Continued from Myth busting – Part 10. If you have not read Part 10 yet, I suggest you go start there, in order to keep everything in context. Thanks!
To be clear on usage of certain terms:
Carbon (organic carbon) means the mineral carbon, an essential building block of all organic life on Earth – plants and animals, including humans.
Carbon dioxide means the gas breathed out by animals, and taken in by plants. Carbon dioxide is a naturally occurring gas in our atmosphere – but human activity burning fossil fuels has increased the amount.
Over millions of years, plants ‘breathe in’ carbon dioxide and use it as a building block for cellular life. As those plants grow up into big strong trees, so the dense wood holds lots of carbon. When the tree dies, the logs fall to the ground and are buried in new growing organic matter. That carbon is taken down into the ground and stored for many years, slowly releasing its mineral content into the soil to nourish other plants and animals. This is a crude explanation, but you get the idea.
Carbon sequestration means ‘taking carbon dioxide out of the atmosphere and storing it as carbon bound up in life forms (such as wood, plants, soil, insects, etc.)
A carbon sink is a place or thing that acts to sequester carbon, such as a tree.
Mother Nature provides places to sequester carbon naturally. The oceans, the topsoil, the forests and peat bogs (peat wetlands or peatlands) are all massive efficient carbon sinks, the world’s top four. The problem is, those carbon sinks are not working optimally.
Where have all the fishies gone?
Approximately 70% of the planet is covered by oceans and seas. Currently, around one third of all the carbon dioxide from the atmosphere is sequestered by our oceans. They could be taking a lot more.
However, there is a problem with our oceans. We have over-fished them for the last century or more, and the result is that early in the 21st century we find that 85% of fisheries worldwide are over-fished and seriously depleted. We have massively reduced fish stocks in our oceans, and the use of trawlers and supertrawlers has decimated marine life, hurting Mother Nature’s ability to restore what we have taken. In some species, over 90% of living stock has been wiped out over a few decades, reducing numbers below a certain ‘critical mass’ to such a point that populations can’t recover. This means the oceans have a reduced ability to sequester carbon from the atmosphere, due to lower levels of biological activity in ocean waters.
You see, it’s supposed to be the life in the water that sucks up the carbon…not the water itself. However, with more carbon dioxide in the air, our oceans are also suffering from something called ‘ocean acidification’ which means the water itself is absorbing carbon dioxide from the atmosphere, because there is more there to absorb, and it’s changing the pH of ocean waters, reducing the oxygen-richness of ocean waters. This makes it harder for marine life to proliferate. It’s a double whammy, and a vicious negative cycle.
We need marine life to proliferate in order to sequester carbon. Ocean acidification, over-fishing and pollution have left the oceans with reduces amounts of algae, phytoplankton, seaweed and fish. The result is that our best carbon sink isn’t working at all well, and the largest part of the planet’s surface, that should supply a huge proportion of our food, is drastically depleted. The answer must be to stop over-fishing, stop polluting our oceans with plastics, chemical waste and more, stop polluting the atmosphere with burned fossil fuels and let the oceans work naturally, the way they are supposed to.
Without trying to sound too melodramatic about it, it’s a bit like the zombie apocalypse, but underwater. Reduced life, pollution, loss of marine biodiversity, massive scars of land destroyed by trawlers, ‘kill squads’ out slaughtering marine life en masse. What’s happening in our oceans isn’t pretty. Read more