Pine Tree Scents can Cool the Climate

Researchers have found a link between pine tree smell and climate change.

The study, conducted by researchers at University of Washington and colleagues, found that the gas released by the coniferous trees creates particles that promote cloud formation and even reflect sunlight, meaning that the particles can cool the local region.

"In many forested regions, you can go and observe particles apparently form from thin air. They're not emitted from anything, they just appear," said Joel Thornton from University of Washington, one of the study authors.

The study shows the association between aerosols released by trees and its effect on global warming.

Aerosols are kind of a wild card in the whole climate change scene. A recent study on volcanoes had suggested that aerosols created by sulfur compounds can lower earth's temperature by blocking sunlight.

Related studies have shown that coral reefs release a compound dimethylsulphoniopropionate, which not only gives the ocean its smell, but also promotes local cloud formation.

Researchers have known that pine trees release gases that form particles, which range between 1 nanometer in size to 100 nanometers. The airborne particles can reflect sunlight and at a large enough size; they can seed clouds.

In the present study, researchers measured particle size from Finnish pine forests. They then simulated particle formation of the same size in an air chamber at Germany's Jülich Research Centre. The team used chemical mass spectrometry to study the evolution of one particle.

They found that the scent-molecule from pine pairs with ozone in the surrounding air. The remaining free radicals then grab oxygen molecules.

"The radical is so desperate to become a regular molecule again that it reacts with itself. The new oxygen breaks off a hydrogen from a neighboring carbon to keep for itself, and then more oxygen comes in to where the hydrogen was broken off," Thornton said in a news release.

The levels of scented compounds are expected to increase with increase in global temperatures, researchers said.

"It's thought that as the Earth warms there will be more of these vapors emitted, and some fraction of them will be converted to particles which can potentially shade the Earth's surface," Thornton said in a news release. "How effective that is at temperature regulation is still very much an open question."

The study is published in the journal Nature.