NOAH’S RAINBOW SERPENT – observations by Ian MacDougall

CARBON CAPTURE AND STORAGE: Global salvation or total folly?

Posted in Uncategorized by Ian MacDougall on January 7, 2021

Carbon capture and storage (CCS) is touted around the place as an answer to the anthropogenic global warming consequent upon the burning of fossil carbon stores – coal and oil – for fuel and venting of the resulting CO2 to the atmosphere. The CSIRO no less is working on it. That the planet is warming as a result can be seen most clearly in the global rise in sea-level as tracked by the Colorado University sea-level group, using satellite altimetry accurate to +/- 0.4 mm.

The idea is to extract the CO2 from the gas mixtures presently being vented to the atmosphere, liquefy it (requiring pressure of the order of 100x normal atmospheric pressure of ~14 psi) and then pump it down disused oil wells or purpose-drilled bore holes where it will hopefully combine with compounds of iron and other elements, to be effectively locked up forever.

I regard CCS as more likely folly than salvation, and for three reasons:

  1. Oil and natural gas are commonly found trapped in natural geological formations such as sedimentary domes and impervious faults as gas-over-oil-over-water. Unless released by and earthquake, orogenic uplift, volcanic eruption or some such event, it will stay trapped there for millions of years. This is why petroleum geologists favour younger sedimentary strata in stable environments for their searches, and it depends upon the well-known fact that oil and water in the same container (eg a bottle of salad dressing) stay separate and do not ‘mix’. If shaken up and left to stand, the oil droplets finish up in a separate layer over the aqueous solution of acetic acid commonly known as vinegar. Unlike CO2, oil does not dissolve in water. Some Roman or French gastronomic genius went on to discover that the addition of some egg-white to the bottle, there followed by vigorous shaking, remedied this situation. That in turn inspired the composition of the French national anthem known to the world as the Mayonnaise. (I’m pretty sure that’s right.)
  2. CO2, once dissolved will be carried at whatever rate in the natural movement under gravity in the groundwater until it reaches an undersea outcrop, where it will mix naturally with the seawater and add to the CO2 load already there, making the oceans a dilute solution of carbonic acid, better known as soda water.
  3. And this is important. The heat-trapping properties of CO2 which make it a problem today will almost certainly be humanity’s future salvation. Because we are at the mid-point of the latest in the series of glaciations (‘ice-ages’) and but for the heating of the atmosphere brought on by its abnormally high CO2 concentration, would be slowly descending into the next glacial minimum, or ice age. The glaciations run on a ~100,000 year cycle. So lock the atmospheric carbon dioxide up in vegetation: forests, seaweeds, pastures or whatever takes your fancy. But don’t lock it away forever. Because human civilisation depends on glacier-free land. (In the last glaciation there was ice about 1 km thick where today we find Central Park, New York City.)

The climate historian Christopher Scotese has an excellent graph under the heading ‘ICE HOUSE OR HOT HOUSE?’ at his climate history website.