Longtime Subscribers to MOST know where we stand on this issue: we’re “Deniers.” At least that’s what the folks on the other side of the issue label us. We prefer to call ourselves “scientists.” But what better way to kick off the 2015 MOST blog than with another chapter in the global warming saga?
Thanks to my bro-in-law for sending me the following link:
This article addresses something of particular interest to water folks on this topic of global warming: the acidification of the oceans of Earth. Is life on this planet doomed by carbon dioxide altering the chemistry of our oceans?
First, higher carbon dioxide levels in the atmosphere will mean that more carbon dioxide dissolves in our oceans. This is because the concentration of a gas dissolved in water is proportional to the amount of that gas in any gas mixture in contact with the surface of that water — in this case, that mixture is the Earth’s atmosphere. So as global atmospheric carbon dioxide levels increase, so must the carbon dioxide in the oceans.
And carbon dioxide will act as an acid when dissolved in water. The pH of water will definitely get lower by the addition of carbon dioxide. Just take out your pH meter and analyze your favorite carbonated soft drink: it will be about 3 — pretty acidic!
However, to leap from these known scientific principles to the end of life on Earth ignores several other scientific principles. The first such principle is one that we have posted on previously: the impact of ocean warming on carbon dioxide levels in the atmosphere. Over five years ago MOST explained the science of solubility of gases in water and the effect of temperature (see “Solubility and Soda Pop” from December 2009). As the Earth warms, so must the oceans. As the oceans warm, dissolved gases will leave the water, in the same manner that your soda goes “flat.” In short, warming of the oceans will drive carbon dioxide out of sea water. In this way, global warming could be the solution to the acidification of our oceans!
Next, we have all heard the dire predictions of catastrophic rising of ocean levels around the Earth, brought about by global warming. How would this happen? If the Earth warms, much of the second largest source of water on our planet, permanent ice, would melt. The cause of the rise of the oceans would be a significant influx of fresh water into the oceans. This would dilute both the salinity of the oceans and reduce the concentration of every water quality constituent, including carbon dioxide. Once again, we see that the solution to acidification of our oceans is global warming!
Yet another scientific principle that applies to this conversation is that of “buffering.” This is the resistance of a solution — such as sea water — to a change in pH when an acid or a base is added to the solution. The resistance to a drop in pH, caused by the addition of an acid such as carbon dioxide, is called “Alkalinity.” In water treatment and water quality, you have probably encountered this concept. In drinking water, the carbonate, bicarbonate, and hydroxide anions are the main contributors to alkalinity, and in fact are considered the “Total Alkalinity.” How do the concentrations of these ions in sea water compare to those in fresh waters?
Overall, the total dissolved solids (TDS) of sea water is about 30-40 times higher than most fresh waters. We can expect a similar thirty-fold increase in the alkalinity of sea water. What does that mean? It is very difficult to change the pH of sea water!
So, will global warming cause — or cure — acidification of our oceans? As a scientist, a professor of Water Utility Science, and a water quality professional for the past four decades — also known as a “Denier” — MOST feels compelled to view all the scientific principles involved, rather than only those that support our theory.
Has anyone heard from Al Gore lately?