Some 62% of African elephants have disappeared from the continent over the last decade. The reason? In central African forests, “elephants are being poached out of existence for their ivory,” wrote the two scientists in the New York Times.
On July 1, the U.S. government took a step toward addressing the problem when President Obama announced a $10 million initiative to combat wildlife trafficking networks between the United States and Africa. But on the same day, researchers also published a study showing that a new application of an old technology could help identify which pieces of ivory are actually illegal—and it’s based, of all things, on above-ground nuclear testing that left radioactive material hanging out in the air for the next several generations to come.
“There’s a whole community of scientists that has made lemonade from lemons out of this,” Kevin Uno, one of the researchers who developed the poaching identification tool told me when I asked him how nuclear testing more than 50 years ago can help determine if a piece of ivory was poached.
It begins with the story of the arms race. After World War II, governments developing nuclear arsenals detonated hundreds of nuclear blasts above ground. And while alarming spikes in radiation registered on monitors at the time, little did those researchers know that they were drastically changing the amount of radioactive carbon in the atmosphere for decades--and that plants, oceans, and even elephants would be the ones to absorb the fallout.
The U.S., the Soviet Union, and the U.K. banned above-ground nuclear testing in 1963, and since, the atmospheric concentration of radioactive carbon has slowly decreased. But as a result, a unique amount of radioactive material has registered in the atmosphere per year, something scientists call the “bomb curve.”
“Let’s say a leaf forms in 1970 and it draws in carbon dioxide,” Uno explains. “If you measure radiocarbon concentration it should be same as the atmosphere. The leaf locks in the carbon 14 concentration--and the elephant walks along and eats the leaf.”
“We use the adage you are what you eat,” Uno said. “And [the radioactive carbon] gets locked into that tissue.”
Researchers used two tusks--one from Kenya, and the other from the Salt Lake City Zoo-- to test the technology at the University of Utah. They only needed the equivalent of a pinch of salt, which they then converted into a gas and a graphite pellet. That graphite pellet was then fed into something called an accelerator mass spectrometer, which allowed researchers to measure the ivory’s concentration of radioactive carbon.
“Our technique tells us if we can sample the base of the tusk, the most recently formed before the animal dies, that tells us when the animal died,” Uno said.
The radiocarbon tool complements another method used to track poachers. Sam Wasser, director at the University of Washington’s Center for Conservation Biology, looked at DNA found in elephant dung to locate where those elephants were killed. Put the “when” and the “where” together, Uno, says, and you have a pretty solid way of figuring out whether ivory is illegal.
The tracking method may even have ramifications for government transparency. Many suspect that since hunting elephants for their ivory was banned in 1989, the countries that have collected illegal ivory in seizures over the years have slowly been leaking their stockrooms for profit, in addition to the armed gangs actively hunting elephants. If the radiocarbon dating tool finds, for example, that a tusk came from an elephant that died before 1989, it’d be likely that the ivory came from a government stockpile rather than a modern poacher.
In the meantime, Uno’s team has not yet been contacted to help out with the new U.S. trafficking initiative. “I was really hoping Obama would call and say this was really cool,” Uno told me. “But unfortunately he hasn’t called yet.”