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On Monday, I wrote about a sweeping new United Nations report warning that humans were destroying Earth’s natural ecosystems at an “unprecedented” pace.

The findings were sobering: As many as one million plant and animal species are now threatened with extinction because of farming, hunting, pollution and, increasingly, climate change. Almost everywhere you look, nature is vanishing before our eyes.

But the report, which was written for world leaders and policymakers, also wrestled with another big question: Why should anyone care about the loss of nature? Why should countries take drastic steps, as the report urges, to halt the decline in biodiversity?