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Extinctions

Extinction – so many ways to say goodbye

We are living in the age of the 6th mass extinction.  The previous five were all the result of some geological/ cosmic event or events, often with an associated climate change.  The current extinction is different - it has a biotic cause.  That biotic cause is the human species and we are on track for matching up to previous mass extinctions.  Previous events have had losses of 17-54% of families, each family having a few or thousands of species (Niles Eldredge)  Incidentally, the famous extinction event which included the dinosaurs was at the lower end of the scale.

What have we done to have such a profound action on the biodiversity of our planet?  Are there lessons we can learn from in looking at how species go extinct.  What should be our response?

We have made extinct through our own deliberate actions –
I can think of only one life-form which we have deliberately eradicated with no regret and that is the smallpox virus (although it undoubtedly still exists in various laboratories, hopefully never to be used for dark purposes).  Others we have made extinct by very deliberate action, but with a pang of regret afterwards.  Our concern was more from the loss of what we thought was a never-ending resource, than from a duty of care – the passenger pigeon was blasted out of the sky for food or entertainment; its roosts were raided.  Flocks of hundreds of thousands or even millions were gone by the early 1900s, with a few sad individuals lingering as a witness to the end of their species.

We have made extinct through ignorance -
From early in their history, humans have loved to move from place to place and as they have done so they have often taken other species with them – some accidentally & some deliberately.  Throughout the world these animals and plants have eaten or pushed out the native species.

We have made extinct through negligence and weakness -
As our species has grown in number we have converted enormous areas of the world to agriculture and urbanisation.  We have destroyed further habitats to extract resources for food, industry, construction, and industry.  We have over-exploited many species – great fisheries of the past have disappeared.  Our pollution and waste can be found even in the middle of the wildest areas of wilderness.  We have known at least a little of the consequences of our actions, but we have not held back – “someone else will exploit it if we don’t”; “my actions have a tiny impact”; “people will suffer if we don’t do it”.

We have destroyed what we did not know –
Only about 1.5M species have been identified.  Estimates of total species numbers are mainly in the range of 5-15M.  Most of these are in tropical forests we are clearing or oceans we are polluting and depleting.  We have not even been able to name these fellow-passengers on Earth; we have not been able to know, cherish, or use them.

Previous mass extinctions have often been linked to climate change ……..and in the current man-induced extinction event we are producing a profound change in climate.  This alone is likely to cause the extinction of many species, but its effects are magnified by our other actions.  The natural reaction of a species to a change in climate is to move, to follow the climate to which it is best adapted.  But most species cannot move across a hostile habitat or man-made barriers.  In much of the world there are now isolated areas of refuge for wildlife, in habitats doomed to change as the climate changes.

We have followed too much the devices and desires of our own hearts,
We have offended against your holy laws,
We have left undone those things which we ought to have done,
And we have done those things which we ought not to have done