February 3rd, 2012 by

By Katrina Marland

(Credit: David Sim)

If you follow environmental science at all, you already know that there’s a lot more we don’t know about how nature works than we actually do. When a new theory is introduced, I’m always interested because there’s that chance that it will explain some mystery people have been wondering about for ages — or (sometimes more fun) upset an existing theory that, while already widely believed, may not be true.

The biotic pump theory claims to be one of the latter. It holds that precipitation occurs over land, not because of differences in temperature, but because of the condensation that forests produce. Have I lost you? Let me explain. The traditional belief is that winds bringing precipitation over land are caused by differences in temperature and pressure. The biotic pump theory holds that those winds are actually created and controlled by forests and the condensation that they produce. Wind is created when air moves from high-pressure to low-pressure areas. The biotic pump theory says that as the forests’ condensation pushes vapor into the air and the vapor condenses from a gas to a liquid, it creates a low-pressure area, pulling the wind in.

What are the implications of this theory, if it should be proved true? Well for one thing, it means that messing with our forests is an even worse idea than we ever realized because we would be getting rid of a vital part of the system that brings us rain. Because the concept of the biotic pump upsets some of the basic processes in mainstream meteorological science, it has been considered fairly controversial since its introduction in 2007 and so has been by and large ignored. At the same time, the theory has been examined and reexamined without being discredited and is now gaining more traction throughout the scientific community. In fact, some recent findings linking deforestation to catastrophic drought that essentially ended the ancient Mayan civilization actually support the biotic pump theory, as does recent research on deforestation and drought in today’s Amazon rainforest.

Mongabay, a popular environmental news site, scored an interview with Victor Gorshkov and Anastassia Makarieva, the scientists behind the theory. It goes into great detail, and you can see the entire transcript here. Take a look and see what you think — could forests really be a major party responsible for our rainfall? And if so, will that news influence the rate at which we are losing are forests? Because one thing is clear: If this theory is proved to be true, we may be relying on our forests more than ever before.