How the oceans can clean themselves: Boyan Slat at TEDxDelft

Boyan Slat combines environmentalism, creativity and technology to tackle global issues of sustainability. Currently working on oceanic plastic pollution, he believes current prevention measures will have to be supplemented by active removal of plastics in order to succeed. With his concept called Marine Litter Extraction, Boyan Slat proposes a radical clean-up solution, for which he won the Best Technical Design award 2012 at the TU Delft.

Once there was a Stone Age,
a Bronze Age

and now we are in the middle
of the Plastic Age.

Because every year we produce
about 300,000,000 tons of plastic

and fraction of that enters rivers,
water ways and eventually the oceans.

If you want to eat a biscuit nowadays

we have to buy a biscuit
within a plastic wrapper,

within a plastic tray,
within a cardboard box,

within a plastic foil,
within a plastic bag.

It's not hazardous nuclear waste --
it's a biscuit.

And this is me. I love diving

just taking you through
my holiday slides here.

This is at the pristine Azores Islands
and this is how their beaches look.

Covered with plastic fragments.

Due to sun and waves over the years

the garbage breaks down
into ever smaller pieces, but remains plastic.

And, well interestingly, you don't see
a lot of red particles in here

because those look like food

to birds more than any other color.

So this is the result.

And well, the debris primarily collects
at these 5 rotating currents

called the gyres, where it doesn't only
directly kills sea life,

but due to the absorption of PCBs and DDTs,
also poisons the food chain.

A food chain that includes us -- humans.

And while diving in Greece

I came across more plastic bags than fish

and astounded by the depressing sights

my Scottish dive buddy turned to me and said,

"A lot of jellyfish is here, dear.
Seen about a thousand."

There were no jellyfish.

I won't talk about
environmental issues in general.

I think the common response is,
well that's a long way off.

That's for our children to worry about.

So hello, here I am.

Why don't we just clean it up?

There are a multiple reasons why

current plastic pollution researchers
believe we should focus on prevention,

for example through education,
rather than attempting a cleanup operation.

Because we would need to deal
with 5 colossal areas -- each moving around.

Plastic sizes ranging from these massive ghost nets
to molecules -- bycatches and emissions.

Furthermore we would need to get
all the plastic back to land.

It would need to be financially realistic and

in fact the total amount of plastic
within the gyres [is] unknown.

But about a year ago, when I was
on my way to the hairdresser's

and I must admit I don't go there often
but I had this little epiphany.

I saw even old people throwing
rubbish in the water

and I thought, well some people
will just never learn, will they?

We'll need the combination of both roads

and we'll need them soon.

So then I simply used this list of concerns

as challenges, and in fact a week later
as a school assignment,

I had a chance to spend a lot of time

on a subject of choice together
with a friend of mine.

And this gave me the perfect opportunity

to do new and fundamental research
regarding plastic pollution.

I then went on a holiday to Greece
taking this manta trawl with me,

which is the common device
for sampling plastic,

and so I had to leave home all my clothes

due to low cost airlines weight limit policies.

Well, the trawl we built, however,
is 15 times finer

than the regular one.
And what we discovered was

that the count of those minute particles
is in fact 40 times higher

than the larger particles.
So we have to take these small plastics out,

but then we wouldn't want to take
the important plankton out as well.

Luckily these could simply be separated
using centrifugal forces.

However, nobody knew how much G forces
common zoo-plankton could survive.

So we took the trawl out again,
and we didn't have a boat,

so and we tested it, and in fact they can survive
over 50 Gs, which is more than enough

for successful separation.

And then in order to know up to which depth
the ocean surface should be cleaned,

we designed and built something
that I call the multilevel trawl.

We basically stuck ten trawls
on top of each other.

Here you can see us testing that
on the North Sea,

I thought it was a great day --
I was the only one who didn't get sick

but then the so perfectly working trawl
broke and

of course we didn't quit there,
because I believe you can't clean up something

you don't know the size of.

I've heard the estimations ranging
from several hundred thousand tons

all the way to a hundred million tons.

I knew we really need a better estimate
-- some scientific data.

So then I simply contacted
some professors from the universities

Delft, Utrecht and Hawaii --
who then actually helped us in determining

how much plastic there is
in the top layers of the gyres.

The result -- a whopping 7.25 million tons
of extractable plastic in 2020.

That's the weight of 1,000 Eiffel towers
floating in the gyres.

Now, researcher and effect discoverer
of the Great Pacific Garbage Patch, Charles Moore

estimates it would take
79,000 years to remediate that.

However, I believe the Great Pacific
Garbage Patch

can completely clean itself in just 5 years.

And that is a difference of 78,995 years.

Well, of course, this is the conventional idea
of extracting litter,

so you have a vessel and a net
fishing for plastic.

Of course multiple vessels could be used
to cover a larger area,

but by spanning booms between
those vessels,

suddenly a much larger area
would be covered,

because the essence is not to
catch the debris, but divert it.

Because there is no mesh size,
we can even get out the smallest particles,

and since all organisms can simply move
under the booms,

we'll be able to eliminate
bycatches by 99.98%.

But, if we want to do something different

shouldn't we also have to think differently.

For example then: the absorption of PCBs
by plastic is not such a bad thing,

it's a good thing.

Get all the plastic out and simultaneously
remove tons and tons

of persistent organic pollutants
from the marine environment.

But how would we minimize environmental,
financial and transportation cost then?

Let's use our enemy
to our advantage, OK?

The oceanic currents moving around
is not an obstacle -- it's a solution.

Why move through the oceans
if the oceans can move through you?

By fixing the "ships" to the seabed
and letting the rotating currents

do their work -- vast amounts of funds,
manpower and emissions will be saved.

The platforms will, of course, be
completely self-supportive

receiving their energy from sun,
currents and waves.

And inspired by my diving at the Azores,
It now actually seems

that the best shape for these platforms
is that of a Manta Ray,

by letting its wings sway
like a real manta,

we can assure contact of the inlet
with the surface

even in the roughest weather.

Well, imagine a zigzag array of just 24
of these platforms cleaning an entire ocean.

Let's make a comparison, OK?

These are the beaches of Hong Kong,
earlier this year.

The largest plastic spill in history.
And this is their source,

just 6 containers.

How much could we get out?

Over 55 of these containers per day.

Not only is plastic directly responsible
for over a billion USD in vessel damages a year,

no, the awesome surprise for me was that

if we sell the plastics retrieved from the 5 gyres
we'd make over $500,000,000

and this is in fact more than
the plan would cost to execute.

In other words -- it's profitable.

But I believe that the key thing is that

only if we realize change is more important
than money, money will come.

And yes, it will be one of the largest environmental
rescue operations yet, but we created this mess.

Heck, we even invented this new material first
before we made this mess,

so please don't tell me
we can't clean this up together.

Thank you very much.

(Applause)