Global Food SecurityColin Orians
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You may find it surprising that 1 billion people on Earth rely on fisheries for their primary source of protein. Fish contribute 15% of animal protein for 3 billion people worldwide. That's more than 40% of people on Earth. There is too much carbon in our atmosphere. This we know is influencing the natural world.
Nowadays when we think about climate change we refer mainly to global warming. But we tend to neglect how this carbon affects our oceans. With carbon dioxide emissions increasing in the atmosphere, the oceans are becoming more acidic. This ocean acidification could have devastating effects on global food security, which would mean less seafood for all of mankind.
Okay, let's rewind. Since the beginning of the industrial revolution, the planet has seen anthropogenic, or human-caused emissions of green house gases dramatically escalate causing a myriad of problems. The most publicized of these problems, global warming, is actually an evil twin to ocean acidification. Why?
Because, in fact it is the ocean that stores 1/3 of the total carbon dioxide on the planet. So our sea water in other words has become a massive carbon sink. Carbon dioxide is a gas that is easily soluble in liquid water. When the gas combines with sea water, the product is carbonic acid. The build up of carbonic acid is leading to a phenomenon known as
ocean acidification which is creating a serious change in the chemistry of sea water. It turns out that the average surface pH of the world's oceans has fallen .1 units on the scale since the industrial revolution and it’s becoming more acidic every decade. We estimate that by the end of the 21st century, the pH level will drop another .3 or .4 units.
If we look to the pH scale of our common household items, this shift would be similar to changing our basic baking soda solution into a more acidic liquid like blood. Let's look at how this affects the world at large. The southern hemisphere is where the sea water is most acidic. Unfortunately, this region is also where marine life thrives on coral reefs.
The acidity of the water leaves the coral reefs fragmented, destroying habitat, and disrupting the patterns of migration for various species. Fish are also undergoing magnified effects as carbonic acid accumulates in their internal tissues. All in all, marine life is becoming endangered. In the grand scheme of things, how will this affect the global community?
Scientists have monitored the acidity of oceans around the world and found that the water at the equator is feeling the greatest shift in chemistry. We predict that subsaharan Africa and parts of south Asia will be devastated by ocean acidification in the next few decades as the marine life becomes scarce and developing nations seek what has long been their main source of protein.
Plankton are at the foundation of almost all marine ecosystems. As pH drops in the next few decades, certain types of plankton will be unable to form their shells. If key species of plankton are lost to acidification, then the many predators that depend on them will begin to disappear as well. Since humans are at the top of this food chain,
ocean acidification jeopardizes our global food security. Both the availability of fish and our access to it. What can we gather from all of this? Ocean acidification in the 21st century is going to come into the focus of conservationists and citizens alike.
The only way to slow the process of ocean acidification is to drastically reduce our carbon emissions if we want to keep fish in the oceans and on our plates. We predict that ocean acidification will move to the forefront of the international arena as we grapple with global food security and preserve a threatened common resource.