GHG Inventory

The measurement of greenhouse gas (GHG) emissions produced by an event is a popular sustainability indicator chosen by event producers.

There is no debate to be had that the GHG emissions of an event should be measured. Measuring GHGs is necessary for so many reasons; from our responsibility to society to disclose our impacts, through to measurement to enable effective management.

Where the controversy lies is in the question of what should be included in the scope of measurement of an event's GHGs. Each event will have a certain set of circumstances, responsibilities and impacts, which combine to factor various GHG contributors in or out of the final 'footprint'.

There's no straightforward, clearly defined, industry-wide accepted scope of inclusion for the GHG impacts of events. Measurement is fraught with controversy and confusion, especially about how far down the line the GHG emissions calculation should go.

There are wildly varying methodologies and inclusions that events are using in measuring their GHG inventories. Some events are including electricity only and calling that a 'footprint', while others are going into extravagant detail and measuring everything that has a sniff of CO2 about it - such as the embedded (lifecycle) GHGs in food served.

Communications Challenge

Many events are claiming measurement of their 'carbon footprint', but the important detail on what this means is lost or buried. To responsibly claim to have measured a 'carbon footprint' events must simultaneously declare and justify what they included their scope of measurement.

As there's currently no widely agreed methodology for an event 'carbon footprint' calculation, this makes claims by events around their 'carbon footprint', a communications challenge for the industry.

A contributing factor is we don't have common measurement protocols, or a system to accurately and independently assess performance claims. There's no one our industry needs to report to, or claims questioned by.

Can we have an industry-wide methodology?

Because of the huge range of events taking place every day across the world, and the corresponding huge variety of what could be interpreted as the event's responsibility, an industry-wide directive or methodology may not even be practical and could be impossible to establish for our industry. But we do need guidance on methodologies to follow and what claims are acceptable to communicate.

We could make a start by following guidance developed by such protocols and standards as the GHG Protocol (international), ISO 14064 (international), PAS 2060 (UK) and the National Carbon Offset Standard (Australia), amongst others.

The National Carbon Offset Standard (Australia) sets the following principles to consider in the calculation of a ‘footprint’ include:

  • Relevance: ensure the GHG inventory appropriately reflects the GHG emissions attributed to the event.
  • Completeness: account for all GHG emissions within the defined boundary. Disclose and justify exclusions.
  • Consistency: ensure methodologies from event to event are consistent to allow for meaningful comparisons.
  • Transparency: ensure collation of GHG emissions data can be evaluated by auditors. Disclose assumptions and reference methodologies and data sources.
  • Accuracy: Ensure quantification is accurate.

Setting a Boundary for event GHG Accounting

First you must set the boundary of which event venues/sites/activities are to be included in calculations. This includes;

  • Venues, sites, activities which are in direct control of the organising body; and
  • Venues, sites, activities which are not in direct control of the organising body but which are perceived to be ‘part of the event.

A single event, for example, is easy to determine a boundary for. A city-wide festival, which has a concert series in a park produced by the event organising body, as well as satellite events and venues through the city under the event’s banner, will find determining boundary a very important first step.

Operational control is usually the deciding factor, however stakeholder perception is also a contributor to deciding what would be included within the boundary of reporting. Operational control is defined as where the event has authority to introduce or implement operating policies, health & safety policies or environmental policies.

What should be measured?

The Greenhouse Gas Protocol prescribes that Scope 1 and Scope 2 emissions are included. While Scope 1 and Scope 2 are valid and necessary inclusions in an event's GHG inventory, they are inadequate to authentically cover what common sense would say should be included as part of an event’s actual GHG impacts.

Scope 1 emissions are those from sources that are owned or controlled by the event – ‘direct’ emissions. For an event, this translates to 'onsite' activities such as;

  • mobile power generators (fuel consumption)
  • bottled gas and mains gas (ignition of gas occurs onsite)
  • fuel used in site plant, equipment and vehicles (onsite)
  • vehicles owned by the company (used on or offsite)
  • if waste is disposed of at the event site and emissions are estimated to be created (ie methane from buried waste) these could also be included in Scope 1 emissions.

Scope 2 emissions from ‘indirect’ sources – purchased heat, steam or electricity used by the event. For example most relevant to events is;

  • mains/grid electricity supply
  • fuel used for heating (indoor venues)

But what about Scope 3?

Scope 3 emissions are ‘other indirect’ emissions – these are emissions that occur because of an event’s activities but occur at sources owned by others. This could include:

  • transport of employees (including all paid contractors, talent, crew)
  • hotel nights for event production (crew, talent, staff, contractors)
  • 'significant additional' freight impact of equipment, goods and services required by the event or waste produced by the event.
  • hired transportation (shuttle buses, taxis, limos, boats, aircraft)

And then going deeper:

  • emissions embodied in the products and materials purchased by the event
  • transport of products and equipment for the event
  • energy used or emissions created in processing waste (liquid & solid)
  • transport of waste (liquid & solid)
  • energy and transport to produce and supply water

and then:

  • attendee travel – the single GHG contributor for many events
  • hotel nights of attendees (for example delegates at a conference/convention)

Looking back to protocols and guidance developed by government, the National Carbon Offset Standard (Australia) prescribes that at a minimum organisations should report Scope 3 emissions from:

  • Business travel of employees
  • Disposal of waste generated (landfill emissions)
  • Use of paper in the course of its business

You can see that this is wholly inadequate for what we know are the biggest impacts of events - attendee travel.

The GHG Protocol guides Scope 3 emissions calculations by firstly determining relevance to the organisation (event). Determining relevance is guided by:

  • include them if particular Scope 3 emissions are large or relatively large compared with the event’s scope 1 and scope 2 emissions
  • include them if particular Scope 3 emissions are deemed critical by key stakeholders
  • include them if the organisation (event) could undertake or influence the potential reduction

The event must transparently document and disclose which Scope 3 emissions have been included in its carbon footprint when making any assertions about emissions reductions.

So What Scope 3 do we include?
We need to decide how far we cast our net over what to include in Scope 3 emissions calculations.

  • Do we include attendee travel? If we use the premise of  ‘direct control or significant influence’ then in some cases attendee travel would be included.
  • Emissions from the processing and transport of waste, water, sewage?
  • Embedded energy in materials, food, supplies?
  • Freighting of materials and products, equipment, infrastructure, etc?
  • How do we separate what would be considered staff commuting, from event crew/workforce transport?
  • Do you include only air travel for talent/performers/speakers/VIPs, or their ground transport as well?

Carbon Offsetting and ‘Neutrality’

Because of the huge variation in methodologies and inclusions an event's GHG calculations, purchasing of carbon offsets and 'carbon neutral' claims being made, is a concern. Our industry must devise some protocols around what should or could be a valid claim of carbon neutrality, including scope and boundary, methodology, reporting assurance and the language used around performance claims.

The first step should be to identify and estimate likely GHG emissions, next to make measurable reductions through our own actions, and only then head for carbon neutrality via carbon offsetting.

In the UK, the British Standards Institution (BSI) has published BSI PAS 2060 – Specification for the demonstration of carbon neutralityThis standard offers guidance to organisations on quantifying, reducing and offsetting GHG emissions. It guides us to include all emissions resulting from core activities to the production of the event. But that is still not a cut and dried directive on what would be considered core.

The event industry needs to still discuss what is appropriate to include as Scope 3 emissions as ‘core’ emissions and what ‘non-core’ emissions could also be voluntarily reported which the event takes responsibility for.

Guidance on when to include attendee travel needs to be developed, along with when does it become ‘bothersome’ to try and gather primary GHG emissions data for other Scope 3 emissions, versus, perhaps ‘secondary’ data that has been provided by consolidating benchmarked figures from our industry’s activities.

PAS 2060 requires the following to calculate GHG emissions and then make carbon neutrality claims:

  • Identify and define what will be included in a carbon emissions calculation.
  • Define, clearly communicate and adequately justify what is included, the methodologies undertaken and emissions factors used.
  • Measure and disclose what the emissions for an event were, or in advance, anticipated to be.
  • Take action to make measurable reductions in carbon emissions.
  • Report/disclose performance indicating what reductions were achieved and  how they were achieved


  • The event industry needs to discuss what is appropriate to include as Scope 3 emissions as ‘core’ emissions and what ‘non-core’ emissions could be voluntarily reported.
  • Guidance on when to include attendee travel needs to be developed
  • Guidance on when to try and gather primary GHG emissions data for 'other Scope 3 emissions', versus, perhaps using ‘secondary’ data that has been provided by consolidating benchmarked figures from our industry’s activities.
  • Guidance on acceptable claims such as 'carbon footprint' and 'carbon neutrality'


Written by Meegan Jones ( for Sustainable Event Alliance. Do not replicate without permission.