Imagine if science developed tools to undo death. Would we take risks more casually and worry less about eating healthy and exercise? Consider a perhaps less futuristic prospect—what if science developed tools to undo animal species extinctions? Would we worry less about wildlife population declines and protecting habitat? Scientists around the world are developing techniques to enable us to “de-extinct” lost species using preserved DNA and tools such as cloning and gene editing. Debates around de-extinction have focused largely on the ecological risks of restoring lost species to the landscape. But what de-extinction does to how we think about conservation may raise even thornier issues.
The idea that extinction can be reversed muddles long-held understandings of what it means for a species to become extinct. Charles Darwin defined extinction as when a “species ceases to exist.”[1] But de-extinction suggests a narrative in which extinction is just a temporary state of arrested animation rather than a complete annihilation of a species. It also risks setting up the expectation that technology can repair the damage we inflict on biodiversity, lulling us into tolerating higher risks of species extinction.
As scientific advances propel increasingly bold proposals to use technology to reverse environmental damage, the context in which biologists define and communicate conservation goals is changing. De-extinction could deeply undermine the most powerful argument for conservation action—preventing the irreversible loss of species. As the public becomes increasingly aware of de-extinction efforts, biologists can either take the initiative to control the message or react as the ground shifts beneath them. Likely they will need to do a bit of both.
Semantic ambiguity over scientific definitions can cause a great deal of trouble. Think of the many headaches evolutionary biologists have suffered over conflation of the word theory with hypothesis, as creationists have seeded widespread doubt with the charge that evolution is “just a theory.” In fortifying extinction against the confusion de-extinction could spawn, biologists could begin by better disciplining their own use of the term. IUCN (1994, 2001) defines a species as extinct if “there is no reasonable doubt that the last individual has died”.[2] Yet scientists frequently publish academic articles using the word extinction when what they actually mean is extirpation—local disappearance of a species.[3]
Misuse of the word extinction undermines its ability to spark the sense of urgency needed to motivate conservation action and policies. The irreparable loss of species has long been a dominant theme in strategic environmental discourse, and with good reason. It’s a theme that resonates powerfully with the public—evidenced by the fact that 90 percent of voting Americans support the Endangered Species Act.[4] When conservationists warn that a species could be forever lost if action is not taken, they assign value and importance to an environmental cause by claiming that inaction will result in consequences that cannot be reversed.
Perceived irreparability of an act can influence decision making in important ways. When the consequences of a decision are considered irreversible, we cannot assume there will be a “next move.” We might also evaluate our actions based on the minimum condition rule—where a threshold criterion is established at the capacity to undo the consequences of the decision.
Where do we project the point of no return for a species declining toward extinction? The answer may depend on how we understand human limits. If we believe we are very limited in our ability to reverse species decline we might define the critical tipping point as the minimum viable population—the minimum population a species needs to survive random events, such as natural disasters and disease outbreaks.[5] But faith in human interventions such as captive breeding programs might shift projections of the point of no return closer to the edge. We may feel that we can bring species back from the brink so long as we maintain a captive population.
US lawmakers have taken this line of thinking to the next logical step, suggesting we can safely reduce endangered species to small numbers so long as we keep some in captivity as insurance. In 1995 lawmakers justified Republican-led efforts to roll back Endangered Species Act protections, saying the law had become “outdated and outmoded by advances in science and technology” and proposed a bill amending it to recognize captive breeding as a means of protecting endangered species.[6] If in the future we place our faith in de-extinction, what new threshold criterion might be established? Will we judge a frozen zoo of tissue samples as sufficient to bring species back from the brink?
Perceptions of de-extinction as an insurance policy against loss of biodiversity could lull societies into downplaying the threat of extinction and the need for conservation action and policies. Consequently societies may divert funding away from mitigation and adaptation or even adopt behaviors that create additional risk. This kind of behavioral response is familiar to scholars and practitioners in economics and insurance. When people think they are protected from a negative outcome they often adopt risker behaviors.[7]
Furthermore, we may be particularly prone to unjustifiably overestimating de-extinction as a remedy because it has a psychological appeal over preventative mitigation efforts. It offers an alluring sense of control by reinforcing the idea that we have the capacity to control our environmental future and can circumvent the long-term, collective action most conservation approaches require.
While de-extinct species might challenge our perception of animal extinction as final and irreversible, in reality extinctions will never be undone. These new animals may resemble species we have lost, but what we will actually create is a new and distinct class of animals rather than the biological and behavioral equivalents of extinct animals.
There are many reasons de-extinct born animals would physiologically and behaviorally differ from their extinct predecessors. Attempts to clone a genomic twin of an extinct species require a surrogate mother and donor egg cell from another species. Consequently, the cloned animal’s epigenetics and microbiome will differ from its extinct predecessors. And then there is the question of how a cloned animal raised in captivity without any of its extinct predecessors would learn to take care of itself, speak its own language and learn its own “culture” so to speak.[8]
They would also differ in their relationships with humans. Unlike their predecessors, the existence of de-extinct species is under the control of and is dependent on human beings. In a sense, de-extinction is just one large step in an already advancing trend. Many “wild animals” are tagged or collared, exist in fenced preserves or surrounded by guards—and all of the world’s wild inhabitants face human-induced habitat changes. And while humans have always influenced nature, the accelerating trend toward control unsettles the notion of “wild” in wilderness.[9]
Now is the time to preserve widespread understandings of extinction as final. Aside from fictionalized accounts of scientists resurrecting dinosaurs in Jurassic Park movies, awareness of real-world efforts to de-extinct species remains low. But rapid advances in genome editing tools, such as CRISPR, and in vitro fertilization techniques are likely to make the lofty goals of de-extinction appear increasingly plausible in the public eye and draw greater attention.[10, 11] The finality of extinction is not without virtue. The finality of extinction makes us grieve, recognize human fallibility and limits, and generates a sense of urgency for the need to take conservation action.[12, 13]
