From cars to aircraft, transport uses as much fossil fuels as electricity-generating plants. Of course, the fuel needs of a single car are negligible in comparison with the enormous needs of a power plant. But the number of cars is many times greater than the number of power plants. In total, transport accounts for about 14% of global greenhouse gas emissions.
Most cars still run on petrol. Burning one litre of petrol produces approximately 2.3 kg of CO2. For example, the average Canadian vehicle, which burns 2,000 litres of petrol every year, releases about 4,600 kg of CO2 into the atmosphere. The internal combustion engine, which powers motor vehicles, releases exhaust gases into the atmosphere, containing nitrogen, water vapour, and CO2 (between 1–12% of the emissions volume), as well as toxic and even carcinogenic compounds (soot and benzopyrene).
Overall, CO2 emissions per tonne of gasoline, from the extraction of crude oil from an oil well to combustion of the refined gasoline in an engine, total 3,769 kg.
The impact of transport on climate change is huge, as most forms of transport use fossil fuels, the combustion of which releases CO2 into the atmosphere. However, different types of transport have different impacts. Railways are the most environmentally friendly, while air flights are considered the most carbon intensive. Overall, cars are responsible for more than 80% of greenhouse gas emissions from transport (Fig. 3.2.6).
Figure 3.2.6 Breakdown of GHG emissions by different modes of transport
The UK estimated the emissions per passenger per kilometre travelled in different modes of transport. It shows that taking a flight leads to more than 20 times more emissions than taking the train, Eurostar (Fig. 3.2.7).
Figure 3.2.7 UK estimates of GHG emissions (gCO2e) from different modes of transport per passenger per km travelled
What can be done to reduce the impact of transport on the climate?
An obvious and highly effective method is to connect with people far away by telephone or video/audio communication instead of travelling to them. The most popular ways are various applications, such as Skype, Zoom, Viber, Telegram, and WhatsApp, which let you communicate with friends anywhere in the world where there is Internet.
The best way to reduce climate impacts from transport is using public transport. If you and your parents can choose how you travel, choose a train. Trains are a more environmentally friendly way to travel long distances than airplanes.
Railway transport technologies have made significant advances in the last decade. Locomotives and rolling stock are built from materials that are less heavy and bulky, and engines have become more efficient.
The number of high-speed trains and networks are growing worldwide, further improving the most energy-efficient mode of transport. The high-speed rail (HSR) network in China is the world’s longest and most extensively used – with a total length of 42,000 kilometres by the end of 2022. HSR is also an increasingly popular and efficient means of transport in Europe. Several countries have built extensive high-speed networks, e.g., Germany, France, the Netherlands, Spain, Italy and the UK, and there are now several cross-border high-speed rail links. Railway operators frequently run international services, and tracks are continuously being built and upgraded to international standards on the emerging European high-speed rail network.
Japan’s high-speed rail, called Shinkansen (Fig. 3.2.8), has recently increased its speed, and cut back its energy consumption by 40%. By reducing the bullet train’s weight and redesigning the shape and length of the nose to be more aerodynamic, the trains are now far more efficient and their use results in less emissions from transportation.
Figure 3.2.8 Energy-efficient ’Shinkansen’ high-speed train in Japan
Figure 3.2.9 The back of this train ticket in Italy informs passengers of their contribution to combat- ing climate change by choosing train travel
Many railway companies take the trouble to remind their passengers of the fact that rail travel is environmentally friendly (Fig. 3.2.9).
If you fly somewhere by plane, then choose airlines that use up-to-date aircraft: modern aircraft do less damage to the environment than older ones.
Speed is no longer the only, or even the main consideration in designing new models of aircraft. Designers today use a more holistic approach that takes account of the aircraft’s fuel efficiency as well as its carbon footprint during manufacture. Developers are looking again at turboprop aircraft, which seemed a thing of the past 20 years ago, as jet aircraft are faster. With improved design, turboprop aircraft could offer good air transport solutions.
Several airlines nowadays offer services to compensate CO2 emissions by their aircraft; there are Internet services that calculate CO2 emissions by all flights and invite passengers to compensate them. For example, a long-distance flight from Berlin to San Francisco by Lufthansa produces 1.4 tonnes of CO2 emissions per passenger. The suggested contribution for carbon compensation with a round trip in economy class is EUR29, which is used to help finance environmental projects related to climate change (Fig. 3.2.10).
Figure 3.2.10 Calculation of CO2 emissions and appropriate compensation for a Berlin–San Francisco return flight in economy class with Lufthansa
The International Civil Aviation Organization is working with its members to find the best ways to reduce emissions from the aviation sector. Along with efficiency improvements, one option is the use of Sustainable Aviation Fuel (SAF) – fuel that does not come from fossil fuels. Airlines already use it, usually blended with regular jet fuel. But many doubt whether SAF can be produced cheaply enough, or in large enough quantities, to meet the needs of the airline industry.
This is why there is growing interest in hydrogen as a fuel for aircraft. Hydrogen can store a lot of energy, e.g., from renewable electricity outside the peak hours of consumption and, when used as fuel, does not produce any CO2.
Reducing carbon emissions from car trips
If your parents are planning to buy a car, tell them about the energy efficiency of different motor vehicles. Suggest that they buy a car that at least meets Euro-4 standards (the Euro standards for vehicles regulate the content of hydrocarbons, nitrogen oxides, carbon monoxide and particulate matter in vehicle exhaust fumes).
The impact of cars on the environment can also be reduced by following ‘eco-driving’ rules, which reduce the carbon footprint from vehicle transport. Eco-driving does not just make sense for the environment – it is also cost-effective for car owners. Explain that to adults who drive cars!
The efficiency and environmental performance of vehicle engines is crucial. Until recently nearly all motor vehicles ran on fuel oil, diesel, or petrol, but now an increasing number of vehicles are running on gas. Fuel consumption using gas is much the same as with traditional motor fuels, but pollutant emissions from gas are much less.
You have probably also heard of ‘hybrid’ cars, electric cars and cars that run on bio- fuel. There are even exotic vehicles that can operate on nothing but water and air movement to make them go (‘wind-mobiles’), as well as solar-powered electric cars. A solar car racing championship held regularly in Switzerland is the best place to see all the latest solar- powered vehicle technologies in action. They are no longer a rarity: there are now solar filling stations in the USA, Bulgaria, Switzerland, Germany, and other countries.
Figure 3.2.11 Parking for electric vehicles
Eco-driving rules: how to reduce a vehicle’s carbon footprint
- Turn off the engine at stops and in stationary traffic
- Look after your car properly: correct adjustment of the wheels reduces fuel consumption by 5-10%, and regular maintenance saves up to 10% of fuel.
- Check tyre pressure regularly: even in urban environments, tyre pressure 25% below the recommended level requires 10% more fuel to make the car
- Use climate control and air conditioning Do not use them if the outside temperature makes them unnecessary. Don’t open the car windows if the climate control is operating.
- Brake smoothly to use the car’s inertia to best effect, reducing fuel
- Carry This is called ‘carpooling’. If you give a lift to three or four people going the same way, you reduce emissions by three to four times.
- Stay in the same lane: weaving from lane to lane increases fuel consumption and therefore CO2
- Start out early, avoid travelling at peak travel times, and plan your route in
- Drive at a moderate and steady Use the brake pedal less and use the car’s momentum more, brake and accelerate smoothly, watch the road ahead (don’t accelerate if there is a red light in sight). Smooth driving saves fuel.
- Do not carry excess loads on the roof. At speeds of 120 km/h an empty luggage carrier on the roof increases fuel consumption by 5–10%, a ski-carrier adds 10–20%, a bicycle 30%, and carrying a case full of luggage uses 35–40% more fuel.
Figure 3.2.12 An electric car
All leading car manufacturers today are designing cars that are more environmentally friendly compared to the previous models. Fuel consumption and environmental impacts have become as important to buyers as quality, safety, and price. Companies are competing with one another to save energy and reduce negative impacts on the environment.
Even though electric vehicles (EVs) have been in use since the beginning of the car industry in late 1900s and early 2000s, it was not until Tesla’s arrival in 2003 that the battery-electric revolution began in earnest. This provided a viable alternative in the efforts to decarbonize road transport and propelled EVs from 0.2% of new car sales a decade ago to 13% in 2022. Sales tripled between 2018 and 2022 and are expected to grow by around 30% annually in the next decade, making up half of all car sales by 2035. By 2025, EV sales are expected to reach almost 40% in Europe and China.
Greenhouse gas emissions in a city can be reduced by encouraging people to use public transport instead of cars. But that is possible only if public transport is fast and convenient, serves all parts of the city, links the centre with the suburbs, and is a more reliable and cheaper alternative to private cars. The use of gas, hybrid and electric engines in public transport can greatly reduce greenhouse gas emissions and improve air quality in cities.
Carpool: sharing journeys by car
Carpooling means carrying other people (including strangers) in your car, usually on regular (daily) journeys.
It is a good way of reducing pressure on the transport system in cities.
Carpooling dates from the 1940s when the Government of the USA was trying to save fuel for World War II needs by requiring car owners to carry passengers on any journey. The policy was successful in reducing fuel use, but its impact was limited because most car owners at the time were well-off and unwilling to share their cars with strangers.
In the 1970s, the city of Los Angeles introduced separate lanes on roads for use by car poolers. Nowadays they exist all over North America and in Europe as well (they are marked by road signs and a white rhombus on the road surface). Carpooling reduces the number of cars on the roads, reduces the demand for parking places and cuts down greenhouse gas emissions. The gains for passengers are evident: they spend less on fuel, vehicle repairs and parking.
Figure 3.2.13 Special carpool lanes on roads in the USA
Bicycles: the most environmentally friendly transport
Bicycles are the most environmentally friendly and healthy form of transport. Scientists have calculated that a person who travels to school or work every day by bicycle instead of using a car saves a tonne of greenhouse gas emissions every year.
Bicycles are the preferred means of transport in the Netherlands, Denmark, Norway, Sweden, and Germany. In Copenhagen, one in three people commute to work by bicycle. In Amsterdam, 40% of people use a bicycle every day, and the total length of bicycle lanes in the city is 400 km.
