Over hundreds of millions of years, Earth and all living things have tolerated five mass extinctions, one of which wiped out over 90% of living things. You might say that such happenings are part of natural processes and beyond the control of Earth’s occupants, but humankind’s ascendency over what is seen as our kingdom defies, maybe even defiles, that judgment.
That over 90% of all organisms that have ever lived on Earth are extinct might elicit mild shock among the disengaged, for such events occurred over a 500 million year span, a very small part of which humans have had body and breath. These extirpations have occurred in bunches centering around five great extinctions, none to which humans were witnesses. Thus in those five extinctions, involving processes spanning millions of years, humans had no part.
The sixth extinction1 may be a different matter, in terms of humankind’s involvement, its overall impact, and extinction’s much-shorter span of devastation.
While video clips — one put together by National Geographic, for example — celebrate the current profusion of beautiful creatures with which we humans cohabit, we still have time to visualize what we are losing, and NG’s “Get Closer” persuasion seems – in the midst of our Earth-ravishing plenty — more like a rebuke or a warning about our profligacy than a persuasion to get involved.
I’m sure the beautiful creatures depicted in the NG video don’t hear the death rattle, but we sentient beings should.
We speak of greenhouse gases (carbon dioxide [CO2]) in the air, which in our polarized world, makes them seem wholesome, part of the human growing experience. Perhaps the familiarity of this “greenhouse” reference elicits an air of normalcy for most of us who are non-scientists. A wordmonger with a negative agenda might call it a harmful gas, though science doesn’t normally seek to deceive.
As our attention is drawn to CO2 in the atmosphere, our oceans have six categories of threat to health among living things: acidification, warming, hypoxia, sea level rise, pollution, and overuse. The first, acidification, is caused by the absorption of CO2 by our oceans, bringing lower Calcium Carbonate levels needed for plankton, mollusks, shellfish, and coral formation. The growing extent of acidification, in the form of lower Calcium Carbonate levels – now and in the future — is tracked below by the Environmental Protection Agency (EPA).
Such tracking covers a relative scrap of time, compared to the Earth’s total span of years, but lacking any comparative measure of alarm we should feel, or a definitive idea of the threat we face, scientists study the ancient past.
A new acidification study says that the seas are losing their ability to sustain many forms of life ten times faster than 55 million years ago. Ocean floor sediment samples show that 55 million years ago, a drastic drop in the ocean’s pH level brought the death of deep-sea calcifiers, the sample further indicating that the corrosive sea water did not actually disperse for over a hundred thousand years. The research of Ridgwell and Schmidt, scientists doing the study, support other researcher claims, namely that the acidification of the ocean today is bigger and faster than anything geologists can find in the fossil record over the past 65 million years.
The problem with studies such as this is that scientists do not have a cast of actors to scare the public or public officials into action. Science cannot realistically portray a singular family of Godzillas that arise due to 400 parts-per-million carbon dioxide in the air and the pollution we’re hurling into our oceans. It cannot point to a climate-change-fueled hurricane with monstrous wind-sheer and water saturation akin to human water torture. It cannot point out tornadoes that level skyscrapers like King Kong’s blows with humongous fists, but only speak of weather extremes.
Scientists can model the conditions we face, and will be facing, using powerful computers, in effect, comparing today’s acidification with that of 55 million years ago. Their studies find that acidification today is ten times faster, that its saturation horizon will reach much shallower ocean depths today, and that extinction would probably be more extensive in today’s world as a result. The difference is today’s greater speed of acidification, our different arrangement of continents, average temperatures, and other variables.
We might take comfort in scientists associating the Eocene era (55 – 34 million years ago), the period under study, with the golden age of mammals, notably mammals associated with our origin. The explanation for this golden age does cite the global warming of the time, but perhaps comparative differences between the periods of then and now must be considered.
The conclusion we must reach, without monster dramatics, is that our carbon-fueled civilization is affecting life everywhere and maybe we should look at changes in our oceans – its changing chemistry — as more important than the air we breathe. It might hold the key to the nature of widespread effects on our lives and the lives of those who follow.
Perhaps there is even time to slap us out of our carbon lunacy into a gossamer green world where frightful monsters are actually banished.
- Elizabeth Kolbert, The Sixth Extinction: An Unnatural History, 2014. [↩]