For the ancients, the sea was always something vast, turbulent and frightening. Sea-going ships rarely ventured out of sight of land.

Is this so surprising after all? We are all creatures of the land, born of the earth and later buried in it, and it’s the land, rocky and reassuring, which gives us our sense of stability — not the undulating seas, not the heaving oceans with their tidal currents and mysterious depths.

For centuries then, human beings feared the ocean and sought to master it. How ironic then, that today the greatest threat to the ocean comes from humankind itself.

June 8 is World Oceans Day 2023, and this year’s theme is “Planet Ocean: Tides are Changing.”

“The tide has turned” is an expression that means that something that was relatively constant has now changed. It is the climate that has changed around the world, and if earlier we took the oceans for granted, it may no longer be so.

Today, the biggest threat to our oceans comes from human excess. One of these is the global warming of the seas caused by rampant industrial pollution, and the second is the death of plant and sea life caused by the presence of plastics. 

Significance of Ocean Day

Oceans are more important to the sustenance of life on Earth than it may seem. After all, life emerged from the oceans. Oceans are home to thousands of species of plants and fish, and around 50 percent of the planet’s oxygen is produced by the oceans.

So World Oceans Day raises awareness about the role of the seas in helping humans survive. Here are some of the reasons why.

Today, the ocean absorbs about 90 percent of the heat generated by rising emissions from industry. Still, the excessive heat and energy which warms the ocean changes the earth’s temperature and leads to unparalleled cascading effects — like the melting of the polar ice caps and the mountain glaciers, the sea-level rise, marine heat waves, and ocean acidification (that is when rising levels of carbon dioxide in the seas slowly kill all marine life).

The livelihood of a significant number of people in the world is dependent on the oceans. But rising sea levels already threaten places like the Brahmaputra delta in Bangladesh, and certain islands in the South Pacific, which will all be engulfed when sea levels rise because of global warming.

Oceans Day encourages people to take action and reduce the amount of damage that human activities have caused to the oceans.

How do human beings damage the ocean?

By making it the dumping ground for all the garbage of the world.

The Great Pacific Garbage Patch (GPGP) in the North Pacific between Hawaii and California, covers an estimated surface area of 1.6 million square kilometers, an area three times the size of France.

For many people, the idea of a “garbage patch” conjures up images of an island of trash floating on the ocean. In reality, these patches are made up of tiny bits of plastic, called microplastics. Microplastics can’t always be seen by the naked eye, not even by satellite imagery.

The microplastics of the GPGP can simply make the water look like a cloudy soup. This soup is intermixed with larger items, mostly fishing gear and jettisoned cargo.

Much of the debris accumulated is not biodegradable. Many plastics, for instance, do not wear down; they simply break into tinier and tinier pieces.

A huge plastic garbage heap

The seafloor beneath the GPGP may also be an underwater trash heap. Oceanographers and ecologists recently discovered that about 70 percent of marine debris actually sinks to the bottom of the ocean.

While oceanographers and climatologists predicted the existence of the GPGP, it was a racing boat captain named Charles Moore who actually discovered the trash vortex. Moore was sailing from Hawaii to California after competing in a yachting race. Crossing the North Pacific Subtropical Gyre (ocean current), Moore and his crew noticed millions of pieces of plastic surrounding his ship.

No one knows how much debris makes up the GPGP. It is much too large for scientists to trawl. Because the GPGP is so far from any country’s coastline, no nation will take responsibility or provide the funding to clean it up.

Charles Moore, who discovered the vortex, says cleaning up the garbage patch would “bankrupt any country” that tried it. Moore estimates that it would take 67 ships one year to clean up less than one percent of the GPGP in the North Pacific Ocean.

Some 80 percent of plastics in the ocean is estimated to come from land-based sources, with the remaining 20 percent coming from boats and other marine sources, fishing gear, for instance. These percentages vary by region.

While many different types of trash enter the ocean, plastics make up the majority of marine debris for two reasons. First, plastics are durable, cheap to produce and use, and malleable, which means that plastics are used in more and more consumer and industrial products.

Second, plastic goods do not biodegrade but instead, break into smaller pieces.

In the ocean, the sun breaks down these plastics into tinier and tinier pieces, a process known as photo-degradation. Most of this debris comes from plastic bags, bottle caps, plastic water bottles, and Styrofoam cups.

Marine debris can be very harmful to marine life in the ocean currents. For they are so minute that birds and fish often consume them and die. Or they may be absorbed into the bodies of the fish which we catch and consume.

Marine debris can also disturb marine food webs in the ocean. As micro plastics and other trash collect on the ocean surface, they block sunlight from reaching plankton and algae below.

If algae and plankton communities are threatened, the entire food web may change. Animals that feed on algae and plankton, such as fish and turtles, will have less food, and a whole food chain is affected.

What is to be done?

Many individuals and international organizations, however, are dedicated to preventing the patch from growing. Success however will be slow, expensive, and demand a change of mindset. This last is the hardest of all.

What lessons can we draw from World Oceans Day? Two, mainly.

Industrial pollution, the main cause of global warming, has so changed the ocean tides that today human coastal habitations are under threat everywhere. Is this process irreversible? Sadly, it is.

And secondly, plastic, the greatest boon of the last century, has also become our greatest curse. Plastics are slowly causing the death of all marine life, and are just one remove away from suffocating us as well.

*The views expressed in this article are those of the author and do not necessarily reflect the official editorial position of UCA News.