There is now a welcome focus on air pollution whether it’s emissions contributing to climate change or health damaging particles and noxious gases.
The British medical research journal The Lancet recently concluded that pollution globally kills 9 million per year (http://www.thelancet.com/commissions/pollution-and-health) with air pollution causing 40 000 deaths in the UK alone (Source: Royal College of Physicians https://www.rcplondon.ac.uk/projects/outputs/every-breath-we-take-lifelong-impact-air-pollution).
Recently Transport for London introduced a T Charge in addition to the congestion charge which aims to improve air quality by discouraging vehicles that emit excessive levels of NO2 and particulates by charging an extra fee. The cost is £10 a day and applies only to older more polluting vehicles particulates.
We are being ‘steered’ to make better choices for the environment
The direction of travel (if you pardon the pun) is undeniable: by stick and carrot we are being encouraged make more efficient choices when we buy a car or choose a mode of transport.
The focus is normally on emissions during the use of a motor car, so-called tail-pipe emissions.
However, the manufacture of a vehicle also results in emissions. This then raises the issue of whether scrapping a working well maintained older car in favour of a newer more efficient vehicle will result in less pollution overall.
Is scrapping your older car for a more efficient model better for the environment?
Generally environmentalist use the waste hierarchy of reduce, reuse, repair and recycle to make eco-friendly choices. This is fine for many day to day objects such as paper, packaging, furniture etc but the picture is blurred when deciding whether to replace or repair energy intensive appliances or cars.
Gut instincts suggest that a new vehicle is better for the environment, particularly with the advent of new less polluting engines, hybrid vehicles and electric cars but there is a manufacturing process that uses considerable resources and energy.
Working out a definitive answer to this question is fraught with difficulty and hugely complex.
Full life cycle analyses have been done so let’s see what conclusions have been drawn.
A comprehensive 2000 study by M.A. Weiss et al., titled On The Road In 2020: A life-cycle analysis of new automobile technologies, looked at the full life cycle of various vehicle types, calculating energy and resource use in manufacture, use and disposal of the vehicle.
They concluded that, at the time of the study, the energy used to make a car compared to fuelling a car over its lifetime was about 13% for some vehicles rising to 50% for some electric vehicles.
This is likely to have changed since the analysis as modern manufacturing methods improve and get more efficient.
A more recent Volkswagen study suggests that with vehicle efficiency rising steadily, 68 percent of the car’s lifetime emissions came from driving it, while the manufacturing process accounts for a higher 22 percent – http://www.greencarreports.com/news/1090899_as-gas-mileage-rises-energy-to-make-cars-gets-more-important
As cars get more efficient at using fuel, the manufacturing process becomes a more significant part of the overall carbon footprint.
Electric cars, meanwhile, have lower lifetime carbon footprints than most gasoline and diesel fuelled vehicles because they convert 80 percent or more of the electricity used to charge them into forward motion – against 25 to 40 percent for combustion-engine cars.
We have seen some attempts at calculating the impacts in The Guardian and The Telegraph but the assumptions on energy use during manufacture are so flawed that we won’t link to them here.
As we understand better the true impact of motoring, the consideration widens to include air pollution effects on health as well as climate change.
The long term ideal choice looks like long lasting electric vehicles, charged by low or no CO2 energy sources.