A new study finds that there could be unintended consequences of building large massive solar farms in deserts around the world. Open research claims that huge solar farms, such as in the Sahara, could introduce environmental crises, such as altering the climate and causing global warming.
The study was conducted by Zhengyao Lu, a researcher in Physical Geography at Lund University, and Benjamin Smith, a research director at the Hawkesbury Institute for the Environment at Western Sydney University. The results of his research were published in a Feb. 11 article in The Conversation.
Solar panels are darker colors like black and blue to attract and absorb more heat, but they tend to be much darker than the ground around the solar panel. The post cites an article that states that most solar panels are between 15% and 20% efficient in converting sunlight into useful energy. The researchers say the rest of the sunlight is returned to the surrounding environment as heat, “affecting the climate.”
The article notes that to replace fossil fuels, solar farms would have to be huge, as they cover thousands of square miles, according to this article. Solar farms of this magnitude can have environmental consequences, not only locally but globally.
The authors of a 2018 study say that climate models show that the installation of a large number of wind turbines would double rainfall in the Sahara Desert and that solar panels would increase rainfall by 50%. The researchers came to this conclusion by determining that solar panels and wind turbines would lower the albedo to the earth’s surface. Albedo is the fraction of light reflected by a body or surface.
From the conversation:
The model revealed that when the size of the solar farm reaches 20% of the total surface of the Sahara, it triggers a feedback loop. The heat emitted by the darker solar panels (compared to the highly reflective desert soil) creates a sharp temperature difference between the land and the surrounding oceans that ultimately reduces the surface air pressure and causes the ‘humid air rises and condenses into raindrops. With more monsoon rain, the plants grow and the desert reflects less energy from the sun, as the vegetation absorbs light better than sand and soil. With more plants present, more water evaporates, creating a wetter environment that causes vegetation to spread.
Turning the Sahara Desert into a lush green oasis could have climatic ramifications across the planet, including the atmosphere, ocean, land, changing entire ecosystems, altering rainfall in the Amazon rainforests, causing droughts and triggering more tropical cyclones.
According to the researchers, the well-intentioned effort to lower global temperature could do the opposite and raise the planet’s temperature.
Covering 20% of the Sahara with solar farms increases local temperatures in the desert by 1.5 ° C according to our model. With a coverage of 50%, the temperature rise is 2.5 ° C. This warming spread around the world by the movement of the atmosphere and the ocean, raising the average world temperature by 0.16. ° C for 20% coverage and 0.39 ° C for 50% coverage. Global temperature change is not uniform: polar regions would warm more than the tropics, increasing the loss of sea ice in the Arctic. This could further accelerate warming, as the melting of sea ice exposes dark water that absorbs much more solar energy.
The authors conclude their article by stating that renewable energy solutions “can help the transition of the fossil energy society, but studies of the terrestrial system like ours emphasize the importance of considering the many coupled responses of the atmosphere, oceans and the earth’s surface when examining its benefits and risks. “