Global warming may exacerbate US Southwest’s rainy season

Science News : As the climate warms, monsoons could become more severe, bringing fewer but heavier rainfalls. In a study published this week in the Proceedings of the National Academy of Sciences, Yemane Asmerom of the University of New Mexico and colleagues analyzed cave formations in the state’s Carlsbad Caverns and compared the data with that from other caves across the Northern Hemisphere. Caves contain clues to past precipitation because features such as stalagmites grow as water seeps into the cave, evaporates, and leaves behind dissolved minerals. What the researchers found was that over long time periods of decades and even centuries, warm weather makes monsoons wetter and cold weather makes them drier. However, because of regional differences such as the concentration of aerosols or types of land surface features, monsoon activity is much less predictable on shorter time scales.