It changed slowly, and then fast. A man was staring at his phone. Then half the adults in the park were doing the same. Someone cried out. The atmosphere changed (appropriately), and I took my phone out of my pocket to see what had happened.

A newsflash had been delivered to my lock screen, even though I had settings that definitely didn’t allow them.

The United Nations, in conjunction with a coalition of the world’s governments, has confirmed that an accelerated atmospheric shift is underway and that it will have ‘profound consequences’ for the Earth and its population. Click for more details.

I clicked, but there were no more details because the network had crashed. I didn’t need to see those details anyway, because I’d seen the rumours over the past few months, and had happily ignored them while worrying instead that I couldn’t speak to the girl I liked, and that I wasn’t sure if I was brave enough to audition for Juliet. That proves that even if you try to keep yourself safe by dwelling on all the bad things you can think of, something huge will always manage to slip through. I knew what the story was: the thawing of the permafrost had unleashed such an unexpectedly massive load of carbon dioxide, laced with various toxins, that it was fast becoming impossible for humans to live here. We didn’t have time to evolve to thrive in our new atmosphere. That at least was what the rumours had said.

Later, when I did get to read the detail, I discovered that it was all true, and a date had been calculated for the definitive change of the air: September the seventeenth. Less than a year away.

Anyone with existing breathing difficulties would probably die before that. So would the birds, and some of the animals. We had done this to ourselves, and to the creatures, and there was very little we could do about it. It was the catastrophic breakdown of everything.

In the park everyone was just staring, like I was. Even the children, who couldn’t possibly have understood, seemed to be frozen, mid-jump, mid-climb, mid-shout.

If the robins in the trees had had phones, they would have been looking at them too (and tweeting: ‘The birds die first?’). The squirrels in the branches (‘And the small animals?’). The dogs on the leads. The cats. The rats. The ants and the mice. The newsflash beamed across the world in a moment, invisible until it landed, and then everywhere.

The world paused. I watched the other people. Everyone had taken something out of a pocket. Everyone was staring. There was a hiatus, because it was not a thing you could understand at first.