Pine forest vapors form small aerosol particles that may significantly cool the climate by reflecting the sun’s energy back into space, according to new findings. Scientists have known for decades that gases from pine
trees can form particles that grow from just 1 nanometer in diameter to 100 nanometers in about a day. The new research, published in Nature, shows the rapid growth of these particles relies on a chemical chain reaction among pine-scented molecules and atmospheric ozone and oxygen. The growing particle then grabs others like it, eventually snowballing into a 100-nanometer particle — one that’s large enough to condense water vapor, prompt cloud formation, and, ultimately, influence climate. Boreal or pine forests give off the largest amount of these compounds, so the finding is especially relevant for the northern parts of North America, Europe, and Russia. But other types of forests emit similar vapors, and the scientists think these may undergo similar rapid chemical reactions.