By Jim Steele
Climate scientists have been funded to find how rising atmospheric CO2 is affecting our climate and global ecosystems. As a result of their predisposed belief in “demon CO2”, simple correlations are misleadingly promoted as causation by both researchers and click-bait media. For example, lowering of ocean surface pH is blamed on a correlation with rising CO2. However, it is well established other factors also lower surface pH.
Climate alarmists use that correlation to scare the public, arguing that any continued burning of fossil fuels will cause pH to fall with catastrophic consequences for marine ecosystems. They simply assume surface pH will continue to fall as growing atmospheric CO2 pumps more CO2 into surface waters. But the data shows that has not always been the case.
Ocean pH drops from ~8.2 at the surface falling to 7.6 by 300-meter depth where respiration and decay of organic matter dominates, releasing CO2 and lowering pH. Observations show wherever that low pH subsurface waters upwell to the surface, surface pH declines. The solid black curve shows surface pH was 8.2 in pre-industrial times but has fallen to 8.1 in modern times (dashed blue curve). However subsurface pH has remained steady throughout. Observed increases in upwelling since the Little Ice Age will have lowered today’s surface pH.
During the depth of the last Glacial Maximum, atmospheric CO2 dropped to 180 ppm as oceans accumulated 850 billion tons more CO2than observed in today’s modern oceans (Anderson, R. F., et al. 2019). Yet despite more CO2 enteringthe ocean, surface pH was 8.3 . As ocean upwelling increased during the shift to the current interglacial, more CO2 was released back to the atmosphere and surface pH fell to 8.1 between 8,000 and 10,000 years ago and that contradicted theory. Assuming a surface ocean in equilibrium with atmospheric CO2, climate scientists expected a surface pH of 8.2 (Martinez-Boti 2015).
The upwelling of more ancient CO2 makes it impossible to accurately separate any effect of rising anthropogenic CO2. So, to minimize confounding upwelling effects, climate scientists have based their pH predictions on measurements taken from regions with low upwelling in the middle of subtropical gyres, such as station Aloha in the Pacific, and in the North Atlantic gyre (BATS; not shown).
Still, gyre stations are not immune to the pH lowering effects from upwelling. Just as the separation of organic matter production by photosynthesis at the surface, from the decay of organic matter at depth results in lower pH at 300 meters, similarly the separation of organic matter production in upwelling zones from the decay of the matter transported towards the center of those gyres, can also lower gyre pH.
The winds along the American west coast cause upwelling of low pH water containing high minerals and high CO2 that promotes abundant productivity. Those winds also create currents that transport that upwelled water and a portion of the generated organic matter towards the gyre’s center. Accordingly, Chavez (2017) has shown that upwelling along the Peruvian coast has greatly increased since the pre-industrial/Little Ice Age times, suggesting a trend of increasing upwelling that would naturally lower a gyre’s pH
Likewise, trade winds cause upwelling which also transports organic matter towards the gyre’s center. Research concludes average trade winds have also strengthened since the Little Ice Age. In addition, people who are informed about ocean circulation know upwelling of the low pH thousand-year-old water around Antarctica can also affect the pH of equatorial currents which in turn can affect gyre pH. The pathway of the Ocean Conveyor Belt brings water that initially sunk in the Arctic, eventually upwells around Antarctica, and then continues into the north Pacific.
Finally, reduced alkalinity also lowers pH. Ninety-five percent of the ocean’s alkalinity consists of aqueous CO2 derivatives: bicarbonate (HCO3-1) and carbonate negative ions (CO3-2) that can consume H+ ions and buffer changes in pH (red rectangle). In stark contrast to indefensible concerns that ocean acidification will hinder calcification by reducing carbonate ions, calcification definitely reduces alkalinity that lowers pH.
No marine calcifying species use seawater carbonate ions. Instead, all species import the more abundant bicarbonate ions (blue rectangle) from which they generate carbonate ions internally by pumping H+ out into the seawater. The resulting calcium carbonate shells of planktonic coccolithophores will sink at a rate of 140 meters per day, carrying away alkalinity stored in their shells away from the surface to ocean depths. And again, this pH reducing dynamic has strengthened, as coccolithophore abundance has increased since 1990 (Krumhardt 2016).
Click-bait media has hyped a few laboratory studies suggesting ocean acidification decreased coccolithophore calcification.