“There are really four dimensions,” begins the narrator of The Time Machine, H. G. Wells’s classic Victorian adventure novel. “Three which we call the three planes of space and a fourth, time.” Humans cannot help but think of time as somehow different, perhaps because, as the narrator muses, we continuously move in one direction along it from the beginning to the end of our lives.
“There are really four dimensions,” begins the narrator of The Time Machine, H. G. Wells’s classic Victorian adventure novel. “Three which we call the three planes of space and a fourth, time.” Humans cannot help but think of time as somehow different, perhaps because, as the narrator muses, we continuously move in one direction along it from the beginning to the end of our lives.
This limitation affects how we see nature. We can fail to appreciate that, for living things struggling to survive, environmental conditions change through both space and time. Consider a plant growing on a windswept mountain versus a sheltered valley, or in the gentle summer sun versus the height of winter. To survive, animals and plants must adapt to all four dimensions of their environment.
Environments can change across days, months and years; in a steady direction, as with the recent warming of mean global temperatures, or in the cycle of seasons. Where conditions change cyclically they are, at least to some extent, predictable, and animals and plants can align phases of their life history with the best periods.
Many mammals, for example, will mate in autumn and winter (depending on how long they gestate) so that their offspring are born in pleasant springtime conditions.
Spring is happening earlier in temperate climates now that the world is warming, but not uniformly so, because different species respond in different ways.
Herbivores seem to respond much more strongly to warming temperatures than the plants they feed on, and insects more than birds. Scientists worry that these differences could disrupt delicately synchronized food chains, where the success of one species depends on them occurring at the same time as another.
