Are Our Seasons Really Getting Out Of Sync?

We wouldn't blame you for taking Earth's four seasons for granted. Spring, summer, fall, and winter have been regularly calling the shots on what we wear, what time we wake up, and how much rock salt we buy since the dawn of time. But the only constant is change, and according to science, Earth's seasons aren't always in sync. With what, exactly? Other parts of Earth.

In a recent study published in Nature, scientists used visual data extracted from global phenology maps to pinpoint hotspots of seasonal asynchronicity across the globe. Phenology is the study of how biological cycles interact with the seasons, and while some parts of the world follow the status quo as far as seasons go, there are just as many geographic regions that experience abnormalities, at least as far as biodiversity is concerned.

Observations of Earth's five Mediterranean climate regions — which include portions of California, Chile, South Africa, southern Australia, and the actual Mediterranean — revealed a hotbed of asynchronicity that's certainly worth a closer look.

One trend this phenology deep dive has revealed is that asynchronous hotspots have a tendency to cluster together. In the case of the aforementioned Mediterranean regions, it's not uncommon for "double peak" seasonal patterns to occur, where forest growth often peaks two months later than surrounding ecosystems. This is particularly evident when contrasting these regions against neighboring drylands, which receive a good amount of summer rain.

The satellite studies revealed similar hotspots in tropical mountain regions. Scientists have hypothesized that these asynchronous zones are a result of the unique influence these tropical mountains have on local airflow. Air patterns impact precipitation and cloud cover, which have a direct effect on the timing of plant growth. There's also elevation to consider: Areas that receive more sunlight, like valleys, may end up generating warmer temperatures and more precipitation, compared to a nearby mountain area that's constantly shielded by clouds.

It's no coincidence that these mosaics of mini-climates are home to some of Earth's most jam-packed biodiversity hubs. Wildlife is drawn to plants, which leads to other wildlife getting all predatory on that first batch of wildlife. It's the circle of life, and it's a big part of this phenological roller coaster.

We're all creatures of habit, which means we can understand the feeling of a routine being ripped out from under us. Now, imagine an animal species that's been relying on a specific region's plant growth cycles as a timekeeper. If this region happens to be undergoing a greater degree of aseasonality, a lack of growth, or an offset "peak" duration, it could completely mess up our animal species' sense of time.

Such a disturbance may impact everything from food collection and migration to seasonal breeding practices. As for human beings, such a blip could affect crop yields, planting and harvest schedules, and even community engagement (think foliage activities, festivals, food drives, and similar events). Oh, and let's not forget about the when, where, ebb, and flow of seasonal allergies.

Nature is a ceaseless beast with delicate sensibilities, and all of us organisms have a penchant for poking the bear. Be mindful of the Earth and how you use it, so that its seasons may routinely return.