The Secretary General highlighted that plastic debris can be found in the most remote places of the planet, noting that the problem is even bigger than everyone thinks.
It kills marine life and is doing major harm to communities that depend on fishing and tourism.
During the event, he welcomed the G7 Plastics Charter but noted that there are additional steps to be taken so that pollution can be ended, keeping in mind that the world is facing additional problems, as climate change that worsens the existing situation.
Ocean acidification is disrupting the marine food chain and record-level ocean temperatures are killing coral reefs and creating fiercer, more frequent storms.
The pollution also affects the 40% of the world's population that lives 100 kilometres of a coast, and are vulnerable to storms, sea level rise and coastal erosion, while also low-lying island nations and many coastal cities are also in danger of floods.
However, Mr Guteres added that there's a plan based on UN's Sustainable Goals, and specifically Goal 14 along with its 10 targets that aim to fight marine pollution and acidification, end overfishing and protect ecosystems.
Meanwhile, Mr Guteres addressed that there will be no development unless the world and the industry acknowledges that there is a global emergency that needs to be addressed.
And that is why I am here today. To sound the alarm. To inject a sense of real urgency in your deliberations and decision-making.
The G7 group consists of Canada, France, Germany, Italy, Japan, the United Kingdom and the United States.