The Great Plains facing climate variability

Mother Nature has provided increasingly erratic rainfall for the Great Plains over the past decade, affecting grasslands, forage systems and cattle production in the region – and scientists expect this trend to continue. intensifies.

Cow / calf operations in the Great Plains are likely to be affected by the increased variability in rainfall which supports forage production for 50% of the country’s cow herd. (Photo by Texas A&M AgriLife)

Texas A&M AgriLife Research scientists and collaborators explored the rural economic impacts of climate variability and identified potential future outcomes for beef cattle production in a research article, “Future climate variability will challenge range beef production in the Great Plains», Recently published in the journal Golf courses.

David Briske, Ph.D., AgriLife Research pathway ecologist in the Department of Ecology and Conservation Biology in the College of Agriculture and Life Sciences To Texas A&M University, Bryan-College Station, was the principal author. The co-authors were John Ritten, Ph.D., University of Wyoming; Amber Campbell, Ph.D., Kansas State University; Toni Klemm, Ph.D., postdoctoral research associate at AgriLife Research; and Audrey King, Ph.D., Oklahoma State University.

The researchers concluded that the key to sustainable beef cattle production in the Great Plains is to prepare for climate change in the region rather than react to climate change and hope their article can guide discussions and encourage future actions. .

Growing climate variability in the Great Plains

Climate change is often seen as a long-term gradual change in weather conditions, such as precipitation and temperature. But future weather conditions in the Great Plains may be characterized by increased variability in precipitation, or increased cases of wet or dry years and less “normal years,” Briske said.

The increased variability in rainfall will have far-reaching consequences for the region, but agriculture and rural economies could be the most vulnerable, Briske said. Cattle farms, which depend on grassland fodder for a large portion of their animals’ feed intake, could be particularly vulnerable to increased variability in rainfall.

The Great Plains contain the largest expanses of grassland remaining and 50% of the country’s beef cows, over 16 million head, representing the main components of the region’s overall agricultural economy. Beef cattle production contributed $ 43 billion to state and local economies on the Great Plains in 2017.

In Texas alone, beef cattle and calves generate the largest total contribution among the state’s agricultural products – $ 8.566 billion in cash receipts alone, according to a 2020 study. Texas A&M Agricultural Extension Service economic impact study focused on food and fiber production.

Highest precipitation variability in the southern Great Plains

A key impact of the increased variability in rainfall is on grassland forage production which supports cow / calf production throughout the region. Researchers are examining past, present and future climate projections and the consequences that increased variability could have on sustainable beef production.

“The focus has been on the change in total annual precipitation, but what is most striking is the increase in interannual variability – the phenomenon where we go from a few years drier than normal to flooding. , then to a drought. and so on, ”Briske said.

It’s important to recognize that it’s different from just dealing with drought, he said.

“I don’t mean to be alarmist, but we want to present this message in the context of agricultural production so that the industry can prepare to offset the impact of greater climate variability on individual producers, grassland conservation and rural economies. “

Research indicates that the number of forage shortage years for the southern plains, which include Texas, Kansas, and Oklahoma, has dropped from two years per decade to three years, four months per decade, and has remained at two years. for the northern plains. The number of years of abundant forage increased from two to five years per decade on the northern plains and from two to three and a half years on the southern plains by the turn of the century.

This indicates that beef producers will experience a greater number of years where annual feed production can vary by 50%. This increases the already difficult task of balancing forage production with demand for livestock. Briske said this increasing weather variability could present sustainability issues for beef cattle operations and regions that have been successful in the past.

This variability will negatively impact the economic viability of beef cattle production and the sustainability of grasslands by creating overgrazed conditions, he said. But effective adaptations that could help cattle producers minimize the impacts require more consideration.

Further slaughter and liquidation of cattle herds during drought years and then restocking in normal or wet years creates the greatest economic hardship for beef producers, Briske said. The researchers highlighted the need for adaptations that will minimize overgrazing of prairies and the need to undergo costly destocking-restocking cycles as being the most critical.

But current climate adaptations, including appropriate stocking rates for conservative grazing, grass reserves, and water development, may be insufficient to compensate for the negative economic impacts of future rainfall variability, a t -he declares. Research suggests that beef cattle production may gradually shift from southern plains states like Texas to the central and northern plains.

For example, Briske said, the Dakotas and Nebraska gained 403,000 cows between 2010 and 2020, while Texas lost 570,000.

It’s earlier now

The researchers stressed the need to act as early as possible and integrate ideas from several sectors of society outside of agriculture to support sustainable beef production in the grasslands.

The action begins by shifting the stakeholder perspective towards a proactive rather than reactive response to severe weather events like drought and flooding, Briske said. Preparedness will require anticipating threats to the sustainability of beef cattle production in the Great Plains at both macro and micro scale.

Southern Plains beef producers were surveyed as part of this research. The majority indicated that they were aware, but uncertain, of future climate impacts, which suggested they would benefit from assistance in developing and implementing appropriate adaptations, Briske said.

Suggesting stakeholders to act now rather than wait for the crisis, he said initial conversations about the potential impacts of increasing climate variability could be led by trade groups and the beef industry. which have political weight at all levels of government. Beef and ranching industry coalitions could make lawmakers aware that changes in state and federal policies regarding sustainability in future climates should be a top priority now and in the future. .

“The key is to start planning and investing in coping strategies during the good years,” he said. “The region is likely to experience an increasing number of wet and dry years in the future. The question is whether industry and rural areas will be prepared.

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To improve climate models, international team turns to archaeological data – ScienceDaily

Climate modeling is forward-looking, its general intention to hypothesize what our planet might look like at a later date. Because Earth’s vegetation influences climate, climate models frequently include reconstructions of vegetation and are often validated by comparisons with the past. Yet such models tend to be oversimplified, obscuring or omitting how people affected the land and its cover.

The absence of such data has led to LandCover6k, a project now in its sixth year that includes more than 200 archaeologists, historians, geographers, paleoecologists and climate modelers from around the world.

Led by archaeologists Kathleen Morrison of the University of Pennsylvania, Marco Madella of the Universitat Pompeu Fabra and Nicki Whitehouse of the University of Glasgow, with the data expertise of Penn landscape archaeologist Emily Hammer and others , LandCover6k’s goal is to aggregate archaeological and historical evidence of land use systems from four time frames – 12,000 years ago, 6,000 years ago, 4,000 years ago and around the year 1500 – in a single database that anyone can understand and use.

The project offers what researchers hope will become a tool to improve predictions about the planet’s future, and fill in the gaps in its past. “Understanding the human impact on Earth is not just about examining the vegetation of the past. It is also important to understand how humans used the land and, in particular, the relationship between human land use and vegetation, ”says Morrison.

Although current models of the Earth system suggest that human activity over the past 12,000 years has influenced regional and global climate, says Madella, “the models do not capture the diversity and intensity of human activities that have affected past land cover, nor capture carbon and water cycles. . “

Archeology provides important land use information that “helps reveal how humans affected past land cover on a global scale,” Whitehouse adds, “including crops and cultivated animals, how they were. cultivated and how much land was needed to feed the growing population. “

In a new PLOS ONE document, the team provides a detailed introduction to LandCover6k’s land use classification system and global database.

Create a common language, a system

Sharing such data first meant creating a common language that scientists from all disciplines could understand. It’s a bigger job than it looks, says Morrison. “Classification means putting limits on something. It’s very difficult, because archaeologists are often much more comfortable with storytelling.”

Partly because of a lack of common terminology, archaeologists did not attempt to aggregate and compare data on a global scale, which paleoecologists and project modelers had already done, adds. she. “We spent years consulting with colleagues around the world, discussing all the different types of land use, and developing a system of communication – the same language, the same terminology – that could be used anywhere. . “

Because these categories have historically had different meanings depending on location, context and period, some archaeologists were initially reluctant to commit to unique definitions for each. Hammer offers the concept of “agriculture” as an example. “The line between what is called ‘agriculture’ and what is considered small-scale food production by hunter-gatherers really varies across the world,” she says. So how could the terrain judge fairly when the actions of hunter-gatherers managing wild plant and animal resources have become “agricultural”?

Questions like these prompted the LandCover6k team to create a hierarchy within the classification system, with a top-level category capturing an idea in its broadest sense and several distinct subcategories descending from there. In the example of agriculture, the research team created a subgroup – low level food production – which could include the work of hunter-gatherers. The hope was to offer enough nuance for the archaeological community while still making the data accessible to climate modellers.

In addition to this flexible hierarchy and uniform terminology, the final classification has three other main characteristics. It is scale and source independent, which means it captures the myriad of ways something can be investigated. It “takes the perspective of the earth rather than people,” as the researchers write in PLOS ONE, and it uses a consistent 8×8 kilometer grid scale. “It’s big enough, archaeologically speaking,” says Hammer, “but we made it so that one person didn’t draw something very small and another person very tall.”

Concrete examples

To show how the classification works, the researchers offer the example of the Middle East 6,000 years ago. This region, the area represented by modern Iraq, Syria, Jordan, Kuwait, Saudi Arabia, Qatar, Bahrain, United Arab Emirates, Oman and Yemen, was home to some of the world’s earliest agriculture. Using the new classification and the new database, the project participants constructed a regional land use map, despite the availability of data which differs from place to place.

“Mesopotamia has been studied since the mid-19th century, so there is a lot of data and syntheses to draw on,” explains Hammer. “Arabia has not been studied as well. There are only a few data points, especially for this period, and due to climatic events, data is even scarcer than for other periods. We wanted to illustrate the approach you would take in a situation where you have a lot of data versus a location with just a little. ”The new Middle East land map is a proof of concept for the project, showing the contrast between the sedentary farms of Mesopotamia and the more sparse lands of Arabia.

Researchers don’t see information gaps, like those in Arabia, as problematic. Rather because the land use database also records the coverage and data quality, it can highlight areas that need more research. “Humans have transformed landscapes for thousands of years,” says Morrison. “But we can’t just say that. We have to demonstrate it.”

And that’s exactly what LandCover6k aims to do, by merging what archaeologists have gleaned about human land use at different times and places into a single database accessible to climate modellers – and to both. others. “This project is really about translating what we do,” says Hammer, “not only about standardizing terminology so that we can speak globally, but also about weaving in stories from the past. “


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