Human beings are such impatient creatures.

So, you use ground penetrating radar on the Sahara and you know what you find?

Rivers. Tons of them. Big and small.

About 20,000 years ago, the Sahara was lush and green and supported loads of human and animal life. Mind you, at the same time, Toronto was covered in a glacier about five kilometers thick.

Here’s the thing – the earth’s axis from time to time “precesses” which is a fancy word for “moves in a circle”. Right now, the earth’s north pole points directly at the star we call Polaris, but about 26,000 years from now it will be pointing in the completely opposite direction although at the same angle.

These changes in the orientation of the earth’s axis together with the fact the planet’s orbit isn’t entirely circular means that, over time, there are massive shifts in the climate. About 13,000 years ago, the glaciers covering a lot of the planet started shrinking instead of growing and the planet became much drier, including what’s now the Sahara, which started as a lush forest and eventually became the arid desert it is today.

Humans, who had already spread over pretty much all of the planet by this time, flocked to river valleys like the Nile, the Tigris/Euphrates, the Yellow, the Indus and the Ganges and created what we now call “civilization”. It appears something similar happened in the Americas too.

So, it’s really just a matter of time. In another 20,000 years I’m sure the Sahara will be lush and green again while Canada will just be covered by a massive glacier except for a tiny part of the Rocky Mountains.

Yes. It is possible. It is also madness, on a scale that only men with too much money can dream of.

The plans are simple on paper. And huge. One plan is to flood the low parts of the desert. Pipe in seawater from the ocean to make great new inland seas. The hope is that the water in the air will make it rain. Another plan is to build solar farms the size of a country. Use the power to make fresh water from the salt. Then use that water to plant a new forest across the sand.

The reasons are obvious enough. More land for food. A new forest to soak up the carbon from the air. But the world’s weather is a delicate thing. The Sahara’s heat and dust are part of it. The dust flies across the ocean and feeds the Amazon. The heat drives the winds. To change the desert is to change the world. You might not like the new one you create.