Nearly 20 years on from when New Zealand and other nations set goals at the 1992 Earth Summit to preserve Earth's health - including that of the world's oceans - researchers say they failed to meet those commitments on ocean health.
Writing in the journal Science, international experts say almost every pledge made at a United Nations Earth Summit in Rio de Janeiro in 1992 have not been met, the BBC reports.
Politicians not only need to improve the management of fisheries, decrease harmful subsidies, eliminate illegal fishing, increase marine protection and slow the loss of biodiversity, but handle new issues such as ocean acidification, invasive species and climate change, researchers say.
Their warning comes ahead of another UN summit in Brazil on June 20, where scientists are urging firm action to protect marine eco-systems.
Progress over the past two decades on pledges to protect key habitat and restrict the size of fishing fleets, has been "pitiful".
Though conservationists are delighted by Australia's move to set up the world's largest network of marine reserves, they say that globally the picture is bleak.
"Our analysis shows that almost every commitment made by governments to protect the oceans has not been achieved," said Jonathan Baillie, director of conservation at the Zoological Society of London (ZSL).
"If these international processes are to be taken seriously, governments must be held accountable and any future commitments must come with clear plans for implementation and a process to evaluate success or failure."
At the landmark 1992 Earth Summit and 10 years later at the Johannesburg World Summit on Sustainable Development, governments vowed to establish an ecologically sound network of marine reserves by 2012, eliminate subsidies that contribute to illegal fishing, protect critical habitat, look after the needs of local fishermen and restore depleted stocks to healthy levels by 2015.
Subsidies have not been eliminated, and illegal fishing is still a major issue in some parts of the world.
Little over 1% of the seas are protected, even though two years ago, governments agreed to raise that to 10% by 2020.
A pledge to restore stocks to healthy levels by 2015 has also seen slow progress, with the deadline extended to 2020 in European waters.
Under discussion at next week's Rio +20 conference are deals to establish marine reserves in international waters, agree on equitable use of the oceans' genetic resources, and help for poor countries on technology.
US negotiators are against pledging to share ocean genetic resources equitably, the BBC reports.