Life in the ocean may never be the same again unless we take immediate action to reduce plastic pollution, says UN oceans chief Lisa Svensson, who issued the warning ahead of a UN environment summit in Nairobi.
For the health of our oceans, Svensson argues we must call on governments, firms and individual people to step up and solve the problem of ocean plastic before it is too late.
"This is a planetary crisis," she told BBC News.
"In a few short decades since we discovered the convenience of plastics, we are ruining the ecosystem of the ocean."
The remarks come after Svensson witnessed the harmful effects of ocean plastic firsthand. At a Kenyan turtle hospital, she met a juvenile turtle named Kai who was getting treated for plastic ingestion. For two weeks she watched Kai get nursed back to health, before they released the turtle back to the ocean.
"It's a very happy moment," she told BBC News.
"But sadly we can't be sure that Kai won't be back again if she eats more plastic. It's heart-breaking, but it's reality. We just have to do much more to make sure the plastics don't get into the sea in the first place."
Kai isn't the only animal in the ocean that has suffered from plastic pollution. The problem is wide-spread, and it is putting a lot of species at risk.
"The scale of the challenge is absolutely enormous," said Svensson.
And right now, she doesn't think the world is doing enough. The current global commitment is to substantially decrease waste inputs into the sea by 2025.
Svensson has a more aggressive plan. This week, she's backing a resolution by Norway to completely eliminate plastic waste into the ocean.
If the measure passes, it will be undoubtedly be a UN success, although some environmentalists worry without a timeline, the enormous feat will never be achieved.
"We welcome that they are looking at a stronger statement, but with billions of tonnes of plastic waste entering the oceans we need much more urgent action," Tisha from Greenpeace told BBC News.
"We need manufacturers to take responsibility for their products - and we need to look at our consumption patterns that are driving all this."
Even Svensson is worried the measure is not enough given the slow UN process.
"It could take 10 years to get a UN treaty agreed on plastic litter and a further two years to get it implemented," Svensson said.
"We have to progress through the UN because this is a truly global problem - but we can't wait that long. We need to get much stronger actions from civil society, putting pressure on business to change - they can switch their supply chains very fast. And we need more individual governments to take urgent action too."
Svensson also called on the media to spread the message. She praised BBC's recent Blue Planet series for bringing public attention to the many environmental assaults the ocean is currently facing - like climate change, the over-exploitation of coral reefs and over-fishing.
"This is a planetary emergency," she said.
"I sense there is a momentum now about the need to act. We just have to be much faster."