"The health of the ocean is in decline. And we have to do everything possible to turn that around for obvious reasons," Thomson said while briefing reporters at the UN headquarters on the preparations for the 2020 UN Ocean Conference slated for Lisbon, Portugal, on June 2-6.

He warned that the oceans are facing such problems as pollution, acidification, deoxygenation and ocean warming.

"Back in 2017, it was about trying to wake the world up to the fact that the ocean was in trouble... Now what we're focused on are the innovative steps we're gonna take in Lisbon that are going to deliver the relationship with the ocean that we want humanity to have," he said.

The 2017 UN Ocean Conference sought to mobilize actions for the conservation and sustainable use of the oceans, seas and marine resources.

"By the time we get to 2030, we're gonna have to take some very important decisions about our relationship with the environment. The ocean is the most important part of the environment," said the envoy. "There is no healthy planetary ecosystem without a healthy ocean ecosystem."

On Tuesday, at the preparatory meeting for the 2020 UN Conference to Support the Implementation of Sustainable Development Goal 14: Conserve and sustainably use the oceans, seas and marine resources for sustainable development, Thomson urged everyone to focus on the "positive tipping points," claiming they "are closer than you think."

These include "scaling up of science and innovation" and other solutions "that we will be concentrating on in Lisbon," according to the envoy.

Thomson also spoke about the strong will of developing countries to participate in sustainable agriculture, windfarms and the greening of shipping, saying that "we are now on the cusp of a great positive revolution."

Goal 14 of UN 2030 Agenda for Sustainable Development is Life Below Water. Statistics show that more than 3 billion people depend on marine and coastal biodiversity for their livelihoods. Oceans also absorb about 30 percent of the carbon dioxide produced by humans. The goal aims to sustainably manage and protect marine and coastal ecosystems from pollution, as well as address the impacts of ocean acidification.