October 10, 2009 years A A paper in the journal Science last week, published by a UCLA scientist (Dr. Tripati), shows that CO2 is higher today than at any time in the last 15 million years. The study looked at fossilized foraminifera, those tiny sea creatures that make up a large part of ocean primary productivity, algae, plankton and the like.
The study of these creatures involves the analysis of their tiny shells, made up of calcium carbonate. Calcium carbonate is basically limestone formed on the ocean floor as countless numbers of these microscopic and near microscopic creatures die and their empty shells accumulate. Limestone has carbon in it, the carbon comes from carbon dioxide. The method used to figure the CO2 concentration of the atmosphere in this case is one of the most complicate. I am going to try and walk you through it because it demonstrates one of the primary reasons why climate change is so difficult to understand – that is because it is so complicated! Stay with me now:
Dr. Tripati and her team determined the boron to calcium and magnesium to calcium ratios of the their fossil shells taken from sea cores drilled into the floor of the Pacific Ocean using a mass spectrometer. From these ratios they were able to determine the hydrogen ion concentration of the sea water at the time the foraminifera created their shells. The hydrogen ion concentration was able to tell them the pH or acidity of the ocean water, and ocean acidity has a direct relationship with atmospheric carbon dioxide concentration. The actual experiment was hundreds of times more complicated than this, I could only wish that I was smart enough to understand everything in the report, much less the supplemental information.
An interesting note in the Tripati paper: Sea level was 80 to 130 feet higher 15 million years ago, when CO2 was the same concentration or a little higher than it is today. One of the most obvious things that the scientists say about our current CO2 levels when compared to prehistoric sea levels is that we have raised CO2 so high so fast that ice melt has had nowhere near enough time to catch up. What this means is that the climate today, because of the great distance between the normal relationship between CO2, temperature and sea level, is far, far from anything ever experienced on this planet in time frames that matter.
Tripati, et. al., Coupling of CO2 and Ice Sheet Stability Over Major Climate Transitions of the Last 20 million years, Science Express ,October 8, 2009.