African elephant herds have faced poaching for decades, but a new wave of poaching has placed them on the edge of extinction, according to a study published Tuesday.

The study was published in the Proceedings of the National Academy of Sciences and is the most comprehensive look at the elephant population in Africa. Using carcass data, as well as models of illegal killing rates and population trends, the researchers confirmed that the levels of poaching have become unsustainable for the species. In fact, the species' population shrank 3 percent in 2011 alone, when 40,000 elephants were poached.

At this rate, lead researcher George Wittemyer told The Washington Post, elephants will be extinct "in 100 years."

"It's been a real disaster," he said. "If things continue as they are today, that's what we can expect."

More than 100,000 elephants have been killed since 2010, according to National Geographic, even reaching elephants experts had been tracking. Richard Bonham, co-founder and the African operations director of wildlife conservation organization Big Life Foundation, had found one of the elephants he followed, Torn Ear, fatally shot by a poison arrow in February.

"I see individuals I identify with and see herds I know nothing about and always wonder if I'll ever see them again," Bonham told National Geographic following the killing. "And if I do see them again, maybe it will be in the form of a rotting carcass."

"I remember the '70s and '80s poaching wave only too clearly and never thought it could get worse," Bonham added. "What we're seeing now puts it in the shade."

Wittemyer, et al

Of the elephants roaming the continent, the ones in Central Africa are most vulnerable, the study concluded. In a map (right) showing the changes in population, researchers pointed out the largely red region where elephant populations have plummeted between 2010 and 2012.

As Wittemyer told The Washington Post, only 25 percent of elephant populations are "stable or increasing." 

"But when the low-hanging fruit and less protected elephants are maybe finished [off] or eradicated," he added, "it will turn the pressure [for ivory] onto the ones who are now more protected."

Indeed, ivory prices on the black market have skyrocketed from the $30 per pound rate in the past to about $100 per pound in the last five years. In 2011, it reached $150 per pound, while in China, one of the largest markets for ivory, the price for a single pound can reach $1,500.

Apply that figure to the weight of tusks an adult male elephant could provide—up to 130 pounds, according to Discover Magazine—and imagine the windfall poachers find when they manage to strike a herd that has elephants with tusks of that size. 

China, meanwhile, has attempted to crack down on illegal ivory shops. The country has about 150 government licensed ivory shops, which use photo IDs to track the ivory supplied for carving, and this summer, authorities found 32 suitcases stuffed with about $1 million worth of ivory.

A licensed shopkeeper noted the difficulty in distinguishing between legal and illegal ivory in an interview with the BBC. "There are illegal shops," he said. "But it's a case of 'one rotten egg spoiling the whole soup'."

Experts have warned of the impending extinction for months. In February, John Scanlon, secretary general of the Convention on International Trade in Endangered Species, told reporters increased poaching "is decimating the African elephant population and we will soon see local extinctions in some areas, in particular within Central Africa."