Ocean acidification is caused by the uptake of atmospheric carbon dioxide (CO2) by the ocean, which changes the chemical composition of the seawater. Over the past 30 years there has been an average increase of acidity of 26 per cent since pre-industrial times. At this rate it will have serious consequences for marine life by the end of the century.
The ocean brings us rainwater, drinking water, weather, climate, coastlines, the food we eat and the oxygen we breathe. The world’s oceans make the Earth habitable for humankind. That is what makes Promise 14 so important. We have to prevent and reduce of marine pollution from land based activities (debris, nutrient pollution), protect and save at least 10 per cent of coastal marine areas, as well as dealing with the problem of ocean acidification.
Rising ocean acidity reduces the availability of carbonate, a critical component of shell-building. If the acidity gets high enough, the ocean water becomes corrosive and shells literally dissolve. If it isn’t dealt with, ocean acidification will affect marine food webs and lead to big changes in commercial fish stocks. This will threaten the protein supply and food security for millions of people.
By mid-century vast ocean regions may not be suitable for coral to grow. Reefs will begin to erode faster than they can grow. Regions dependent on healthy coral reefs for fisheries, tourism, and storm protection will be profoundly impacted.
Over three billion people depend on marine and coastal biodiversity for their livelihoods. However, today we are seeing 30 percent of the world’s fish stocks overexploited, meaning they cannot recover fast enough each season.
Oceans absorb about 30 percent of the carbon dioxide produced by humans, but a 26 percent rise in ocean acidification is affecting that. Marine pollution from land-based sources is another serious problem, with an average of 13,000 pieces of plastic litter to be found on every square kilometre of ocean.
Enhancing conservation and the sustainable use of ocean-based resources through international law will help mitigate some of the challenges facing our oceans.
A framework of international instruments has been developed that addresses different aspects of fisheries management. For example, the Agreement on Port State Measures to Prevent, Deter and Eliminate Illegal, Unreported and Unregulated Fishing, the first international binding agreement to combat illegal fishing, entered into force in June 2016 and the number of parties to the Agreement has rapidly increased and stood at 58 as of February 2019.
Small-scale fisheries are present in almost all countries, accounting for more than half of total production on average, in terms of both quantity and value. To promote small-scale fishers’ access to productive resources, services and markets, most countries have developed targeted regulatory and institutional frameworks. However, more than 20 per cent of countries have a low to medium level of implementation of such frameworks, particularly in Oceania and Central and South Asia.