HONOLULU — Robert Macfarlane, in his book “Landmarks,” about the connection between words and landscapes, tells a revealing but stunning story about how recent editions of the Oxford Junior Dictionary (aimed at 7-year-olds) dropped certain “nature words” that its editors deemed less relevant to the lives of modern children. These included “acorn,” “dandelion,” “fern,” “nectar,” “otter,” “pasture” and “willow.” The terms introduced in their place, he noted, included “broadband,” “blog,” “cut-and-paste,” “MP3 player” and “voice-mail.”

While this news was first disclosed in 2015, reading it in Macfarlane’s book still shocks me for what it signifies. But who can blame the Oxford editors for dumping Amazon words for Amazon.com ones? Our natural world is rapidly disappearing. Just how fast was the major topic here last week at the global conference held every four years by the International Union for Conservation of Nature, which I participated in along with some 8,000 scientists, nature reserve specialists and environmentalists.

The dominant theme running through the I.U.C.N.’s seminars was the fact that we are bumping up against and piercing planetary boundaries — on forests, oceans, ice melt, species extinctions and temperature — from which Mother Nature will not be able to recover. When the coral and elephants are all gone, no 3-D printer will be able to recreate them.

In short, we and our kids are rapidly becoming the Noah generation, charged with saving the last pairs. (This is no time to be electing a climate-change denier like Donald Trump for president.)