"Maybe we could cut sections from the fallen branch—to show the tree rings going back to before the Industrial Revolution." Lotte was just getting going on this idea when her phone buzzed and her eyes flicked briefly to it. Saskia, hardly for the first time, had to bridle her annoyance at the fact that this contraption was interrupting a perfectly good conversation. But Lotte was no stranger to multitasking. Her brow dimpled momentarily at whatever had come up on the phone—some kind of troubling news, apparently—and then she looked back into her mother’s eyes and returned to her theme. "Maybe there’s some kind of analysis that could be done in a lab. On that wood, I mean. On the different tree rings. Showing how a tree ring that was created two hundred years ago, before the Industrial Revolution, showed a lower amount of CO 2 in the air than the more recent rings."