Global health. The current scenario and future perspectives

78 c) Ecosystem degradation Ecosystems are the entire network of relationships between a particular environmental habitat and the plants, animals and humans that depend on it. However, some of these ecosystems are not under the control of one or more nations. So, who should be responsible for protecting these areas? At the same time, some ecosystems are under the control of a nation, but that nation may not have the resources or inclination to protect them. Should countries be concerned about environmental damage in another country that does not have clear cross-border effects (without affecting the sovereignty of that country)? Oceans are an example of these problems. They are used for economic activity, recreation and sustenance in many nations worldwide. However, since they do not belong to a single nation, oceans can be considered the “common heritage of humankind”, a resource that is not owned by anyone but used by all, and which can eventually be irreparably damaged because no one takes responsibility to protect them. This situation can turn into a tragedy due to the dependence of all human beings on the oceans. As they cover approximately 70% of the Earth’s surface, oceans play a vital role in the environment and economic activity worldwide. According to the UN, “Oceans are a highly productive system that continually recycles chemicals, nutrients and water through the hydrological cycle, while driving climate and weather and regulating global temperature by acting as a giant heat reservoir.”. Moreover, oceans form the foundation for a wide variety of industrial, commercial and recreational activities such as fishing, maritime transportation and navigation. Lastly, habitable coastal marine areas are significant: in 2015, 44% of the world’s population lived within 100 kilometers of ocean coasts and about 10% of the world’s population lives in coastal areas less than 10 meters above sea level. Several issues affect oceans. Different types of pollution reach the oceans from various sources, including wastewater, agricultural runoff, oil spills and non-biodegradable waste. Unsustainable consumption of living marine resources is another serious problem: in 2012, up to 13% of the world’s fisheries collapsed due to commercial overexploitation. Additionally, through dredging for port creation, waste dumps, construction and recreation, coastal areas have been significantly altered and reshaped for human purposes. Scientists have estimated that nearly 10-30% of the world’s coral reefs have been permanently lost, while 70% are threatened with damage attributable simply to direct physical destruction. The burning of fossil fuels increases the ocean’s acidity and harms ecosystems, which induces marine and coral degradation.