Chemical Behind Pine Scent Slows Global Warming, Study Says

The chemical that gives pine trees their smell also makes clouds thicker, helping to cool the earth, according to a study by scientists in the UK and Germany. Pines and other trees release the chemicals, called terpenes, which react to form tiny particles in the air. Those particles help turn water vapor into clouds. Thicker clouds reflect up to 5 percent more sunlight, according to the study’s computer modeling. That increase “might not sound like a lot, but that is quite a strong cooling effect,” said one author, Dominick Spracklen, of the UK’s Leeds University. Along with trees’ capacity to absorb planet-warming carbon dioxide, “it gives us another reason to preserve forests,” he said. Trees put out more terpene in warm weather, suggesting that forests are all the more important in slowing climate change as it drives up temperatures.