Climate Change and the Oceans
The Importance and Ecology of the Oceans
First, let’s establish the importance of the oceans.
Oceans cover more than seven tenths of the Earth, and represent 97% of our the water on the planet. Estimates of how much of our oxygen supply is produced from the oceans vary from 50% to 85%. However, there’s general agreement that the figure is at least half. They provide most of our precipitation and drive the weather. For centuries, they have been the highway system that has enabled global civilization. They have provided much of the world’s food. They are a supreme stabilizing force for the climate, the atmosphere, and the hydrologic cycle. Aspects of their importance could fill the page, were there enough room.
In short, oceans are on the short list of Earthly phenomena that has enabled complex life, human existence, and complex technologies.
The point is that we must have the oceans as partners for our indefinite future. The ability to achieve a sustainable society mandates quality stewardship of the oceans. However, throughout human history we have viewed them as bottomless cesspits and have tried to remove everything edible under the fiction that the oceans were an infinite cornucopia.
Thor Heyerdahl reported some half-century ago that, on his Ra expedition across the Atlantic, they were never out of sight of floating human garbage. We have dumped billions of tons of garbage, medical waste, nuclear waste, toxic chemical waste, and everything else imaginable into the oceans. Giant ocean tankers, negligently maintained and managed, have dumped billions of gallons of crude oil right into ocean waters. Imagine dumping a bucket of sewer sludge into your full bathtub before getting in to bathe, and you kind of get the idea.
Now, years later, there are vast islands of floating garbage in the oceans. The largest of these is in the mid-Pacific, dubbed “Gilligan’s Island,” and is twice the size of the state of Texas.
Some reports have alleged declines of ocean plankton, presumably as a result of toxic pollution. The phytoplankton are our most important oxygen generators, and the total plankton are the essential food for much of the ocean’s food web. No plankton, and much of life on Earth is threatened. Ironically, at the same time we’ve had catastrophic phytoplankton blooms right where we didn’t want them, because of near-shore nutrient pollution.
And everyone is familiar with the ocean mercury warnings. We’ve poured so much mercury into the oceans, along with other chemicals, that the U.S. government has warned us not to eat ocean fish more often than once per week because of mercury levels!
After all this, it must be understood that the world’s fisheries are not in danger of collapse. They have
Newfoundland cod was so plentiful in 1497 that John Cabot reported they impeded his ship’s forward movement. They were harvested at the rate of a quarter-million tons per year from the mid-1800s to the mid-1900s. Then the giant trawlers came in, and the harvest peaked at almost a million tons in 1968, and declined catastrophically thereafter until the entire remaining fish stock six years later was estimated at just under two thousand tons — that is, all the cod left alive in that region of the ocean.
But fish are still being hauled out of the oceans in staggering quantities. What’s critically important to understand is that the harvest of certain species, such as cod or mackerel, has catastrophically declined but the fishing efforts have shifted to other species viewed as less desirable, less accessible or less profitable in the past and so were still relatively plentiful. We are now trying to decimate those fishery stocks as well.
Part of the problem in re-establishing fish stocks is that we cannot see them easily and have very poor understanding of their life and reproductive dynamics. The prevailing assumptions about fish populations have often proven untrue. We have assumed that the oceans are relatively stable environments for reproduction, and we’ve found out the falsity of that. They also depend on non-ocean resources, as we’ve found after causing the complete extinction of several subspecies of salmon.
It’s yet another case of human arrogance producing catastrophe before we even have the ability to understand the causes of catastrophe. There were actually plenty of warnings starting some four decades ago, but they were ignored by the vast majority of the Earth. Wesley Marx laid it out quite graphically in 1967 in his book The Frail Ocean, and we didn’t pay any attention. We must pay attention now. We must have the oceans as a food source and as a biosphere partner.
Climate Change and the Oceans
But all this is preliminary to the REAL problem, the BIG problem, dwarfing all others: climate change is killing our oceans in several important ways. The oceans are disproportionately absorbing heat from the atmosphere, which is one of the main reasons that the Earth’s surface and air hasn’t seemed to warm as fast as expected. This is not only drastically changing ocean ecologies, but also causing sea-level rise, as ocean waters expand when warmed. As far as the ocean ecologies are concerned, all marine life can only exist within a certain temperature range. The important food fish, in particular, need colder waters, so are migrating farther north. Another of the problems is that warmer ocean water cannot hold as much dissolved oxygen as the colder water.
The oceans are also absorbing huge quantities of carbon dioxide from the atmosphere. This is making the oceans measurably more acidic. This in turn is inhibiting the growth of coral, and both slowing the growth of coral reefs and in many places actually killing off the coral and starting to dissolve reefs. Since coral reefs are critical around the world for protecting coastlines and harbors, this will be a disaster. Oceanic storms will come inland with far more energy and do far more destruction.
Another critical issue is that the really cold waters of the Arctic preserve methane “clathrates” in the seabed sediments. Clathrates are essentially methane deposited in a gelid form. Methane is a far more potent greenhouse gas than carbon dioxide, but fortunately, there is far less of it in the atmosphere. However, there are billions of tons of methane in not only frozen tundra, but even more in these seafloor deposits. Warmer Arctic waters mean that these clathrates are being warmed enough to start releasing gaseous methane, which bubbles up through the ocean waters to enter the atmosphere. These already are being observed.
The oceans disproportionately absorb the heat from global warming. The predictions of rising atmospheric temperatures have fallen short of predictions, and the reason, it turns out, is that all that heat is going into the oceans much more quickly than predicted. This has multiple levels of serious consequences:
The tipping point here is that the oceans will reach a point where they become barren desserts, UNRECOVERABLE ON A HUMAN SCALE.
To make a long story short, we’re causing the Sixth Major Extinction of life on the Planet Earth.