It’s difficult to imagine the Sahara as anything but thousands upon thousands of miles of ever-shifting sands. And yet, studies tell us this vast desert was once a lush expanse of green.

Today, of course, the Sahara desert is harsh and dry, largely uninhabitable for people and agriculture. Even more concerning, the desert is advancing at an alarming pace, creeping into land that is vital for the people who live in bordering nations. Driven by drought, climate change, and unsustainable practices like overgrazing, desertification is fast becoming a global problem.

Luckily, the Sahara is also a source of hope. In fact, while deserts cover much of the Earth’s surface, much of that desert (as much as 30% of the globe) consists of eroded, currently wasted land that is actually suitable for trees to grow — and even more incredibly, we have the technology to restore them.

In an unprecedented symbol of international cooperation and environmental awareness, over 20 countries have banded together to plant The Great Green Wall, a band of trees that will stretch across the entire continent of Africa to hold the advancing desert at bay. The theory is sound, and the initial results are promising — over 20 million hectares of degraded land has been restored in Ethiopia, Nigeria, and Sudan. Already, the wall is saving livelihoods all across Africa.

Our efforts should not stop at merely containing the desert, however. The Sahara represents 3 million square miles of prime, wasted land — land that could be put to work to benefit all of Africa and, indeed, all of the world.

Reforestation may sound like fantasy, but recently an innovative new project has proved that not only is a Saharan oasis within our reach, but it may be easier than we imagined. The Sahara Forest Project combines several proven technologies — solar power and seawater greenhouses — into an an incredibly elegant system, “a mean, green super-massive biomachine.”

Using only seawater and sunlight, this greenhouse facility produces it’s own energy and has extra leftover, perhaps even enough to power all of Africa and Europe. It’s crop yields rival commercial farms in Europe, and designers predict that a larger scale model could surpass these impressive numbers to supply Qatar with all of the tomatoes, eggplants, peppers, and cucumbers that are currently imported from abroad. The detail that best catches the imagination, however, is an unexpected side effect. Not only do these greenhouses turn the Sahara into prime agricultural land inside, but the moist, cool air that escapes actually creates spontaneous plant growth in the surrounding area and drops the air temperature by 10°C.

There are other plans as well, from using reforestation robots, to waterboxes that allow trees to survive in the existing conditions, to using geoengineering to cover the sands in trees.

What is clear are the overwhelming benefits of reclaiming the Sahara as an oasis of productivity and progress. A reforested Sahara promises a better life for the many people who rely on this inhospitable land. What is now a desert could become a source of food, water, and energy for thousands. It is not only Africa that stands to gain, either. Covering the desert in green could absorb enough carbon to offset the effects of global warming, converting a worldwide crisis into an opportunity for better lives.