25 July 2018

Erik van Sebille on the NRC climate blog

The fight against plastic soup needs its own 'climate panel'

We need to act very soon against the plastic debris in the ocean. But not without scientific evidence. This evidence should be collated by an organisation comparable with IPCC, the climate panel of the United Nations, urges Utrecht researcher and leader of the Tracking of Plastics in Our Seas project, Erik van Sebille.

This blog was published on 28 June 2018 on the climate blog of the NRC. The previous blogs by scientists from Utrecht University were written by Maarten Hajer and Appy Sluijs.

Whenever we, scientists, set out to find plastic in the ocean, we find it. This is extremely alarming. Every year, an estimated eight million tonnes of plastic waste enters the ocean.  Even more disturbing is that vast areas of amassed plastic on the oceans' surface equals a mere 1% of all the plastic that ever ended up in the ocean. 

I started a research project in 2017, aspiring to map out all of the plastic in the oceans. As a result of this a two-dimensional matrix model that predicts the movement of plastic on the surface has been made, which can be installed on an ordinary laptop. But if you use this model to add up the total amount of plastic that is already discarded in the ocean, you come up with around 250,000 tonnes. That is far too low. So, the question is: where has the rest gone?

Matrix model predicting the movement of plastic on the ocean surface. Credit: PlasticAdrift.org

Part of it has washed ashore, another lot is on the ocean floor, and some of it has disappeared into the stomachs of marine animals. We do not know the exact amount of any of these stocks, nor how it has dispersed over this immense area.

This is precisely what is being investigated in the project TOPIOS (Tracking Of Plastics in Our Seas), which recently received funds from the European Research Council (ERC). Whose plastic ends up where? Where is the greatest risk to our health and the environment? Where can the plastic be cleared most efficiently? And how to most effectively spend the funds at the national, European and worldwide level?

A 3D map

For this project, we are developing a three-dimensional model of the way in which plastic moves around the oceans. The 3D map must eventually be a combination of a circulation model and concrete observations of the location of the plastic in the oceans. With the help of a super computer and satellites, we want to create simulations of the plastic's disintegration and descent to the bottom of the oceans.

There is an overlap here with the climate models used by the IPCC, the climate panel of the United Nations, to support the international policy on climate. That is our intent. Discussing solutions to the plastic problem is all well and good, and very important, but we do need a proper diagnosis.

That is why I am advocating an ‘IPCC for plastic debris’, an organisation based on science that regularly makes large-scale assessments of the status quo of all the plastic in the sea and elsewhere, as well as its effects and future risks. Like the IPCC, it should be an international collaboration that looks into the way in which the issue can be eased as effectively as possible, where scientists are under mutual scrutiny, and that meets the standards of 'open science'.

This obviously does not relieve us from our duty to do something about the enormous amount of plastic that ends up in the sea each year. Prevention is better than cure. But if we do want to administer a cure, we should do so on the basis of sound scientific evidence.