This episode of Nature Notes was originally broadcast on October 7th, 2010, and was written by Megan Wilde of the Chihuahuan Desert Research Institute.
The breeze gently clapping a cottonwood’s leaves. The fierce gust that flings dirt into your eyes. Wind’s energy is revealed in myriad ways in the Chihuahuan Desert. Many plants and animals here, including people, have learned to exploit its perpetual motion. What is wind energy? And how do the desert’s inhabitants take advantage of it?
Like so many things, wind’s energy comes from the sun. Radiation from the sun heats the earth’s surface—a hodgepodge of mountains, oceans, rivers, forests and deserts and such. These different features absorb, release and reflect solar energy in different ways. Because of this, the air above earth’s surface warms up unevenly.
Where the air is warmer, air molecules have more energy and rise, lowering the air pressure. Elsewhere cooler air drops to earth, causing higher air pressure. Now, keep in mind that nature likes balance. So having a mass of high-pressure air right next to low-pressure air just won’t do. To restore balance, air rushes from high-pressure areas into low-pressure ones. That moving air is wind. And moving things have kinetic energy.
The first creatures to exploit this were fungi and plants, who cast their spores and pollen into the air to spread themselves around. Conifers, grasses, oaks, cottonwoods and willows are among the plants that still depend on wind for pollination. Instead of relying on insects or animals, these plants throw pollen to the wind, and lots of it. Only a tiny fraction blows onto the right part of the right plant at the right time. While this might seem inefficient, wind-pollinated grasses and conifers dominate many landscapes in the Chihuahuan Desert region and are some of earth’s most successful plant families.
Other desert plants count on wind to scatter seeds. Tucked away in our mountain ranges, bigtooth maples produce seeds that look like papery propellers—perfect for twirling into a breeze. On our wind-swept flats, the winged seeds of four-wing saltbush can cruise on a dust devil for miles. But the most notorious wind hitchhikers here are tumbleweeds. As the wind rolls their prickly remains across the desert, these invasive species drop scads of seeds.
In the animal kingdom, turkey vultures use wind energy with utmost grace. With wings outstretched, they soar up columns of warm, rising air, and then glide until they find another tower of circling wind. By riding these aerial escalators, turkey vultures rarely have to expend their own energy as they search for carrion.
Humans have been tapping wind’s energy since wind-propelled boats cruised the Nile 7,000 years ago. Around 200 B.C., the first simple windmills extracted water in China and ground grain in ancient Persia. In our region, windmills began pumping underground water for steam trains and ranches in the late 1800s, opening this arid land for settlement.
Today, these windmills’ descendents work in much the same way to churn out electricity. Wind sizzling through wind turbines creates lift, turning the blades. This spins a shaft that turns a generator, which converts the mechanical energy into electricity. Texas now leads the nation in wind-energy production, thanks in part to the Trans-Pecos’ many wind farms. As you might guess on a gusty spring day, our buttes and mountain passes have some of the state’s highest wind speeds.