Earth recorded its hottest year ever in 2024, with such a big jump that the planet temporarily passed a major climate threshold, weather monitoring agencies announced Friday. It's the first time in recorded history that the planet was above a hoped-for limit to warming for an entire year, according to measurements from four of the six teams. Scientists say if Earth stays above the threshold long-term, it will mean increased deaths, destruction, species loss and sea level rise from the extreme weather that accompanies warming.