Experts called for global efforts to address several challenges facing the ocean as well as approaches to balance utilization with conservation to ensure the ocean's sustainable development.

They made the remarks on Tuesday during the annual general meeting of the China Council for International Cooperation on Environment and Development.

Liu Zhenmin, under-secretary-general of the United Nations and secretary-general of the Second UN Ocean Conference, emphasized the importance of the ocean as an environmental unity and the challenges it faces in sustainable development.

During his speech, Liu said that humans have neglected the critical role the ocean plays in maintaining biodiversity, the climate system and the water cycle.

"However, there are still challenges in achieving the sustainable use of the ocean due to a lack of deep understanding, scientific knowledge, technology, financial resources and even a sense of responsibility in some nations," he said.

The declaration adopted at the Second UN Ocean Conference held in Lisbon, Portugal last year addresses the challenges of protecting and sustainably using the ocean, he said.

The declaration expresses deep concerns about the urgent global situation facing the ocean. These challenges include rising sea levels, deteriorating coastal conditions, increasing ocean temperature and acidity, worsening marine pollution, overexploitation of 33 percent of fish populations, ongoing decline in marine biodiversity and the significant threat posed by invasive species to marine ecosystems and resources.

"It is crucial to prioritize solving the factors influencing the development of ocean science including the issue of fragmented global ocean governance. And a balance should be struck between the utilization and conservation of the ocean," Liu said.

Kristin Halvorsen, CCICED vice-chairperson and the former deputy prime minister of Norway, said that we need to ensure we address the multiple usages of the oceans, and that available space is used as effectively as possible. Fisheries, the fish farming industry and offshore energy production — the possibilities are many.

But there are also potential conflicts, and governments should work together with the various industries to avoid them, she said.