So, today (and this week!) has been a bit surreal. I had my first-ever paper published in Science, Plastic waste inputs from land into the ocean. I had more interviews than I ever knew were possible in a 3-day time span… we also had a press briefing at AAAS – it went great. I thought I would post the transcript of the comments I made at the briefing here. I am so grateful I get to do a job that allows me to work on my passion and I remain hopeful about the future of our oceans.
Good morning everyone. My name is Jenna Jambeck and I am an assistant professor of environmental engineering from the University of Georgia. When I had to choose a focus in environmental engineering, I fell in love with the study of solid waste, which is trash, or better known as anything that you recycle or throw every day. The reason I felt waste was so different from designing water or wastewater facilities was that it so closely involved people. And people have strong reactions to it – especially when a waste management system might be physically close to them. Yet it is something we create every day and have to manage. So as I talk today, I will go over many numbers, but as I do, I hope you’ll keep in mind the same thing that I do – that there are always people behind these numbers.
It seems like we have been hearing a lot lately about the concerns over plastic in our oceans and estimates of plastic in the ocean. Research interest in this issue has grown tremendously in the last 10 years. And the results you’re hearing today arise from a scientific working group that was founded at the National Center for Ecological Analysis and Synthesis 3.5 years ago. We are a diverse group – oceanographers, marine ecologists, solid waste experts, statisticians, industrial ecologists, polymer scientists and engineers. When we got together, our starting point was to ask ourselves – What are the major sources of plastic in the ocean? Quickly, we found out that that land-based inputs would be a major source. So we set out to find out how much it was.
Now what we did is different than the numbers you have heard before – those numbers estimate the amount of plastic already in the ocean – we call this “the standing stock”. What we looked at was an annual input – how much goes in each year. And this is exciting to report because this is the first time we have been able to connect the ocean to the land with a number, and I’ll explain more about this number but the way we are most comfortable reporting this is to say “We estimate that people added 8 million metric tons – and a metric ton is 1000 kilograms, so that’s 8.8 million American tons – of plastic to the ocean in 2010.”
Our methods for this estimate were to look at per person waste generation rates in 2010 from 192 countries with a coastline in the world. Because people’s activities nearest the coast are responsible for most of the plastic going into the water, we limited our analysis to a 50km strip of the coastline. From there, we looked at what percent of that waste is plastic, and what percentage of THAT is mismanaged waste (which means litter or when waste is not captured and dumped on the land). From there we had three scenarios of input into the ocean: low, mid and high. Our 8 million metric ton estimate is that mid-range scenario. 8 million metric tons of plastic is equal to 5 bags (like this) filled with plastic going into the ocean along every foot of coastline in the world. That… is HUGE.
And it can get worse. If we assume a business as usual projection with growing populations, increasing plastic consumption and increased waste generation, by 2025, this number doubles – we may be adding 17.5 million metric tons of plastic per year. If that happens, then our cumulative input over time from 2010 to 2025 is projected to be 155 million metric tons.
The purpose of this work was to create this global estimate. But remember what I said before – behind these numbers are people, people living in culturally and socially different countries of the world. And we had to use country-level data to build out our framework – so we do indeed have a list of countries that are top contributors. And this has been getting a lot of attention so I want to be clear about how we think about this list – it is not about finger pointing, but examining things that strongly influence a country’s rank in this list: first, the population density in the coastlines – how many people are generating waste within 50 kilometers of the sea? Next, how MUCH plastic waste is each person generating? And finally the mismanaged waste percentage plays a role – how much of what all those people throw away accidentally ends up in the ocean? So what you will find near the top are mostly middle income countries with rapidly growing economies that have not yet been able to develop waste management systems to handle the increase in waste generation that comes along with economic growth. There is one high income country on the list, the United States, and while our waste management systems are well-designed and very effective, and the only mismanaged waste is from litter, we have a large coastal population and a large waste generation rate.
We know the solutions: we must cut back on plastic waste generation and increase the amount we capture and manage properly. That sounds simple. We know how to design waste management systems, but waste management is not just a design problem, it is also has social and cultural dimensions. So we need to work together at a combination of local and global initiatives… and we need global participation from various stakeholders, and based upon the diverse global interest in this work – I am optimistic this will happen. By changing the way we think about waste, valuing the management of it, collecting, capturing and containing it, we can open up new jobs and opportunities for economic innovation, and in addition, improve the living conditions and health for millions of people around the world and protect our oceans.