Why the Loss of Grasslands Is a Troubling Trend for Agriculture, in 11 Maps and Graphs

, Kendall Science Fellow | August 10, 2016, 9:54 am EST
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In the theme of troubling trends for climate adaptation, and as one of UCS’s agricultural experts, I want to talk about a biome you probably remember from middle school science—the grasslands—and why it is so important to protect them.

A grassland environment in the Nebraska Sand Hills. Photo: Aaron Price

A grassland environment in the Nebraska Sand Hills. Photo: Aaron Price

Grasslands might seem self-explanatory, but are much more exciting than the straightforward name implies. Quite simply, they are open areas of grass (and occasional trees) located in the mid-latitude regions across the globe. They’re found in areas with more rain than the desert and less than the tropics, and as a result, are ideal places for humans to inhabit.

We use grasslands for many purposes—from raising livestock to providing recreational space to protecting wildlife. The US Forest Service outlines a host of grasslands benefits but the ones I want to focus on are related to climate.

Grasslands provide protection against floods and droughts, have the potential to store carbon in the soil, and in turn, help increase overall climate stability. Compared to crops that need to be planted every year (annual crops such as corn and wheat), grasslands do not require chemical and water inputs.

In short, using grasslands for things like wildlife habitat or grazing animals (like cattle), which eat the grass and convert it to human food, is often less resource intensive than agricultural systems featuring annual crops, which might not be as well suited a use for such environments.

You might be thinking: Shouldn’t we be protecting grasslands if they provide so many climate benefits? The obvious answer is yes, but let me use a few maps and graphs to illustrate what is really happening.

The problem is that grasslands are disappearing

Our nation’s remaining grasslands are largely concentrated in the Great Plains and Intermontane West regions, and are actually disappearing at an alarming rate.

The Washington Post recently published a comprehensive piece on this trend, noting that the confluence of biofuel expansion, improved crop genetics, a longer growing season (due to climate change), as well as the oil boom in North Dakota, contributed to a precipitous decline of grasslands.

Grassland regions of North America. Source: Wikimedia Commons

Map 1. Grassland regions of North America. Source: Wikimedia Commons

As an agricultural scientist concerned with climate impacts, the Post coverage reminded me that scientists from South Dakota State University reported in 2013 that the rate of grassland loss (because of conversion to annual crops such as corn and soybeans) from 2006-2011 was comparable to that of tropical deforestation in Indonesia, Malaysia, and Brazil. It’s also becoming increasingly clear that the loss of grasslands has grave impacts for biodiversity as well.

Tyler Lark and colleagues from the University of Wisconsin tracked land and planting patterns dating back to the 1970s across the lower 48 states, using U.S. Department of Agriculture data. They found that during the period of 2008-2012, large swaths of new ground were “cultivated” or plowed and planted to annual crops for the first time. Most of this land was in the center of the United States—the Great Plains states and western stretches of the Corn Belt. They also calculated that the majority of newly cultivated cropland was from—you guessed it—grasslands. In fact, this extends the pattern of cropland establishment in the U.S., since most of today’s Corn Belt replaced grasslands and prairies.

 

Lark et al fig 3

Chart 3. Source: Tyler J Lark et al 2015

What crops replaced the grasslands? The next map illustrates that there are several crops that took their place, including cotton in western Texas, wheat in the southern Great Plains, and corn and soybean in the northern Great Plains.

This is the opposite of what climate adaptation ought to look like

This is an alarming trend because we need grasslands for climate adaptation (buffering floods and droughts) as well as for carbon storage and mitigation. It is also alarming because the crops that are replacing grasslands require more water.

These three US Department of Agriculture maps, which trace irrigated crops, line up oh-so well with those that are replacing grasslands. So in essence, we’re trading grasslands that do not require extra water for crops that need irrigation to survive, a counter-intuitive move, particularly in areas where irrigation and drinking water supplies are dwindling.

WHEAT

COTTON

Source: USDA 2012 Census of Agriculture

Maps 5, 6, 7. Source: USDA 2012 Census of Agriculture

It is further troubling because of what the past climate record and future predictions tell us. Across the lower 48 states, the areas where grasslands are being lost are the same ones where flood frequency has increased the most, and soil moisture is predicted to decline the most.CS_soil_moisture_v9

Map 8. Source: National Climate Assessment

Source: National Climate Assessment

Map 9. Source: National Climate Assessment

Is current policy helping or hurting grasslands protection?

USDA spends billions of dollars every year on conservation programs that are meant to protect areas such as grasslands. Unfortunately, funding for such programs has fallen flat over the last many number of years. And because of many confounding factors—including a bubble in commodity prices due to the ethanol boom—grasslands protected by USDA’s Conservation Reserve Program have transitioned out of the program.

Source: USDA

Map 10. Source: USDA

Source: USDA

Chart 11. Source: USDA

One policy initiative intended to help protect grasslands is the “Sodsaver Provision,” an addition to the 2014 Farm Bill. It was meant to limit crop insurance subsidies available to producers who planted crops on previously uncultivated land (or native sod) in specific Upper Midwest and Plains states, where wetlands and grasslands are abundant (the region highlighted in red in Map 2).

However, as our colleagues at the National Sustainable Agriculture Coalition have noted, there are many shortcomings in the rule as currently written and administered. As its currently being interpreted by USDA, it would inadequately collect and report information on newly plowed lands and still includes a provision that would allow insurance to kick in after four years if newly plowed lands were first planted to non-insured crops. Both of those issues almost defeat the purpose of the provision.

What about broader agricultural adaptation initiatives?

It’s worth mentioning a few promising climate change adaptation policies on the horizon. Earlier this year, USDA released its “Building Blocks for Climate Smart Agriculture & Forestry” framework, which includes grasslands protection principles such as conservation of sensitive lands and grazing lands. California Congressman Jared Huffman introduced the Healthy Soils and Rangelands Solution Act, which would establish a competitive grant program for activities that store carbon in the soil, including management of grazing lands. Further, California’s Department of Food and Agriculture established the Healthy Soils Initiative to help producers achieve soil sustainability and climate change resilience through financing opportunities and further research.

There are many other programs funded by the Farm Bill that seek to optimize agricultural land management—including grasslands—for climate benefit. Unfortunately they are woefully under-funded. The National Sustainable Agriculture Coalition outlined a number existing Farm Bill programs that seek to improve soil health, increase carbon stored by soil and help strengthen climate resilience. All could benefit from increased funding. The Congressional Research Service reports that these programs often have demand from farmers that far exceeds the monies that Congress makes available. For example, popular programs such as the Environmental Quality Incentives Program and the Conservation Stewardship Program fund approximately half of the applications they receive. Crop insurance, on the other hand, is available to 100% of eligible producers who sign up and works more like a blank check without any payment caps.

So, although policies have tried to help protect grasslands and strengthen agricultural resilience to climate change, there is a lot more work to be done. With increasing climate impacts, time is of the essence.

Could we be creating another Dust Bowl?

A bit of history to close: the infamous, expensive, and painfully detrimental Dust Bowl of the 1930s resulted from a confluence of climate and economic drivers. (If you want to better understand the human impact, I recommend Timothy Egan’s excellent book The Worst Hard Time or Ken Burns’ documentary mini-series The Dust Bowl). Given a similar intersection of climate and economic factors at present, scientists now speculate that we could be headed for another Dust Bowl.

We now know clearly how to avoid such a scenario by focusing on protecting sensitive and important regions like grasslands. This is ever more important given the climate change trends already surrounding us and affecting our food and agriculture system. Policies designed to protect sensitive ecosystems such as grasslands ought to be prioritized in a responsible, comprehensive manner. As outlined in the Toward Climate Resilience report, such policies should incorporate a systems approach and reflect a long-term vision, one that protects climate buffering landscapes.

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  • L.A. CHEFs Column

    Thank you for this excellent article! Just a couple things to add on methane and water.

    Regarding methane, people also forget that once soil is tilled, left expose and or treated with nitrogen inputs, the soil microbial activity and especially the methanotrophic activity is greatly reduced. In these two studies from India-

    -Singh, Jay Shankar 2011. Methanotrophs: the potential biological sink to mitigate the global methane load. Scientific correspondence Current Science, VOL. 100, NO. 1, 10 January 2011 29
    -Singh, Jay Shankar and Shashank Tiwari and D P Singh 2015.Methanotrophs and CH4 sink: Effect of human activity and ecological perturbations. Climate Change and Environmental Sustainability (April 2015) 3(1): 35-50

    it is noted that maintained grasslands ecosystems function as methane sinks that can bank as much as 15% of the earth’s methane. However when soil is tilled, left exposed (due to heat) or treated with nitrogen inputs, the soil microbes that oxidize atmospheric methane (methanotrophs) are destroyed so these grasslands no longer function in this methane oxidizing capacity. So intact grassland ecosystems with healthy soils have the capacity to bank BOTH carbon and methane, thus when functioning properly any enteric methane generated via wild or domesticated ruminants is offset. Offset in some circumstances so much so that grassland ecosystems WITH ruminants are GHG sinks NOT emitters. Furthermore grazing per this study- Grazing affects methanotroph activity and diversity in an alpine meadow soil: https://www.researchgate.net/publication/237823417_Grazing_affects_methanotroph_activity_and_diversity_in_an_alpine_meadow_soil – also seems to increase methanotrophic activity.

    When industrial critiques are made of extensive systems to promote intensive ones, these critiques do not account for any mitigation of GHG’s from either carbon sequestration or methane oxidation.

    As for water, your article points out the absurdity of using global water footprint averages that don’t take into account appropriate land use. People like to banter around statements like it takes 2000 gallons to make a pound of beef without any understanding of what those numbers mean. 98% of water represented in a water footprint number for beef is amount of water to grow the feed, forage or grasses that a head of cattle eats over its lifetime (rather than water directly consumed- which is approx. 1% of the water footprint number). For cattle raised in grassland ecosystems 98% of that 98% is “green” water which is primarily rain fall. (Grain finished cattle the number is around 92%). The grasses don’t need to be irrigated so little to no blue water is required. As you point out in your article, when crops other than grasses are grown, blue water is often required. That blue water is ground water pumped from aquifers and or diverted from river/lakes. “Blue” water is what’s critical NOT green water.

    So often annual crops with small water footprint numbers have the most adverse environmental impact because they require the most blue water use. This is especially true in California where most of the United States produce is grown. Thus arguments for crops instead of ruminants are often ironic when assessing adverse water use impacts. So the real issue with water footprint numbers is appropriate land. That is what’s the most effective use of the land where “green” water or rain falls. Plus on a final note, with healthy soils that aren’t compacted in intact grassland ecosystems, the infiltration rates are much higher, so rain that does fall is more effectively utilized.

  • Tim Roberts

    The first map has “shurbland” instead of shrubland.