View source for CO2 emission tracker

= CO₂ Tracking & Eco Footprint Report =
The CO₂ Tracking feature calculates the estimated carbon footprint associated with an event and produces an '''Eco Footprint Report''' in PDF format.

The report gives you a breakdown of the emissions associated with the travel and accommodation included in your event, helping you understand the environmental impact of your event logistics.
[[File:CO2 Emissions PDF.png|thumb|CO2 Emissions PDF]]

== What does the report calculate? ==
The footprint calculation can include emissions from different types of event logistics, including:

* '''Flights''' – calculated based on the distance travelled, number of passengers and applicable flight emissions factor.
* '''Accommodation''' – calculated using the number of room nights and the applicable emissions factor for the accommodation's country.
* '''Ground transport''' – where the transport type and journey information can be matched to an applicable emissions factor.
* '''Other eligible transport''' – the calculation can take other bookable transport into account where sufficient information is available to calculate its footprint.

The exact items included in a report depend on the information available for the bookings and whether an applicable emissions factor exists for that type of activity.

== Understanding the report ==
The report starts with a '''Total Footprint''' summary. This shows the estimated footprint for each calculated category and the overall total, expressed in tonnes of CO₂e.

For example, a report might show:
{| class="wikitable"
!Section
! align="right" |Footprint
|-
|Flights
| align="right" |80.061 t
|-
|Accommodation
| align="right" |0.564 t
|-
|'''Total'''
| align="right" |'''80.625 t'''
|}
The report also shows the number of people, computed travel legs and uncosted items associated with the calculation.

=== Calculation details ===
The '''Details''' section shows how individual items contribute to the total footprint.

For each calculated item, the report can show:

* The entity or booking being calculated
* The activity amount, such as passenger-kilometres or room-nights
* The emissions rate used
* The resulting CO₂e value

For example, flights are calculated using passenger-kilometres and a corresponding kgCO₂e/passenger-km factor, while accommodation uses room-nights and a kgCO₂e/room-night factor.

== Assumptions ==
Where booking information is incomplete, the report may make an assumption so that the item can still be calculated.

Any assumptions made are listed in the '''Assumptions''' section of the report.

For example, if a flight booking does not contain a cabin class, the calculation assumes '''economy class'''.

The report also explains how journey information has been interpreted where necessary. For example, a multi-day car journey may be represented as individual one-way journeys based on the available booking information.

== Uncosted items ==
Not every item in an event will necessarily contribute to the calculated footprint.

If an item cannot be calculated, it appears in the '''Uncosted items''' section of the report, together with the reason it was excluded.

This can happen when:

* There is not enough information to calculate a journey distance.
* The transport type does not have a corresponding published emissions factor.
* The item represents an activity that is outside the scope of the available emissions factors.
* The item is not itself a journey, such as a parking booking.

For example, in the sample report, hire cars are not calculated because their pick-up and drop-off addresses are stored as plain text without coordinates, meaning a journey distance cannot be determined. The report also identifies activities and parking as outside the scope of the calculation.

'''Important:''' An uncosted item does not mean that the booking has been ignored by the event system. It means that the information available does not allow an emissions calculation to be made using the current methodology.

== How are emissions calculated? ==
The report uses published emissions conversion factors to calculate estimated CO₂ equivalent ('''CO₂e''') emissions.

The example report uses the '''UK Government GHG Conversion Factors for Company Reporting''', published by DESNZ, using the 2026 edition and methodology version 2026.2.

The calculation generally combines the relevant activity data with an emissions factor. For example:

'''Travel distance × passengers × applicable emissions factor = estimated CO₂e'''

For flights, the report uses passenger-kilometres and the relevant factor for the journey and travel class.

For accommodation:

'''Room nights × applicable country factor = estimated CO₂e'''

The example report calculates 35 room-nights in the United States using the published factor for a hotel stay in that country.

== Flight emissions and radiative forcing ==
Flight emissions factors in the report include '''radiative forcing''', accounting for the additional non-CO₂ effects associated with aviation at high altitude.

The methodology also includes an uplift for these non-CO₂ high-altitude effects within the flight factors.

== Why use the Eco Footprint Report? ==
The report gives event teams a consistent way to understand the estimated carbon impact of their event logistics.

It can be used to:

* Understand the environmental impact of planned event travel and accommodation.
* Identify which areas of an event contribute most to its estimated footprint.
* See the assumptions used in the calculation.
* Identify bookings that could not be included in the calculation.
* Provide a documented footprint calculation for an event.

The report is intended to provide an '''estimated footprint based on the booking data and emissions methodology available to the system'''. It should therefore be read alongside the assumptions and uncosted items sections rather than treated as a complete measurement of every environmental impact associated with an event.