Ammonia, long known as the backbone of global fertiliser production, is increasingly being examined as a potential pillar of the clean energy transition. Energy-dense, carbon-free at the point of use, and already traded globally at scale, ammonia is emerging as a candidate fuel and a carrier of hydrogen. But its climate promise comes with a contradiction: today’s dominant method of producing ammonia carries a heavy carbon footprint.

A new study by researchers from the MIT Energy Initiative (MITEI) attempts to resolve this tension by answering a foundational question for policymakers and industry alike: under what conditions can ammonia truly become a low-carbon energy solution?

A global view of ammonia’s future

In a paper published in Energy and Environmental Science, the researchers present the largest harmonised dataset to date on the economic and environmental impacts of global ammonia supply chains. The analysis spans 63 countries and evaluates multiple production pathways, trade routes, and energy inputs, offering a comprehensive view of how ammonia could be produced, shipped, and used in a decarbonising world.

“This is the most comprehensive work on the global ammonia landscape,” says senior author Guiyan Zang, a research scientist at MITEI. “We developed many of these frameworks at MIT to be able to make better cost-benefit analyses. Hydrogen and ammonia are the only two types of fuel with no carbon at scale. If we want to use fuel to generate power and heat, but not release carbon, hydrogen and ammonia are the only options, and ammonia is easier to transport and lower-cost.”

Why data matters

Until now, assessments of ammonia’s climate potential have been fragmented. Individual studies often focused on single regions, isolated technologies, or only cost or emissions, making global comparisons difficult.

“Before this, there were no harmonized datasets quantifying the impacts of this transition,” says lead author Woojae Shin, a postdoctoral researcher at MITEI. “Everyone is talking about ammonia as a super important hydrogen carrier in the future, and also ammonia can be directly used in power generation or fertilizer and other industrial uses. But we needed this dataset. It’s filling a major knowledge gap.”

To build the database, the team synthesised results from dozens of prior studies and applied common frameworks to calculate full lifecycle emissions and costs. These calculations included feedstock extraction, production, storage, shipping, and import processing, alongside country-specific factors such as electricity prices, natural gas costs, financing conditions, and energy mix.

Comparing production pathways

Today, most ammonia is produced using the Haber–Bosch process powered by fossil fuels, commonly referred to as “grey ammonia.” In 2020, this process accounted for about 1.8 percent of global greenhouse gas emissions. While economically attractive, it is also the most carbon-intensive option.

The study finds that conventional grey ammonia produced via steam methane reforming (SMR) remains the cheapest option in the U.S. context, at around 48 cents per kilogram. However, it also carries the highest emissions, at 2.46 kilograms of CO₂ equivalent per kilogram of ammonia.

Cleaner alternatives offer substantial emissions reductions at higher cost. Pairing SMR with carbon capture and storage cuts emissions by about 61 percent, with a 29 percent cost increase. A full global shift to ammonia produced with conventional methods plus carbon capture could reduce global greenhouse gas emissions by nearly 71 percent, while raising costs by 23.2 percent.

More advanced “blue ammonia” pathways, such as auto-thermal reforming (ATR) with carbon capture, deliver deeper emissions cuts at relatively modest cost increases. One ATR configuration achieved emissions of 0.75 kilograms of CO₂ equivalent per kilogram of ammonia, at roughly 10 percent higher cost than conventional SMR.

At the far end of the spectrum, “green ammonia” produced using renewable electricity can reduce emissions by as much as 99.7 percent, but at a significantly higher cost—around 46 percent more than today’s baseline. Ammonia produced using nuclear electricity showed near-zero emissions in the analysis.

Geography matters

The study also reveals that the viability of low-carbon ammonia depends heavily on geography. Countries with abundant, low-cost natural gas are better positioned to produce blue ammonia competitively, while regions with cheap renewable electricity are more favourable for green ammonia.

China emerged as a potential future supplier of green ammonia to multiple regions, while parts of the Middle East showed strong competitiveness in low-carbon ammonia production. In contrast, ammonia produced using carbon-intensive grid electricity was often both more expensive and more polluting than conventional methods.

From research to policy

Interest in low-carbon ammonia is no longer theoretical. Countries such as Japan and South Korea have incorporated ammonia into national energy strategies, including pilot projects using ammonia for power generation and financial incentives tied to verified emissions reductions.

“Ammonia researchers, producers, as well as government officials require this data to understand the impact of different technologies and global supply corridors,” Shin says.

Zang adds that the dataset is designed not just as an academic exercise, but as a decision-making tool. “We collaborate with companies, and they need to know the full costs and lifecycle emissions associated with different options. Governments can also use this to compare options and set future policies. Any country producing ammonia needs to know which countries they can deliver to economically.”

As global demand for low-carbon fuels accelerates toward mid-century, the study suggests that ammonia’s role will depend less on ambition alone, and more on informed choices—grounded in data—about how and where it is produced.

Octopuses are already odd enough — eight arms, no bones, a brain that wraps around their throat — but one detail still stops people in their tracks: they have three hearts. Not two. Not one. Three.

And the reason is surprisingly practical.

Three Hearts for a Tough Life Underwater

Two of the hearts — called branchial hearts — do a very specific job: each one pushes blood through a gill, where it can pick up oxygen. The third, the systemic heart, takes that oxygen-rich blood and pumps it to the rest of the body.

In other words: two hearts to breathe, one heart to live.

Why Their Blood Is Blue

Another strange thing: their blood isn’t red at all.

It’s blue — literally blue — because it’s based on copper, not iron.

The copper-based protein, hemocyanin, works better in the cold, low-oxygen parts of the ocean where many octopuses live. It keeps them alive in places where most animals wouldn’t last a minute. But it’s not very efficient, so their bodies need extra pumping power to keep the oxygen flowing.

Evolution’s answer? Give them more hearts.

A Heart That Stops When They Swim

Here’s the part that sounds almost fictional: when an octopus swims, its main heart actually stops.

Imagine going for a swim and your heart taking a break halfway through. That’s why octopuses prefer to crawl on the seafloor. Swimming is simply too tiring — it literally costs them heartbeats.

The Ocean’s Quiet Genius

When you combine all of this — the blue blood, the three hearts, the bizarre nervous system, the ability to vanish into their surroundings — you get one of the most unusual and surprisingly intelligent creatures on the planet.

Octopuses don’t just survive in harsh oceans; they’ve evolved in ways that feel almost alien. And maybe that’s why we’re endlessly fascinated by them — they remind us how strange and creative life can be.

When an earthquake strikes, we experience its violent shaking on the surface. But new research from MIT shows that most of a quake’s energy actually goes into something entirely different — heat.

Using miniature “lab quakes” designed to mimic real seismic slips deep underground, geologists at MIT have, for the first time, mapped the full energy budget of an earthquake. Their study reveals that only about 10 percent of a quake’s energy translates into ground shaking, while less than 1 percent goes into fracturing rock. The vast majority — nearly 80 percent — is released as heat at the fault, sometimes creating sudden spikes hot enough to melt surrounding rock.

“These results show that what happens deep underground is far more dynamic than what we feel on the surface,” said Daniel Ortega-Arroyo, a graduate researcher in MIT’s Department of Earth, Atmospheric and Planetary Sciences, in a media statement. “A rock’s deformation history — essentially its memory of past seismic shifts — dictates how much energy ends up in shaking, breaking, or heating. That history plays a big role in determining how destructive a quake can be.”

The team’s findings, published in AGU Advances, suggest that understanding a fault zone’s “thermal footprint” might be just as important as recording surface tremors. Laboratory-created earthquakes, though simplified models of natural ones, provide a rare window into processes that are otherwise impossible to observe deep within Earth’s crust.

MIT researchers created the “microshakes” by applying immense pressures to samples of granite mixed with magnetic particles that acted as ultra-sensitive heat gauges. By stacking the results of countless tiny quakes, they tracked exactly how the energy distributed among shaking, fracturing, and heating. Some events saw fault zones heat up to over 1,200 degrees Celsius in mere microseconds, momentarily liquefying parts of the rock before cooling again.

“We could never reproduce the full complexity of Earth, so we simplify,” explained co-author Matěj Peč, MIT associate professor of geophysics. “By isolating the physics in the lab, we can begin to understand the mechanisms that govern real earthquakes — and apply this knowledge to better models and risk assessments.”

The work also provides a fresh perspective on why some regions remain vulnerable long after previous seismic activity. Past quakes, by altering the structure and material properties of rocks, may influence how future ones unfold. If researchers can estimate how much heat was generated in past quakes, they might be able to assess how much stress still lingers underground — a factor that could refine earthquake forecasting.

The study was conducted by Ortega-Arroyo and Peč, along with colleagues from MIT, Harvard University, and Utrecht University.