On the ethical implications of the biomass of domain archaea

A friend of mine is a graduate student doing research in microorganisms in the domain archaea. Archaea are one of three domains of life, the other two being eukaryotes and bacteria; plants, animals, algae, protozoa, slime molds, and fungi are included in the domain eukaryotes.

In talking with my friend graduate student recently, he mentioned that some biologists believe that organisms of the domain archaea might well comprise a significant portion of the biomass of the planet; archaea and bacteria together probably comprise half the biomass of the planet. Many organisms in archaea live in extreme environments, like deep sea ecosystems. It is unclear to what extent archaea and bacteria will be affected by global climate change, but at the very least deep sea ecosystems may remain relatively unaffected for some time.

This raises an interesting ethical point. A popular ethical argument says we should stop global climate change because it will lead to massive species extinctions. But what is really meant is that global climate change will cause extinctions to a small percentage of organisms in the domain Eukaryotes, specifically larger plants and animals; that is, it may be that a small portion of the earth’s biomass will be affected.

Considered another way, while a huge number of species may be driven to extinction by global climate change within a relatively short time, that’s in comparison to past numbers of extinctions within a given time period. But if you compare the number of extinctions to the total number of species on Earth, then it’s a very small number.

So from an ethical point of view, what we find most troubling about global climate change is that it has the potential for killing off the species with which we are most familiar, and on which we are most dependent. We know so little about archaea, and cyanobacteria, and the hundreds of thousands of insect species that have yet to be described, that it’s hard for us to have much in the way of concrete ethical concern for them — we don’t even know if we should be concerned for them. My friend the graduate student put it something like this: We don’t really know what the effects of global climate change are going to be, but it seems likely that most of earth’s organisms won’t be affected by it.

This doesn’t mean that we shouldn’t be concerned about global climate change. We should be desperately concerned about global climate change. But any ethical concern should stem from our ethical concerns about how it is going to affect us human beings — whether global climate change will kill species we love, ruin ecosystems we depend on, and maybe even drive us to extinction. Our ethical concern should not stem from worries about archaea, or even about termites, both of which comprise a great deal of the earth’s biomass and both of which will probably survive global climate change quite nicely, thank you.