If you take another day trip Sahara desert in North Africa you will bring plenty of water and plenty of sunscreen. But if you are planning to stay overnight, you should also bring a cozy sleeping bag.
This is because the temperature in the Sahara can drop as the sun goes down, from an average altitude of 100 degrees Fahrenheit (38 degrees Celsius) during the day to an average low level of 25 degrees Fahrenheit (minus 4 degrees Celsius) at night, according to NASA.
So why is this dramatic temperature shift happening in arid deserts like the Sahara? And how do native animals and plants handle such wild extremes?
Related: Can the Sahara ever be green again?
Heat and humidity
The reason for arid deserts ̵
Unlike a thermos, sand does not retain heat very well. When heat and light from the sun hit a sand desert, sand grains in the upper layer of the desert absorb and also release heat back into the air, according to a 2008 report from NASA’s Jet Propulsion Laboratory in Pasadena, California. During the day, the sand radiation of the sun’s energy overheats the air and causes the temperature to soar. But at night, most of the heat in the sand radiates quickly into the air, and there is no sunlight that can heat it up again, and the sand and surroundings become colder than before.
However, this phenomenon does not account for such a drastic drop in temperature. After all, when the sun goes down on a tropical beach, you do not have to wear a winter coat.
The main reason for the strong temperature change is that the desert air is extremely dry. In arid deserts like the Sahara and The Atacama Desert In Chile, the humidity – the amount of water vapor in the air – is practically zero, and unlike sand, water has an enormous capacity to store heat.
Water vapor in the air traps the heat near the ground like a giant invisible blanket and prevents it from spreading into the atmosphere, according to the World Atlas. Air with high humidity also requires more energy to heat up, which means that it also takes more time before the energy disappears and the surroundings cool down. Therefore, the lack of moisture in deserts allows these dry places to heat up quickly, but also cool down quickly.
Adapts to extreme temperatures
Despite these rapid temperature fluctuations, desert animals are well adapted to the extreme temperature changes of the desert.
“It tends to be a relatively small problem for them,” said Dale DeNardo, an environmental physiologist at Arizona State University who specializes in desert animals. “The bigger challenge is to get enough food and water to survive.”
Reptiles, the most widespread and diverse group of animals in the desert, are well adapted to extreme temperature variation because they are cold-blooded or ectothermic, which means that they do not need to invest energy in maintaining a constant body temperature. In other words, reptiles can use this energy elsewhere, such as hunting. Many reptiles also benefit from being small, allowing them to find shady hooks during the day or warmer rocks at night. “There are many different places to go to be warmer or cooler, especially when you are little,” DeNardo told WordsSideKick.com.
Related: How do lizards cool off?
However, large warm-blooded or endothermic mammals are like camels, are too large to hide from the sun and can not let the body temperature drop. Rather, camels survive by maintaining a constant body temperature in both hot and cold conditions. They do this by having a lot of insulation in the form of fat and thick fur, which prevents them from getting too much heat during the day and losing too much at night, DeNardo said.
In contrast, desert birds use evaporative cooling – where they use water to transfer heat from the body, such as how people sweat and dogs pant – through a variety of methods (some vultures urinate on their legs to cool down). However, their ability to fly long distances between water sources or to tear food means they do not have to worry as much about conserving water as other desert animals. “I call it cheating because they do not really experience the limitations of a desert,” DeNardo said.
Plants, on the other hand, are more vulnerable to extreme temperatures. “They face a much bigger challenge because they are not allowed to move,” DeNardo said. Therefore, iconic desert plants, such as cacti, have developed a number of defenses, such as spikes and toxins, to protect their precious water from predators. However, freezing temperatures at night can be fatal to plants because water freezes and expands in the tissue, which can cause irreversible damage. Therefore, plants grow only in areas where the air temperature does not fall below freezing for more than a couple of hours each night, known as freezing.
Researchers are still figuring out how Climate change can affect dry places and organisms, but “we will definitely see changes,” DeNardo said. “For most deserts, we predict an average temperature increase of 3 to 4 degrees Fahrenheit [1.7 to 2.2 C]. ”
However, research indicates that “The nights are going to get warmer, but it’s not as bad as warmer days,” DeNardo noted.
Instead, the real problem is that climate change can affect the amount of annual rainfall that desert creatures depend on. “It will be less consistent, you will have relatively wet years and relatively dry years,” said DeNardo. “But even if most people are wet enough, it will only take one really dry year to cause major problems.”
Originally published on WordsSideKick.com.