The Untold Story of How Water and Plants Already Cool our Climate (and Could Do Much More, if We Let Them)
Humans can help ecosystems thrive--or not. But if we do, then ecosystems will provide cooling services, habitat and more
The Water & Climate Course, coming up in July, will tell you stories that you may have never heard before. Or if you have heard them, it’s because you have been hanging out with the small minority of us who know that “nature cools.”
We will study the power of water as it flows through ecosystems.
We are not primarily talking about bodies of water such as lakes, rivers and oceans. We are mainly talking about water as it flows through ecosystems and especially through plants and trees.
What happens when water flows through a tree and what happens after that?
Trees soak up water through their roots. Then the water flows upward through the tree and then out the leaves.
When water flows out the leaves and evaporates, it provides a cooling effect. It also supplies the water vapor needed for subsequent rainfalls. This water vapor passes through pores in the leaves, called stomata.
As the water vapor flows from the stomata, something else comes with it: condensation nuclei. These include bacteria and volatile organic compounds (VOC’s), and they make condensation possible, because condensation can only occur if the water molecule sticks to something solid. The condensation nuclei are solid objects to which the water molecules cling as they condense.
Condensation makes clouds possible. You would think clouds are made of water vapor, because they are up there in the air, but they are actually little droplets of liquid water.
How does evaporating water cool our environment?
When water evaporates it causes a cooling effect. This is an everyday experience.
Step out of the shower or the pool, and your skin feels cold because water is evaporating. When water evaporates it carries heat energy away from your skin.
The same is true when we sweat or perspire. Evaporating water makes us feel colder because it is carrying heat from one place to another. Actually, it is making the heat disappear.
How does heat disappear? When water evaporates from our skin, heat disappears because it takes a certain amount of energy to make a gram of water evaporate.
That energy turns from one form of energy called sensible heat--heat we can feel--to another form of energy called latent heat--heat we cannot feel.
So evaporation causes this conversion of heat from one form to another, and the effect is that the heat temporarily disappears.
Almost like magic, except that this happens every day all the time continuously and on a large scale, worldwide. We just need to make it happen more, so that we can have more “evaporative cooling.”
This process of water evaporating and causing heat to disappear is one of the great untold stories in the climate conversation.
The heat doesn’t disappear entirely. But it travels to a place, where it is much less problematic, up in the clouds.
As opposed to what?
Well, worldwide the sun shines on plants, except where it doesn’t because it is shining on bare dirt or desert sand or pavement. We have a choice. We could make it shine on plants, by installing plants in place of bare dirt or desert sand.
If the sun shines on plants, then those plants cause water to evaporate, thereby causing a cooling effect. But if the sun shines on something like dirt, pavement or desert sand, then it has a heating effect and not a cooling effect.
That is why the number one call to action in this course is to increase the plant matter as much as we can wherever we are, in our forests, on our farms and in our landscapes.
If we increase plant matter, then it has a cooling effect, because of the evaporation that plants perform all day long.
Why haven’t we heard this?
What I’ve just told you is hardly ever talked about in the mainstream climate conversation. The mainstream climate conversation is all about greenhouse gases, especially carbon dioxide.
The great thing about plants is that we don’t have to neglect carbon drawdown. We can do both. We can employ water cycles to cool the planet, even while we are “using” plants to draw down carbon from the atmosphere.
How plants enrich the soil, even as they remove carbon from the atmosphere
Plants remove carbon dioxide from the atmosphere through photosynthesis. This is part of the ongoing climate conversation. But what is rarely mentioned is that plants use photosynthesis to manufacture sugars which they then “plow” (inject, exude) into the soil.
Plants turn the carbon dioxide into sugars, some (about ⅓) of which they exude out of their roots into the soil, where those sugars become food for organisms in the soil, thus initiating the underground food chain called the soil food web.
This is another one of the great untold stories in climate change, the soil food web. The soil food web is a characteristic of healthy soil. Healthy soil, by definition, is home to a robust soil food web.
Soil food web ⇐ ⇒ soil organic matter
A robust soil food web naturally produces an abundance of soil organic matter, a spongy material, which, along with the soil food web, defines healthy soil.
Many regenerative farmers have improved their soil organic matter from 1%, which is low, to over 5%, which is very good by most standards.
According to the USDA, every time a farmer increases soil organic matter by 1% in the top six inches, that soil will hold an additional 20,000 gallons of water (or more, estimates vary).
And if you improve your soil organic matter by 5% over the course of time--an achievable goal--you will have an additional 100,000 gallons per acre.
What can you not do with an additional 100,000 gallons of water per acre?!?
This further illustrates the principle that carbon and water flow together.
When your soil has more carbon, then it can hold more water. Over the course of time, carbon and water will flow into the soil if the soil is becoming healthier. Conversely, over the course of time, carbon and water will flow out of the soil if the soil is being degraded.
This is a virtuous cycle: More plants ⇒ healthier soil ⇒ more water in the soil ⇒ more plant growth ⇒ healthier soil ⇒ and so on!
The virtuous cycle:
When the soil does have a healthy soil food web, then it has a lot of organic matter.
Organic matter increases the capacity of the soil to hold water.
When the soil can hold more water, it can grow more plants.
When the plants grow, they take more carbon out of the atmosphere and put it into the soil food web
Thus plants grow more and put more carbon into the soil
And so on in a virtuous cycle.
This is why in the Climate conversation we don’t have to choose between focusing on water and focusing on carbon. If we enrich the soil with carbon, then we will cause a great deal of carbon and water to flow in the same direction: Out of the atmosphere and into the soil.
Our job is to give ecosystems space. Our job is to be a keystone species, like a beaver.
What is a keystone species?
A keystone species is one that is so vital to an ecosystem that it makes the ecosystem possible.
For example, beavers build dams. Dams hold water. Water makes life possible for myriad plants, animals, fungi and bacteria, all because the beaver first came along and built the dam. That’s a keystone species.
Humans can be keystone species by using our knowledge to nurture ecosystems, instead of using our knowledge to destroy or degrade ecosystems.
So … let’s be a keystone species, by making ecosystems possible.
In the Water & Climate course, we will tell this and other untold stories, stories that are not being told in the mainstream climate conversation.
As we hear these stories, we will see possibilities. Mainly, we will see possibilities for what we can do all around us, to nurture ecosystems and set the stage for those ecosystems to provide things we need, such as food, water and “air conditioning.”
If you find this material interesting, there is still time to enroll in the Water & Climate course, by clicking on this link.
Check out the Water & Climate course, starting in July.
Water & Climate - Biodiversity for a Livable Climate
https://bio4climate.org/course-offerings/water-and-climate/?blm_aid=26405
The untold story of how water drives climate change … what climate models miss about the power of water.
