Achieving Peak Pasture

In the last 20 years, something truly remarkable has occurred, something that few predicted: the amount of land devoted to grazing animals to produce meat and milk has begun to shrink across the world.

Pasture expansion has been one of the most significant challenges the world has faced for conserving biodiversity and mitigating climate change. It has been a major driver of deforestation in the Amazon and degradation of many of the world’s natural grasslands, releasing vast amounts of carbon stored in soils and plants into the atmosphere.^{Poore, J. & Nemecek, T. Reducing food’s environmental impacts through producers and consumers. Science (80-. ). 360, 987–992 (2018).}

And the problem has been getting worse for centuries. Since the 1700s, an area nearly the size of North America has been converted to pasture.^{Ramankutty, N. et al. Trends in global agricultural land use: Implications for environmental health and food security. Annu. Rev. Plant Biol. 69, 789–815 (2018).}

Today, grazing livestock is by far the single largest human land use on the planet.^{Blomqvist, L., Nordhaus, T. & Shellenberger, M. Nature unbound: decoupling for conservation. (The Breakthrough Institute, 2015).} Globally, we use approximately twice as much land for grazing animals as we do for growing crops.^{Ramankutty, N. et al. Trends in global agricultural land use: Implications for environmental health and food security. Annu. Rev. Plant Biol. 69, 789–815 (2018).} And when the land used to produce livestock feed is taken into account, ruminants require nearly half of the Earth’s agricultural land area.^{Mottet, A. et al. Livestock: On our plates or eating at our table? A new analysis of the feed/food debate. Glob. Food Sec. 14, 1–8 (2017).}

Pasture’s staggering environmental impacts are precisely why pasture’s recent decline is not only unprecedented but also remarkable. If global pasture continues shrinking, it could be a boon for humans and the environment.

But the continued contraction of global pasture is far from guaranteed.

Understanding the drivers of ‘peak pasture’ is the key to further shrinking the footprint of meat and milk production, even while meeting rising demand in the next several decades, as economies grow rapidly in low-income countries.

A Global Turnaround

The Food and Agriculture Organization of the United Nations (FAO) has reported that global pasture area began to decline around the turn of the century (Figure 1).^{Poore, J. Call for conservation: Abandoned pasture. Science (80-. ). 351, 132 (2016).} Between 2000 and 2016, pasture area fell an estimated 74 million hectares (Mha), roughly the size of Chile.

Figure 1: Global Pasture Area Has Been Declining Since 2000

Despite some legitimate concerns about the accuracy of the FAO data,^{Searchinger, T. et al. Creating a sustainable food future: Interim findings. (World Resources Institute, 2013).} peak pasture is not a data artifact. The contraction of global pasture is corroborated by long term models and remote-sensing methods.^{Klein Goldewijk, K., Beusen, A., Doelman, J. & Stehfest, E. Anthropogenic land use estimates for the Holocene – HYDE 3.2. Earth Syst. Sci. Data 9, 927–953 (2017)., Ramankutty, N. & Foley, J. A. Estimating historical changes in global land cover: Croplands from 1700 to 1992. Global Biogeochem. Cycles 13, 997–1027 (1999).}

Nor is the pasture contraction outweighed by cropland expansion for animal feed. While cropland for cattle feed has increased by around 25 Mha, the total agricultural land devoted to producing meat and milk from ruminants has shrunk by approximately 50 Mha since 2000.^{Mottet, A. et al. Livestock: On our plates or eating at our table? A new analysis of the feed/food debate. Glob. Food Sec. 14, 1–8 (2017)., Alexander, P. et al. Drivers for global agricultural land use change: The nexus of diet, population, yield and bioenergy. Glob. Environ. Chang. 35, 138–147 (2015).}

Peak Pasture is a Widespread Trend

Arguably the most surprising fact of pasture’s decline is that, rather than reflecting anomalous trends in select countries, it is a widespread global phenomenon. Between 2000 and 2016, pasture area was flat or declining in two-thirds of countries and in nearly all major world regions.

In some countries, pasture area has actually been falling steadily for decades. Such countries are mostly high-income ones, which have seen an average contraction in pasture area of about 10% since 1961. Both Europe and North America have less pasture now than they did in 1961, as does Australia, which has experienced the single largest decline worldwide (Figure 2).

More recently, pasture area has also begun to contract or plateau in countries that saw large expansions in the 20th century — in particular, rapidly developing upper-middle-income countries with large populations and vast amounts of available land to clear. For example, Brazil and China have seen their pasture area level off after growing rapidly in previous decades.

Figure 2: Pasture Area Is Declining or Flat in Nearly All Regions Since 1961

A Potential Boon for the Environment

The shrinking footprint of global pastureland has the potential to mitigate climate change and safeguard biodiversity. Reforestation of former pasture area (as well as avoiding deforestation in the first place) increases soil and aboveground carbon stocks. Although carbon sequestration rates are highly variable and depend on a wide range of local agroecological conditions, recent assessments have estimated that reforestation in temperate and tropical climates typically increases sequestration by 2.8 and 4.7 tons of carbon per hectare per year, respectively. These rates are several-fold higher than typical rates associated with “natural climate solutions” for improving pasture, such as an estimated rate of around 0.6 tons per hectare per year by planting legumes in pasture.^{Griscom, B. W. et al. Natural climate solutions. Proc. Natl. Acad. Sci. 114, 11645–11650 (2017).}

Indeed, although some former pastureland has been converted to cropland or urban uses, there are indications that substantial land has been reforested or otherwise restored in environmentally beneficial ways. For example, according to FAO records, between 1990 and 2015, the area of forest in Europe (a region that has experienced some of the most significant declines in pasture) has increased by about 12 Mha, nearly 8%.

Even restoration of marginal and arid lands has benefited biodiversity. Although limited levels of grazing can be compatible with wildlife in some landscapes, reductions in pasture area have resulted in important conservation successes. In Iran, for example — where pasture area has contracted considerably — the Asiatic cheetah, one of the world’s most elusive and endangered big cats, is showing signs it could be coming back from the brink of extinction as conflict with nomadic herders eases.^{Poore, J. Back to the wild. New Sci. 235, 26–29 (2017).}

However, the environmental benefits of pasture contraction vary widely by biome, region, and climatic zone. While contraction appears to have led to a net carbon sequestration, it could still have a negative impact on wildlife and biodiversity if it results from a large contraction in arid regions and a comparatively smaller expansion in tropical areas. Unfortunately, this may be what has been occurring.^{Ontl, T. A. & Schulte, L. A. Soil carbon storage. Nat. Educ. Knowl. 3, (2012).}This scenario underscores the importance of accelerating the factors driving the reduction in pasture area — particularly in tropical regions.

The Livestock Revolution

What is responsible for pasture’s global decline? The answer is remarkably simple: increasing livestock and pasture productivity. Not only has pasture been declining, but this decline has been occurring against a backdrop of continued increases in production. Between 2000 and 2013, aggregate production of meat and milk from cattle, buffalo, goats, and sheep rose by 13% and 32%, respectively (Figure 3). In other words, it appears that production is becoming decoupled from pastureland.

Figure 3: Production Continues Increasing

The upward march of productivity can be considered a ‘livestock revolution,’ analogous to the dramatic increases in crop productivity that has been dubbed the Green Revolution. Facing rising demand for meat and milk, livestock producers have been shifting from extensive production systems in which grazing occurs on unmanaged natural grasslands to more-intensive production systems that manage pasture to increase grass production and incorporate energy-rich feeds such as cereal crops.^{Delgado, C. L., Rosegrant, M., Steinfeld, H., Ehui, S. & Courbois, C. Livestock to 2020: The next food revolution. Outlook on Agriculture 30, (2001).}The cattle industry, the most dominant user of pasture globally, saw meat and milk yields — the amount each animal produces — grow 29% & 22% since 1961.^{Omitting production data for countries that were part of the former Soviet Union.} Feed efficiency, which is the amount an animal produces per unit of grass, cereal, and other feed consumed, has also steadily increased.

Measures of productivity are generally highest, and have increased the most, in higher-income countries (Figure 4 and 5). For instance, beef yields in Africa, Brazil, and China are all substantially lower than in higher-income Australia — 40%, 12%, and 46% less, respectively. Similarly, feed efficiency in the higher-income regions of Western Europe, North America, and Oceania has historically been particularly high, contributing to large-scale pasture contraction.

Figure 4: Animal Yields Have Increased Most in High-Income Countries

Figure 5: Feed Efficiency Is Highest in High-Income Regions

Stocking rates — the number of animals on a given amount of land — have also seemingly increased, though only with long term productivity benefits in some cases. Increased stocking rates can raise the amount of meat or milk produced per hectare in the short term, but high rates are not necessarily sustainable. They can lead to overgrazing, which damages the soil, reduces forage production, and therefore diminishes overall productivity.^{Garnett, T. et al. Grazed and confused? Ruminating on cattle, grazing systems, methane, nitrous oxide, the soil carbon sequestration question - and what it all means for greenhouse gas emissions. (Food Climate Research Network, 2017).}Overgrazing is particularly acute in sub-Saharan Africa, where researchers estimate that approximately 48% of grassland area used for agriculture is degraded.^{Otte, J., Pica-Ciamarra, U. & Morzaria, S. A comparative overview of the livestock-environment interactions in Asia and Sub-saharan Africa. Front. Vet. Sci. 6, 37 (2019).}

Putting aside ambiguous productivity gains from higher stocking rates, the improvements in animal yields, feed efficiency, and other productivity metrics have spared vast amounts of forest and other land from being converted to grazing. If the efficiency of the global cattle system were the same in 2016 as it was in 1961, more than 4 billion additional hectares of pasture — an area of land larger than China, the US, and Canada combined — would be required to support the same level of production.^{Assuming, for simplicity of calculation, that all pasture was devoted to cattle production.}

An Uncertain Future

Will larger populations, more meat-heavy diets, or even a slowdown in productivity cause the recent peak in pasture to reverse? It’s possible. And it may well occur, most especially if productivity in low-income regions fails to keep up with demand for meat and milk.

At some point in their history, most regions have gone through an expansionary phase, when demand grew faster than productivity. Some low-income regions, including sub-Saharan Africa, now seem poised to enter the expansionary phase. Although economic development will probably drive productivity improvements as demand increases, a period of considerable pasture expansion is likely. One global land-use model,^{The MESSAGE- GLOBIOM model, under the Shared Socioeconomic Pathway 2 (SSP2) baseline, projecting change from 2010-2050.} for instance, projects pasture area to expand by 73 Mha by 2050 in the Middle East and Africa, offsetting all the global reductions observed since 2000.^{Riahi, K. et al. The shared socioeconomic pathways and their energy, land use, and greenhouse gas emissions implications: An overview. Glob. Environ. Chang. 42, 153–168 (2017).}

To a great extent, then, the future of global pasture — whether it continues contracting or expands once again — hinges on whether, and how quickly, the livestock revolution comes to emerging economies.

Spreading the Livestock Revolution

As it has elsewhere, increased productivity in low-income countries will require greater input use, more-intensive management, and in many cases larger-scale operations — hereafter referred to with the shorthand “intensification.”

The good news is that intensification has enormous potential to meet rising demand while preventing pasture expansion and even reducing it further. While the FAO projects that demand for ruminant meat and milk will rise dramatically (approximately 50% between 2010 and 2050), studies suggest that intensification could meet this demand by doubling or even tripling productivity on existing lands.^{Alexandratos, N. & Bruinsma, J. World Agriculture Towards 2030/2050: The 2012 Revision. (2012)., Sheehan, J. Estimating the potential intensification of global grazing systems based on climate adjusted yield gap analysis. AGU Fall Meet. Abstr. 13, GC13D-1229 (2016).}For instance, a 2014 study found that beef production per hectare in Brazil was only at one-third of its potential. Raising productivity to 70% of its potential would liberate from production 36 million hectares, about one-fifth of Brazil’s current pasture area, allowing this land to be returned to nature.^{Strassburg, B. B. N. et al. When enough should be enough: Improving the use of current agricultural lands could meet production demands and spare natural habitats in Brazil. Glob. Environ. Chang. 28, 84–97 (2014).}

This land savings can pay huge carbon dividends. Ruminants in parts of East Africa produce 50–100 times more GHG emissions per unit of meat than in much of Europe.^{Deblitz, C. & Dhuyvetter, K. Cost of production and competitiveness of beef production in Canada, the US and the EU. Agri Benchmark Beef and Sheep Network (2013)}Cattle are commonly fed only crop byproducts, which provide poor nutrition, as a result of which they require about one order of magnitude more feed per kilogram than beef produced than in Europe or North America, and thus substantially more land.^{Deblitz, C. & Dhuyvetter, K. Cost of production and competitiveness of beef production in Canada, the US and the EU. Agri Benchmark Beef and Sheep Network (2013).}

Moreover, substantial productivity improvements are not just theoretically possible, but also practically attainable. A study of mixed crop-livestock production systems in East and West Africa found that meat and milk production on the best-performing sites in a region was nearly 170% higher than on lower-performing farms nearby.^{Henderson, B. et al. Closing system-wide yield gaps to increase food production and mitigate GHGs among mixed crop-livestock smallholders in Sub-Saharan Africa. Agric. Syst. 143, 106–113 (2016).}

Of course, while increasing productivity is an important objective for reducing land-use change, it is one of many possible social, economic, cultural, and environmental goals, and intensification efforts should respect the integral role of livestock in the lives, livelihoods, and cultures of local communities.

Although there is no one-size-fits-all pathway, there are three general ways to increase livestock productivity: using more efficient livestock feeds, adopting and developing higher yielding breeds, and improving animal health.

Spreading knowledge is key to driving the adoption of new practices in each of these areas. Lack of access to technical knowledge limits producers’ adoption of productivity-enhancing practices and inputs^{Godde, C. M., Garnett, T., Thornton, P. K., Ash, A. J. & Herrero, M. Grazing systems expansion and intensification: Drivers, dynamics, and trade-offs. Glob. Food Sec. 16, 93–105 (2018).} and programs are needed that transfer knowledge to farmers and ranchers, such as public agricultural extension programs, which have been shown to raise productivity.^{Gil, J. D. B., Garrett, R. & Berger, T. Determinants of crop-livestock integration in Brazil: Evidence from the household and regional levels. Land use policy 59, 557–568 (2016).}

Technical know-how is not enough, however. Spreading the livestock revolution to developing regions will entail helping producers overcome barriers to the widespread adoption of new practices. Livestock producers face upfront costs and limited incentives to intensify when land is inexpensive.^{Garrett, R. D. et al. Intensification in agriculture-forest frontiers: Land use responses to development and conservation policies in Brazil. Glob. Environ. Chang. 53, 233–243 (2018).}They also face financial risks, upfront costs, and credit constraints when adopting new practices.^{Herrero, M. et al. Livestock and the environment: What have we learned in the past decade? Annu. Rev. Environ. Resour. 40, 177–202 (2015).}

What are needed, then, are targeted efforts by the public sector to enable and incentivize intensification. Crucially, this must include efforts to ensure that producers have access to productivity-raising inputs such as better feeds, which are typically expensive.^{Deblitz, C. & Dhuyvetter, K. Cost of production and competitiveness of beef production in Canada, the US and the EU. Agri Benchmark Beef and Sheep Network (2013).}

Better access to high-quality inputs also requires physical infrastructure — such as roads, ports, and processing.^{Godde, C. M., Garnett, T., Thornton, P. K., Ash, A. J. & Herrero, M. Grazing systems expansion and intensification: Drivers, dynamics, and trade-offs. Glob. Food Sec. 16, 93–105 (2018).}Better road access in rural Kenya, for example, raised market participation, fertilizer use, and agricultural yields.^{Kiprono, P. & Matsumoto, T. Roads and farming: the effect of infrastructure improvement on agricultural intensification in South-Western Kenya. Agrekon 57, 198–220 (2018).}At the same time, road-building efforts must also aim to minimize these corridors’ harm to habitats and ecosystem health. The majority of planned road expansion is in developing countries, particularly in Africa and Latin America, and is likely to lead to severe habitat fragmentation and wildlife loss in biodiversity hotspots.^{Laurance, W. F., Campbell, M. J., Alamgir, M. & Mahmoud, M. I. Road expansion and the fate of Africa’s tropical forests. Front. Ecol. Evol. 5, (2017).}

But measures to drive systemic intensification need to be paired with land use policy to minimize the risk of agricultural land expanding due to lower input costs, referred to as the rebound effect.^{Garrett, R. D. et al. Intensification in agriculture-forest frontiers: Land use responses to development and conservation policies in Brazil. Glob. Environ. Chang. 53, 233–243 (2018).,Angelsen, A. Policies for reduced deforestation and their impact on agricultural production. Proc. Natl. Acad. Sci. 107, 19639–19644 (2010).}Although intensification does indeed have reliable land-sparing benefits globally, rebound effects can negate any potential benefit at smaller scales. Prudent land-use policies can counteract rebound by making land conversion expensive, thereby making intensification a more appealing alternative.^{Deblitz, C. & Dhuyvetter, K. Cost of production and competitiveness of beef production in Canada, the US and the EU. Agri Benchmark Beef and Sheep Network (2013).,Harfuch, L., Palauro, G. & Zambianco, W. Economic analysis of investment for the cattle ranching expansion. (Brazil: Input: Iniciativa Para o Uso da Terra, 2016).}

To meet rising demand for beef and milk sustainably, low income countries need a livestock revolution. The fate of global pasture and its environmental impacts depend on it. Much is at stake, but the solution is plain and well within reach.