PROVIDENCE — The amount of plastic choking the planet, most notably the world’s oceans, is unfathomable. The evidence of this unrelenting assault overwhelming. The scale of this toxic pollution horrifying.

Consider:

It’s estimated that there are 5.25 trillion pieces of plastic debris in the ocean, from 269,000 tons afloat on the surface to some 4 billion plastic microfibers per square kilometer in the deep sea.

Plastic bags break up into smaller pieces, but their footprint never vanishes. If they do break down, it’s into polymers and toxic chemicals. Some 500 billion single-use plastic bags are used annually worldwide. If you joined them end to end, these petroleum pouches would circumnavigate the globe 4,200 times. Only a minuscule fraction are recycled or reused.

Twenty-five billion Styrofoam cups are thrown out annually in the United States alone.

A single tube of facial scrub can contain more than 330,000 plastic microbeads. A single microbead can be a million times more toxic than the water around it.

Nearly 3 million plastic bottles, every hour of every day, are used in the United States. Less than 30 percent are recycled.

More than 300 million plastic straws are used every day in the United States. Straws are too small to be easily recycled, so they typically become trash. Plastic straws are one of the top beach polluters worldwide.

Eight million tons of plastic are dumped into the world’s oceans every year.

About 100,000 marine creatures die every year from plastic entanglement.

About a million sea birds are killed every year by plastic. A record 276 pieces of plastic where found in one dead bird. It was 90 days old.

At least two-thirds of the world’s fish stocks are suffering from plastic ingestion.

A 2016 study warns that there will be more waste plastic, by weight, in the ocean than fish by 2050, unless humans clean up their act.

“We’ve plasticized the entire biosphere, including our bodies,” said Marcus Eriksen, research director and co-founder of the 5 Gyres Institute. “The impact of plastic is widespread, and it’s destroying the oceans.”

Eriksen was one of four guests who spoke March 4 at Brown University during a panel discussion titled “The Plastic Ocean.” The discussion also featured photographer Chris Jordan, Georgia State University professor Pam Longobardi and author Carl Safina.

In January, ecoRI News hosted a screening of A Plastic Ocean at the Cable Car Cinema. Both events highlighted a serious problem.

Plastics production has increased twenty-fold since 1964, according to last year’s The New Plastics Economy: Rethinking the future of plastics study. Production is expected to double again in the next 20 years, and almost quadruple by 2050.

The world’s plastic problem was first identified in the 1970s. In 1987, a law was eventually passed to restrict the dumping of plastics into the ocean. The Marine Plastic Pollution Research and Control Act went into effect Dec. 31, 1988, making it illegal for any U.S. vessel or land-based operation to dispose of plastics in the ocean.

However, this act and other laws like it, such as the Microbead-Free Waters Act of 2015, can’t compete with mass consumption and throwaway societies.

In 2000, Eriksen traveled to Midway Atoll — a 2.4-square-mile island roughly equidistant between North America and Asia — where he found hundreds of dead Laysan albatross with plastic-filled stomachs. The visit narrowed Eriksen’s environmental focus, and led to the creation of his Los Angeles-based nonprofit that empowers action against the global health crisis of plastic pollution through science, art, education and adventure.

More than 600 animal species are impacted by plastic, through ingestion or entanglement, both of which can sicken or kill them, according to the 5 Gyres Institute. Birds, fish, turtles, dolphins, sharks and whales can be poisoned or trapped by plastic waste.

“There’s pieces of plastic out there with shark bites, turtle bites,” said Eriksen, noting that smaller pieces of plastic can be found everywhere in the world’s oceans. “The world is covered by microplastic particles. The fact we can find plastic in the middle of the ocean is a tragedy of the commons.”

Photographer Chris Jordan followed Eriksen to Midway Atoll. He has visited the far-flung island in the North Pacific Ocean several times. His photographs have vividly captured the destruction caused by plastic. The experience was soul-crushing.

Jordan, the first speaker at the recent panel discussion, introduced himself this way: “I’m the guy who took the horrible photos of the birds with plastic in their stomachs.”

As the Seattle-based photographer shot pictures and videos of plastic-ridden bird carcasses, he found himself sobbing. “Being with dying birds and seeing their suffering … I felt the grief,” he said. “I never knew how much I cared about these animals.”

“We could be living in such a different way,” Jordan said. “There’s nothing standing in the way of radical change in global behavior. Science is telling us that we need this change.”

In 2006, after discovering mountains of plastic on remote Hawaiian shores, Pam Longobardi founded the Drifters Project. During the past decade, the nonprofit has removed tens of thousands of pounds of debris, mostly plastic, from the natural environment and reused the material as communicative social sculpture, to create awareness of the problem.

“The ocean ecosystem is full of life … and it’s in trouble,” Longobardi told those gathered in the Brown University auditorium. “The ocean is vomiting plastic because it’s full.”

She called plastic a crime against nature, and noted that all this pollution is creating an environmental and racial crisis.

“Plastic comes back to haunt us,” she said. “It’s the ghost of our consumption.”

Longobardi has led “forensic beach cleanings” around the globe, from emptying plastic-filled caves on Kefalonia, an island in the Ionian Sea, west of mainland Greece, to scrubbing beaches in Hawaii. She’s currently running a project in Lesbos, a Greek island in the northern Aegean Sea off the coast of Turkey.

Change is possible, and the four speakers noted that, despite the best efforts of lobbying groups such as the American Chemistry Council, a tipping point is fast approaching.

For instance, applying circular economy principles to global plastic packaging flows could transform the plastics economy and drastically reduce negative externalities such as leakage into oceans, according to the 2016 report by the World Economic Forum and Ellen MacArthur Foundation.

“Why are we packing yogurt that lasts three weeks into containers that last forever?” Eriksen asked.

Individual behaviors are also changing.

“When I see a piece of plastic, I pick it up,” Longobardi said. “I know it won’t be consumed by a bird or animal.”