Pine smelling vapours may be responsible for global warming ‘pause’

Scientists have discovered a strange link between climate change and pine-scented vapours emitted by coniferous trees.

Research by German, Finnish and US scientists has uncovered a process by which gas from the trees creates particles that can either reflect sunlight or promote cloud formation, with important impacts on the climate.

“In many forested regions, you can go and observe particles apparently form from thin air. They’re not emitted from anything, they just appear”, explained Joel Thornton, a University of Washington associate professor of atmospheric sciences who worked on the study.

The team suggests that these particles are an important source of aerosols over boreal or pine forests. Aerosols have been named by the Intergovernmental Panel on Climate Change as one of the biggest gaps in the understanding of climate change.

“I think a lot of missing puzzle pieces in atmospheric chemistry will start to fall into place once we incorporate this understanding”, Thornton added.

The study authors suggest that by forming clouds that block sunlight and reflecting the sun’s rays back into space, the particles have played a significant role in mitigating rising global temperatures. 

“If you go into a pine forest and notice that pine forest smell, that could be the smell that actually limits climate change from reaching such levels that it could become really a problem in the world”, lead author Dr Mikael Ehn, now based at the University of Helsinki, told the BBC.  

Ehn added that this effect was likely to get even stronger in the future.

“In a warmer world, photosynthesis will become faster with rising CO2, which will lead to more vegetation and more emissions of these vapours”, he said.

“This should produce more cloud droplets and this should then have a cooling impact, it should be a damping effect.”

However, the scientists warn that this mechanism will also be compromised by climate change in some areas, as trees will be negatively affected by resulting rising temperatures or water scarcity.

Further reading:

Global warming slowdown linked to ban of ozone depleting chemicals

Research shows link between aerosols and climate change

IPCC climate report: global temperatures likely to exceed 2C this century