January 9, 2018<\/p>\n
A new paper published in Science magazine shows that oxygen concentrations in ocean water are declining, not least as a result of climate change. This is in turn posing a serious threat to marine life and people dependent on the ocean.<\/p>\n
The study, compiled by a network of scientists initiated by the UN,\u00a0also highlights the importance of reining in both climate change and nutrient pollution to halt the expansion of low-oxygen zones spreading around the globe.<\/p>\n
\u201cOxygen in fundamental to life in the oceans,\u201d said Denise Breitburg, lead author and marine ecologist with the Smithsonian Environmental Research Center. \u201cThe decline in ocean oxygen ranks among the most serious effects of human activities on the Earth\u2019s environment.\u201d<\/p>\n
The study notes that the oxygen content of the open ocean and coastal waters has been declining for at least the past 50 years, largely because of human activities that increased global temperatures and nutrients discharged to coastal waters.<\/p>\n
For example, the amount of water in the open ocean with zero oxygen has increased more than fourfold in the past 50 years whilst in coastal water bodies, including estuaries and seas, low-oxygen sites have gone up over 10-fold since 1950. With rising temperatures, oxygen content in the ocean is projected to decline further, which would threaten biodiversity and result in stunted growth, diseases, suffocation and the death of many animals.<\/p>\n
The study \u2013 conducted by a team of scientists from the Global Ocean Oxygen Network, a new working group created by the UNESCO\u2019s\u00a0Intergovernmental Oceanographic Commission<\/a>\u00a0\u2013 puts the spotlight on the biggest dangers to the ocean and coastal communities, and what it will take to keep Earth\u2019s waters healthy and productive.<\/p>\n Need to Tackle Multiple Causes of Disappearing Oxygen in the World\u2019s Oceans<\/strong><\/p>\n Climate change is a clear culprit. Due to rising temperatures, warming surface waters make it harder for oxygen to reach the ocean interior. As the ocean gets warmer, the amount of oxygen decreases. In coastal waters, excess nutrient pollution from land creates algal blooms, which drain oxygen as they die and decompose. \u00a0But there are other causes which need to be addressed in tandem with reducing greenhouse gas emissions.<\/p>\n To keep low oxygen in check, the scientists said the world needs to take on the issue from three angles:<\/p>\n What the UN is Doing to Tackle the Problem<\/strong><\/p>\n The UN\u00a0Sustainable Development Goal<\/a>\u00a014 aims to \u201cconserve and sustainably use the oceans, seas and marine resources for sustainable development.\u201d<\/p>\n Through a wide range of initiatives, the United Nations is leading global efforts to step up cooperation for safeguarding the world\u2019s oceans. Last month, the UN General Assembly recently\u00a0adopted a resolution<\/a>\u00a0to convene negotiations for an international treaty to protect the marine environments of the high seas.<\/p>\n During the United Nations Environment Assembly in Nairobi, Kenya, in December 2017, UN delegates\u00a0passed a resolution<\/a>\u00a0aimed at tackling threats emerging from ocean pollution and preventing plastic waste from entering the ocean. Among other measures, the agreement also envisions the formation of an international task force that will advise countries on ways to combat marine pollution.<\/p>\n The Fijian COP23 Presidency also launched an ocean initiative \u201cThe Ocean Pathway<\/a>\u201d to improve ocean health and protect critical ocean ecosystems threatened by climate change at the annual UN Climate Change Conference in Bonn, Germany, in November last year.<\/p>\n\n