Can we make the Sahara green again?

Turning a desert into a patch of vegetation is possible, although doing so with the largest and hottest desert on the planet would be a huge challenge.

One idea would be to plant trees and plants, and pump desalinated water from the Sahara coast to irrigate them.

To prevent evaporation, the water would have to be transported in underground pipes directly to the roots of the plants.

The ideal plants for the task are eucalyptus trees, given their robustness and ability to survive in hot environments. In addition to this, they also grow very fast.

As the plants put down roots, the soil is replenished with nutrients and minerals, and rainfall increases in the region. The overall temperature of the Sahara would drop by several degrees.

But there would be no shortage of problems. As the region becomes wetter, the risk of plagues of locusts increases, and one swarm of them is capable of wiping out the equivalent of food eaten in a day by 2500 people.

The biggest problem, however, would be the domino effect that greening the Sahara would have on the rest of the world.

The Sahara sand is carried by the wind towards South America, and as it crosses the ocean it gets soaked with moisture, setting the stage for the heavy rain that falls on the Amazon rainforest.

A green Sahara could prevent the necessary water from reaching South America, and would mean no more Amazon rainforest, along with the disruption of many other ecosystems.