Our options when it comes to disposing of our mortal remains have up until recently been pretty limited.

Around 70 per cent of Australians who died last year were cremated, and the rest were buried, mostly in traditional coffins in cemeteries.

Most of us avoid putting too much thought into dying, and often when we've just lost a loved one, we're not in the right headspace to research the latest in post-mortem innovation.

But as we become aware of the environmental footprint of our lives, more of us are looking to reduce the footprint of our deaths.

Here are a couple of environmentally conscious alternatives to traditional burial and cremation you might want to consider before it's too late.

Melted down

If there was an option to have your body dissolved down to liquid and poured on plants when you die, would you be interested?

A handful of people have already chosen alkaline hydrolysis, as it's known, for their mortal remains in New South Wales — the only state where it's currently available.

Their bodies were put in a stainless steel drum filled with hydrogen peroxide and water, and heated to around 93 degrees Celsius.

Similar to traditional cremation, after a few hours their bones were the only solid things left.

Although advocates say it's safe to do so, difficulties with approval from Sydney Water meant the liquid remains couldn't be poured in the sewer, as it is in the United States after animals are treated.

Instead John Humphries, the founder of Australia's only alkaline hydrolysis group Aquamation, has negotiated an agreement to pour the liquid remains on plantation forests.

"It's a perfect fertiliser," Mr Humphries said.

"People have asked if they can spread it on gardens. Personally I find that a bit yucky...[but] we'll now be spreading it on forests."

Traditional cremation uses around 36 kilograms of gas to fire our bodies at around 1,000 degrees Celsius for around 90 minutes.

The emissions include CO2 from burning gas, the CO2 from our bodies, but also mercury from the dental amalgam used in fillings in our teeth.

In the UK, until 2012 when filters were put on crematorium chimneys, around 16 per cent of the UK's mercury emissions came from the mouths of the dead.

On average, each of us carries between 2 and 4 grams of mercury around in our teeth, and just over 100,000 Australians were cremated last year.

The emissions from alkaline hydrolysis are mainly CO2 as the liquid remains of our bodies continue to break down post treatment, and CO2 from the energy used to heat the alkalised water solution.

But unlike traditional cremation, metals like mercury remain in their solid state.

This means foreign objects like hip and knee replacements can be recovered, and pacemakers don't need to be cut from the body before treatment.

Freeze-dried and shattered?

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But if going out as a liquid isn't your style, there are other green options to consider.

Like having your body snap frozen in liquid nitrogen and smashed into little pieces.

While this option isn't technically available today, if you're not planning on turning up your toes for a while, it's slated to be coming to a funeral home near you.

It's been successfully tested on pigs, which are anatomically similar to humans, and actually makes a lot of sense once you can get past the '90s sci-fi film connotations.

Step one of promession as it's known, involves blasting the body with liquid nitrogen at minus 190 degrees Celsius.

Step two sees your frozen-solid, crystallised corpse shattered by ultrasonic vibrations into tiny pieces. Those pieces are then freeze dried, removing the large amount of water that comprises our bodies.

Mercury and other foreign objects are then separated from the remains before they're transferred to a biodegradable vessel and shallow buried.

The buried remains become soil within about 12 months, said Swedish biologist Susanne Wiigh-Masak, who founded the promession process.

"What promession is offering is new life to the soil," she told ABC RN last year.

"Bringing new life to plants and flowers instead of seeing death as the final end."

The advantage of promession is that there are virtually no emissions.

The by-products are mainly nitrogen — a non-greenhouse gas — and water, and the inevitable CO2 from our decomposing remains.

There's no need for large burial plots or coffins, and your remains are able to be quickly absorbed by plants and soil biota.

Keeping it simple

Untreated coffins break down faster and don't leach lacquers into the soil. ( Emmah Hellings (ABC Gippsland) )

But with all this freezing and shattering and liquefying, are we just complicating a very simple process?

Why can't we just take a body, put it in the ground and let nature run its course?

Traditional burials bury the body at around 1.5 metres deep, and often in treated timber or metal caskets, lined with plastic.

While the caskets themselves take a long time to break down, the lack of oxygen means much of the body decomposes anoxically, producing the powerful greenhouse gas methane.

Embalming, though less common in Australia than places like the United States, is another potential issue in traditional burial, where embalming fluid including formaldehyde can leach into the soil once the casket is breached.

There's also the environmental cost of mining and shipping headstones, and the building of cemetery infrastructure to consider, which can add up to a significant ecological debt, according to Kevin Hartley from not-for-profit group Earth Funerals.

"Headstones, particularly the coloured stuff — those lovely blues and reds that look very elaborate, they come from China," he said.

"Then there's the operation of the cemetery — roads, buildings, lawns, and then all the maintenance ... once someone is buried in a lawn cemetery there is a tacit understanding that that lawn is going to be maintained in perpetuity."

In contrast, green burials place the body in a biodegradable wicker basket or shroud, and although laws vary by state, bury the body around a metre deep.

Rather than manicured lawns, green burial sites are typically planted with trees, and headstones are often eschewed altogether in favour of GPS mapping of bodies.

Mr Hartley's group plan to offer natural burials on donated farmland away from traditional cemeteries, and redirect the profits toward revegetating degraded land.

"We're looking at wooded grassland — which is quite natural in Australia. When the burial ground is filled, 50 to 60 years hence, the amount of work that goes into maintaining that is no more than open bushland," he said.

"Every burial would reforest about an acre of bushland."

The idea is that once an area of land reaches its burial capacity, it becomes a nature reserve. Restoring natural bushland not only provides animals with habitat, but the planted trees continue to reduce the carbon footprint of the deceased long after they're gone.

While exploring low impact options for our bodies might not be easiest path, Mr Humphries thinks it's worth it.

"It's a little bit of effort but a great example to set," he said.