How Much Can the Seasons Bend Before They Break?
Yearly weather patterns are changing. Our traditions need to keep up.
In a strip of soil outside my house, between the sidewalk and the curb, there’s a living symbol of the seasons. In winter, it is a sleeping skeleton, branches bare except for the occasional mantle of ice or snow. In early spring, tufts of pale leaves burst from gray bark. By summer, its overlapping foliage is a vivid green, fluttering in the slightest breeze. Around this time every year, it gradually catches fire, tinges of red spreading through the cells of each leaf until they all glow. As the maple tree finishes reabsorbing its stores of chlorophyll and sealing itself against the coming chill, it allows its leaves to fall to the ground—and the cycle continues.
The seasons have shaped humanity for millions of years. When our ancestors migrated across continents, dramatic fluctuations in the weather determined what was available to hunt and gather; demanded innovation in clothing, shelter, and transportation; and dictated agricultural practices. Perhaps the long, hard winters of glacial periods encouraged early humans to linger in caves, which became incubators of art and language. Since at least the time of ancient Greece, the four seasons have been a mainstay of Western art and culture. We still organize major holidays around the seasons and celebrate their ephemera, decorating our homes with daffodils, gourds, and simulated snow. And we keep drawing analogies between the progression of the seasons and the life spans of both individuals and empires. In short, we still depend on one of the oldest and most fundamental concepts in the history of human thought: that our environment changes in an orderly way, year after year.
Yet the seasons as we know them are warping. Climate change cannot substantially alter Earth’s axial tilt or elliptical orbit, and therefore does not have much effect on the solstices and equinoxes that define the astronomical seasons. But as our species makes the planet hotter, the atmosphere wetter, and weather more extreme and unpredictable, we are starting to experience the four seasons differently. Broadly speaking, climate change is prolonging summer, compressing winter, and weirding every season. From 1952 to 2011, the annual period of warmest weather in the Northern Hemisphere increased from 78 to 95 days, while the stretch of coldest weather decreased from 76 to 73 days. Scientists predict that if climate change continues unabated, then by 2100, the weather we associate with summer will span nearly six months of each year, whereas wintry weather will last less than two.
In Concord, Massachusetts, where Henry David Thoreau wrote Walden, trees and shrubs are leafing out nearly three weeks earlier than they did in the 1850s, creating asynchronies in the life cycles of plants and animals. Cherry blossoms have started to emerge more than a week early in Kyoto, Japan, forcing long-standing traditions to adapt. As a trend, fall colors in the deciduous forests of the eastern United States are appearing later than usual and losing their vibrancy. In many colder regions of the world, snowpack is diminishing and spring snow is melting sooner compared with past decades, reducing runoff and fresh-water availability. In contrast, the period of the year most prone to heat waves and wildfires is rapidly expanding.
Some of these seasonal shifts have dire consequences; others entail more subtle or uncertain complications. As people around the globe learn to cope, those of us living in the planet’s temperate zones should remember an important fact easily obscured by traditional education and prevailing customs: The four-season system we take for granted, the one so many people assume to be standard and universal, is anything but. It never has been. A calendar year with four approximately equal seasons applies only to the pair of geographical bands that encircle the planet’s midlatitudes. The concept of seasons has varied dramatically by region and culture throughout history.
Ancient Egyptians recognized three main seasons corresponding to the rhythms of the Nile River: Akhet, the season of inundation; Peret, the season of emergence, when fertile land resurfaced; and Shemu, the season of harvest in low water. In ancient Japan, the year was divided into 24 stages that were further split into 72 microseasons lasting a few days each, with evocative names such as “mist starts to linger,” “wild geese fly north,” “first lotus blossoms,” and “deer shed antlers.” Both the Hindu and Cree calendars have six seasons to accommodate events such as monsoons and the freezing and thawing of ice. The Larrakia people of northern Australia have a particularly diverse and colorful vocabulary of seasons, including Balnba (the season of early rains), Mayilema (“speargrass, goose egg, and knock ’em down” season, in which bird and turtle eggs become more available and storms flatten grasses), Damibila (a time for barramundi fish and bush fruit), Dinidjanggama (heavy-dew time), Gurrulwa guligi (big-wind time), and Dalirrgang (the hot and humid season of buildup). Other tropical cultures recognize only two major seasons: wet and dry. Antarctica and the North Pole are likewise said to have two discernible seasons: summer, when the sun never sets, and winter, when the sun never rises.
In this time of rapid transformation, a more culturally and ecologically expansive understanding of seasonality is both reorienting and heartening. In Western culture, four distinct seasons of virtually equal length became synonymous with the calendar year, as seemingly fixed as the arrow of time itself. But that was always a fallacy. Seasons are not so much laws the planet obeys as rhythms it discovers. What we experience as seasons are periodic fluctuations within the interconnected living system we call Earth. Seasons are localized expressions of our planet’s anatomy and physiology. And on a body as vast and dynamic as Earth, those expressions vary enormously—not only by location, but also through time. Earth is more than 4.5 billion years old. For long stretches, the planet was so cold that glaciers covered much of its surface or so hot that ice could not readily form anywhere. Until about 380 million years ago, when trees and other plants began to spread across the continents, autumn and spring as we understand them—the retreat and resurgence of the living landscape—arguably could not have existed. Flowering plants and deciduous trees are even more recent introductions. Over the eons, life did not simply adapt to the seasons. It helped create them.
Today’s seasonal distortions arise from the actions of a single species: our own. To confront them is to reckon with the extent to which we have disrupted some of our living planet’s most fundamental rhythms. Yet as both Earth history and world cultures reveal, the four seasons are not the default system they are so often assumed to be. If our predecessors defined the seasons in so many different ways in different parts of the world throughout time, then surely we have inherited enough resilience to do the same. Our position is unique, however: We now understand enough about the planet to choose how we continue to shape the seasons. Winter, spring, summer, and fall may not return to their classical demarcations for a long while, regardless of our climate policies—but we still have time to prevent their complete erasure.
As I write this sentence, the maple tree outside my house in Portland, Oregon, is half ablaze, its lower foliage mostly green, its highest branches smoldering in shades of coral and carmine. One of its middle branches, caught in an unusually early windstorm, has split at the base. This coming year, I will try to adopt a new relationship to the seasons, one defined not by expectation and longing, but by patient observation. I will attempt to witness and document the seasons as they happen, moment by moment. Instead of expecting the tree to leaf out or change color because it is a certain month of the year, I will instead wait for the Week of New Growth and the Day of First Blush, whenever they might be. If the crocus bulbs I planted around the tree’s roots bloom early, I will appreciate their beauty even as I steel myself for the possibility of losing them to frost.
If the seasons are changing, I will try to change with them—at least as far as such adaptation is possible. A rhythm bent gradually a little this way or that is still recognizable. Twist it too hard too fast, and, like a branch overcome by a gale, it might just break.