Could nuclear weapons save the elephants?

Researchers have found a way to use radioactive isotopes from above-ground nuclear testing to determine the age – and thus the legality – of ivory. 

Erik De Castro/Reuters/File
People watch as a backhoe crushes confiscated smuggled elephant tusks at the Ninoy Aquino Parks and Wildlife Center in Quezon City, Philippines, in June. By measuring radioactive fallout deposited in elephant tusks, conservationists can now determine the year ivory was obtained, and therefore its legality.

Researchers have come upon a new tool in the fight against poaching of elephants, rhinos, hippos, and other endangered wildlife: nuclear weapons.

No, they're not launching nuclear missiles at the poachers, a tactic that even the most passionate conservationists would probably deem excessive. Instead, they're using the fallout from above-ground nuclear tests to determine the ivory's age, and thus its legality.

Here's how it works: Beginning with the Trinity test on July 16, 1945,and continuing until the Partial Test Ban Treaty was signed in 1963, the United States, Russia, China, France, and the United Kingdom detonated hundreds of thermonuclear devices above ground. Neutrons hurtling from these blasts fused with nitrogen in the air to form a heavy, radioactive isotope of carbon. Known as carbon-14, this isotope quickly dispersed throughout the atmosphere, where it then made its way into plants, animals, and whatever tusks, teeth, and horns they might have.

Since then, the amount of carbon-14 has been steadily declining, with most of it soaked up into the oceans. In 15 years or so, atmospheric concentrations will return to pre-atomic levels.

But for now, these microscopic Cold War relics allow scientists to precisely date tusks, teeth, and horns, according to research appearing in the current issue of the Proceedings of the National Academy of Sciences.

It's a bit like counting the rings on trees, except that you measure the amount of carbon-14 at various points along the length of the ivory. By comparing them with carbon-14 measurements from samples whose age is known, scientists now say they can determine the time of the animal's death within about a year, as long as it was killed after 1955.

International treaties banned ivory from Asian elephants after 1975 and from African elephants after 1989. In the United States, ivory is legal if it was imported before 1989, or, if it was imported after 1989, it must be at least 100 years old.

Yet until now, there has been no way to refute dealers who say their ivory predates the bans.

"With an accurate age of the ivory, we can verify if the trade is legal or not" said Kevin Uno, the study's lead author, in a press release. Dr. Uno did this research for his doctoral dissertation at the University of Utah. 

Each year, about 30,000 elephants are killed for their tusks, with most of them ending up in China and the United States. There are only about 420,000 African elephants remaining in the wild. 

The study's authors say that the test can be performed for about $500. 

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.