Digital transformation is lauded as a planet-saving measure thanks to hyperscale cloud providers' scalable infrastructure and history of eco-conscious messaging. But what type of impact do Amazon Web Services (AWS), Google Cloud and Microsoft Azure actually have on the environment?

As environmental, social and governance (ESG) regulations continue to evolve, enterprises of all sizes are striving to work with cloud providers that maximize the benefits of moving to the cloud and accurately market their environmental impact. Whether it's the corporate buzz around sustainability or the record-breaking heatwave that piqued your interest in this topic, it's clear that hyperscale cloud technology will play an integral role in the future trajectory of climate change.

[ Related: Big Tech ESG update: How Cisco, HPE, VMware, IBM and Dell stack up ]

In an attempt to aid IT decision-making that supports sustainability-focused operations, here is a somewhat definitive (but entirely objective) ranking of the hyperscalers' environmental impact.

Wait, somewhat definitive? Yes, you read that right.

While SDxCentral's editorial team doesn't have access to the resources of industry-ranking organizations like the Carbon Disclosure Project (CDP) or analyst firms, we also aren't accepting payment in return for consulting services, gated reports or editorial content. This is good old-fashioned reporting, and our rankings are based on publicly reported data and metrics. (See our Methodology at the end of this article.)

Environmental impact can be a highly subjective arena, so we're narrowing our scope to focus on Amazon, Google and Microsoft's sustainability targets, annual emissions totals, included emissions categories, legacy emissions strategy, renewable energy stature and data center power use efficiency (PUE).

Google Cloud Platform (GCP)

In 2007 Google claimed to be the first major company to reach a carbon neutral status across its operations, which meant the tech giant bought enough carbon offsets and renewable energy to technically calculate its scope 1 and scope 2 operational emissions as zero.

The hyperscaler’s current carbon neutral status represents scope 1, scope 2 (market-based) and scope 3 emissions from business travel and employee commuting, but does not include scope 3 emissions from the other 13 subcategories, according to Alphabet’s most recent CDP disclosures.

Ten years after the start of its carbon neutral messaging, Google began matching 100% of the company's annual energy use with renewable energy purchases.

And in 2020, Google continued its purchase of "high-quality" carbon credits to erase (at least on paper) its environmental impact dating back to the first days of Google. That year the hyperscaler also issued $5.75 billion in sustainability bonds to fund new or existing projects with a focus on environmental or social responsibility.

Carbon-free energy, net-zero commitments 

The kingpin of Google’s sustainability ambitions is the hyperscaler’s commitment to run its data centers and offices on 24/7 carbon-free energy (CFE) by 2030, meaning it will match each hour of its electricity consumption with CFE on every grid where the provider operates.

In the traditional renewable energy approach, a company makes up for its nonrenewable energy usage by supplying renewable energy to power grids anywhere in the world. But this means that the energy it directly uses is still likely from traditional carbon-intensive power grids based on fossil fuels.

Google’s commitment, however, is to eliminate nonrenewable energy sources for its own operations and fund green energy elsewhere. According to Google's 2022 environmental report, 66% of its 2021 data center electricity use was matched on an hourly basis with carbon-free sources.

CFE provides a pathway for Google to reach its commitment to net-zero emissions across its operations and value chain – including scope 3 emissions resulting from the use of sold consumer hardware, data center servers and networking equipment – by 2030.

Specifically, Google’s net-zero strategy aims to reduce 50% of the hyperscaler’s emissions compared to 2019 levels, with investments in nature-based and technology-based carbon removal accounting for any remaining emissions.

Water, resource use

Although electricity use constitutes a majority of Google's operational impact, data center water use isn't negligible. The hyperscaler is committed to replenish 120% of its water consumption by 2030 while "actively supporting water security and ecosystems'' where the company operates.

In addition, Google aims to "maximize the reuse of finite resources across our operations, products and supply chains.'' For example, in 2021 the hyperscaler reported 27% of the components used in Google server upgrades were refurbished hardware. And rather than shipping unusable components to landfills, the hyperscaler aims to erase leftover data and resell those components.

Google’s score: 🌿🌿🌿🌿

Based on Google’s reported emissions, publicized ambitions, current initiatives, data center PUE and renewable energy use, among other factors, we’re giving the hyperscaler a score of 4 out of 5.

According to Google’s latest environmental report, it released 45,073 metric tons (MT) of scope 1 carbon dioxide equivalent (CO2e) emissions; 1,823,132 MT of location-based scope 2 emissions; 6,576,239 MT of market-based scope 2 emissions and 9,503,000 MT of scope 3 emissions in 2021.

In addition, Google data centers claim a PUE score of 1.10, where 1.0 represents optimal efficiency.

Let’s talk about that legacy footprint situation. One major reputational benefit of removing a legacy carbon footprint is the picture it paints for stakeholders. It aims to create the sentiment that Google, as a company, had effectively never existed or taken advantage of how easy it was to make money while contributing to the development of climate change – however unwittingly those contributions may have been. For example, a company’s economic growth is tied, by its nature, to increases in resource consumption, including carbon intensive fossil fuels.

While it’s likely Google has a few NDA’ed projects going on behind the scenes, even they most likely can’t go back and remove – let alone accurately measure – the extent of the company’s impact on climate change.

With that said, Google was one of the first companies to attempt to address its historical emissions, so we do give the hyperscaler credit for that. Some action will always be better than no action at all, and Google’s tenure in the industry lends itself well to being a role model.

Microsoft Azure

Microsoft joined the cloud race in 2008 and has been marketing its operations as carbon neutral since 2012.

But behind those claims was Microsoft’s investment in carbon offsets that avoid emissions (for example, by paying a landowner to not cut down trees) rather than remove emissions that have already been released (by planting new trees).

In 2020 the hyperscaler announced its intention to be carbon negative across scope 1, scope 2 and scope 3 categories by 2030, which means it will reduce its carbon emissions by 50% and remove additional carbon from the atmosphere to reach a negative carbon total.

That year the hyperscaler also launched a $1 billion climate innovation fund with its own capital to support the development of carbon reduction, capture and removal technologies.

Carbon negative, clean energy commitments

Microsoft’s move toward carbon negative supports the company’s statement that carbon “neutral is not enough to address the world’s needs,” according to President Brad Smith. In comparison to net-zero ambitions, carbon negative goals include extra plans for carbon removal or capture that – with some carbon math – push footprints into negative territory.

With the introduction of its carbon negative strategy based on technologies like afforestation, reforestation, soil carbon sequestration and direct air capture (DAC), Microsoft aims to remove more carbon than it emits to eliminate its legacy direct and electricity consumption-based emissions by 2050.

As an interim step, Microsoft plans to reduce its scope 1 and scope 2 operational emissions to almost nothing by the middle of the decade.

Specifically, the hyperscaler plans to use 100% renewable energy by 2025 through power purchase agreements (PPAs) that cover all fossil fuel-based energy use at Microsoft data centers, buildings and campuses. In 2022 Microsoft reported 62% of the energy it used was directly from renewable sources, meaning that the remaining 38% was nonrenewable and accounted for by the hyperscaler’s funding of renewable energy elsewhere.

In the same vein as Google, Microsoft aims by 2030 to match 100% of its energy use on an hourly basis with carbon-free energy. The hyperscaler also plans to shift its global campus operations vehicle fleet to electric vehicles by 2030.

In terms of scope 3 emissions, Microsoft is targeting at least 50% reduction from a 2020 base year by the end of the decade. The company expects its internal carbon tax and other supply chain sustainability efforts will fuel these reductions.

Water, resource use

To address the cloud’s water use, Microsoft is working toward a goal to be water-positive by 2030, meaning the hyperscaler will lower its water consumption, replenish more water than it uses, provide 1.5 million people with water and sanitation access and engage in water policy.

Microsoft has also committed to reuse or recycle 90% of its cloud computing hardware assets by 2025. The company reported four of its data centers renewed their zero waste certifications in 2022, which helped it reach 82% of cloud hardware recycled or reused that year.

Microsoft’s score: 🌿🌿🌿

Based on Microsoft’s reported emissions, publicized ambitions, current initiatives, data center PUE and renewable energy use, we’re giving the hyperscaler a score of 3 out of 5.

According to Microsoft’s environmental data, it released 139,413 MT of scope 1 CO2e emissions; 6,381,250 MT of location-based scope 2 emissions; 288,029 MT of market-based scope 2 emissions and 16,340,000 MT of scope 3 emissions in 2022.

Noelle Walsh, Microsoft’s VP of cloud operations and innovation, shared in a blog that the hyperscaler’s newest generation of data centers, including one being constructed in Chile, have a design PUE of 1.12. The hyperscaler does not, however, provide its older data centers’ PUE or an average data center PUE in its environmental reporting.

Amazon Web Services (AWS)

AWS emerged as the first major cloud provider in 2006 and has held a majority share in the cloud infrastructure and services market for years.

In 2019, Amazon committed to reach net-zero carbon emissions by 2040 through what it dubbed The Climate Pledge, a program that doubles as a net-zero bandwagon for other organizations with similar sustainability ambitions.

Amazon plans to reach net-zero by prioritizing lower-carbon alternatives, transitioning to renewable energy, engaging suppliers, driving efficiency and neutralizing carbon.

Net zero, clean energy commitments

As an interim step to net-zero, Amazon aims to source 100% renewable energy for its operations, which include AWS data centers, Amazon fulfillment centers and physical stores. The company claims to be five years ahead of this 2030 goal, with completion expected in 2025.

According to 2022 data, 90% of the company’s annual electricity consumption, including a significant number of computing regions, came from renewable sources like wind and solar power projects.

To address its scope 3 emissions from customer use of Amazon devices, the company plans to invest in additional wind and solar farm capacity equivalent to global Echo, Fire TV and Ring device energy use by 2025.

Once that 100% renewable energy mark is reached, Amazon’s research suggests transitioning on-premises cloud workloads to AWS could lower organizations’ cloud-related carbon emissions by up to 96%.

Water, resource use

Similarly to its hyperscale rivals, Amazon is committed to be water-positive by 2030, implying it will return to local communities more water than its data center operations consume.

In the data center, AWS is expanding the lifespans of servers to reduce hardware-related emissions. Beginning in 2020 the hyperscaler provided software updates that extended useful server life from three years to five years, and in 2022 it extended server life to five years and networking equipment lifespans from five years to six years.

The hyperscaler also utilizes reverse logistics hubs where functional but retired data center hardware is securely tested, repaired and reused.

AWS’ score:🌿🌿

Based on Amazon’s reported emissions, publicized ambitions, current initiatives, data center PUE and renewable energy use, we’re giving the hyperscaler a score of 2 out of 5.

According to Amazon’s latest environmental report, it released 13,400,000 MT of scope 1 CO2e emissions; 2,890,000 MT of market-based scope 2 emissions and 54,980,000 MT of scope 3 market-based emissions in 2022 – a much larger footprint than Google or Microsoft.

Amazon only reports its scope 2 and scope 3 environmental impact data based on market-based reporting methodologies, which tend to provide lower numbers based on averages rather than granular location-specific data.

While noncloud emissions are less material to hyperscale services, they are still important to consider in the broader context of which companies are supported by IT decision-maker spending.

The portion of Amazon’s carbon emissions that stem from its vast noncloud operations likely impacts the company’s ability to fully measure, report and address its environmental impact. For example, Amazon has not publicly committed to address its legacy emissions and does not publicly report its data center PUE, both of which negatively impacted the hyperscaler’s ranking.

Methodology