US farmers extract water from the Ogallala aquifer faster than they can replace, warns an expert

Every summer, the central plains of the United States dry up, leading farmers to exploit groundwater to irrigate sorghum, soybean, cotton, wheat and corn, and maintain large herds of cattle and pigs.

As the heat increases, anxious irrigators gather to discuss whether they should adopt more stringent conservation measures and how they should do it.

They know that if they do not conserve, the Ogallala Aquifer, the source of their prosperity, will dry up. The Ogallala, also known as the High Plains Aquifer, is one of the largest underground freshwater sources in the world.

It lies beneath an estimated 174,000 square miles of the Central Plains and contains as much water as Lake Huron.

It waters portions of eight states, from Wyoming, South Dakota and Nebraska in the north to Colorado, Kansas, Oklahoma, New Mexico and Texas in the south.

But the current drought affecting the region is unusually strong and persistent, which makes farmers more dependent on the aquifer and sharpens the debate about their future.

Ogallala, also known as the High Plains Aquifer, is one of the largest underground freshwater sources in the world. It lies beneath an estimated 174,000 square miles of the Central Plains and contains as much water as Lake Huron. Changes in water levels shown since 1950s-2015

Ogallala, also known as the High Plains Aquifer, is one of the largest underground freshwater sources in the world. It lies beneath an estimated 174,000 square miles of the Central Plains and contains as much water as Lake Huron. Changes in water levels shown since 1950s-2015

A current assessment of the US Drought Monitor, published by the University of Nebraska-Lincoln, the United States Department of Agriculture and the National Oceanic and Atmospheric Administration, shows large swathes of the southern plains experiencing a drought that is "serious" to "exceptional". & # 39;

These troubling perspectives form the dramatic backdrop of & # 39; Ogallala: water for a dry land & # 39 ;, now in its third edition.

In it, my fellow historians John Opie and Kenna Lang Archer and I established current debates about the Ogallala Aquifer in the context of the region's equally conflictive past.

Draining the source

In the 1880s, farmers in the region claimed that there was a constant movement of water under their feet, which they called "overflow," from the Rockies to the east.

Geologist F.N. Darton from the US Geological Survey UU He located the first contours of the aquifer near Ogallala, Nebraska.

His discovery fueled the ambitions of farmers and irrigation promoters. One impeller, William E. Smythe, visited Garden City, Kansas, and applauded the irrigated future.

Pumping underground water, he told his audience, he would build "nice little houses with architecture."

We will surround you with beautiful meadows and skirt them with trees and hedges … in a new Kansas dedicated to industrial independence.

That bucolic vision took decades to realize. Windmills could only pump so much water, which limited the amount of land that farmers could put into production.

The current drought that ravages the region is unusually strong and persistent, which makes farmers more dependent on the aquifer and sharpens the debate about their future

The current drought that ravages the region is unusually strong and persistent, which makes farmers more dependent on the aquifer and sharpens the debate about their future

And the sand and gravel composition of Ogallala slowed the downward flow of surface water to fill it, even in wet seasons.

This did not matter until farmers began adopting better drilling technology, gas water pumps and high-tech irrigation systems after World War II.

These advances converted the Central Plains into the world market for bread and the meat market, annually generating food worth 20 billion dollars.

As more pumps were drilled into the aquifer to capture its flow, some began to appear dry, which resulted in more drilling and pumping.

Between the end of the 19th century and 2005, the United States Geological Survey estimates that irrigation has depleted the aquifer by 253 million acre-feet, approximately 9 percent of its total volume.

And the pace accelerates. When analyzing the federal data, The Denver Post discovered that the aquifer contracted twice as fast between 2011 and 2017 as in the previous 60 years.

The current drought is only adding to these evils. University of California-Irvine hydrologist Jay Famiglietti identified the Ogallala region and the Central Valley of California as the two most overheated and water-poor areas in the United States.

Relying on technological solutions

This is not the first time that humans push the ecosystems of the Central Plains to the point of rupture. From the end of the 19th century, settler-colonists cultivated native grasses that protected the soil.

When a series of intense droughts hit in the 1930s, the dry topsoil was prepared to erode into the infamous Dust Bowl.

Howling wind storms widely known as "black blizzards" erased the sun, sweeping away the exposed earth and displacing much of the human population.

The farmers who survived during World War II put their hope in highly designed solutions, such as high power pumps and central pivot irrigation systems.

Every summer, the central plains of the United States dry up, leading farmers to exploit groundwater to irrigate sorghum, soybean, cotton, wheat and corn, and maintain large herds of cattle and pigs .

Every summer, the central plains of the United States dry up, leading farmers to exploit groundwater to irrigate sorghum, soybean, cotton, wheat and corn, and maintain large herds of cattle and pigs .

These innovations, along with the ongoing experiments to determine the most profitable crops to grow and the animals to raise, profoundly altered the global food systems and the lives and livelihoods of the farmers in the plains.

Today some advocates support a similar solution for farmers' water needs: the so-called Greater Kansas Canal, which would pump large quantities of water from the Missouri River in the east more than 360 kilometers west of the driest counties of Kansas.

However, this project could cost up to $ 20 billion to build and will require annual energy disbursements of $ 500 million. It is unlikely to be built, and it would be a Band-aid solution if it were.

The end of irrigation?

In my opinion, farmers in the plains can not afford to continue to push land and water resources beyond their limits, especially in light of the cumulative impact of climate change in the Central Plains.

For example, a recent study postulates that as droughts bake the land, the lack of moisture in the soil increases temperatures. And as the air heats up, it dries the soil even more.

This vicious circle will accelerate the rate of exhaustion. And once the Ogallala is emptied, it could take 6,000 years to recharge naturally.

A current evaluation of the US Drought Monitor. UU It shows large swaths of the southern plains that experience a drought ranging from "serious" to "exceptional." Crop circles in Kansas are shown

A current evaluation of the US Drought Monitor. UU It shows large swaths of the southern plains that experience a drought ranging from "serious" to "exceptional." Crop circles in Kansas are shown

WHY ARE CLIMATE MODELS DIFFICULT TO PREDICT?

The main problem with climate models is uncertainty.

In particular, something called the measure of "equilibrium climate sensitivity" has been causing scientists headaches.

This is a very influential measure that describes how much the planet will heat up if the carbon dioxide doubles and the Earth's climate adjusts to the new state of the atmosphere.

Studies have found a wide range of possibilities for this key measure, somewhere between 1.5 and 4.5 ° C, with 3 ° C.

Most scientists try to restrict ECS by observing historical warming events.

During the last 25 years, the UN Intergovernmental Panel on Climate Change (IPCC), the highest authority on climate science, has established itself in a "probable" range of 1.5 ° C to 4.5 ° C (2.7 ° F to 8.1 ° C). ° F).

Heating to less than 1 ° C is "extremely unlikely" and more than 6 ° C is considered "very unlikely", the panel concluded.

However, some scientists dispute this figure.

In the words of Brent Rogers, director of District 4 Groundwater Management in Kansas, there are too many straws in a cup that is too small.

Some farmers with a vision of the future are responding to these interwoven challenges. Although they pursue irrigation efficiency, many are changing from intense water crops such as cotton to wheat.

Others, especially in West Texas, are returning to rainfed agriculture without irrigation, a recognition of the great limitations of irrigation dependence.

Farmers who are depleting other aquifers in Latin America, Eastern Europe, the Middle East and Asia may face similar options.

Whether these initiatives are generalized or can sustain agriculture in the central plains, it is an open question. But, instead, farmers and ranchers must drain the Ogallala aquifer in search of quick profits, the region may never recover.

The conversation

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