Losing our Biological History, and Perhaps Ourselves, in the Sixth Mass Extinction

Richard Leaky and Roger Lewin’s book The Sixth Extinction traces the history of life on the planet as we understand it in biology, paleontology and related disciplines, and tries to find a place and meaning for the human species.  The fossil record demonstrates five mass extinctions in the history of life on the planet after the Cambrian explosion (in the last 500 million years), where up to 65% of extant species went extinct.    Scientists estimate that we are in the midst of a sixth mass extinction and this one is man-made.  Coming to terms with mass extinction and subsequent species renewal (granted within geological not human timeframes), one might conclude that the extinction we are experiencing does not matter.   The history of life on Earth tells us that extinction like change is inevitable.  Why the mass extinction we are driving matters can be found in a mixture of tangible and intangible values.  Leaky and Lewin suggest three ways that we can value biodiversity: 1) the tangible benefits we can extract from our environment, such as food, raw materials, and medicines, 2) the less tangible benefits, the maintenance of the physical environment, in its circulation of gases, chemicals, and moisture, and 3) the intangible benefits, such as the esthetic pleasure individual humans derive from their experience of the diversity of life around them.

The value of the first two is obvious, as is the fact that their loss is detrimental to our own existence.   No one would reasonably argue for destroying the planet’s biota to the point where it no longer sustains human life.  But as with climate change, there is considerable uncertainty about the exact impacts of species loss.  We know there are consequences, but we do not fully understand them.  How many species can we lose without significant change, and at what point will the Earth’s ecological and biological systems stop functioning altogether?

The third, intangible method of valuation needs more consideration as well.  What does the loss of millions of species, most un-recorded, mean for understanding our history as well as our future?  I would draw an analogy.  After the U.S. invasion of Baghdad in 2003, little was done to stop the looting and pillaging of museums and other cultural sites (perhaps because it simply wasn’t possible).  The world watched in horror as pieces of our human cultural heritage, in a place some would consider the cradle of civilization, were stolen or altogether destroyed.  We feel a tremendous loss when something that is considered an irreplaceable part of our cultural heritage is destroyed and we make efforts to protect and preserve such heritage wherever we can.   Should we not feel some similar attachment to the multiple components of our biological heritage?  To the multiple species that are an integral part of how we have come to exist today and that shape existence on our planet. I guess the parallel question is if climate change is causing the extinction of millions of species, is there a place for intangible valuation within climate policy?  Can we find a way to account for nature without an economic calculation?  If the intrinsic value of our cultural heritage is any indication, our biological heritage deserves equal consideration.  In destroying Earth’s species, we are collectively looting the world of treasures that we cannot replace.

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