Earth out of sync.

• Author: Larsen, Janet
• Position: Global temperature - WORLD WATCHER

SPRING AWAKENING long has provided fodder for poets, artists, and almanac writers. Even for a notoriously fickle time of sunshine, rain, and temperature swings, some old-fashioned seasonal wisdom was consistent enough to be passed down through generations. The first blooming of a specific flower, for instance, traditionally could signal when to find certain fish running the rivers, when to hunt for mushrooms, or when to plant crops. The timing of such seasonal events is coordinated in an intricate dance--a dance underappreciated, perhaps, until something jolts it out of step.

With average global temperatures up 0.5[degrees]C since the 1970s, springtime warming is coming earlier across the Earth's temperate regions. A number of organisms have responded to warming temperatures by altering the timing of key life cycle events. The problem, however, is that not all species are adjusting at the same rate or in the same direction, thus disrupting the dance that connects predator and prey, butterfly and blossom, fish and phytoplankton in other words--the entire web of life.

The timing of seasonal biological events, otherwise known as phenology, has been tracked in some places for centuries. Japan's much-feted cherry tree blossoming has been recorded carefully since before 1400. The trees showed no clear trend in timing until the early 20th century, when they began to bloom earlier, with a marked advancement since around 1950.

The meticulous records of Henry David Thoreau help us gauge how spring has changed in Concord, Mass., since the mid 1800s. Comparing his notes on more than 500 species and subspecies of plants with modem surveys and records in between, researchers have found that springtime blooming advanced by an average of one week over the past 150 years as local post-winter temperatures rose.

Earlier springs and later autumns mean longer growing seasons--as long as plants do not succumb to a surprise late cold snap or wilt in the peak summer heat. In Germany, apricot and peach trees now bloom more than half a month earlier than in 1961. Apple trees in the northeastern U.S. moved up flowering by eight days between 1965 and 2001; apple trees require chilling time before they flower, and warmer winters have been tied to smaller harvests. Earlier spring blooming has lengthened pollen seasons in some places by weeks. Allergy sufferers beware: this trend is likely to get worse as the planet gets warmer.

A longer growing season could benefit some...