The challenges of data centres trying to meet their climate goals

A team of researchers from Microsoft and WSP Global has published a groundbreaking study in Nature demonstrating that advanced cooling methods like cold plates and immersion cooling can cut data centre emissions by 15-21%, energy use by 15-20%, and water consumption by 31-52% compared to traditional air cooling.

The life cycle assessment, led by Husam Alissa of Microsoft, Mukunth Natarajan, and Praneet Arshi of WSP, among others, also provided actionable insights to help the Information and Communications Technology (ICT) industry meet its climate goals. “Our [life cycle assessment] has shown that reducing data centre energy use through advanced liquid-cooling technologies will lead to marked reductions in data centre environmental impacts,” the authors wrote in their paper.

Electronics versus rising temperatures

Electronics heat up like crowded kitchens: billions of microscopic switches (transistors) are like cooks working nonstop, bumping into each other while flipping electrical dosas (data). The tighter they are packed — that is smaller the chips are — or the more tasks they handle, the more they collide and create heat, just like a packed kitchen gets hotter, needing fans and ACs to cool down. A laptop is like a kitchen with one burner: a simple fan suffices. A data centre is like a thousand laptops working at full speed in a single room, generating heat like a massive bonfire compared to a single candle. Without cooling, the intense heat will melt the hardware in minutes.

Heat slows down electrons, like runners in thick mud. If the chips get too hot, they may malfunction or altogether fail. Cooling keeps them running smoothly, ensures a longer lifespan and fast and reliable performance, and prevents heat damage. Just like an athlete needs water to stay sharp in a race, electronics need efficient heat removal.

Race to cut emissions

In data centres, cooling consumes nearly as much power as computing, like an AC fighting oven heat in a busy kitchen. To curb climate change, the ICT industry needs to cut emissions by 42% by 2030 (from its 2015 levels). Data centres need greener designs that use less energy and water, and have lower greenhouse gas emissions to help meet global climate goals and keep warming below 1.5°C. Urgent upgrades to energy, efficiency, and cooling are critical.

Chips are also getting smaller, faster, and more energy-efficient, like upgrading your phone every year without draining the battery faster. As the demand for cloud services increases, so must data centre capacities and heat mitigation strategies.

Ice packs and oil baths

Two prominent cooling techniques have emerged as viable alternatives. Cold plates, also known as direct-to-chip cooling, are small heat exchange modules equipped with microchannels to enhance heat transfer. Think of a cold plate like an ice pack strapped to a feverish forehead, but for computer chips. It sits directly on hot components, with small coolant-filled channels absorbing heat into tiny channels filled with coolant.

When it becomes warmer, the coolant — such as 25% polyethylene glycol and 75% water — flows away and dumps the heat outside, while fresh coolant entering the veins keep the cycle going. This method is more efficient than fans the same way swapping a handheld fan for an ice-cold bath is better. In a cold-plate system, the liquid-to-air heat transfer ratio ranges from 50% to 80%, sometimes more.

The second technique, immersion cooling, is like dunking a hot frying pan into a pool of heat-hungry oil instead of blowing air on it. The oil, which is good at dissipating heat within itself, soaks up 100% of the pan’s heat and keeps it from overheating. In the one-phase cooling method, like swirling cold water around the pan, the oil stays liquid but carries heat away. In two-phase cooling, the technique works the way water cools in a mud pot: the coolant fluid bubbles into vapour at a low temperature, rises into a cooling coil, condenses, drips back down, and repeats. “These techs cut corrosion, boost reliability, and slash carbon footprint — all while running silent without fans,” the researchers wrote.

Pioneers like Microsoft and Alibaba are already deploying these systems at scale.

Green or just less dirty?

To truly lower the carbon footprint of cooling technologies, scientists, policymakers, and lawmakers need to weigh its full impact. While the new solutions are innovative, they face hurdles. Coolant fluids involve different regulations, and complex designs delay deployment. Using them is like swapping plastic straws for paper: they are greener, but not without trade-offs. The world could end up trading one ecological problem for a different, even worse, one.

If the electricity for an electric car comes from a coal power plant, the car’s carbon footprint is still high. Similarly, cooling gains can backfire if pollution is merely shifted elsewhere.

The study team’s cradle-to-grave life cycle assessment evaluated air-cooled, cold-plate, and immersion cooling across emissions, energy, and water use, proving that sustainability demands systemic thinking, not isolated fixes.

Twin engines of a green data centre

The assessment revealed that with grid electricity, cold plates and immersion cooling cut greenhouse gas emissions by more than 15%, energy use by more than 15%, and water consumption by more than 31% — making them superior to conventional cooling technologies in use today. With 100% renewable energy, the team found the cuts could jump to 13% for emissions, 15% for energy, and 50% for water.

“Switching to renewables slashes emissions by 85-90%, energy use by 6-7%, and water demand by 55–85%, regardless of cooling tech,” the researchers wrote.

Thus, life cycle assessments can reveal sustainability trade-offs either within the same cooling technology or when comparing different technologies. Ultimately, the calculus is clear: ICT’s climate future hinges on tackling how the industry cools its data centres.

T.V. Venkateswaran is a science communicator and visiting faculty member at the Indian Institute of Science Education and Research, Mohali.