Trees are struggling to trap carbon dioxide in warmer, drier climates, meaning that they may no longer serve as a solution for offsetting humanity’s carbon footprint as global warming accelerates, a study by Penn State university found. ‘We found that trees in warmer, drier climates are essentially coughing instead of breathing,’ said Max Lloyd, assistant research professor of geosciences at Penn State and lead author of the study recently published in Proceedings of the National Academy of Sciences. ‘They are sending CO2 right back into the atmosphere far more than trees in cooler, wetter con…