(excerpts from an essay*)
The Carboniferous Period 359 – 299 million years ago (mya): For over sixty million years the Earth was covered with tropical forests where the first land lizards crawled from the seas and the air teemed with flying insects. From these forests the air was enriched with oxygen and coal laid down.
Gippsland brown coal …was laid down between 50 to 15 mya. The land was covered with tropical rain forest until about 20 mya when a cooler drier climate occurred effecting the distribution of tree species.
During the 1700s the industrial age was born with the mining and burning of coal predominantly used to manufacture iron and steel. Later in the 1800s oil and gas were mined, initially for lighting and heating and later for motor vehicles and transport.
Over the past half million years CO2 levels have fluctuated between 150 ppm and 300 ppm in a fairly regular cycle, ascertained by ice core samples. More recently however we see that CO2 concentration has exceeded 400 ppm and steadily rising. Scientists attribute this to the burning of fossil fuels. We see a rise in mean ocean temperature, receding polar and glacial ice, rising sea levels and more extreme weather (floods and forest fires). Marine plankton and forests are the natural removers of CO2 from the atmosphere. Increased world human population, industrialization, wars and deforestation further aggravate the situation.
This presents chemists and engineers with a huge problem: what to do with the emitted carbon dioxide? The solutions are (i) Let it enter the atmosphere to be dealt with naturally (ii) Store it deep underground in stable rock formations. Neither of these solutions is satisfactory. Firstly, we have committed ourselves to zero emissions by mid-century via the ‘Paris Agreement’ and the follow up ‘Glasgow Accord’. So option (i) is out of the window.
Option (ii) seems plausible at first until we examine it closer. Is there such a thing as ‘stable rock formation? True, we have mined water, oil and natural gas that was held deep underground for millions of years but can we risk a situation of a sudden outpouring of millions of tons of CO2 at some future date? This might be caused by earth tremor or fracking or some other human activity long into the future when this storage has been forgotten.
The only clean hydrogen is that procured by simple electrolysis of water using solar electricity, producing both hydrogen and oxygen. As described earlier in this piece, coal, oil and natural gas were laid down over hundreds of millions of years. To return carbon to our atmosphere in just a couple of hundred years does indeed spell catastrophe for the biosphere. But it is of no use to blame past generations when Eco-science was in its infancy or poorly understood. With our current knowledge we must forge new ways to solve these environmental problems to preserve life on this planet as we know it.
*this is from a long article – an extension of an earlier blog on the same subject. The author noted that the dual thrust of his article included the danger of reducing oxygen in the atmosphere as well as increased carbon dioxide and asked that the full article be provided on request. Make the request here.