Once, Lake Poopó was the second-biggest lake in the country of Bolivia. People made a living fishing in its salty waters. But now it seems like nothing lives near Lake Poopó—nothing except beetles eating bird carcasses in the hot sun.

Lake Poopó was officially declared evaporated in December. When the lake dried up, people there no longer had a way to make money. Hundreds and maybe thousands of them sold their sheep, llamas, and alpacas. They packed up their fishing nets. More than half of the population is gone now—along with 75 kinds of birds. Some elderly people stayed. Young people left. They knew they had no future near the dried-up lake.

But will Lake Poopó stay dried up forever? It has dried up other times. Locals say it was dry between 1994 and 1997. Then the lake filled up again. It filled so much that it became twice as big as the city of Los Angeles, California.

Evo Morales is the president of Bolivia. "My father told me about crossing the lake on a bicycle once when it dried up," he says. He thinks Lake Poopó could make a comeback. After all, it has come back before.

But why is Poopó so dry? There is more than one reason. People redirected Poopó’s tributaries. Tributaries are rivers that feed into larger bodies of water. They used the tributary water for farming and mining instead of letting it flow to the lake. Instead of water, the lake filled with dirt.

People are also blaming the dry lake on droughts caused by El Niño. (El Niño is a series of changes in climate. It interrupts normal weather patterns.) Others blame mines that sit upstream from Poopó. Those mines have dumped pollutants into Poopó for a long time.

Our records about Lake Poopó go back only about 100 years. That’s not very long in the history of weather! We don’t know how many times Lake Poopó has dried up and filled again. Will it come back this time? We can only wait and see.