NASA's Earth Observatory has posted some staggering photos of the vanishing Aral Sea. The lake, tucked between Kazakhstan and Uzbekistan, was once the fourth-largest in the world. Today, after decades of being drained for irrigation, it's nearly gone.

The lake dwindled to its smallest size ever in August of 2014: "For the first time in modern history," NASA noted at the time, "the eastern basin of the South Aral Sea has completely dried." Things have rebounded slightly since then, but only slightly. Here's a comparison between 2000 and 2016:

The Aral Sea: August 2000 (left) versus August 2016 (right)

Note that even the somewhat bigger lake back in 2000 was just a puddle compared to what it was in the 1960s, as the historical photograph below suggests:

The Aral Sea in 1964

What happened? Historically, the Aral Sea was fed by both the Syr Darya and the Amu Darya rivers flowing down from the mountains. But in the 1960s, the Soviet Union diverted both rivers — through a network of dams and canals — for use in cotton fields and other agriculture.

NASA explains what happened next: "Although irrigation made the desert bloom, it devastated the Aral Sea. As the lake dried up, fisheries and the communities that depended on them collapsed. The increasingly salty water became polluted with fertilizer and pesticides. Blowing, salty dust from the exposed lakebed became a public health hazard and degraded the soil. Croplands had to be flushed with larger and larger volumes of river water."

By the 2000s, the Aral Sea was roughly 10 percent of its original size. The area's once-vital fishing industry had been completely eradicated, leaving entire communities unemployed. The disappearance of the sea also affected the local climate — summers have been getting hotter, and winters have been getting colder.

And now the lake keeps shrinking during dry years. In 2014, a paucity of snow in the nearby mountains combined with continued high levels of water withdrawals for irrigation helped dry out the eastern basin for the first time in likely 600 years, explained Philip Micklin, a geographer emeritus from Western Michigan University.

The lake tends to ebb and grow with wet and dry seasons. As you can see in NASA's photos, the eastern side of the lake rebounded this year. Meanwhile, there are some projects to try to save the deeper western basin of the Aral Sea from vanishing entirely. But it's unlikely the lake will ever return to what it was before the 1950s.

Further reading: 15 before-and-after images that show how we’re transforming the planet