Ocean Acidification and Global Warming

The planet passed another milestone this week, nothing dramatic just a way point towards the inexorable collapse of ocean fisheries. The milestone is the the fact that the atmosphere now is at 400 parts per million (PPM) Carbon Dioxide, a condition not seen in over 3 million years. Whereas the composition of the atmosphere and climate change slowly over time without human intervention, the unprecedented change now is happening faster than has ever been seen before.

Human activities such as the burning of fossil fuels and deforestation are adding Carbon Dioxide (CO2) to the atmosphere at a geometrically increasing rate. Global_Carbon_Emissions.svg This was happening long before the recent technological advances which have increased the rate that we can produce oil and gas here in the United States. Those advances may look good for energy independence but serve to exacerbate the rate of global warming hence climate change via the release of CO2 to the atmosphere.

If you wondered why I mentioned the ocean earlier here’s why. Of the CO2 added each year to the atmosphere about a quarter is absorbed by the oceans. A lot of gases dissolve in water. If oxygen didn’t dissolve in water, there would be no fish in the seas. But CO2 is unique among atmospheric gases because not only does it dissolve, it also reacts. Carbon Dioxide reacts with water to form carbonic acid.
This is the same stuff of soda pop, it adds tartness to a beverage. It is not a problem for us because we have systems in our bodies which can buffer, basically neutralize, the acidity. No such system exists in the open oceans. If you add more CO2 to the oceans they become more acidic. And this can be a problem of catastrophic proportions.

The shells of many many organisms will not form or actually dissolve in the presence of too much acidity, from the littlest limpets to the corals of the Great Barrier Reef. And herein lies the possibility of a catastrophe. The coral reefs are the nurseries of the ocean.Coral_reef_locations It is here where the food chain begins, and it is here where the ocean fisheries will end if the corals die off. They are already stressed by higher ocean temperatures. Caribbean corals are experiencing a condition known as bleaching, actually dieing. Increased acidity can add to the die-off.

And now there is evidence of acidity impacting ocean organisms. For ocean organisms, the canary in the coal mine is a little known group of animals called sea butterflies. LimacinaHelicinaNOAA Shell thinning among the sea butterflies is occurring making them more susceptible to predation. They occupy the antarctic ocean. Gases are more soluble in cold water so it is not surprising that the effects of acidification of the ocean will be observed in the antarctic ocean first. Just as the canary is more sensitive to toxic gases, the sea butterfly in the antarctic ocean is more sensitive to acidity.

The question becomes just how long do we go on polluting the atmosphere and the oceans? How much damage to the biosphere is enough to convince us to change our ways? H. L. Mencken said it best: It is the nature of the human species to reject what is true but unpleasant, and to embrace what is obviously false but comforting.

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