Oceans under Threat

The threats to our oceans are huge and getting worse and our members see this in all latitudes of the world.

The marine habitat is degrading through pollution from chemicals, plastics and the extensive use of agricultural and horticultural nutrients. In turn, this is leading to species extinction and biodiversity loss. This is compounded by illegal fishing, overfishing, and careless and unnecessary bycatch.

Moreover, every year ghost nets (commercial fishing nets that have been lost, abandoned, or discarded at sea) are responsible for trapping and killing millions of marine animals including sharks, rays, bony fish, turtles, dolphins, whales, crustaceans, and birds.

Some of the most evident degradation of the marine environment is witnessed in the damage and destruction of coral reefs. As cruisers, we all know that healthy coral reefs are teeming with life and many thousands of species depend on coral reefs for their continued existence.

These vital habitats are threatened by a range of human activities and especially pollution, unsustainable fishing practices, disease, global climate change, ship groundings and careless anchoring. Coral ecosystems face serious threats, mainly from the effects of global climate change, unsustainable fishing, land-based pollution, and ocean acidification.

The massive global industrialisation over the last 200 years has brought considerable economic and social benefits for many people all over the world, but at the same time the concentration of carbon dioxide (CO2) in the atmosphere has increased due to the burning of fossil fuels and land use change. About 30 percent of the CO2 that is released in the atmosphere is absorbed by the oceans, and as levels of atmospheric CO2 increase, so do the levels in the ocean.

CO2 causes seawater to become more acidic and reduces carbonate ions which are essential for the growth of sea shells and coral skeletons, threatening such as oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. In addition, acidification decreases the ability of some fish, such as clown fish, to detect predators and can add a further threat to marine ecosystems.

One of the biggest threats to ocean cruisers comes from weather pattern disruption, caused by climate change. As the temperature increases, more and more sea ice is lost, with a rapid thinning of ice now taking place in the Arctic - the region is warming at three times the global rate and its ice is essential for keeping the planet cool. This is now affecting the large system of ocean currents in the Atlantic – which includes the Gulf Stream, otherwise known as the Atlantic Meridional Overturning Circulation, or AMOC, which transports warm, salty water from the tropics northward at the ocean surface and cold water southward at the ocean bottom. If that system collapses, it would lead to dramatic changes in worldwide weather patterns.

Furthermore, sea ice loss leads to rising sea levels which pose a very serious threat to coastal communities and the people of low-lying islands and countries.

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