What is the Rub Al-Khali?

The Rub Al-Khali, or Empty Quarter, is the vast expanse of desert that covers much of the Southern half of the Arabian Peninsula. It makes up about a third of Saudi Arabia and extends into both Yemen and Oman. Its size makes it one of the world’s largest deserts, as it covers about 25,000 square miles (40,232.45 square km) of land.

The harsh conditions of the Rub Al-Khali mean that it has seldom been inhabited or even explored by humans. The nomadic Bedouins that have lived on the Arabian Peninsula for thousands of years deliberately set up travel routes that would only skirt the edges of the Rub Al-Khali. This is not surprising, since on an average summer day, the temperature can easily rise to 131 degrees F (55 C). Surprisingly, the extreme temperatures of the Rub Al-Khali still allow for many species of birds, plants and insects to flourish.

The Rub Al-Khali is of great importance from a natural resources standpoint. It is generally considered to have the highest amount of untapped oil. Some of the largest oil fields in the world extend into this forbidding desert. Yet, the normal conditions of the desert life make it hard to stray too far into the Empty Quarter. At one point, before 300 BCE, some trade routes of the Bedouins did cross into the Rub Al-Khali, but these had to be planned very carefully. Some of the sand dunes in this desert reach heights of over 1000 feet (304.8 m), making it an impossible climb for a slow moving caravan.

One interesting aspect of the Rub Al-Khali is the number of dry lake beds that can be found there. Scientists estimate that likely about 40,000 years ago, the Empty Quarter was a fertile place, benefiting from monsoon seasons. Climatologists believe that the monsoons gradually moved, benefiting areas like Egypt and India, and resulting in the drying up of numerous water sources in the Saudi desert. Fossil records show freshwater shells and a thriving population of animals that could not survive the Empty Quarter’s current conditions.

The Empty Quarter is really not so empty, although it can appear so to the naked eye. In addition to having the largest oil supply on Earth, many discoveries of existing plant and animal life have been made since 2006, when a huge expedition of scientists of several different disciplines explored large sections of the Rub Al-Khali. Scientists found 31 different plant species, and 24 different birds that make the Rub Al-Khali home. There are also impressive records of meteor rocks and a large number of fossils, expanding the catalog of creatures and plant life that have existed or still exist on the earth.