Turning the Tide

Ocean pollution is severe, but some interventions clearly work when they are funded and enforced. The challenge is scaling them up fast enough. Here is what the evidence supports:

• River interception — devices like The Ocean Cleanup's Interceptor trap plastic in rivers, which carry a large share of ocean plastic, before it reaches the sea
• Fertilizer regulation — the European Union's Nitrates Directive has measurably reduced dead zones in parts of the North Sea by capping farm runoff
• Wastewater treatment — upgrading plants to tertiary processing strips out nitrogen, phosphorus, and pharmaceuticals before the water is discharged