On the 50th anniversary of the Endangered Species Act, a threat looms

Bert, a male black-footed ferret, peers out from a cage at the US Fish and Wildlife Service on 11 April 2007. Photograph: Rick Wilking/Reuters

Imagine a cosmic rock billions of years old yet vibrant with water, light and life. Not too close to the sun and not too far away. Tilted on its axis and turning daily to render seasons, sunrises and sunsets. A place so bountiful and varied that it has nourished and inspired humanity through our entire history. This is Earth, our only home. And that stunning array of life – countless species evolved over millennia and evolving still – is what scientists today call biodiversity.

That biodiversity is in trouble.