Why do deserts get so cold at night? - Livescience.com

So, why does this dramatic temperature shift happen in arid deserts like the Sahara.

The reason that arid deserts — dry regions covering about 35% of Earth's land — get so hot, and subsequently so cold, is a combination of two key factors: sand and humidity.

When heat and light from the sun hit a sandy desert, sand grains in the desert's top layer absorb and also release heat back into the air, according to a 2008 report from NASA's Jet Propulsion Laboratory in Pasadena, California.

The main reason for the stark temperature change is that 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 a huge capacity to store heat.

Despite these rapid temperature swings, desert animals are well adapted for the desert's extreme temperature changes. .

"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.

In contrast, desert birds use evaporative cooling — where they use water to transfer heat away from their bodies, like how humans sweat and dogs pant — through a range of different methods (some vultures urinate on their legs to cool down).

But their ability to fly long distances between water sources or to scavenge food, means they don't have to worry as much about conserving water like other desert animals?

"I call it cheating because they don't really experience the limitations of a desert," DeNardo said?

That's why iconic desert plants, like cactuses, have developed a range of defenses, such as spikes and toxins, to protect their precious water from predators.

"For most deserts, we are predicting an average rise in temperature of 3 to 4 degrees Fahrenheit [1.7 to 2.2 C]." .