Reducing greenhouse gas emissions associated with travel

ANU has committed to reducing greenhouse gas (GHG) emissions from energy, waste, university travel and direct on campus activities to net zero by 2025 and below zero by 2030 as part of the ANU Below Zero Initiative. 

Travel for University-related activities accounts for at least half of total ANU GHG emissions within the scope of Below Zero. This large proportion of emissions points to the integral role travel has for University staff and students. However, it also contributes heavily to climate change and its impacts on the environment and our way of life.  

Is there a way to balance the need to travel with reducing our contribution to climate change? COVID-19 had a paralysing effect on travel, especially in Australia, forcing us to be creative in engaging with our networks. Can we take some of these newfound travel alternatives forward into the future and link them with tools to reduce our impact when we decide to travel? 

After consultation with staff and students from across the University, we have developed a voluntary pilot program to assist individuals in considering their greenhouse gas footprint while making travel plans.   

The proposed approach seeks to improve ANU staff and students' ability to make informed decisions around their travel, including making the GHG impacts of travel transparent and facilitating low emissions approaches. It is strongly advised that staff and students consider their health and safety while making travel plans. 

To participate in the pilot, we ask that you work through the following five steps:

Step 1. Review the Draft Guidelines for Low Carbon Travel

Access these guidelines here


Step 2. Consider each step of the decision tree for when and how to travel

The ANU Community is encouraged in all circumstances to consider alternatives to travel. Still, it is recognised that some travel is necessary to achieve scholarly, professional and institutional outcomes and impact. Necessary travel is travel which demonstrably and significantly enhances research, teaching, learning or engagement. 

Best practice for travel decision tree
1. Is your travel necessary? If no, avoid travel
2. Reduce your need to travel for ANU-related activities

3. Travel without flying

4. Fly when no alternative and choose low emission itineraries
5. Offset emissions from travel using high calibre carbon credits *

*ANU is developing a University carbon offset scheme to be launched by 2025


Step 3. Calculate the greenhouse gases associated with your travel plans and choose the lowest emission itinerary available, with consideration of your health and safety while travelling

Remember to account for a round trip where it is appropriate. See the FAQs for more detailed information on these calculators.

For flying:

Please input the airport/city for your origin, destination and any stopovers, where indicated, then click "Compute" to get the emissions in kilograms. 

NB:  There is an increased warming effect that other non-CO2 emissions, such as nitrous oxides, have when released at high altitudes. This increased effect can be fairly significant and is referred to as radiative forcing.  Therefore, please double the calculator's figure for flight emissions to include these additional emissions

Flight emissions calculator


For land-based travel modes:

This calculator uses distance to calculate emissions, please find the number of kilometres for your trip. Remember to calculate the distance to your destination, any other stops (if practical) and the return to the origin city.  

Calculate distance at Google Maps, Bing Maps or any mapping platform. Please ensure to calculate the kilometres for the correct mode of travel, e.g. journey via roads for cars or buses or choose rail if travelling by train.

Car emissions calculator

Bus/Rail calculator


Step 4. Report the emissions associated with your trip in the ANU Travel Approval eForm 

Calculate the emissions associated with your booked itinerary, note down the total kilograms provided by the calculators and enter it into the appropriate box when prompted in the ANU Travel Approval eForm.


Step  5. Send us your feedback

You are welcome to provide feedback vis with this online form or send any suggestions or questions to the Below Zero team on



  • What consultation has happened in developing this pilot program?

In August 2020, an online survey of the ANU community was conducted as a foundation for consultation. 183 students and 374 staff responded, indicating high levels of support for the Below Zero Initiative, together with high levels of willingness to engage in processes of change. This included changes to patterns of travel. You can see the full report for the survey here.

In Sept/Oct 2020, we had a University-wide consultation on what the ANU community thought we should be doing to reduce emissions as fast as possible. You can see the report from the consultation here.

Since February 2021, a Below Zero Travel Working Group, comprising academic and professional staff from across the University have been meeting regularly and consulting with staff, student representatives and groups across ANU to develop recommendations on how to effectively inform travel-related decision-making and reduce travel-related emissions.

  • What approach was taken when developing this pilot?

The key recommendation of the Below Zero Travel Working Group is that, in order to reduce emissions, we need to create an enabling culture for informed and responsible decision-making around reducing travel. Travel will continue to be part of the University's work and as a result, the aim is to modify and reduce travel whenever possible. This requires a process of cultural change, as opposed to developing a system that is based on compliance or auditing.  The working group recognises the importance of recognition of the self-managed/relative autonomous nature of academic decision-making and the equity considerations that attach to career-enhancing travel opportunities for staff and students. Our approach has been to capitalise on intrinsic motivation from overarching commitment to act to reduce climate change, reflected in the survey results above, together with enabling alternatives to travel assisted by computational and technological platforms and supporting individuals and business units' ability to gauge the carbon footprint of their planned travel.

There is also a secondary but important goal of measuring and improving capacity to report travel-related emissions, as our current data and reporting are inadequate. 

  • Why are we using multiple calculators?

A thorough review of publicly available GHG calculators has revealed that there is currently no single GHG calculator that accurately reports these emissions across land and air travel to university standards.  The development of GHG emission calculators is a rapidly moving field. It is anticipated that the second stage of this component of the pilot would be the development of a more integrated approach where a single GHG calculator would be integrated into the travel booking process. If you are interested in being a part of building this platform, let us know at   

  • How to best use the calculators?

It is advised that these calculators be used after you've decided that travel is necessary, to understand which methods and routes have the smaller number of emissions. For instance, you can compare the various modes of transportation (e.g. coach, train, car or flight) to get to one destination or different flight path options to your destination. In all cases, you should consider your health and safety while choosing which itinerary is best.

For land-based travel - The Carbon Footprint Calculator is hosted by Carbon Footprint, a company based out of the UK which assists businesses seeking to become carbon neutral. Their calculator has the capability to calculate emissions for multiple transport modes based on the distance travelled. The tabs at the top of the window allow users to toggle between the various types of travel modes.

First, obtain the distance being travelled (via a mapping service like Google or Bing) then enter this result into the appropriate part of the calculator. For car travel, you will be asked about the type of car you plan to use. If you are not sure of the vehicle specifics, choose the "average car" options to the best of your knowledge.

For bus or coach travel - if travelling interstate, use the coach option. For travelling around a city via public transport, use the bus option. Note that the calculator for train travel is based on electric trains which operate in the UK and Europe, as well as in some areas of Asia and the Americas. Unfortunately, Australian train travel is via diesel engine locomotives, so these results do not accurately reflect train travel in Australia. There is no calculator available for diesel train travel, please use the calculations for coach travel until this option is made available.

Read more about the Carbon Footprint Calculator on their website.

For travelling by aircraft - The calculator for flights is provided by the International Civil Aviation Organization (ICAO), a specialised agency of the United Nations. The methodology for calculating emissions using the ICAO Carbon Emissions Calculator is based on accurate, real-world flight data. This type of data is not available through the Carbon Footprint calculator, so we've elected to use the ICAO Emissions Calculator for flights to obtain a more accurate result.

To use the ICAO calculator, you must know the airport names for all of the stops on your itinerary. You may include multiple itineraries if necessary to get a more comprehensive number of emissions for your trip. Note that this calculator pulls real-world flight path information reported by airlines. If you are not able to see your destination in the drop-down menu after entering the airport at origin, this may be because you will need to include any stopover airports for your trip.

A radiative forcing index is not included in the ICAO calculator. To account for the impact of non-CO2 GHGs while flying, multiply the result from the ICAO calculator by two. This will provide a more comprehensive estimate of GHGs associated with that trip.

Read more about the ICAO Carbon Emissions Calculator methodology on their website and FAQ pages.

  • What is radiative forcing?

There is an increased warming effect that other non-CO2 emissions, such as nitrous oxides, have when they are released at high altitudes. This increased effect can be fairly significant and is referred to as radiative forcing.

The Intergovernmental Panel on Climate Change released a special report in 1999, called Aviation and the Global Atmosphere stating that these emissions compound the effects of climate change by two to four times that of carbon dioxide.  

The amount of radiative forcing depends on many factors, such as altitude and flight duration, so producing a singular factor by which to account for this effect is difficult. For this reason, the ICAO have chosen to not include this in their methodology. For this travel pilot exercise, we've chosen to balance accuracy and ease by asking you to increase the emissions from air travel by a factor of two, or doubling the result from the ICAO calculator. This will more accurately reflect the impacts of the flight being examined.

Read more on the challenge of tackling aviation's non-CO2 emissions here, and how radiative forcing impacts your choices on the various modes of travel here.

  • Is there an easier way to compare flight emissions before booking?

We are working towards an integrated service that includes GHG considerations during the booking process. In the meantime, we offer an alternative way to understand the impacts of travel through the tools in this pilot program. We appreciate any constructive feedback on how we can improve the experience of making more sustainable decisions around travel. Provide your feedback here.

Booking websites are starting to show emissions associated with the various route options. For instance, Skyscanner shows routes with fewer emissions by labelling them as the Greener Choice. Greener flights are calculated based on aircraft type, capacity and number of stops. Similarly, Google Flights displays the emissions for each flight shown in the search result as well as how those emissions compare against the typical amount for that route. Read more about how to use this feature and how they calculate emissions here.

  • What are all the different travel mode options for my journey?

It is not always easy to determine the various ways to get from point A to B, especially when travelling to and within new destinations. Rome2rio is an online service that searches across thousands of multi-modal routes that will get you from one place to another. They do not yet provide emissions associated with each transportation mode or route. Take the results from your search on Rome2rio and input the different options into these calculators provided above to compare the emissions profile for each route.

  • How do I find sustainable accommodation?

There are a few well-known websites that help search for accommodation options that have adopted a badge system for promoting sustainable practices through hotels. You can read more about how these websites measure sustainability as well as how to use this feature for each site at the links below.

TripAdvisor Green Leaders Travel Sustainable

  • What are some travel alternatives?

Virtual meetings

There are times when a conversation with colleagues located in other cities can be facilitated by a virtual meeting that can save everyone time and money. Setting up a meeting for multiple participants using digital conferencing tools will effectively cancel all transportation emissions that would have occurred otherwise. Alternatively, does your cohort have multiple meetings throughout the year? Make the collective decision to hold at least half of these virtually. This would reduce the emissions associated with your travel by half as well as those associated with your colleagues from other places.

Digital events

Are you organising a conference or series of seminars or meetings, which includes participants from interstate or internationally? There are options available to host this event either fully or partially online. This might not only reduce the emissions associated with the event but also increase the ability or access for potential attendees to participate via a more simplified engagement process.

Multi-nodal events

How about hosting a multi-node conference or meeting? A multi-node conference hosts in-person participants at multiple locations across the country or the globe. Individuals can travel to their closest node, joining other colleagues at the same satellite location and gaining that in-person experience without having to travel more broadly, reducing the number of emissions associated with their attendance.

Want to see more information about reducing emissions associated with hosting events at ANU? View the ANU Low carbon emissions events sub-guide.

Want more options for travel alternatives? The Below Zero Travel Working Group is working on different ways ANU can best support its staff and students in finding alternatives to travel. You can expect to hear more on travel alternatives later in the year.

Do you have ideas or have you found a great alternative to travel in certain situations? We would love to hear about it. Send us an email at


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