Creating a Climate on the High Seas
Emma Williams
It can be difficult for us to understand the complex and important roles that ecosystems play, and the value they not only add to the world as a whole but to all of us too. This can be even harder to recognise when the ecosystem we are talking about seems entirely disconnected from most of us. Other than from the great heights of an aeroplane, many of us will never even see the open ocean for ourselves. However, we are more connected to the high seas than you may realise. It governs so much of what we know and experience no matter where in the world you live.
80% of the world’s goods are transported by ships across the open ocean. Photo: Pexels.
Humans utilise the high seas for many reasons. It provides convenient shipping routes connecting the far corners of the world. An estimated 80% of all goods including textiles, building materials, chemicals, fuel and food are transported using shipping routes across the open ocean. Cargo vessels have been joined by fishing fleets now able to access and exploit fish stocks previously inaccessible to them thanks to remarkable technological advances. Approximately 40% of all global fishing grounds are now located in the high seas. Many of the most sought after fish, including tuna and sardines, are largely caught here. Our dependence on this ecosystem for food is likely to grow as our population does.
However, the true value of this remarkable ecosystem doesn’t come from what we take but from what it gives.
The high seas shape the global climate.
The enormous size of the open ocean and the chemical properties of water mean it is able to absorb large amounts of heat without experiencing big temperature fluctuations itself. The oceans are responsible for absorbing more than half of the solar radiation reaching the Earth from the sun as well as large amounts of excess heat produced by anthropogenic activities. Like all energy, heat never disappears; it is simply moved around the oceans by currents, tides and waves and released back into the atmosphere through direct reheating, melting ice or water evaporation. Even hurricanes which form over oceans help to distribute heat to higher altitudes. The continuous heat exchange between the oceans and atmosphere drives the Earth’s water cycle, mediating patterns of rainfall and drought.
The ocean plays a big part in creating the world’s weather systems. Photo: Pexels.
The influence of the high seas doesn’t stop there. It plays a crucial role in removing carbon dioxide from the atmosphere and producing oxygen. The oceans ability to absorb enormous quantities of CO2 has helped to slow down the effects of anthropogenic global warming, having absorbed around 30% of the CO2 produced by human activities in the last 200 years. The all important phytoplankton play a vital role in removing CO2 from the atmosphere by incorporating the carbon into organic material through photosynthesis in the same way trees do. Although the tiny phytoplanktons are not as large or long lived as our huge trees, they have the potential to lock carbon away. When phytoplankton die they sink to the bottom of the ocean trapping carbon as organic matter far out of reach of the atmosphere. This process is known as carbon sequestration, and can trap carbon for millions of years.
Thanks to the process of photosynthesis, phytoplankton not only lock carbon away, they also produce oxygen. In fact, marine plants are responsible for producing over half of the oxygen we breathe. So, although the forests are often thought of as the lungs of the Earth, maybe it is more accurate to say, like the human body, we have two lungs. However, in this case one is green and the other is blue.
Carbon sequestration traps carbon in dead phytoplankton at the bottom of the ocean, removing it from the atmosphere. Photo: Unsplash.
So as you can see the ecosystem services provided by the high seas are immense. Although there is not yet an economic value for the entire ecosystem, one study conducted estimated the ecosystem services provided by the Eastern Tropical Pacific alone as approximately $17 billion annually. The ecosystems function in catching and storing carbon was by far the most valuable services of all, being valued at $12.9 billion annually, while commercial fishing was just $2.7 billion.
Historically, dramatic changes in climate have been the result of changes in the ocean’s circulation and ocean-atmosphere interactions. These climatic changes can have far reaching consequences including physical, chemical, biological, economic and social effects. By regulating these global processes the open oceans play a vital role in making our planet the place we can call home.