By Matt McGrathEnvironment correspondent, BBC News
New research suggests a strong link between the powerful smell of pine trees and climate change.
Scientists say they've found a mechanism by which these scented vapours turn into aerosols above boreal forests.
These particles promote cooling by reflecting sunlight back into space and helping clouds to form.
The research, published in the journal Nature, fills in a major gap in our understanding, researchers say.
One of the biggest holes in scientific knowledge about climate change relates to the scale of the impact of atmospheric aerosols on temperatures.
These particles form clouds that block sunlight as well as reflecting rays back into space.