The UN secretary-general for oceans has said trillions of euros has to be pumped into measures to tackle climate change.
Ambassador Peter Thomson told the Institute of International and European Affairs (IIEA) that significant investment is needed to transform how people live from day to day.
Mr Thomson said there is enough renewable energy to power human life many times over.
"We don't want millions of billions of dollars to flow into the sustainable blue economy. We want trillions of dollars," Mr Thomson told the IIEA.
"#COP26 saw some progress made in protecting our oceans but still a lot more to do. Yes, these negotiations can be slow and progress not as quick as we like but I have yet to hear a credible alternative to a multilateral approach given the scale of the challenge" - Amb. Thomson pic.twitter.com/aBCRw9fNa5
- IIEA (@iiea) November 16, 2021
"We need those dollars to secure the health of the ocean and thereby the planet and thereby the wellbeing of our grandchildren.
"We need the trillions of dollars to decarbonise the global shipping fleet and the ports that service it, funding a transformation that has already begun moving from powering our ships with the filth of bunker oil to pollution-free green hydrogen.
"We need the trillions of dollars invested to feed the future through sustainable agriculture and farming the ocean to produce new sustainable nutritious forms of future food, seaweeds, phytoplanktons and other ethical non-fed forms of agriculture.
"We need the trillions because if we invest now in offshore energy, in wind, tidal, wave and other ocean technologies, we'll have all the renewable energy we need many times over to power our ways of life."
Mr Thomson said everyone has been involved in the decline of the ocean's health.
He said the only way to stop the decline is to govern activities with a "logical and ethical dedication" to sustainability.
He warned that now is the time to accept the exploitation of finite planetary resources is a "dead end street".
"We've reached a point on humanity's path whereupon global transformation to circular recycling systems of production and consumption has become a straightforward matter of survival or not," he added.
The Sustainable Development Goal 14, known as SDG 14, is a universal target to conserve and sustainably use the oceans' resources.
"Millions or billions of dollars are not enough to build a #Sustainable #BlueEconomy, we need trillions" says Amb. Peter Thomson.
"We need trillions to decarbonise our global shipping fleet and to promote more sustainable agriculture and aquaculture". pic.twitter.com/GrADXQ76s3
- IIEA (@iiea) November 16, 2021
Mr Thomson said the "nemesis" of the plan is the continued burning of fossil fuels.
"The massive scale at which we burn fossil fuels, grading the greenhouse gases, blanketing our atmosphere, are commensurately changing the composition of the ocean," he added.
"The ocean is absorbing 90% of the heat from global temperature rises so it should not be a surprise that immense changes are under way, and we now witness such phenomena as escalating marine heatwaves and the death of coral reefs."
He added that developing countries also need the funding to adapt to the effects of climate change.
"I don't want to point fingers, but you know, we all know, where the greenhouse gases have come from," he said.
"We all know where most of the money is on this planet, and that money needs to be channelled to developing countries, so they can undertake the adaptation required in the face of what's coming at us."