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Airport Carbon Accreditation (ACA)

Airport Carbon Accreditation (ACA) is a carbon management certification standard for airports developed by ACI Europe. The programme independently assesses and recognises the efforts of airports to manage and reduce their carbon emissions with six levels of award.

The programme is institutionally endorsed by ECAC (European Civil Aviation Conference) and EUROCONTROL and is overseen by an independent Advisory Board including representatives of the European Commission, ECAC, EUROCONTROL, ICAO, UNEP (United Nations Environmental Programme) and Manchester Metropolitan University.

> See the list of accredited airports worldwide and their level of accreditation


What are the benefits of an airport being accredited?

  • To acknowledge your diligent efforts in managing and reducing carbon emissions
  • ​To attain tangible and quantifiable reductions in emissions
  • To enhance operational efficiency and cost-effectiveness through proficient carbon emissions management
  • To effectively communicate your environmental commitment to external stakeholders, thereby bolstering the airport's reputation and credibility.

Level 1: MAPPING - Footprint measurement 


  • Determine the operational perimeter and the emissions sources within that boundary which are Scope 1 and Scope 2 sources, as defined by the Greenhouse Gas Protocol
  • Collect data and calculate the annual carbon emissions for the reference year of application for those sources
  • Compile a carbon footprint report
  • Prepare an environmental policy and ensure it is publicly accessible
  • Engage an independent third party to verify the report before submission, to ensure that the carbon footprint calculation is in accordance with ISO14064 and accreditation requirements.

Level 2: REDUCTION - Carbon management towards a reduced carbon footprint

Meet all Level 1 requirements, plus: 
  • Provide evidence of effective carbon management procedures, including target setting
  • Show that a reduction in the carbon footprint has occurred by analysing the carbon emissions data of consecutive years

Level 3: OPTIMISATION - Third-party engagement in carbon footprint reduction

Meet all Level 2 requirements, plus:
  • Create a comprehensive plan for engaging with third-party operators
  • Presentation of evidence of engagement with third-party operators to reduce wider airport-based carbon emissions.
  • Expand the carbon footprint assessment to encompass various Scope 3 emissions, such as: landing and take-off cycle emissions, surface access to the airport for passengers and staff, staff business travel emissions and other Scope 3 emissions which the airprot chooses to include.

Level 3+: NEUTRALITY - Carbon neutrality for direct emissions by offsetting

Meet all Level 3 requirements, plus:
  • Offset its remaining Scope 1 and 2 carbon emissions (GHG Protocol) to show its commitment to achieving carbon neutral operations for all direct emissions and indirect emissions over which the airport has control, using internationally recognised offsets

LEVEL 4: TRANSFORMATION – Transforming airport operations and those of its business partners to achieve absolute emissions reductions.

  • Policy for absolute emissions reduction
  • Include additional (to Level 3) Scope 1 and Scope 3 emissions into its carbon footprint
  • Formulate a long-term absolute carbon emissions reduction target aligned with the IPCC 1.5°C or 2°C pathways
  • Develop a Carbon Management Plan to achieve the target.
  • Development of a Stakeholder Partnership Plan

LEVEL 4+: TRANSITION – Compensation for residual emissions with reliable offsets

Meet all Level 4 requirements, plus: 
  • Offset the residual carbon emissions over which the airport has control, using internationally recognised offsets
  • Strengthen stakeholder engagement.
> For more information, read our F.A.Q.

Source: Airport Carbon Accreditation