Climate change is caused in part by airborne particles that make clouds more or less reflective - thus raising or lowering temperatures on Earth. Now scientists say there are chemicals from trees that could turn cloud reflectiveness up to maximum.
In a paper published in Nature this week, a group of scientists explain that boreal forests emit hydrocarbons called "volatile monoterpene compounds," some of which cause the distinct smell of a pine forest. These are all basically particles that float into the clouds, and interact with ozone and other compounds to form small, semi-liquid droplets called cloud condensation nucleii (CCN). The key here is that monoterpene causes more of these CCN droplets to form, which are what make the clouds so reflective. Essentially, it's just sunlight reflecting off water held together with other chemicals.
So if these giant pine forests are always emitting so many monoterpenes, why would the Earth ever warm up? The problem is a compound that comes from deciduous trees and other vegetation called isoprene. Isoprene cancels out monoterpene, and causes fewer of those reflective droplets to form. As the climate changes, it's likely we'll see more of the kinds of plants that make isoprene, and fewer that make monoterpene.
The obvious solution is geoengineering. Why not synthesize a reasonable quantity of monoterpenes and seed the clouds with them? It's a naturally-occurring chemical which would normally float up to the clouds anyway. And it would encourage the production of reflective droplets in our cloud cover, thus reflecting back more sunlight and lowering temperatures.
Either that, or let's start boreal farms whose sole purpose is cloud engineering.
Photo by peterkelly