This is not your grandparents’ drought

How climate change is making megadroughts and aridification part of the US’s new normal

Climate change is transforming America’s Heartland. I decided to investigate how the region becomes drier, hotter, saltier, wetter and sicker. I talk to experts from different perspectives to learn how research and science can help us adapt and prepare for what’s to come.

How long does a drought have to last before it turns into something else?

In a new episode my podcast Challenging waterJonathan Overpeck, dean of the University of Michigan’s School of Environment and Sustainability, told me that while every year is different—some not too dry and some really dry—areas of North America have been in a state of megadrought since 1999. In the American West in particular, he said, the current drought “isn’t just the kind of drought that our grandparents had, where you just wait for it to end.”

This reality prompted Overpeck, an expert on climate change and climate-vegetation interactions, to adopt new terms, mega drought and aridization, to explain what is happening.

There are two halves to the problem: one is how much rain is falling, and the other is simply warming. And warming is of primary importance because it is permanent, therefore more predictable; we know that the planet will continue to warm in the coming decades. However, rain, especially heavy or without it, is not. Persistently high temperatures lead to greater evaporation and greater moisture loss regardless of total precipitation.

Climate change is drying up areas of the United States that produce food, provide water, and facilitate global trade.

The implications of this shift are easy to see: over the past decade, groundwater irrigation has steadily increased in the western parts of the Mississippi River basin. And when the rain falls in extreme but fleeting cases, it may not be there when the crops need it. In some cases, increased rainfall intensity may lead to wetting of the soil at critical stages of growth.

All this leads to instability for people, economy and nature.

Overpeck and I talked about solutions, including how farmers can diversify their incomes with renewable energy and smarter water management, which are critical but little-known parts of the equation for a stronger future. And then Overpeck, or “Peck” as many call him, said there is a way to rebuild rural America, but people embracing change, not fighting it, is important. In his view, a focus on equity can “move things forward faster and more to the benefit of all.”

Today, devastating floods, destroyed crops and high food prices are the new normal, and poor communities and vulnerable populations suffer disproportionately. The claim that fairness is the basis of adaptation may not seem like the domain of science, but its relationship to the rate of change warrants investigation. Investing in the changes that will bring the greatest return is a simple concept that has wide application. Let’s launch it in America’s Heartland.

Listen to my conversation with Jonathan Overpeck to delve into the science of aridification and a drier future for the Mississippi River Basin.