Planetary bioengineering on Earth to return and maintain the atmospheric carbon dioxide to pre-industrial levels: Assessing potential mechanisms

Abstract

We are all familiar with the episodes in the deep time history of Earth that enabled life to emerge in such abundance. Episodes like the formation of a Moon large enough and near enough to cause tides in the Earth’s waters and rocks, a core of sufficient iron with sufficient angular momentum to generate a protective magnetosphere around Earth, and assumption of a planetary axis angle that generates the ecological variation of our seasonal cycles. The living things that did arise on this planet have been modifying their habitats on Earth since they first appeared. Modifications that include the greening of Earth by photosynthetic organisms, which turned a predominantly reducing atmosphere into an oxidising one, the consequent precipitation of iron oxides into iron ore strata, and the formation of huge deposits of limestone by calcifying organisms. The episodes on which we wish to concentrate are 1) the frequent involvement of marine calcifiers (coccolithophores, foraminifera, molluscs, crustacea, corals, echinoderms), that have been described as ecosystem engineers modifying habitats in a generally positive way for other organisms, and 2) the frequent involvement of humans in changing the Earth’s biosphere in a generally negative way for other organisms. The fossil record shows that ancestral marine calcifiers had the physiology to cope with both acidified oceans and great excesses of atmospheric CO2 periodically throughout the past 500 million years, creating vast remains of shells as limestone strata in the process. So, our core belief is that humankind must look to the oceans for a solution to present-day climate change. The marine calcifiers of this planet have a track record of decisively modifying both oceans and atmospheres but take millions of years to do it. On the other hand, humanity works fast; in just a few thousand years we have driven scores of animals and plants to extinction, and in just a few hundred years we have so drastically modified our atmosphere that, arguably, we stand on the verge of extinction ourselves. Of all Earth’s ecosystems, those built around biological calcifiers, which all convert organic carbon into inorganic limestone, are the only ones that offer the prospect of permanent net removal of CO2 from our atmosphere. These are the carbon-removal biotechnologies we should be seeking to exploit.

An Assessment of the Potential Value for Climate Remediation of Ocean Calcifiers in Sequestration of Atmospheric Carbon

“…In particular cases (oysters and giant clams, for example), such restoration repairs the losses caused by generations of overfishing. And from the very first harvest, every metric tonne of live shellfish harvested removes a quarter tonne of CO2 from the atmosphere, permanently [7,10,11].…”

“…Yet we maintain that the fossil record clearly illustrates that the ancestors of today's marine calcifiers possessed the physiological tools to flourish with both acidified oceans and great excesses of atmospheric CO2. These organisms have regulated extremes of atmospheric CO2 and ocean pH earlier in Earth's history; we should empower them to provide these services again [2,6,8,10,11].…”

“…Comparing the potential of this blue carbon biotechnology with artificial/industrial CO2 Capture and Storage (CCS) solutions [8][9][10][11] we find that industrial CCS facilities deliver, at considerable cost, nothing more than captured CO2, for which safe, reliable, long-term storage, so far untested, of course, must be engineered at even further cost. Whereas aquaculture enterprises cultivating shell to capture and store atmospheric CO2 permanently also provide nutritious food and perform many ecosystem services like water filtration, biodeposition, denitrification, enhanced biodiversity, reef building, shoreline stabilisation and wave management.…”

“…In several recent publications we have advocated that shellfish farmers should greatly expand their production specifically to generate more shell to sequester atmospheric carbon [1][2][3][4][5][6][7][8][9][10]. Our core conviction is that humankind must look to the oceans for the solution to the excess CO2 in the atmosphere that drives climate change, and that marine calcifiers (coccolithophores, Foraminifera, Mollusca, Crustacea, Anthozoa, Echinodermata and some annelids) are the tools that will provide that solution.…”

A Shellfish Manifesto for Sequestering Atmospheric Carbon in Quantity

“…Securing that future for marine ecosystems suffering the effects of climate change is evidently a political challenge as much as an ecological or social one. The political limitations of conventional ecosystem governance have been recognised, but the immense promise of calcifier blue carbon science is so strikingly evident that it must be taken more seriously [5][6][7][8]. More than anything else this requires the recognition that cultivation of coccolithophores, corals, crustacea and molluscs on a massive scale would have the effect of removing a massive amount of CO 2 directly from the atmosphere; here, now and permanently, making a continued contribution to the health of the whole planetary ecosystem.…”