Today is World Ocean Day, which, among other things, is a good time to take stock of the health of the world's oceans. As Secretary of State John Kerry wrote in a press statement on June 7: "As we continue working and developing on and near the water, we cannot forget the impacts on our ocean - and we need to work vigilantly to protect it." 

These days, those words ring truer than ever; even a passing glance at one of the globe's major bodies of water will likely reveal the bobbing, red fin of a Coke bottle, the iridescence of a green plastic bag glinting in the sun, or a school of tiny plastic microbeads. Those are just parts of a larger ecosystem of trash in the world's oceans, weighing in at an estimated 130 million metric tons. And as Huffington Post reports, 5 to 13 million additional tons are added to that swelling mass each year. At the going rate, within a decade that'll be about a pound of plastic for every three pounds of fish.

"The part that floats is the part people are concerned about, but it's only a small part," according to Andrew Morlet, chief executive of the Ellen MacArthur Foundation, who spoke about marine pollution at the World Ocean Summit last week in Portugal.

That trash iceberg Morlet was referring to is a constant concern among environmentalists, scientists, and politicians. Imagine a Venn diagram composed on one side of plastic and on the other, the ocean. In the middle, then, would undoubtedly be the Great Pacific Garbage Patch (or the Pacific trash vortex, depending on where you’re from)––that vast edifice of human material waste that swirls in the North Pacific Ocean and can be seen from space.

That an amount of trash floating in the ocean is on par with the Grand Canyon from an astronaut’s perspective is troubling. That it’s only one particularly congealed example of the plastic clogging our oceans is even more troubling.

World Ocean Day and the World Ocean Summit in Portugal come on the heels of a study published in Science back in February that tried to quantify our oceans’ broader plastic problems with some pretty terrifying results. In 2010 alone, researchers calculated that of the 275 million metric tons (MT) of plastic waste generated in 192 coastal countries, anywhere from 4.8 to 12.7 million MT of that entered the ocean––or 10.5 billion to 28 billion pounds. As Mother Jones’ Climate Desk points out, the median of those two calculations is almost 1.5 times the weight of the Great Pyramid at Giza, in plastic, in the oceans. What's more, those numbers are only expected to rise.

Instead of just measuring the amount of plastic in the oceans, scientists led by University of Georgia environmental engineer Jenna Jambeck wanted to trace where all of that plastic is coming from. To do so, they compared per-capita waste generation, the percentage of waste that is plastic, the percentage of that waste that’s disposed of improperly, and population size within 50 kilometers of the ocean in each of the world’s 192 coastal countries.

Not surprisingly, it can be hard to track what percentage of mismanaged waste is plastic and how much of it actually ends up in the oceans. So although researchers weren’t able to get crystalline pictures of exactly how much plastic waste different countries contribute to the sea, they got a pretty good idea of the ballpark total plastic pollution each country contributed, and further, how pollution might increase a few years down the road. China, for example, contributed some 5 billion pounds of plastic waste into the ocean in 2010. Indonesia played second fiddle, clocking in around 2 billion pounds. But perhaps the most interesting, if not troubling finding was expected pollution growth relative to population growth.

The worst polluters, according to the study, are middle-income nations that have recently experienced economic growth spurts. But some of these countries have bypassed development in waste management infrastructures to keep pace with growth of populations and economies. China has been on the rise for years now, and has been a shining example of below-average waste management and pollution control. Not surprisingly, in that country, plastic pollution is expected to double by 2025. Southeast Asian and North African countries are on a similar pace. India is particularly troubling, expected to generate more than three times its mismanaged waste within ten years.

It’s important to note that expected pollution increases don’t necessarily mean that all that plastic is destined for the sea. Rather, those predictions measure mismanaged waste, a portion of which will inevitably end up in the water. While the study’s predictions were fairly broad, they’re no doubt illustrative of a growing problem that will need a solution. We know that the trillions of pieces of plastic, which we can’t always see, are a detrimental force in the world’s watery ecosystems. It's estimated that each year, some eight million MT of plastic––about 34 times the size of Manhattan––enters the oceans each year. The report’s findings only predict that number to go up.

The report found, somewhat surprisingly, that the U.S. was near the bottom of the list, contributing less than half a million pounds of plastic in 2010. And according to researchers, exporting waste management known-how, if not essential, could be a step in the right direction.

“We can help waste management infrastructure follow economic development more closely,” Jambeck told Fast Company. “Now that we know that plastic is such a large part of our waste stream, we can be better prepared to deal with it.”

Maybe it's heartening to know that that about half of the new plastic that goes into our oceans comes from five countries: China, Indonesia, the Philippines, Vietnam, and Sri Lanka. If the problem is this isolated, it might be easier to address. Most important, though, is to simply know about the scale of the problem, and the repercussions it could have down the road. "The ocean makes up a significant portion of the surface of our planet that it plays a tangible role in creating the air we breathe, regulating our climate, growing the food we eat and cleaning the water we drink," wrote Kerry.

"We're not talking about a vague threat, far off in the distance; the ocean is under enormous stress right now. And overfishing, pollution, and ocean acidification all threaten global standards of living." 

For a great visualization of this data, head over to Mother Jones.