by From vast expanses of scorching sand to huge ice caps, deserts can take many different forms. But which hot and cold deserts are the largest on the planet? And what kinds of life can survive in these extremely dry places?
To answer this record question, it is important to consider what exactly makes a desert a desert. According to Jonathan Wille (opens in a new tab)an Antarctic meteorologist and climatologist at the University of Grenoble in France, any area that receives less than 9.8 inches (25 centimeters) of precipitation per year is considered a desert.
When all these regions are considered, Antarctic qualifies as the largest cold desert on Earth, and the Sahara is the largest hot desert.
“Over 14.2 million square kilometers [5.5 million square miles]Antarctica is the largest desert in the world,” Wille told Live Science. “Some parts of Antarctica, like the McMurdo Dry Valleys, would have had no precipitation for 14 million years.” epic lack of precipitation is largely due to cold temperatures, nearby mountains blocking clouds, and strong winds sucking moisture from the air.
Even for a desert, this region is exceptionally arid. According to scientists who are part of the National Science Foundation LTER (opens in a new tab) (Long Term Ecological Research) In Antarctica, the McMurdo Dry Valleys have no snow or ice except for a few permanently frozen lakes. But it’s not completely sterile. There are microbes, mosses, and lichens that can tolerate dry freezing.
Related: Why do deserts get so cold at night?
Wille, who led a 2021 study in the journal JGR atmospheres (opens in a new tab) gazing into the Antarctic rainfall, think this frozen wasteland is often overlooked. Although the far interior regions of Antarctica are mostly devoid of life, he said more organisms, such as petrels and penguins, are settling where they can capture fish and other sea creatures. in the frigid waters, and seals sometimes come ashore.
As you might expect, the Sahara Desert, which stretches across North Africa, is the opposite of Antarctica. It measures 3.55 million square miles (9.2 million square kilometers). But although some may see it as a wasteland, it is surprisingly diverse. This desert reveals a variety of geographical features and life forms, depending on André Vicente Liz (opens in a new tab)PhD student at the University of Porto in Portugal.
“The Sahara presents obvious geographical characteristics which largely contradict the established perception, mainly a very great diversity [landscape] and different… types [of materials beneath the surface] but also considerable spatial variability in climate,” Liz told Live Science.
The varied landscapes of the Sahara not only include its famous sand dunes, but also rocky terrain, salt flats, mountains and savannahs that may even have water. There have been drastic changes in the desert climate in the past, which has led to vast biodiversity in different regions of the desert. Liz conducted a study in 2022 in the Journal of Biogeography (opens in a new tab) the exploration of Saharan animal species which had hitherto not been the subject of much attention.
In hot deserts, cold-blooded creatures thrive because their body temperature adapts to the temperature of their surroundings as they move from scorching sunlight to cool burrows. Liz has observed many species of small lizards that have adapted particularly well to the arid environment. Some reptiles and amphibians can also hibernate in times of drought. Besides lizards, snakes, scorpions, beetles and ants, and even a few frogs and toads that live in rock pools, the Sahara is also home to mammals and birds. Antelopes, camels, cheetahs, ostriches and desert foxes are just a few of the warm-blooded animals that can survive in the Sahara.
There are certain areas, such as rock pools called “gueltas”, where biodiversity is particularly high as they serve as refuges for species that have had to flee their habitats due to sudden and intolerable climate change. In the face of climate change, Liz and her colleagues are studying these regions closely to find out what makes them good places to survive.
“These areas are known as biodiversity ‘refugia’ and are of particular interest for conservation planning in the current climate emergency, where they can play a key role as climate buffers,” said he declared.
So deserts can be deceptive places that only seem lifeless until something crawls or creeps. They may be dry, but that means anything but monotonous.
