The passengers and crew aboard the Mayflower didn’t have an easy time of it. For one thing, they traveled for months aboard ships with freshwater and food stored in crates and barrels without benefit of vacuum sealing or sterilization.
More of them might have survived the voyage if they’d had shelf-stable packaged foods and bottled water like we do. And if they had used those things and tossed the packaging overboard: that plastic would still be in the ocean today — some 398 years later.
Of course, plastic wasn’t produced extensively until the mid-20th century. But that has been more than enough time for our careless disposal of it to litter waterways all over the planet. Byproducts of trash have been poisoning wildlife for decades. And some scientists fear it may pose as great a threat as climate change.
Jenna Jambeck is a National Geographic Explorer and assistant professor of environmental engineering at the University of Georgia. Her research is featured in National Geographic’s June issue about the “Planet or Plastic” campaign, a multi-year initiative to raise awareness about the global plastic crisis and the environmental hazards of single-use plastic.
Three years ago you published an estimate of just how much unrecycled plastic ends up in the ocean every year. What went into that calculation?
We knew that our daily activities and waste we produce from those daily activities was probably a significant contributor. So we looked at 192 countries in the world that have a coastline and knew that that’s where the interface of our land activities and our oceans meet. And of those we looked at the per-person waste generation rate: so every day, the quantity of trash that we produce, the percentage of that that is plastic and then the percentage of that that’s actually mismanaged or ends up on the land and then from there makes it into the ocean.
The range between the minimum and maximum that you calculated is enormous. Why is it so hard to pinpoint the exact amount?
It was between about 5 million and 13 million metric tones. This was the first time this calculation had ever been done; we used the best available data. But there are still a lot of questions in terms of, well, there hasn’t been great data collected around the world for waste management. So of these 192 countries, we had to build these models based on data and then build in some of the gaps with economic status and region of the world. And then also we’re lacking scientific data on once plastic ends up on our land, how much actually makes it to the ocean. So that went into that sort of large range.
5.3 million metric tons sounds like a lot; 13 million metric tons sounds like a lot. But it’s a little hard to picture. There is a visual about bags of trash lined up on the shoreline.
If you can imagine all of us standing holding hands, covering the entire coastline of the world, we take up about one foot of space. So in front of each of us, there would be five grocery size bags filled with plastic. And that is what we estimate going into the ocean every year.
How does all that plastic get there? Are people just being incredibly careless when they are at the shoreline or traveling on the oceans?
It’s a variety of ways. One of them is called inadequately managed waste, and that’s waste that’s not managed in a formal waste management system. Oftentimes this is places that don’t have the infrastructure of a collection system. Many of us in the US are able to just put our trash out in a trash can and somebody comes to collect that. There are many places around the world where that is just not developed yet. Then even the disposal and recycling systems are not developed, so you see leakage from there.
And then the other component is littering. Even where we do have the robust waste management systems like here, it is either the inadvertent carelessness or the actual intentional littering that, depending upon how much waste you produced, even a small percent of litter encompasses quite a large amount.
Why is Asia believed to be the primary source of plastics in the ocean, at least as continents go?
There was a lot of economic growth, rapid growth, and per-person waste generation is coupled with that. As the economy grows quickly, the waste that was generated was growing quickly. Also at the time, plastics were becoming so essential in our daily lives and everything was now coming packaged in plastic. So it was sort of this perfect storm in that there was a great increased use of plastic for packaging as well as this economic growth that happened so rapidly they simply couldn’t keep up with the infrastructure to manage that waste that came with economic growth.
China has decided not to take in as much foreign garbage to process for recycling. What are the implications of that?
For decades, countries more highly developed, for example like the US and European countries, have been exporting some of their waste — including plastic scrap — to China. This was advantageous for both countries in terms of managing the waste and getting raw materials. However, it’s an environmental and social justice issue, because China did not entirely have the infrastructure to be able to manage that. So now I think people are sort of examining both the quantity and the quality of waste we are producing, and many think about how can we improve that so we can actually manage it and recycle it more domestically.
It always seems to me that the ability to recycle plastic is a good thing. Lots of people have access, you can just put it out at the curb and theoretically it can be recycled. I wonder if that doesn’t make it a little less guilt inducing for us to use more plastic than we would otherwise.
Yes, and the statistics, unfortunately, are such that we only see about 9 percent of recycled plastic globally. In the US, we are about at the average. Even though it is quite easy for us, it still doesn’t happen. So I do think what you are saying also can happen where people say, “I’ll just recycle this so I can use it.” But the fact of the matter is that it isn’t happening as of yet, so it’s not even a good excuse.
So what happens to plastic that ends up in the ocean? How long does it remain pretty much intact?
This is a more recent research topic, because we are really not sure. We know that large pieces are getting into the ocean, because we also see the ocean sort of spitting them back. But we don’t know the exact time frame of those. But we know that when it’s exposed to sunlight, wind and wave action, what happens is the plastic does not biodegrade in this ocean environment, it simply fragments into smaller and smaller pieces. You can think of it like plastic confetti. I’ve stood on the coastline in the Canary Islands and seen with each wave this plastic confetti washing back up onto the shore, because there are various islands that are sort of interrupting these ocean currents. You can tell, here is a small piece of straw, a bottle cap. But we are really not sure about those time frames. We know it is all still there breaking down into smaller and smaller pieces.
In what ways does plastic become a health hazard for wildlife?
The most common ways that we’ve seen are the entanglement and the ingestion. It doesn’t biodegrade, and it doesn’t digest in the bellies. In terms of being consumed by animals, it simply fills their belly and then if it’s not expelled, they will feel full but not get any nutrition. It can also lacerate and do various things to their internal system. They could get an infection.
The entanglement is oftentimes some of the larger items, especially the derelict fishing gear, which is one of the most dangerous debris items that can be in the ocean. Animals get very curious and play with those items, and they are designed to kill, really.
Do you agree with the assessment that this is a problem on par with climate change?
I think climate change really overarches everything right now and is the biggest issue. What is similar here is that this is a global issue, and we have the oceans as this ultimate transporter of plastic around the world. So really in some ways, once it’s there, it doesn’t matter where it came from, it becomes everyone’s problem.
Certainly also it has parallels in that many of these solutions are actually really local — country level to municipality level is how we manage our waste, and I think that’s a real parallel to climate change. This might be easier to tackle — there is a lot of agreement with this issue, and it’s also very visual. I think it could be helpful. If we can come together globally to tackle this, maybe then we could learn a lesson for tackling something bigger like climate change.
This Q&A is edited and condensed from a recent interview by Krys Boyd on Think. You can listen to the full episode at kera.org/think.
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