Forests Export Rain

The value of an intact tropical forest exceeds the value of the timber extracted from it

This week, the outstanding environmental news outlet Mongabay published this article: The Amazon’s most valuable export isn’t timber — it’s rain, based on this scientific paper from Nature: Quantifying tropical forest rainfall generation | Communications Earth & Environment

Photo by Rutuja Jadhav on Unsplash

They are quantifying phenomena that are well known but are not widely discussed in climate circles: That forests cause rain.

Mongabay writes:

“Tropical forests actively generate rainfall by releasing moisture into the atmosphere, with each square meter producing hundreds of liters of rain annually across surrounding regions. Clearing even small portions can measurably reduce precipitation, especially during dry seasons.”

Unfortunately, in climate circles, trees and forests are described solely in terms of their ability to sequester carbon. But trees and especially mature forests possess the ability to recycle moisture in ways that disappear when we clear the forest or even degrade it.

And when we allow forests to recycle moisture, they contribute to rainfall many miles from their location. Scientists know this--though they often fail to emphasize it. Indigenous people have known this for time immemorial. And Europeans, such as Christopher Columbus and Alexander von Humboldt observed the reduction in rain due to the removal of trees, according to Judy Schwartz in Water In Plain Sight.

But this recent study goes further in that it quantifies the forests’ export of rain to remote locations.

Mongabay:

“Much of the rain that falls far inland originates from forests through long-distance moisture transport known as “flying rivers,” meaning farms, cities, and reservoirs may depend on ecosystems located hundreds or thousands of kilometers away.”

The call to action is to make an effort to protect our forests. Naturally, the economic forces that drive industry and therefore government are always at the ready to chew away at our forests, typically claiming:

1. That logging is good for economic growth,

2. That logging is needed for agriculture,

3. That logging produces renewable energy and

4. That logging even protects us from wildfires

All these claims are spurious, i.e., not what they purport to be. I will make the following claims, without trying to prove them:

1. That logging is not needed for the type of agriculture that grows actual food and grows it sustainably

2. That logging for “biomass energy” is not renewable in any meaningful sense

3. That logging to prevent wildfires does not work, as I have written elsewhere, drawing on the work of many, including the John Muir Project

4. That logging is bad for economic growth

The value of the rain produced by an intact forest exceeds the value of the timber if they cut down that forest. This is one of the main points of the Mongabay article and the underlying study: That an intact forest is worth more than a harvested forest.

What’s problematic is having to reduce everything to a dollar value. But if we are going to count everything in dollars, does it make sense for an intact forest to be valued at zero?