While ocean plastic chokes our waters, it’s killing millions of marine animals every year. Nearly 700 species, including endangered ones, are known to have been affected by it.

Some are harmed visibly. They are strangled by abandoned fishing nets or discarded six‑pack rings. Sea turtles and toothed whales gulp down plastic bags. They think the plastic is a jellyfish or squid. Young birds like albatross have been found dead, their stomachs full of plastic garbage.

Many more animals are probably harmed invisibly. Marine species of all sizes, from zooplankton to whales, now eat microplastics. Microplastics are small plastic pieces less than five millimeters (one‑fifth of an inch) long. Animals eat them without knowing it.

Seabirds scoop up floating plastic pellets, which can resemble fish eggs. Parent birds then regurgitate the plastic to feed their young. Plastic doesn’t provide energy or nutrients. Instead, it slowly kills animals.

In crabs, microplastics remain in the gut six times longer than food does. The crabs eat, but can’t get enough nutrition to survive. What’s more, eating plastic causes some species to store less fat, protein, and carbohydrates. When a predator like a bird eats a marine worm, the bird gets a less nutritious meal. It also gets the plastic that worm has eaten. That’s how plastic passes up the food chain.

How do we keep plastic out of our ocean? First, we need to understand how it’s getting there in the first place. Today, we produce more plastic waste than we can dispose of.

“This isn’t a problem where we don’t know what the solution is,” says Ted Siegler. He’s a resource economist who has spent more than 25 years studying garbage. “We know how to pick up garbage. The reality is, we just need to collect the trash. Most countries that I work in, you can’t even get it off the street. We need garbage trucks and help institutionalizing the fact that this waste needs to be collected on a regular basis.”

There are two main ways we can begin to tackle the trash and plastics problem, according to Siegler. First, we can design new plastics and new plastic products that are either biodegradable or more recyclable.

Second, we can build better waste removal systems in countries that need more help. Siegler even suggests a worldwide tax. Companies would pay a penny on every pound of plastic they manufactured.

The tax would raise roughly six billion dollars a year. That money could be used to build and manage garbage collection systems in developing nations.