Transport is one of the top emitting sectors globally, and within many major (developed) countries.
In this guide, we look at potential solutions for reducing emissions in the transport industry.
Summary – How To Reduce Greenhouse Emissions From Transportation
There might be two components to reducing greenhouse emissions from transportation:
1. Understanding the main causes of emissions in transport
These might generally be …
Passenger vehicles and light trucks as the type of transport that emits the most as a % share compared to other types of transport. As an example, passenger cars and trucks made up 17% of the US’s total GHG emissions in 2016. epa.gov also outlines that behind passenger cars and light duty trucks: ‘… sport utility vehicles, pickup trucks, and minivans account for over half of transport sector emissions in the US’. Freight may also require some consideration in countries like Canada where freight makes up to 41% of total transport emissions, according to nrcan.gc.ca.
Petroleum based products/fuels (like gasoline and diesel) compared to other types of fuel and energy
Internal combustion engine cars as the main type of car that uses petroleum based products/fuels
Cities specifically, where the highest concentrations of people and vehicles are
Although improvements have been made in things such as fuel efficiency and tailpipe emission rates, the total distance travelled annually by all vehicles is not decreasing i.e. consumption is not decreasing
You can read more about the main causes of emissions in transport, and the carbon footprint of different types of transport in this guide.
2. Having some consideration for the main causes of transport related emissions in the solutions
So, solutions might be based around things such not adding to the total numbers of vehicles on the road, not adding to the total number of miles or kilometres driven every year, using cleaner fuels and alternate types of vehicles, and improving city designs to help transport become more efficient
It’s not as simple as just switching to electric and hybrid cars though – overall consumption (total distance travelled and use of GHG emitting fuels) may need to be reduced
Using modes of transport that have a lower per passenger, per unit of distance travelled emission rate might be of benefit too
Public transport and mass transit options like trains and trams might be one way to decrease the number of vehicles on the road and improve per passenger emission rates (and ultimately cut consumption rates)
Both these approaches can help cut down on total consumption in the transport sector – which might be the best approach for reducing emissions in cities
Simply switching to electric vehicles and alternative fuel vehicles may not provide the reduction in emissions that cutting overall consumption might
In terms of alternate fuel and alternate system vehicles …
The most fuel efficient hybrid models might be the most eco friendly passenger car on the market in the short to medium term. But, some data shows some popular hybrids being overtaken in terms of a lower emissions footprint by popular full electric models after the first 100,000 miles travelled
Electric cars might provide some solutions, but still have drawbacks, and practical challenges to their use
In general, electric cars might be better in the long term – but not until the cities using them have lower carbon electricity grids. There’s also the issues such as scaling production, mining of precious metals, and being economically competitive – just to name a few
If we use China as one example, they intend on having 5 million electric cars on the road by 2020, but the problems with that are that China’s energy grid is still mostly run on coal, and some sources state that both electric cars and traditional cars in China have similar CO2 emissions and PM2.5 levels per kilometer driven
You can read more about China’s challenge in transitioning from coal to cleaner forms of energy in this guide
Beyond the factors above, large scale external factors like population growth, economic growth and level of industrialization also feed into an increased demand for travel
*Note – This guide contains generalized solutions only. A greenhouse gas solution plan should be put together for each individual country, or city. It should take into account their specific transport industry and emission factors.
Global Greenhouse Gas Emissions From The Transport Sector/Industry
Some sources indicate that transport makes up about 14% of total global emissions as a sector on average.
But, each country has a different emissions share by sector, so each individual country should requires a look at their emissions breakdown by sector/industry.
China and the US are of particular significance as they are currently the two biggest annual emitters of GHGs in total.
Also, note that different sectors emit different types of GHGs in different quantities, so this requires consideration too. As one example, methane and nitrous oxide from agriculture might be more significant than in any other sector.
Carbon dioxide is said to be the main GHG emitted from the transport sector/industry
How To Reduce Greenhouse Emissions From Transportation – Potential Solutions
Some of the key solutions to reducing emissions from transportation might include:
Focussing specifically on technology and practices/strategies to decrease emissions in the areas that produce the most carbon dioxide in transport – passenger vehicles and light trucks (personal vehicles, and freight industry vehicles), petroleum based products/fuels (like gasoline and diesel), internal combustion engine cars, and cities specifically (where there are more people and vehicles)
We’ve already increased fuel efficiency and decreased tailpipe emissions over the last few decades, but total distance travelled (miles or kilometres) by all vehicles per year needs to be reduced as a main solution
Part of reducing the total distance travelled annually might involve decreasing the total number of vehicles in circulation
External and large scale social factors like population size and economic growth and demand (as well as level of industrialization) play a part here too
If there are any more improvements to be made in fuel efficiency and reduction of tailpipe emissions, these should obviously be developed too. These might include vehicle weight, vehicle design, features like regenerative braking and carbon capture devices in the tailpipe, and other technologies, design, and materials
Reducing the per passenger mile/kilometer emissions of all vehicles (this takes into account the carrying capacity of each vehicle and type of transport)
Part of reducing per passenger mile/kilometer emissions might involve more public transport (where the average number of people per trip increases compared to a regular passenger car), or greater use of per passenger, per distance efficient forms of transport
When it comes to addressing emissions specifically for cities (as opposed to towns and rural areas), various sources note that mass transit, the reduction of single person vehicles, and reducing consumption (as opposed to relying on electric vehicles), are all key solutions to focus on.
Cleaner and higher quality fuels than regular petroleum based products. Cleaner fuel might include renewable energy being used for electric vehicle batteries. Higher quality fuel could be more efficient
For electric vehicles and hybrid vehicles, how clean the electricity is matters. So, cities may have to make progress in making their power grid cleaner over time if majority of electric and hybrid cars are getting electricity from the power grid
Whilst some may point to electric vehicles being the answer, the problem with electric vehicles is that they have their own set of pros and cons
Hybrid cars could provide some type of answer to the drawbacks of electric cars in the short term in terms of emissions reductions, but it depends on several factors. There’s a few articles that outline the potential emission footprints of models like Prius’ and Teslas from production, through to the first 100,000 miles
Apart electric cars and hybrid cars, hydrogen fuel cell cars and other alternate fuel or alternate type cars might help reduce emissions (as long as the energy source is cleaner than petroleum based fuels)
Other solutions to decrease emissions in transport might include:
Consider how working from home and remote work, either full time or a certain number of days per week, can decrease overall commute, in terms of miles/kilometres travelled by workers per year
More easy to access information for consumers on the eco rating and efficiency of vehicles (including production footprint, and the first 100,000 miles footprint)
Improvement in design of cities and urban areas for efficient car use – less need for extended travel, and constant accelerating and braking
Improving driving practices and vehicle maintenance
Public transport rails that run parallel with main commuter roads
More people walking and biking – living car free for one year is estimated by some sources as one of the highest impact actions individuals can take to reduce their own carbon footprint
Consider the use of carbon offsets
Consider the use of legislation, regulations and possible tax schemes for emissions from vehicles. One example is emission standards for new cars. epthinktank.eu discusses this in greater detail
Looking at carbon footprint at the manufacturing stage of vehicles is also worth it, despite most emissions coming from the operation stage
It’s worth noting that more sustainable transport has several potential solutions (that currently involve trade offs) that might help address emissions and air pollution
EPA.gov, c2es.org, greenfleet.com.au, ec.europa.eu and sciencedaily.com all outline some more potential solutions
Carbon Footprint Of Different Types Of Transport
Read more in this guide about the carbon footprint of different types of transport, and a general breakdown of emissions in the transport industry.
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