Poo. Everybody does it...
I don't.
...but with the exception of new parents and six-year-olds,
most of us don't talk about it.
But could our number twos be the answer
to some of the world's biggest problems?
The average adult flushes away 730 litres of pee
and around 91kg of faeces every year.
But are we missing a trick?
In Ancient Rome, no human waste went to waste.
Untreated excrement was used as manure in kitchen gardens
while urine was used to produce fabric.
In Henry VIII's time, one of the country's top positions
was Groom of the Stool.
Wiping the king's bottom was well worth it
for the benefit of having his ear.
"About that castle..."
Cesspits were emptied overnight by gong farmers
who sold the content to local farmers.
Urine was collected and used to soften leather.
While it's probably sensible to leave untreated manure
in the past where it belongs -
think of the pathogens -
we can learn from our predecessors' attitude to poo.
It could be the solution to some of our most pressing problems of today.
Let's start with our need for energy.
Unlike solar or wind power, which can be unreliable,
all it takes is a healthy fibre intake
to ensure a constant supply of poo.
Now that's a whole other kind of wind power.
The sludge left behind after sewage is processed
is good raw material for generating methane.
Modern treatment plants add bacteria to the sludge,
generating bio-gas,
which can be piped to homes or used to power vehicles.
It's a much cleaner fuel than petrol or diesel.
While poo has plenty of uses,
there's a reason wee is number one.
Seventy two percent of global water use is in agriculture
and population increases coupled with climate change
will only exacerbate the demand for water.
Some countries could face having populations displaced
by water scarcity within the decade.
In addition to the two litres of pee each adult in the UK produces daily,
each adult also sends around 140 litres of water
used at home down the drain.
Could recycling that water save the planet from apocalyptic droughts?
Absolutely.
The technology is available and already in use.
Israel currently captures almost 90% of used water
which is recycled to provide
a whopping 56,000 Olympic swimming pools' worth of water annually
for agricultural use.
Speaking of agriculture,
every living thing relies on phosphorous to survive.
But due to chronic overmining, it's a rapidly declining natural resource
which can't be replenished.
The US, China and India might run out of their domestic supplies
in the next generation.
Without adding this vital nutrient to farmland,
humanity could only produce around half the food it does today.
We could however emulate our ancestors
and return our sewage to the soil,
making use of solutions such as composting toilets,
or the nutrient-rich dried residue left over from bio-gas generation.
Reinventing the toilet could also be a gamechanger
for 4.2 billion people
currently living without access to safe sanitation.
Innovative toilet designs that operate without water
could help prevent the deaths of an estimated 800 children under five
each day.
Bill Gates predicts this developing toilet market
would not only be lifesaving but lucrative.
By 2030, toilets could become a six billion US dollar market,
with every dollar spent providing a $5 return.
While poo remains a word that never fails to raise a giggle,
your faecal matter is no laughing matter.
If we act now, poo may very well help to save the planet.