What is 'human composting'—and how does it work?

What should happen to your body after you die? It's hardly a topic you'd bring up over dinner, but it's a decision that will eventually need to be made, either by you or by those you leave behind.

In Australia, the choice has traditionally been between burial and cremation. However, concerns about environmental impact, limited cemetery space and the desire for more sustainable alternatives have encouraged interest in other approaches.

These include natural burial, water cremation and shrouded cremation—where no coffin is used.

Now, New South Wales has become the first Australian state to pass legislation allowing another option: "human composting," technically known as natural organic reduction, and legally termed "terramation." The process uses microorganisms to transform human remains into a compost-like material.

The idea of turning a human body into compost might sound unusual, or even unsettling. But how does it actually work? Is it a better alternative to existing methods?

To answer these questions, we first need to understand decomposition and its essential role in nature.

The body doesn't simply disappear

Throughout history, humans have developed rituals to protect, preserve and dress the dead. Some want a quick return to the earth, while others seek to preserve the body.

From ancient burial vessels and elaborate tombs to coffins, shrouds and embalming, these practices reflect cultural and religious beliefs. They also affect how bodies decompose.

Decomposition begins shortly after death. As cells break down, microorganisms already living inside the body, along with those from the surrounding environment, begin breaking down its tissues.

Carrion insects, particularly flies and beetles, can feed on soft tissues remarkably quickly when temperature, moisture and access to the body are favorable. This is nature's way of recycling organic matter and returning nutrients to the environment.

The body does not simply disappear. But the timescale and extent of its transformation depend on the conditions, processes and materials involved.

What happens after a burial?

Traditional burial usually places a body in a coffin or casket, 1.5 to 2.7 meters underground (5 to 9 feet).

Depending on how the body was prepared and the environmental conditions, decomposition can take years or even decades.

In our research on 408 human bodies exhumed from cemeteries in northern Italy, we found that bodies placed inside sealed stone tombs could take more than 40 years to skeletonize—the final stage of decomposition where all soft tissue is gone, and only bones remain. Meanwhile, bodies buried in sandy or gravelly soils became skeletons in less than 10 years.

Traditional burial raises concerns about cemetery space, the environmental impact of coffins (most are lined with plastic), embalming chemicals and even the fibers in clothing.

Long before modern green burial, Aboriginal peoples had their own burial traditions, including Wiradjuri practices involving carved trees marking burial sites. These practices hold deep cultural significance and reflect connections to Country.

Natural or green burial avoids embalming and uses biodegradable materials, such as a shroud or simple coffin, allowing the body to decompose naturally in the soil.

However, decomposition can cause the ground to sink and release substances that affect nearby plants, so planting a tree directly over a fresh grave is not recommended. Some cemeteries also restrict grave markers and availability varies across Australia.

How does 'human composting' compare?

Terramation speeds up natural decomposition under controlled conditions.

The body, wrapped in a natural shroud, is placed in a specially designed vessel with organic materials such as wood chips, straw and alfalfa. These help maintain the moisture and airflow needed for microorganisms to break down tissues.

Temperatures of around 55–70°C (131–158 degrees Fahrenheit), combined with controlled moisture and oxygen, speed up decomposition and help destroy pathogens. Depending on the design of the vessel, it's also periodically turned 360 degrees or gently rocked side to side, to speed up the process.

Within two to three months, terramation produces approximately one cubic meter (35 cubic feet) of nutrient-rich, compost-like material that can support plant growth.

Not everything in the body breaks down completely. Bones and teeth may need further breaking down. Someone will also have to remove artificial materials, such as dental implants, surgical screws, joint replacements and silicone implants (the same is true for cremated remains).

Terramation was pioneered in the United States by Katrina Spade, who launched the Urban Death Project in 2014 and later founded the green funeral home Recompose.

Human composting is now permitted in 14 U.S. states. In Australia, plans for the first facilities are progressing, with the first terramation anticipated no sooner than 2029.

While the new NSW legislation opens the door to terramation, regulations, specialized facilities and sufficient demand are still needed before it becomes a practical option.

Which option is better?

There is no simple answer. Each method—traditional burial, natural burial, cremation, aquamation (water cremation) or terramation—has environmental benefits and drawbacks.

Sustainability claims for each deserve scrutiny, and we don't have the full data to weigh them up. And returning our nutrients to the earth doesn't necessarily offset the environmental impact of our lives.

Ultimately, whether we become ashes, remain buried or return to the earth as compost, our bodies are part of nature's cycle. The question is not whether we decompose, but how, where and how quickly.

What happens to our bodies after death is a deeply personal choice. Discussing our wishes while we are alive, making informed decisions and preparing ahead can help ensure our wishes are respected, giving those we love a greater sense of closure when the time comes.

Who's behind this story?

Gaby Clark

MA in English, copy editor since 2021 with experience in higher education and health content. Dedicated to trustworthy science news. Full profile →

Andrew Zinin

Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Citation: What is 'human composting'—and how does it work? (2026, October 26) retrieved 26 October 2026 from https://phys.org/news/2026-10-human-composting.html

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