Plants Can Adapt to Heat — Until Suddenly They Can’t, Landmark Global Experiment Finds

A sweeping international field experiment has delivered one of the clearest messages yet about biological adaptation in a warming world: plants can evolve under climate pressure, but only up to a point. Researchers tracking identical populations across dozens of sites found that some genetic variants improved survival in hotter, drier conditions, showing that evolution can move on surprisingly short timescales. That is the encouraging half of the story. The darker half is the threshold. Beyond a certain combination of heat and drought, even the best-performing variants stopped coping and whole populations collapsed. That finding matters far beyond wild plants, because agriculture depends on similar limits; once environmental stress crosses them, adaptation is no longer a strategy — it is a countdown.