The range of 4.8 to 12.7 million metric tons of waste comes from uncertainty in the total amount of waste generated, the amount of that waste that is plastic, and the amount of mismanaged waste that enters the ocean.

This article compares and contrasts solid waste management (SWM) practices in developed versus developing countries. SWM practices in industrialized countries are often affected by public health, the environment, resource scarcity, climate change, and public awareness and participation. However, urbanization, inequality, economic growth, and socioeconomic factors often complicate SWM in developing countries.

This research examined the sizes and locations of plastic particles found in the world's oceans. When plastic objects in the ocean are exposed to sunlight, they tend to break up into small particles because sunlight weakens the plastic structure and waves provide mechanical force. The small plastic particles are quite durable. Most of the plastic debris recovered and measured during this study was about 2 mm in diameter. The total amount of plastic in the ocean estimated by this study was less than predicted from plastics production and input rates. The "missing" plastics were hypothesized to be removed through one or more of the following processes: shore deposition (being deposited on shore somewhere), nano-fragmentation (breaking up into very small pieces), biofouling (small organisms grow on the plastic particles, and the plastics become heavy enough to sink), and ingestion (being consumed by marine life). The pathway and fate of the "missing" plastic is unknown.

When sea ice forms, it traps particulate matter from the water column such as microplastics. When sea ice melts, the particulate matter is released back into the ecosystem. This study examines the concentration of microplastics in Arctic Sea ice and finds that sea ice contains high concentrations of microplastics and other manmade particulates. Melting sea ice has the potential to release large amounts of microplastics back into the ocean.

Articles in Science are very brief. Supplementary materials available online can include text or images such as figures and graphs. Supplementary materials can provide additional information about how the research was conducted or additional evidence that supports the article's conclusions.

An ocean gyre is a circular ocean current formed by Earth’s wind patterns and rotation. The area in the center of a gyre tends to be very calm, and the circulation patterns of the currents draw debris into the stable center, where it becomes trapped. The debris is composed of objects both manmade and natural (i.e., driftwood). Many kinds of sea life live on and near the debris, such as gooseneck barnacles. Goldstein and Goodwin examined the digestive tracts of gooseneck barnacles to see if the barnacles consumed any plastics. One-third of the 385 barnacles examined had plastic particles present in their digestive tracts, and larger barnacles tended to contain more plastic particles. The effects of plastic particle ingestion on the ecosystem are still unknown.

This paper connects to Vision and Change Core Competencies and Disciplinary Practices 6 by presenting the ecological consequences of marine plastic pollution in a societal context.

A United Nations resolution seeks to “prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution,” by 2025.

For more information, see this link: http://www.telegraph.co.uk/science/2017/12/13/193-nations-sign-pledge-tackle-global-crisis-plastic-oceans/

The problem of plastic waste in the ocean can be addressed from two sides: allowing less waste to enter the ocean, or collecting the waste after it has entered the ocean. Many proposals have been developed for ways to clean up trash after it arrives in the oceans. One small-scale approach uses a submerged garbage can that pumps water through a filter and captures debris, while one large-scale approach relies on deploying a 1- to 2-km-long floating tube that gathers and concentrates floating plastic debris for eventual transport back to land and recycling.

Read more about these approaches: https://www.theguardian.com/sustainable-business/2016/mar/30/seabin-ocean-pollution-epa-marina-miami-garbage and https://www.theoceancleanup.com/.

The authors developed a model to represent a large-scale system. Next Generation Science Standards: Connects to Practice 2: Developing and using models https://ngss.nsta.org/practices.aspx?id=2

This paper connects to Vision and Change Core Competencies and Disciplinary Practices 3 and 4 by using modeling and emphasizing the interdisciplinary nature of science.

An order of magnitude is a comparison of size used when the item being compared is 10 times larger or smaller than the item it is being compared to. The difference between 1 and 10 is an order of magnitude, as is the difference between 10 and 100. The difference between 1 and 100 is 2 orders of magnitude, and the difference between 1 and 1000 is 3 orders of magnitude.

A MT (metric ton) is a unit of weight equal to 1000 kilograms (2205 pounds).

Population density is a measurement of how many people live in a particular area. It is often expressed as people per square mile or kilometer. A city is a location with a high population density, while a desert is a location with a low population density.

Here the authors restate the goal of their investigation.

Flux is a measurement of the amount of an object that passes from one place to another. Here, flux is the total amount of litter that traveled from land to ocean in one year.

Weathering is when pieces of plastic are mechanically broken up into smaller pieces. This is a problem because marine organisms can eat the smaller pieces but are unable to digest them. See the annotation for reference 16 for more information.

Ice covers the Arctic Ocean. Over the course of a year, ice increases during fall and winter and melts during spring and summer. All of the ice does not melt entirely during the spring and summer; some of the ice persists from one year to the next.

It is hoped that this number can be minimized through improved waste management techniques and infrastructure.

Waste management infrastructure is the collection of processes and facilities that properly dispose of wastes and reduce pollution. A major goal of waste management is often to reduce the amount of waste deposited in landfills by reuse or recycling.

The article connects to the Learning Standards, Common Core: Statistics and Probability (Construct viable arguments and critique the reasoning of others).

This paper connects to the English Language Arts Standards 11-12.1. It analyzes the problem of plastic waste in the ocean and explains the method used to estimate which countries likely generate most of the waste. The authors describe the sources of uncertainty in their estimates, and this paper also identifies strategies for reducing the amount of plastic waste entering the ocean in the future.

Market sector is an economics term that describes a part of the economy made up of multiple industries. Examples of market sectors include energy, health care, consumer goods, media, utilities, etc.

Exact numbers are not available for the mass of plastic waste entering the ocean, so the authors used a series of estimates in their calculations.

There is international recognition that plastic pollution in the ocean is a global problem, and policy decisions by governments have worked to address it.

Plastic pollution in the ocean has been known to be a problem for a long time.

This early work (reference 1) looked at which types of pollutants might pose a future threat to ocean resources and mechanisms of how each pollutant ended up in the ocean.

Per capita is a Latin phrase which means for each person. Here, the authors are looking at the mass of waste generated per person per year.

Fragmentation is the process of being broken into smaller pieces or parts.

A standard ton is 2000 pounds, while a metric ton is 1000 kilograms (2205 pounds).

The Jambeck et al. paper focuses on sources of plastic waste entering the oceans. A 2018 publication from Lebreton et al. presents research on the size of the Great Pacific Garbage Patch, a collection of plastic waste floating halfway between California and Hawaii. The patch contains about 1.8 trillion pieces of plastic, collectively weighing 88,000 tons (more than 500 jumbo jets) and covering an area more than 600,000 square miles (more than twice the size of Texas) in extent. The plastic is "collected" by winds and ocean currents.

For more information, see these links: https://www.usatoday.com/story/tech/science/2018/03/22/great-pacific-garbage-patch-grows/446405002/ and https://www.nature.com/articles/s41598-018-22939-w

This study looked at the sources and fate of local marine debris near the Hawaiian islands. Debris from a large community was captured using surface traps, and wooden drifters were released to examine the effect of nearshore currents and tides on debris distribution. This study demonstrated that local pollutants can be retained nearby, contribute to the island's debris-accumulation area, and quickly spread to other islands.

This article discusses the idea of designing buildings and objects to be made using the minimum of materials and a maximum of efficiency. 3D printing and biodegradable materials are explored as examples of ways to improve product design and reduce waste.

This document released by the American Chemistry Council is a reference book on plastic resins. It contains information about North American resin production, sales, industry capacities, and utilization rates from 2002-2012. Sales data are presented for various end-use markets, and tables show historical trends from 1973 to 2012. The publication explains the basic chemistry of plastics and manufacturing processes. It also details the history of plastics development and modern-day applications and provides a glossary of basic plastics terms. Jambeck et al. used this reference to estimate the amounts of plastic production in North America and plastic in the U.S. waste stream.

Polypropylene is a plastic polymer used in packaging, reusable containers, laboratory equipment, and medical devices. It is a polymer made of repeating subunits (groups of atoms) with three carbons in each subunit. Polypropylene is the second-most widely produced synthetic plastic, after polyethylene.

Polyethylene is a polymer, made of repeating subunits (groups of atoms) with two carbons in each subunit. It is the most commonly produced plastic in the world, used in applications such as plastic bags, films, and bottles.

This review article summarizes the uses humans have for plastics, the effects of plastics on the living and nonliving parts of the environment, and future concerns about the manufacture and disposal of plastic products.

This population growth data from the United Nations was used to predict future amounts of plastic waste entering the ocean from individual countries.

Another important part of science is recognizing sources of uncertainty in the data that lead to uncertainty in the results.

An important part of science is recognizing the limits of the conclusions that can be drawn from a given data set.

The authors' estimate of plastic waste entering the ocean is between 10 and 1000 times greater than the previously reported amount of waste floating in the ocean.

The authors predicted the amount of plastic waste that entered the ocean from coastal regions in 2010.

The authors calculated the mass of plastic waste that came from coastal regions in 2010.

Other authors have estimated similar amounts of waste generated by humans.

Using population density data and waste generation rates, the authors estimated the total amount of solid waste generated in 2010 by people living in coastal countries.

Plastic debris is plastic waste that has accidentally or deliberately been released into the marine or terrestrial environment.

Waste management is the set of systems required to manage waste from when it is created to when it is finally disposed of. Steps of waste management include collection, transport, treatment, and disposal.

Plastic resin beads are the raw materials from which items such as plastic water bottles are made.

In this context, persistence means that the plastic materials are very stable and resistant to degradation.

Mitigation is an action that reduces the severity or seriousness of a problem.

Extrapolation is the process of extending a graph or range of values by predicting unknown values from trends in the known data.

The authors use population density data and waste accumulation rates to predict how much plastic might enter the ocean as marine debris.