energy into transportation . Grid-connected traction offers the only realistic option for significantly reducing oil use in transportation over the next 10 years . If such a shift does not begin during this decade , the risk of a global economic collapse and/or geo-political conflict over the world 's remaining oil reserves would become dangerously elevated . Making a significant dent in transportation 's oil addiction within 10 years is sooner than fuel cells , biofuels , battery-electric vehicles and other alternative energy technologies will be ready to deliver change . Biofuels that could power aircraft now cost hundreds of dollars per gallon to produce . Batteries that a big enough charge to power vehicles between cities are still too big and expensive to make electric cars and buses affordable . But grid-connected electric trains have been operating at scale and across continents for over a century . And when the Japanese introduced modern high-speed trains through their Shinkansen , in 1964 , the utility of electric trains was greatly extended . Since the 1980s , countries across Asia and Europe have been building new high-speed rail infrastructure to deploy electric mobility between major cities up to 1,000 kilometers apart . For intercity trips between 200 and 1,000 kilometers , high-speed trains have proven their success in drawing passengers out of both cars and planes , as well as meeting new travel demand with a much lower carbon footprint than driving or flying could have done . If we are serious about reducing oil 's considerable risks to global prosperity and sustainability , we will not miss the opportunity offered by high-speed rail to decrease transportation 's oil consumption sooner , rather than later . Tony Bosworth is a campaigner for Friends of the Earth , in its energy and climate team . He has a long track record of working on environmental issues , including a spell as transport campaigner for the environmental campaigning charity . Across the world governments are looking to high speed rail to provide fast , modern transport systems fit for the 21st century . By the end of 2012 China is expected to have more high speed rail lines than the rest of the world combined , while President Obama aims to give 80 per cent of Americans access to fast rail travel within 25 years . But if governments want high speed rail to spearhead the drive towards a cleaner transport system they must look further than simply providing faster trains . The UK is currently mulling over a high speed rail link between London and Birmingham , a city about 160 kilometers north-west of the capital . But according to official estimates , it 's unlikely to lead to significant carbon dioxide cuts -- and may even increase climate-changing emissions . So what 's stopping high speed rail being a major part of a greener transport future in Britain ? First there 's the electricity to power the trains . Over two thirds of the world 's electricity comes from fossil fuels so until ( or unless ) power stations are weaned off fossil fuels , electric trains will still have a significant climate impact -- although rail travel is still better than flying or driving . Secondly , will high speed rail entice people off the roads and short-haul flights ? French TGVs and the Channel Tunnel rail link have succeeded , but official calculations estimate that only 16 per cent of anticipated passengers for the London to Birmingham line will have swapped from planes or cars . One of the main factors is cost . Despite soaring fuel prices , motoring and flying are still expected to be cheaper than high speed rail . If faster rail travel is to become a realistic alternative it must be affordable too . The UK 's high speed rail link is expected to cost a whopping $ 54 billion . But living as we do in cash-strapped times there 's surely a strong case for investing some of that that money in less grandiose , but more effective , projects . Perhaps some high speed rail money could be diverted to upgrade commuter and longer-distance services , making life easier and cheaper for ordinary passengers -- and making a bigger and fast contribution to cutting emissions . High speed rail can play a major role in tackling climate change around the world -- if it 's affordable , powered by clean energy and gets people out of their cars and off planes , we really will be speeding in the right direction .
HSR can significantly cut oil use in transport in next 10 years , says Anthony Smith . He believes HSR can reduce oil use before alternative energy technologies are ready . If power stations use fossil fuels , HSR will still affect climate , says Tony Bosworth . He argues HSR must be made affordable to get energy out of cars .