April 1938: A dust bowl farmstead in Dallam County, Texas, showing the desolation produced by the dust and wind on the countryside adding to the problems of the depression in the USA. (Photo by Three Lions/Getty Images)

Climate change and the environment were the forgotten issues of the 2012 election—at least, before Superstorm Sandy put them square on the map. But even before that hurricane slashed through the Northeast, killing more than a hundred people and causing likely more than $50 billion in damages, the U.S. was already in the grips of a slow-motion ecological disaster. 2012 saw one of the biggest and most severe droughts in American history, with the Corn Belt in particular gripped by withering heat and aridity. Yields of corn and soybeans—the staple crops of the U.S. food system—shriveled, leading to higher food prices and a hit to the U.S. economy that could be as much as 1% of GDP.

But while the 2012 drought may have been the worst in a half-century, it has nothing on the great Dust Bowl of the 1930s. That decade-long drought—exacerbated by poor farming techniques that left topsoil crumbling in the wind—changed the face of the U.S. and led to massive migrations out of farming states in the Midwest. As the master filmmaker Ken Burns shows in his new documentary The Dust Bowl—airing on PBS Sunday night and Monday night—it’s a man-made disaster that still has lessons for us today. (The 4-hour documentary will also be available as a DVD-check it out here.) “The Dust Bowl has never gotten the attention it deserves,” says Burns. “But we can see today with this year’s drought, or with climate change, that we can affect the environment, whether we want to acknowledge it or not.”

The Dust Bowl is vintage Burns, with the documentarian mixing archival photographs and footage with interviews of elderly Dust Bowl survivors. What stands out is that while the 1930s certainly saw a number of severely dry years, the sheer scale of the Dust Bowl had much more to do with farmer’s practices than with the weather, as well as the financial catastrophe of the Depression, which reduced demand for crops—all after farmers had spent the previous decade and half plowing more and more land. The result was a vicious circle, as Allen Best writes in the Denver Post:

When demand drooped and prices flagged, the new dryland farmers plowed yet more to compensate for reduced revenue. Compounding the problem were the so-called suitcase farmers, from Denver and elsewhere, absentee landowners who plowed massive swathes of prairie sod. In these ways, millions and millions of acres of soil were rendered naked.

In the end, 25% of the affected population in the affected southern Great Plains area would flee, an Okie exile that John Steinbeck would describe in The Grapes of Wrath. The Dust Bowl sped the Westward migration of the American population and its urbanization, as ruined farmers fled for the cities. Before the Dust Bowl, nearly 50% of Americans lived in rural areas; today, that figure is closer to 17%. The disaster literally changed the face of the country.

Thankfully, the Dust Bowl also led to changes in how Americans farm, with more emphasis put on soil conservation that has been able to prevent the sort of ceaseless erosion that ruined whole states. The 2012 drought is actually a sign of just how resilient American agriculture has become. Despite one of the driest growing periods in decades, American farmers will actually produce far more corn and other crops this year than they did in a good year as recently as the 1980s. And farm incomes—thanks largely to government-subsidizes crop insurance—could actually hit a record high this year. Unlike during the Dust Bowl, the 2012 drought won’t see massive numbers of farmers driven off their land—though with only 2% of Americans now working in agriculture, there aren’t many farmers left to be driven off.

It’s difficult for climate scientists to connect dry years like 2012 to man-made climate change. (In fact, a study published in Nature last week argued that drought hasn’t actually increased over the past 60 years, even as carbon emissions have increased and global temperatures have risen.) But most climate models agree broadly that as the planet warms, dry areas—like much of the U.S. Midwest and West—are likely to get even drier, which could imperil the American breadbasket. That something that worries Burns. “Politicians aren’t taking climate change seriously, and it has the potential to be so devastating,” he says. “In The Dust Bowl, we can see for ourselves what happens when bad weather is compounded by man-made mistakes. Here’s hoping that we’re finally learning.