Updated Carbon Methodology for the AWS Customer Carbon Footprint Tool

To support our customers’ sustainability journeys, we launched the Customer Carbon Footprint Tool (CCFT) in the AWS Billing and Cost Management Console in 2022. CCFT is a tool that helps customers track, measure, and review the carbon emissions generated from their AWS usage. The CCFT accounts for Scope 1 and Scope 2 emissions, as defined in the Greenhouse Gas Protocol, covering the full range of AWS products, including HAQM EC2, HAQM S3, AWS Lambda, and more. The emissions are provided as Metric Tons of Carbon Dioxide equivalent (MTCO2e).

Today, we are publishing three updates as part of our ongoing process to enhance the CCFT:

1. Easier data access: We’re making it easier for customer access to their carbon emissions data through the Billing and Cost Management Data Exports service.
2. More granular carbon data: We’re increasing granularity in the CCFT to show AWS Regions.
3. Updated, independently-verified methodology: We’re publishing an updated allocation methodology (v2.0) and accompanying methodology document and assurance, received by APEX.

As a result of these changes, customers can see carbon emissions that reflect the updated methodology for their AWS usage from January 2025 forward, and some customers may see changes in their estimated emissions figures. Consistent with common industry practices, CCFT data from December 2024 or earlier will still use the previous v1.0 methodology.

Today’s CCFT update in detail

1. Making it easier to access data
To make it easier to use the data from the CCFT, customers can now export their January data through AWS’s Billing and Cost Management Data Exports service. The carbon emissions data export delivers carbon emissions estimates for all the member accounts linked to their management account, when customers use AWS Organizations. The Data Exports service automatically delivers monthly updates in CSV or Parquet format to HAQM S3, allowing customers to automate the processing of carbon data across their entire AWS organization. With our customers’ first export, they will receive up to 38 months of historical data in their S3 bucket to allow for historical analysis. The data for December 2024 and earlier will be calculated using methodology version 1.0, while January 2025 onwards will use version 2.0. Customers can learn more about how to set up a Data Export in the Data Exports user guide.

2. AWS Regional Granularity
Customers can now see their carbon emissions broken down by AWS Region (ex: US East (Ohio)), with HAQM CloudFront CDN usage broken out as well (represented as a single Global Services category). This means customers can identify the Regions where their usage contributes the most to their carbon footprint to help them re-assess the regional distribution of their workloads on AWS.

3. The updated v2.0 methodology
Customers often use a wide array of AWS services across multiple regions and as a result, tracking and apportioning carbon emissions based on workloads can be challenging. While there is no industry standard for allocating carbon emissions for cloud usage to customers, the update to the v2.0 methodology leveraged existing standards to support the CCFT, including: GHG Protocol Corporate Standard, GHG Protocol Product Standard, ISO 14040/44 (LCA), ISO 14067 (Carbon footprint of products) and ICT Sector Guidance.

Customers can read more in the full-length methodology document, but here is a brief overview of the approach:

Scope 1 Emissions (Direct) Overview for v2.0
Scope 1 includes direct emissions from sources owned or controlled by AWS, such as fuel combustion in backup generators at our data centers. AWS receives Scope 1 activity data for the prior year in the first quarter of the following calendar year, as a result of our HAQM-wide annual assurance process. Then, we calculate estimated carbon data with site-level granularity and aggregate it to cluster-level. An AWS cluster can be an AWS Region (e.g., us-east-1, eu-central-1), or an AWS CloudFront Edge Cluster (e.g., CF in North America, CF in South America).

Scope 2 Emissions (Indirect) Overview for v2.0
Scope 2 includes indirect emissions from purchased electricity, and the CCFT uses the market-based method. For instance, grid mixes such as the percent of carbon free energy from the grid–and emission factors (kgCO2e/kWh)–are updated annually and validated as part of HAQM’s carbon footprint assurance. For Scope 2, the CCFT uses emission factors based on the geographical location and follows the emission factors hierarchy recommended by the Greenhouse Gas Protocol.

The v2.0 Allocation Overview
The model first allocates emissions to server racks at the AWS cluster level, then maps those emissions to specific AWS services based on their resource consumption. The model accounts for dependencies between foundational services with dedicated hardware (ex: HAQM EC2) and non-foundational services built on top of that infrastructure (ex: AWS Lambda). Finally, emissions are attributed to each customer account utilizing those services.

The model works as follows:

1. 1. 1. Allocate estimated cluster-level emissions to server racks in the cluster.
      2. Allocate estimated carbon emissions associated with server-racks to AWS cloud services based on utilization of server racks resources, accounting for inter-dependencies.
      3. Allocate estimated carbon emissions associated with each cloud service to individual customer accounts.

Some customers may see their estimated emissions change as a result of the updates to the CCFT’s methodology because v2.0 allows for a more precise attribution of carbon emissions to customers, which is a better reflection of their actual usage of AWS services.

Three key updates in the v2.0 methodology:

1. 1. 1. We now allocate unutilized capacity to all AWS customers. AWS provisions enough server racks to effectively meet all customer needs. At times, this means we have unused capacity. The estimated carbon emissions associated with the unused capacity are now proportionally allocated to all customers using AWS services. This is because the GHG protocol, its associated ISO standards on product-level carbon reporting (ISO 14040/14044), and the cloud and data center services industry sector guidance require inclusion of all waste and inefficiencies required to provide the product/service to the customer.
      2. Improved logic to allocate estimated emissions from AWS services without dedicated hardware such as AWS Lambda or HAQM Redshift, between AWS customers and HAQM teams.
      3. Update to allocate overhead associated with running the data centers, such as estimated carbon associated with networking racks and launching new regions for AWS customers.

We will continue to improve our tooling, working backward from customers’ needs. Customers can learn more about these updates by reading the methodology document and checking out the CCFT user guide and the Data Exports user guide.

Moving forward, we’ll continue to post updates on our methodology based on evolving data, climate science and more, and will continue to invest in features and functionalities that help customers in their sustainability journeys.

Commitment to The Climate Pledge

To learn more about The Climate Pledge—HAQM’s commitment to reach net-zero carbon by 2040—and our investments in sustainability across our businesses, including AWS, please visit our sustainability site here.