Climate change is expected to make the dry places on Earth even drier. That's bad news for countries like Cape Verde, a cluster of islands off the coast of West Africa that averages less than three inches of rain a year.
Droughts here have killed tens of thousands of Cape Verdeans and forced many more to emigrate. But the islanders who remain have begun to adapt using a range of technologies to grow food in an increasingly arid land.
Dust and Heat
Cape Verde offers two climates: dry and parched. The island of Sal is in the parched category. From the air it looks like a flattened sand dune, but from the ground, it's a moonscape.
"There is no rain," Emilio Lobo says. "Only dust and heat."
Lobo grew up on Sal, and a few years ago, he made an odd choice: He decided to become a farmer, despite the lack of water or arable land.
Lobo says he found ways to solve these problems — on the Internet.
Lobo's greenhouses feel as if you've found a portal to another place on Earth. The air is moist and the light is soft, and there are rows and rows of glistening, flawless produce.
Lobo points to rows of tomatoes, cucumbers, peppers, zucchini and lettuce.
He walks down a row of lettuce plants grown hydroponically. The plants hang in a white, plastic trough several feet above ground. A pump streams water and nutrients past the dangling roots of each plant. They look a bit like patients being fed intravenously.
"This is a variety from Brazil, which is one that can hold better the heat," says Lobo, pointing to a type of lettuce.
Tourists and Tomatoes
Lobo's hydroponic farm is possible because of something new on Sal: tourists.
A couple of decades ago, tourists discovered the white sand beaches, the crystalline seas — and the bargain rates.
And because tourists need fresh water, the island built a massive desalination plant. Lobo realized this plant represented a major opportunity for a modern farmer, and his research on the Web showed him what to do.
"The technology, it's easy stuff," he says. "It's not complicated."
Hydroponic farming uses only about half the water of traditional agricultural farming practices. Even so, Lobo buys about 100 tons of water every day; it accounts for one-third of his costs.
Fortunately, his business is thriving, thanks in part to European tourists who expect salad with their meals.
Lobo says that he has virtually no competitors.
"In Sal, I am the king of tomatoes," he says.
Scientists worry about the lack of rain in Cape Verde and the swath of Africa just below the Sahara.
"We know that in this region, there's a decadal trend which has been downward for rainfall since the late '60s, early '70s," says Greg Jenkins, a meteorologist at Howard University in Washington, D.C.
He has done field research in this area, known as the Sahel. Jenkins says it's not clear whether the drought is permanent, or will get worse because of global warming.
But in either case, Jenkins says, it would have drastic consequences for a place like Cape Verde.
A Fragile Climate
And there are ominous signs. Jenkins says there has been a shift in rainfall patterns.
"If you look at the 1990s vs. the 1960s in places like Senegal, you see that shift," says Jenkins. "You say, 'Hey, what happened to all the rain?'"
Jenkins is talking about the area to the east of Dakar, where the water patterns have shifted, and moved toward the south.
When weather shifts, it is borderline places like Cape Verde that are most vulnerable.
They sit right on the margin between climates with a little rain and climates with almost none. Push the weather south just a few degrees, and Cape Verde becomes part of the Sahara.
"I remember that when I was a kid, we used to go out into the streets and play in the rain and the running water, and I remember that there was much more water than there is now," says Jose Pimenta Lima, Cape Verde's chief meteorologist.
People from other islands tell similar stories.
About 300 miles south of Sal is the island of Santiago. It gets a little rain in the mountains, but not much on the coasts. And there aren't enough tourists in Sal to pay for big desalination plants.
From Selling Sand to Selling Crops
For decades, people along the coasts of Santiago have made a living by selling sand to the construction industry.
Mafarola, a woman who lives near the city of Chao Bom, used to scoop beach sand in a bucket, then carry it back on her head. When the dry sand ran out, she waded into the surf. Eventually it became too difficult.
Fortunately for Mafarola, Cape Verde was changing. It had gained independence from Portugal in 1975, and during the next few decades, the new republic appealed to the international community for help.
By the time Mafarola gave up on sand, the Cape Verde government was working with aid agencies to drill a series of deep wells around Chao Bom. In some places, engineers drilled more than 300 feet before hitting water.
But the effort paid off. It provided drinking water to thousands of residents and allowed Mafarola and several dozen other women to stop digging sand and become farmers.
Farming remains uncertain, though. If too much water is pumped from the wells, it turns salty. But for now, Mafarola and about 50 other farmers are supporting themselves by selling their crops at local markets.
In the mountains of Santiago, there are more patches of green, but not because of wells. Valleys have small streams, at least during the rainy season.
During good years, one of those streams provided just enough water for Pedro de Moura to coax a single crop from a shear hillside near the village of Lagoa.
But as the rain decreased, there were many bad years. De Moura says that during those seasons, he lost most of his sweet potatoes or sugarcane.
"Lots of people gave up, not because they wanted to," De Moura says. "It's because there is nothing for them to do here. Some of them moved to Praia, the capital city, looking for jobs."
But now, some of them are coming back.
A New Type of Farming
Two years ago, aid agencies helped the farmers build a concrete sluice that brings water year round. It's part of a new system that makes the most of every drop that flows through this valley.
"You have catchment structures upstream, such as check dams with reservoirs, and from the reservoirs the water is fed into these drip irrigation systems and often you'll have terracing to create space for drip irrigated cultures," says John Riley, who works for the nonprofit group, ACDI-VOCA.
The techniques aren't new or complicated, but they've transformed the island.
"Today there are vegetables on the market all year round, and in a certain abundance," Riley says.
De Moura is standing on one of his terraced plots, surrounded by aquamarine cabbages the size of bowling balls.
His neighbors grow carrots, lettuce, green beans and zucchini. And they're getting three crops a year instead of just one.
De Moura says he has a lot more neighbors these days. He gestures toward a farmer who comes by to chat.
"Like this guy here had left and worked as a driver in the city," De Moura says of his neighbor. "But after the introduction of new technology, he came back and worked on his farm."
For awhile, at least, the harvests have returned to Cape Verde, even if the rain hasn't.