Green cloud computing: five major providers compared

Updated 12 August 2026. Every provider claim on this page was checked against that provider's own published material on that date, and each claim links to the source it came from.

Cloud providers all publish something about their climate performance, and the claims do not line up. Renewable matching, carbon neutral, net zero and 24/7 carbon free energy mean four different things, and one provider often makes more than one of them.

This page sets out what green cloud computing means, what each of five major providers publishes about its own footprint, and how to read those claims without merging them. Every figure and target date below is linked to that provider's own disclosure, because a provider's own disclosure is the only source worth quoting on its emissions.

What is green cloud computing?

Green cloud computing is the practice of reducing the environmental impact of IT infrastructure: the electricity a data centre draws, the carbon intensity of the grid supplying it, the cooling load, and the embodied emissions of the hardware. It is not a defined standard, so the term carries whatever meaning the person using it intends.

Two mechanisms sit behind most of the efficiency argument. Server virtualisation puts more workloads onto fewer physical machines, which cuts idle capacity and the electricity that goes with it. Data centre consolidation moves workloads out of on-premises server rooms and into purpose-built facilities, where utilisation and cooling are managed at scale.

Those are environmental benefits of cloud computing rather than a definition of green cloud computing, and the difference matters once the numbers reach a report. Under the GHG Protocol, purchased cloud services are Scope 3 Category 1, purchased goods and services, for the customer, and Scope 1 and Scope 2 for the provider running the data centre. A provider's efficiency work reaches your own inventory only through the emission factor or the supplier-specific figure you apply to your cloud spend or usage.

Why does cloud emissions data matter for Scope 3 reporting?

Cloud spend is often one of the larger lines in an IT-heavy organisation's Scope 3 Category 1 total, and it is one of the few categories where the supplier publishes a customer-facing emissions figure at all. That makes it one of the easier lines to move off a spend-based average and onto supplier-specific data.

It also lands inside the frameworks reporting teams already work to. ESRS E1 under CSRD asks for material Scope 3 categories with the calculation method stated. CDP asks for Scope 3 by category and for the data quality behind each figure. SBTi target boundaries include Scope 3 where it is material. In every case the question asked of a cloud number is the same: where did it come from, and can a third party follow it.

What is the difference between carbon neutral, net zero and renewable matching?

These are four separate claims with four different meanings, and a provider that publishes one has not made the others. Upgrading a provider's wording when you record it creates a claim that provider never made, which is the fastest way to lose a cloud line in review.

• Renewable electricity matching. The provider contracts renewable generation, through power purchase agreements or energy attribute certificates, in a volume equal to its annual electricity consumption. The matching is annual and across a portfolio, not hour by hour in each grid.
• 24/7 carbon free energy. Carbon free supply matched to consumption in every hour, in every grid where the provider operates. A stricter measure than annual matching, and reported as a percentage of consumption, so read the percentage rather than the headline.
• Carbon neutral. Emissions inside a stated boundary balanced to zero, commonly using carbon credits or energy attribute certificates. The boundary is the part to read, because a claim covering operations is far narrower than one covering a value chain.
• Net zero. Deep absolute reductions across a stated boundary, with only residual emissions neutralised. The SBTi Corporate Net-Zero Standard requires validated near-term and long-term targets covering Scope 1, Scope 2 and Scope 3, so a net zero statement made outside that process is a company target rather than a validated one.

Record three things for every provider: the exact wording of the claim, the boundary it applies to, and the date of the disclosure it came from. None of the three survives a paraphrase, and all three are what an auditor asks for.

Five major cloud providers, and what each one publishes

Each of the five vendors below publishes environmental data about itself, and most of them also publish a tool that reports emissions from your own usage of their services.

1. Amazon Web Services (AWS)
2. Microsoft Azure
3. Google Cloud Platform (GCP)
4. IBM Cloud
5. Salesforce

Each section names the provider's own tool and quotes the provider's own wording for every figure and target date, with a link to the document it came from. A climate claim restated second hand is a claim you cannot defend, so take the wording from the linked source rather than from a comparison article, including this one.

1. Amazon Web Services (AWS)

AWS publishes the Customer Carbon Footprint Tool inside the AWS console. AWS states that the tool shows Scope 2 and Scope 3 emissions calculated using the market-based method by default, broken down by AWS Region and by service, with Amazon EC2, Amazon S3 and Amazon CloudFront reported separately and everything else grouped as Other. Data covers the previous 38 months, and new data is usually published between the 15th and 21st of the month after the usage occurs (AWS documentation). Note the gap: the tool does not report Scope 1, so it is an input to your cloud line rather than the whole of it.

Amazon's corporate claims are separate from the tool, and there are two of them with two different boundaries. The Climate Pledge, co-founded by Amazon and Global Optimism in 2019, is a commitment to reach net-zero carbon emissions by 2040. On electricity, Amazon states that 100% of the electricity consumed by Amazon was matched with renewable energy sources in 2025, for the third consecutive year. A 2040 target and an annual matching result are not the same claim, and they should stay apart in your report.

2. Microsoft Azure

Microsoft publishes the Emissions Impact Dashboard for Azure and Microsoft 365. Microsoft states that carbon emissions from Azure services are reported as Microsoft's Scope 1, 2 and 3 emissions, consistent with the GHG Protocol, and that collectively they become the customer's Scope 3 emissions (Microsoft documentation). That sentence is the one worth keeping, because it tells you where an Azure figure belongs in your own inventory before anyone argues about the number itself.

What a reporting team gets out of it:

• A scope split. Scope 1, Scope 2 and Scope 3 shown separately for the Microsoft services you consume, which maps onto the categories your inventory already uses.
• Monthly data at subscription level. Microsoft states that emissions data for a given month is available by the 15th day after the end of that month, and that the dashboard presents data at subscription level rather than resource level.
• A methodology you can cite. Microsoft states that the methodology and its implementation went through third-party verification against the GHG Protocol Corporate Accounting and Reporting Standard, under ISO 14064-3.

Microsoft's own targets sit in its environmental sustainability reporting. Microsoft states a commitment to become carbon negative by 2030 by reducing emissions across our operations and value chain, and removing more carbon than we emit, alongside water positive and zero waste commitments for the same year, and reports that it has matched 100% of its annual global electricity consumption with renewable energy. Carbon negative by 2030 is a target and the renewable matching is a reported result, so do not merge them into one line.

3. Google Cloud Platform

Google Cloud publishes Carbon Footprint in the Cloud console. Google states that it provides Scope 2 market-based and Scope 2 location-based emissions data alongside Scope 1 and Scope 3, analysed by Google Cloud service, project, region and month, that its calculation methodology is published, and that a third-party review statement concludes the methodology is a reasonable and appropriate way to calculate and allocate emissions from Google Cloud products under the GHG Protocol (Google Cloud).

Region is the part worth acting on. Google publishes a Google CFE% and a grid carbon intensity figure in gCO2eq/kWh for every Google Cloud region, and defines Google CFE% as the average percentage of carbon free energy consumed in a particular location on an hourly basis. The published figures run from 1% to 100% depending on the region (Google Cloud region carbon data), so workload placement is a decision with an emissions consequence attached rather than a latency decision alone.

Google also surfaces idle infrastructure. The Unattended Project Recommender flags projects with no recent activity. Turning an unused project off removes its emissions rather than reducing them, which is why it is usually the first thing to look at in a large cloud estate.

Google's own claims are two separate things, and the difference is the whole point of this page. Google states a goal to "operate on carbon-free energy, 24 hours a day, 7 days a week, 365 days a year" by 2030 (Google 24/7 carbon-free energy). Separately, Google reports that it matched 100% of its electricity consumption with renewable energy purchases in 2025, for the ninth consecutive year (Google 2026 Environmental Report). Annual matching is a reported result and 24/7 carbon free energy is a 2030 goal, so the two are not interchangeable.

4. IBM Cloud

IBM's approach is hybrid cloud, so workloads move between public and private infrastructure and can sit where capacity is used best. Red Hat OpenShift is the placement layer. IBM Turbonomic handles resource management, matching allocated capacity to what applications actually consume, so idle capacity is reclaimed instead of being paid for and powered.

A customer-level cloud figure for IBM services is normally built from your own spend or usage data. IBM publishes its own goals on its energy and climate page: to reach net-zero operational GHG emissions by 2030, and to procure 75% of the electricity it consumes worldwide from renewable sources by 2025 and 90% by 2030 (IBM). The word doing the work there is operational. That is a Scope 1 and Scope 2 boundary, not a value chain one, so it is a narrower claim than a net zero target covering Scope 3, and it should be recorded as the narrower claim.

5. Salesforce

Salesforce sells carbon accounting software of its own, Net Zero Cloud, and that is a separate thing from Salesforce the vendor sitting in your spend data. Keep the two apart: the product is something you might buy, the corporate footprint is something you report.

Net Zero Cloud is built for a corporate reporting team:

• Data consolidation. Activity data pulled from multiple sources into one inventory, with the origin of each figure retained for reports investors or regulators will read.
• Value chain engagement. Emissions data requested from vendors and tracked across the value chain.
• Target tracking and forecasting. Progress against stated targets, with projections for future emissions.

On its own footprint, Salesforce announced on 21 September 2021 that it had achieved "net zero residual emissions across its full value chain" and "100% renewable energy for its operations", covering Scope 1, Scope 2 and Scope 3, and stated that the achievements were confirmed by its third-party assurance provider (Salesforce newsroom). Read the two boundaries rather than the headline: the net zero claim is stated across the full value chain, the renewable energy claim is stated for operations only. Salesforce reports against both in its stakeholder impact report, which is where to check the current position rather than relying on the 2021 announcement.

On the software side, verification status varies widely across carbon accounting tools, and our benchmark post lists every vendor we checked, verified or not, with the verifier and the evidence for each: Who's really verified? A reality check on carbon software assurance.

So which cloud provider is the greenest?

These five cannot be ranked from their published claims, because the claims are not the same claim. Amazon holds a 2040 net-zero carbon target and reports annual renewable matching. Microsoft holds a 2030 carbon negative target across operations and value chain. Google reports annual renewable matching and holds a separate 2030 goal for hourly carbon free energy. IBM's 2030 net zero target is stated for operational emissions. Salesforce states net zero residual emissions across its full value chain, achieved in 2021. Five boundaries, five mechanisms, five dates. A league table built from that would be a league table of disclosure styles.

What does compare is the work in your own inventory. Take each provider's figure from its own disclosure, record the wording and the boundary, note the date, and apply it to your actual spend or usage with that provenance attached. That gives you a cloud emissions line a third party can audit, which no comparison article will ever give you.

DitchCarbon provides verified emissions data for over 2 million organisations, so procurement, sustainability and finance teams can measure and act on supply chain and portfolio emissions from one source. For a cloud vendor that means the provider's published figure where one exists, a calculated figure where it does not, and the source and change history behind whichever one you used. The DitchCarbon Portal calculator is verified to ISO 14064-3, limited assurance, by UL Solutions, renewed annually, and our industry emission factor methodology for spend-based Scope 3 Categories 1 and 2 was independently assessed by Globus Thenken in August 2025. Both reports are downloadable from the DitchCarbon trust centre, which is what makes a cloud line auditable and audit-ready rather than asserted.

See the emissions profile of the cloud providers in your spend

Your cloud vendors are already in your spend data, alongside every other organisation you buy from or invest in. DitchCarbon shows what each of them publishes, what has been calculated where nothing is published, and where the coverage gaps are, because gaps get shown rather than hidden. See how the company emissions data works.

If you are on the other side of the request, and a customer or an investor is asking your organisation for its emissions data, you can publish your figures once and reuse them instead of answering each survey from scratch. Claim your company profile.