Every time I look out from the beach, the vastness of the ocean fills me with awe. Would life be the same should the world be covered 75% by land instead of by sea? I think we would end up much worse.
The ocean may look like a desert where nothing grows. However, there exists another world much bigger below the surface. In the ocean, all creatures and plants live in a three-dimensional space because they swim or float in the water at different depths. On land, only birds and insects are able to move naturally and freely in three dimensions.
The ocean sustains life on land but not the other way around. Why? All land animals and plants need water to survive. As you know, 75% of the human body consists of water, about the same percentage as the ocean coverage of the earth’s surface. This does not seem accidental, does it? In addition, the origin of animal life on land can be traced to the ocean when the first sea creature crawled ashore millions of years ago. Our living earth is no doubt a water world. All the other planets have no life just because they have no water on the surface.
How does the ocean sustain the land? First, it requires water to freeze and boil within a relatively small range (only 100 degrees Centigrade). Second, it requires the sun to act as an engine of water recycling. The sun’s heat evaporates part of the water in the ocean to form clouds. The wind carries the clouds to land and deposits them as rain or snow. Why does the wind blow inland? During the day as the land heats up faster than the sea, the air on land expands and rises, drawing in air (or wind) from the sea. There also exist the powerful jet streams higher up generated by the sun’s heat and the earth’s rotation. Imagine if the ocean occupies a surface much smaller than 75%, there would not be sufficient clouds formed from evaporation unless the sun gets much hotter. The land would be much drier due to less precipitation from smaller clouds.
Besides fresh water brought in by clouds, the ocean is the largest source of food supply for many maritime countries. This should help us appreciate the great depths of the ocean. The Mariana Trench in the Pacific measures the deepest at 35,800 feet, surpassing the height of Mount Everest at 29,029. The ocean’s great depth and surface area make up a huge water space capable of tremendous seafood production.
Another benefit we take for granted is that food from the ocean is produced wild and free. On land, we have to feed domesticated animals like cows, pigs and chickens for their meat. In the ocean, the big fish feed on the small fish. We just go out to harvest all kinds of fish, without having to feed them in the first place. The ocean is the last frontier where we can still find wild rather than farmed produce to eat.
The economic benefits derived from the ocean can easily be seen through history. Among all the world powers, an overwhelming majority are maritime countries with a large fishing industry, a strong navy, and actively engaging in trans-ocean commerce.
We depend on the ocean for survival much more than we know. Because it is vast and moving, we tend to treat the ocean as a dumping ground, thinking that the garbage or pollutants will somehow disappear without any consequences. We also tend to overfish before the ocean has enough time to replenish its stocks. In recent decades, the amount of greenhouse gases released into the atmosphere is disrupting the natural recycling of fresh water from ocean to land. As a result, some places receive too much precipitation while others not enough, hence more severe floods and droughts occurring worldwide.
As the world becomes more crowded and connected, the importance of the ocean in sustaining life is rising in our consciousness. We should treat the ocean as a great living resource rather than a garbage dump. We should also learn how to nurture the ocean whose regenerating powers can sustain the world for a long time to come.