Growing Rain

Water ecologist Alpha Lo explains the different water cycles and how farmers play a role in buffering rain patterns

Acres U.S.A. Could we start with your background? How did you become a climate water scientist? 

Alpha Lo. I went to grad school in physics, and then afterwards I got into permaculture and did some work on some permaculture places. I was living in California, and there were so many fires there year after year. I started to wonder if there was some permaculture solution, because the only solution people were giving was just to cut down more vegetation. 

I found a video by Zach Weiss about how you could actually create rain again with the small water cycle, and also how there are ways to hold more hydration in the land. So, that got me interested. And then I learned about Charles Eisenstein, who wrote a book called Climate, which talks about how water is a self-organizing force in the whole ecosystem climate. That kind of got me even more interested in water, and so I just started delving in more and more.

I got connected with a bunch of people, including a friend who ran a permaculture magazine, and we organized this Regenerative Water Alliance. The goal was to bring a lot of people together to discuss water, and it just kind of grew. Then I started writing about it, and more people started reading my blog, and my podcasts started getting attention. I’m back in graduate school now to do more research on this.

Acres U.S.A. Yeah, it’s really important work. A lot of our readers are at least familiar with these issues. We did an interview in the past with Walter Jehne, so I think people understand the idea that water plays a huge role in climate. And of course, ecological farmers are very familiar with the ideas of water sinking and spreading and trying to retain as much water on their farms as possible. But can you describe what the large water cycle is and then what the small water cycle is, and how they differ and why that’s important?

Lo. Sure. The large water cycle is the ocean moisture blowing in, and that adds moisture to the air, which then creates rain. Then the small water cycle, which is called “precipitation recycling” by the climate scientists, is where the land captures some of that rainfall. Instead of most of it becoming runoff, some of it can also get transpired up to add to the ocean moisture to create rain. 

So, the small water cycle is really a key factor. If you don’t have forests, if you don’t have grassland, if you don’t have soil absorbing the rain, then it just becomes runoff. And then you have a lot less rain, because all of that is just going out to the river and out to the ocean immediately. That’s also why it’s important to slow the water down in the landscape and also why it’s important to recharge the aquifers, because the trees are also bringing water up from the groundwater with their root systems and putting that into the rain. 

So, there’s actually actually a third cycle, which is the groundwater cycle. In addition to the small water cycle and the large water cycle, it’s also very important in creating rain.

Acres U.S.A. The large water cycle is continental, right? That wouldn’t be something that nations, even, or large landholders, could really change. But we can affect the small water cycle to some degree, correct? I know that’s one of the big questions — how much land do you have to regenerate to change some of these cycles?

Lo. But you can change the large water cycle too. That’s the idea of the biotic pump. It’s the theory that you can change the ocean moisture when it comes into the land two months earlier. Usually there’s this thing called the ITCZ — this rain band in the middle of the equator that moves up and down — and that tells you when the wet season and dry season is. But you can actually bring in that water earlier. Research has shown that the Congo rainforest and the Amazon rainforest actually change that — even that large water cycle. 

Acres U.S.A. Can you explain the biotic pump idea a bit more?