Already climate change–in the form of a changing pattern of global rainfall–seems to be affecting the planet in significant ways. Take the massive, almost decade-long drought in Australia’s wheat-growing heartland, which has been a significant factor in sending flour prices, and so bread prices, soaring globally, leading to desperation and food riots across the planet.

A report from the Bureau of Meteorology in Australia makes clear that, despite recent heavy rains in the eastern Australian breadbasket, years of above normal rainfall would be needed "to remove the very long-term [water] deficits" in the region. The report then adds this ominous note: "The combination of record heat and widespread drought during the past five to 10 years over large parts of southern and eastern Australia is without historical precedent and is, at least partly, a result of climate change."

Think a bit about that phrase — "without historical precedent." Except when it comes to technological invention, it hasn’t been much part of our lives these last many centuries. Without historical precedent. Brace yourselves, it’s about to become a commonplace in our vocabulary. The southeastern United States, for instance, was, for the last couple of years, locked in a drought — which is finally easing — "without historical precedent." In other words, there was nothing (repeat, nothing) in the historical record that provided a guide to what might happen next.

Now, it’s true that the industrial revolution, which led to the release of greenhouse gases into the atmosphere at historically unprecedented rates, was also, in a sense, "without historical precedent"; but most natural events — unlike, say, the present staggering ice melt in the Arctic — have been precedented (if I can manufacture such a word). They have been part of the historical record. That era–the era of history–is now, however, threatening to give way to a period capable of outrunning history itself, of outrunning us.

Just as this week begins, scientists at the Mauna Loa observatory in Hawaii have released new information on carbon dioxide in the atmosphere–and it’s at a record high of 387 parts per million (ppm), "up almost 40% since the industrial revolution and the highest for at least the last 650,000 years." 650,000 years. Think of that. The historical era is well less than 10,000 years old. According to a recent study by renown NASA climatologist Jim Hansen published in Science magazine, "if we wish to preserve a planet similar to that on which civilization developed," we need to create the necessary conditions that will return us to 350 ppm of CO2 in the atmosphere–and soon. Environmentalist Bill McKibben, who has started a new website called calls that 350 "the most important number on Earth."

The planet in its long existence may have experienced the extremes to come, but we haven’t. The planet, unlike much life on it, may not–given millions or tens of millions of years to recover–be in danger, but we are.

When you really think about it, history is humanity. It’s common enough to talk about some historical figure or failed experiment being swept into the "dustbin of history," but what if all history and that dustbin, too, go… well, where? What are we, really, without our records? Once we pass beyond them, beyond all the experience we’ve collected, written down, and archived since those first scratches went on clay tablets in the lands of the Tigris and Euphrates–now being stripped of their cultural patrimony — at least two unanswerable questions arise. Once history has been left in the dust, where are we? — and, who are we? If Hansen, McKibben, and other scientists are correct, can we stop just short of the cliff of the post-historical era?