(CNN)We've known for some time now that Greenland's ice sheet is melting at an alarming rate.
Greenland lost more ice last year than in any year on record, and the melting has accelerated rapidly since the 1990s.
But in the context of Earth's 4.5 billion-plus year history, melting in any one year or even a few decades amounts to the blink of an eye.
Whether the rapid disintegration we're seeing on Greenland today compares to anything that has happened in the past is a question on which the science is not completely clear.
Now, a new study published in the journal Nature provides some answers, and it is not good news: The rate of melting we're seeing today already threatens to exceed anything Greenland has experienced in the last 12,000 years.
Over the last two decades, Greenland's ice sheet has melted at a rate of roughly 6,100 billion tons per century, a rate approached only during a warm period that occurred between 7,000 and 10,000 years ago.
"We know there's a lot of year-to-year variability, so what we were interested in doing is capturing the more meaningful trends over decades and maybe up to a century," said Jason Briner, a professor of geology at the University at Buffalo and the lead author of the study. "And when you do that, and think about the direction that Greenland is heading this century, it's pretty clear we're in quite anomalous times."