In order to solve a problem
you first really need to understand it well.
We’re investigating the amount and the location
and composition of plastic in rivers worldwide.
Rivers are super diverse.
We will have hundreds and even thousands of scenarios
playing out in the real world.
Rivers are really the arteries
that carry the plastic from land to sea.
What we see now is that 80% of riverine plastic emissions
are actually caused by over 1000 rivers.
So the map you see behind me is our global river model,
that precisely shows how much plastic is emitted
for each river in the world.
Now, every one of these red dots,
is one of the top 1000 heaviest polluting rivers.
We’ve been actually working on this really since 2017,
since we built our last model.
And, only a few months later, there was another team,
led by Christian Schmidt, who produced a very similar study.
And actually, that study became more famous.
It had this bold number in there,
10 rivers, do something like 80 or 90 percent of the pollution.
And, eventually discussing the problem with them,
we eventually decided, hey, we can actually refine this model,
and then we basically worked together on this new study,
and it just gives this tremendously new insight, which is much more nuanced,
you know it’s not 10 rivers, it’s 1000 rivers.
And it’s not the great rivers of the world,
it’s sort of smaller rivers, through cities in rising economies,
you know that’s where the plastic pollution hot spots of the world can be found.
So actually producing this research, has been quite an adventure.
I mean, it’s part Silicon Valley, it’s part Indiana Jones.
Where, on one hand, you have this super complicated modelling that we’re doing,
and on the other hand you actually have to go to these countries,
and, you know, deploy measurement devices in rivers,
you know you have to collect observations, to go into the jungle.
So, yeah, our team has done quite a lot of work, to actually get to this result.
The Juan Pablo Duarte Bridge, exactly in that area...
(Speaking Spanish)
He’s saying that if we start to count them, you can have more than 15 cañadas.
It’s like some drains, that come directly to the river Ozama, and contribute to the pollution.
(Speaking Spanish) Is this a cañada as well? Yes over there is one as well.
It's another day at the river Klang, in Malaysia, and we’re doing another day of sampling here,
with both the net we have here, and the visual counting.
We’re going to count the amount of plastics flowing by,
and we define them in different categories.
What you do see, it’s a lot of textiles, so they all got trapped by the sand bars,
and all the floating plastics just flow down.
We started out with the research question, how much plastic is actually floating into the ocean through rivers,
and we started with doing field work, but soon we realised we cannot measure all these rivers.
So, we really felt the need for a global approach,
so we started to also take the top-down approach, which is global modelling,
and we created a new modelling framework to address this problem.
If you look at the list of countries that rank high
on plastic emissions into the ocean through rivers,
you see that there are actually some smaller countries
and some larger countries on that list.
That not only has to do with the amount of waste generated in these countries,
but also with the probability for waste to actually reach the ocean.
A high probability is really caused by high rainfall rates, high wind rates,
but also a high amount of rivers.
So if a lot of people live close to rivers, and these rivers are close to the ocean as well,
so you really see this in archipelagos like
Indonesia, the Philippines, Malaysia, but also the Dominican Republic and Central America,
that there are many rivers, and the distance towards the coast is always small.
So, what we really learnt is that areas where the population lives near rivers, near coastlines,
these areas have the highest probability of emitting plastic into the ocean.
So these are also the countries where addressing the plastic pollution problem
is the most urgent, from the perspective of waste leaking into the ocean.
The more you observe where the plastic is coming from,
and the more you observe these river systems,
you see that the role of rivers is really important,
and maybe more important than was assumed to date.
So we see that rivers are really the main, let’s say, conveying mechanisms
of land based plastic waste into the rivers,
and then through these rivers, they either make it into the ocean, or not.
So, we also see that a lot of plastic is actually deposited on river banks as we see here,
and on a global scale, we now estimate that
about two percent of the mismanaged plastic waste make it to the ocean,
meaning that the vast majority of the plastics remain somewhere in the river systems,
where they cause a lot of additional negative impacts.
And then with the paper, we show that it’s really a global problem,
it’s not just these 10 rivers that are very much polluted with plastics,
but it’s rivers around the world.
And it implies that we have to do even more,
to make sure that our rivers are becoming clean again,
and that they don’t emit all these plastics into the ocean.
This global picture of where river plastic emissions occur,
it's very useful for The Ocean Cleanup,
but I think it’s really powerful information for everyone.
We’re non-profit, we want to help ourselves out of business as soon as possible,
so that’s why we’ve published this open access,
so that anyone can use this data,
and deploy interventions in these heaviest polluting rivers in the world.