March 9, 2017 5:21 AM EST

February temperatures broke records across the South and the Eastern seaboard, offering an early end to harsh winter weather. But the phenomenon–linked to long-term man-made climate change–may have troubling side effects:

OFF-BALANCE ECOSYSTEMS

Earlier springlike weather means many plants bloom earlier than usual. (In the Arctic, some species are blooming nearly a month earlier than they did a decade ago, according to a December study in the journal Biology Letters.) But the warming does not affect all plants equally, which could disturb the fragile balance of ecosystems and open the door to invasive species. Moreover, those plants that do bloom early face increased chances that they might be killed off if temperatures drop again.

ENDANGERED FOOD SUPPLIES

Many creatures rely on plants for food. And if flowering schedules change, those food supplies could be in jeopardy. Bears, for example, could awake from hibernation out of sync with the plants they normally eat, and pollinators like bees could have a tougher time pollinating crops (and thereby sparking seed production). That’s bad for plants and human farmers alike, since pollinators are needed to produce more than 90 commercial crops in North America, including nuts, fruits and vegetables.

WORSE ALLERGIES

The beginning of spring tends to kick off allergy season for tens of millions of Americans, and research shows that its early arrival extends and exacerbates those problems.

–JUSTIN WORLAND

This appears in the March 20, 2017 issue of TIME.

Write to Justin Worland at justin.worland@time.com.

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