Yields and Land Use in Agriculture - Our World in Data [PDF]

If we view the map below in “chart” mode, we see how the allocation of land to agriculture has changed over time acr

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Idea Transcript


Yields and Land Use in Agriculture by Max Roser and Hannah Ritchie

I. Empirical View

I.1 Yields over the long-term Yields in the UK over the Long Run In the charts below, we see the average agricultural yield of particular crops over the long-term in the United Kingdom, from 1885 onwards. In the first chart, we have plotted cereal crops (wheat, barley and oats). Overall, we see that improvements in cereal yields from the 19th century into the first half of the 20th century were relatively slow-- by the 1940s, yields were typically in the range of 2-2.5 tonnes per hectare. Productivity gains between the 1950s and 1990s was rapid, growing 2-3 fold over this period. Since the turn of the millennium however, cereal yields in the UK have been relatively stagnant. In the second chart below we see UK yields in sugar beet and potatoes--these roots and tuber crops tend to have much higher yields than cereal crops by mass (although they are likely to have a much higher percentage of water weight). Similarly to cereal yields, productivity gains in sugar beet and potatoes have been most impressive over the latter half of the 20th century. Since 1960, yields in sugar beet have more than doubled, rising from 30 tonnes to more than than 80 tonnes per hectare. Potato yields have also almost doubled, increasing from just over 20 tonnes in 1960 to more than 40 tonnes per hectare in 2014.

Long-term cereal yields in the United Kingdom

Average agricultural yields in key crops in the United Kingdom from 1270-2014, measured in tonnes per hectare. Wheat

8 t/ha

Barley

6 t/ha

Oats

4 t/ha

2 t/ha

0 t/ha 1270

1400

1500

1600

1700

Source: OWID Long-term crop yields in UK - OWID (2017)

1800

1900

2014

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Long-term agricultural yields in the United Kingdom Average crop yields in the United Kingdom, measured in tonnes per hectare.

Sugar beet

80 tonnes/ha 70 tonnes/ha 60 tonnes/ha 50 tonnes/ha

Potatoes

40 tonnes/ha 30 tonnes/ha 20 tonnes/ha 10 tonnes/ha 0 tonnes/ha 1500

1600

1700

1800

Source: OWID Long-term crop yields in UK - OWID (2017)

1900

2014

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Wheat Yields across Europe from 1850

Long-term wheat yields in Europe

Wheat yields across selected countries in Europe, measured in tonnes per hectare. Belgium Netherlands Germany United Kingdom

8 tonnes/ha

Denmark France

6 tonnes/ha

Austria Norway Hungary Bulgaria Italy Romania

4 tonnes/ha

Greece Spain Russia

2 tonnes/ha

0 tonnes/ha 1850

1880

1900

1920

1940

Source: Long-term wheat yields - FAO (2017) & Bayliss-Smith (1984)

1960

1980

2000 2014

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

US average corn grain yields, 1866-2014 In the chart below we have plotted average corn (maize) yields in the United States from 1866-2014, based on data from the United States Department of Agriculture (USDA) and UN FAO. As seen below, average corn yields in the United States remained relatively flat throughout the 1800s until the 1930s. In the period since 1940, yields have increased more than five-fold. What caused this significant drive in yield improvements? There are a number of factors which are likely to have contributed to sustained yield gains: fertilizer application, irrigation, increased soil tillage, and improved farming practices. However, a key driver in the initial rise in yield is considered to be the adoption of improved corn varieties from plant breeding developments. The initial period of yield gains in the late 1930s-early 1940s coincides with the transition period of farmers from open-pollinated varieties to hybrids. This process of cross-breeding between open-pollinated varieties, combined with improved breed selection practices is thought to define the key turning point in US corn yields.1

Average corn yields in the United States, 1866-2014 Average corn (maize) yields in the United States, measured in tonnes per hectare.

10 tonnes

8 tonnes

6 tonnes

4 tonnes

2 tonnes

0 tonnes 1866

1880

1900

1920

1940

1960

1980

2000

2014

Source: United States Department of Agriculture (USDA) & UN Food and Agricultural Organization (FAO) OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Cereal yields in Chile, 1929-2014 In the chart below we see the average yields in key cereal crops (wheat, barley and oats) in Chile from 1929-2014. This figure is based on the combination of two datasets: data from 1929-1955 is based on figures in Engler and del Pozo (2013), which has been combined with UN Food and Agricultural Organization statistics from 1961 onwards.2 Also shown on this figure are specific technological, economic or policy events which are likely to have influenced the change in cereal yields over this period--these events have been highlighted by Engler and del Pozo (2013).

I.2 Yields since 1960 Our data on agricultural yields across crop types and by country are much more extensive from 1960 onwards. The UN Food and Agricultural Organization (FAO) publish yield estimates across a range of crop commodities by country over this period. The FAO report yield values as the national average for any given year; this is calculated by diving total crop output (in kilograms or tonnes) by the area of land used to grow a given crop (in hectares). There are likely to be certain regional and seasonal differences in yield within a given country, however, reported average yields still provide a useful indication of changes in productivity over time and geographical region. In the chart below we see the change in average yield for key crop commodities since 1961. In this visualisation, you can select/deselect which crops you wish to see and compare, and you can also view these trends across any country or region using the "change country" wheel.

Agricultural yields in key crops per hectare, 1961-2014, Western Europe Average yield outputs across key crop commodities by country, measured in tonnes per hectare.

Potatoes

40 tons

30 tons

20 tons

Maize Wheat Barley Rice, paddy Peas, dry Millet Soybeans Beans, dry

10 tons

0 tons 1961

1970

1980

1990

Source: UN Food and Agricultural Organization (FAO)

2000

2010 2014

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

I.3 Yields across the world in key crops Wheat yields

Wheat yields, 2014

Average wheat yields, measured in tonnes per hectare.

0 tonnes 4 tonnes 8 tonnes 12 tonnes No data 2 tonnes 6 tonnes 10 tonnes Source: Crop yields by country - FAO (2017)

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Rice yields

Rice yields, 2014

Average yields in paddy rice, measured in tonnes per hectare.

0 tonnes 4 tonnes 8 tonnes 12 tonnes No data 2 tonnes 6 tonnes 10 tonnes Source: Crop yields by country - FAO (2017)

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Soybean yields

Soybean yields, 2014

Average soybean yields, measured in tonnes per hectare.

0 tonnes 2 tonnes 4 tonnes No data 1 tonnes 3 tonnes Source: Crop yields by country - FAO (2017)

8 tonnes

6 tonnes

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Yields of other crops Global interactive maps of yields for the following crops are also available to explore: Maize (corn) Potatoes Sugar cane Rapeseed Cocoa beans Tomatoes

I.4 Agriculture land use over the long-run Total agricultural land use over the long-run The visualisation below shows total land used for agriculture (which is a combination of cropland and grazing land) over the long-term (since 10,000 BC), measured in hectares. In the following sections you can find disaggregated data for cropland and grazing land change over time.

Total agricultural area over the long-term

Total areal land use for agriculture, measured as the combination of land for arable farming (cropland) and grazing in hectares. Greenland Oceania

4 billion

Africa

India

3 billion

China Rest of Asia (excl. India & China)

2 billion

Middle East Brazil Latin America and the Caribbean (excl. Brazil) Canada United States

1 billion

Russia Europe (excl. Russia)

0 10000 BCE

8000 BCE

6000 BCE

4000 BCE

2000 BCE

Source: Land Use Data - HYDE (2017)

0

2016

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Cropland use over the long-run The visualisation below shows total cropland (which does not include land for grazing) over the long-term (since 10,000 BC), measured in hectares.

Cropland use over the long-term

Total cropland area, measured in hectares. Cropland refers to the area defined by the UN Food and Agricultural Organization (FAO) as 'arable land and permanent crops'. Greenland Oceania

1.4 billion ha

Africa

1.2 billion ha

India China

1 billion ha

Rest of Asia (excl. India & China)

800 million ha

Brazil Latin America and the Caribbean (excl. Brazil) Canada United States

600 million ha 400 million ha

Middle East Russia

200 million ha

Europe (excl. Russia)

0 ha 10000 BCE 8000 BCE

6000 BCE

4000 BCE

2000 BCE

Source: Land Use Data - HYDE (2017)

0

2016

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Grazing land use over the long-run The visualisation below shows total grazing land over the long-term (since 10,000 BC), measured in hectares.

Grazing land use over the long-term Total land used for grazing from 10,000 BC, measured in hectares.

Greenland Oceania

3 billion ha

2.5 billion ha

Africa

India

2 billion ha

China

1.5 billion ha

Rest of Asia (excl. India & China) Middle East

1 billion ha

Brazil Latin America and the Caribbean (excl. Brazil) Canada United States Russia Europe (excl. Russia)

500 million ha

0 ha 10000 BCE 8000 BCE

6000 BCE

4000 BCE

2000 BCE

Source: Land Use Data - HYDE (2017)

0

2016

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

I.5 Land use definitions and categories The following discussions on global land use (particularly in relation to agriculture) cover a number of definitions and combined categories. It is therefore useful to understand the differences between land use terminology; for example, the definition of "arable land" versus "agricultural land". To provide some clarity on the definitions used here (and the common terminology within the literature) we have visualised these land use categories and groupings in the chart below. Also shown are the definitions of each. The groupings and definitions shown below are based on the UN Food and Agricultural Organization (FAO) and should therefore be consistent with most international data sources.

I.6 Breakdown of global land area today The graphic below details the breakdown of global land allocation and use based on areal extent. Only 71 percent of Earth's land surface is defined as habitable; the remaining 29 percent comprises of glaciers and barren land. Here, 'barren land' refers to land cover in which less than one-third of the area has vegetation or other cover; barren land typically has thin soil, sand or rocks and includes deserts, dry salt flats, beaches, sand dunes, and exposed rocks. Humans use half of global habitable area for agricultural production (of the remainder, 37 percent is forested; 11 percent as shrubbery; and only one-percent is utilised as urban infrastructure). More than three-quarters of our agricultural land is used for the rearing of livestock through a combination of grazing land and land used for animal feed production. Despite being dominant in land allocation for agriculture, meat and dairy products supply only 17 percent of global caloric supply and only 33 percent of global protein supply. In other words, the 11 million square kilometres used for crops supply more calories and protein for the global population than the almost 4-times larger area used for livestock.

How the world's land is used: total area sizes by type of use & cover Visualising land use areas on a global map is perhaps the most relatable way to understand the scale of different land uses across the world. In the chart below we show the graphic displayed above - on the breakdown of global land use & cover - by scale on a global map. Here, land use groupings are aggregated to show the total surface area allocated for each. Note that these are not used to represent the distribution of each: this figure does not mean the United States is wholly used for livestock, or that Europe comprises only of barren land. It is used to indicate the global areal extent of each land use only. We see that: global land allocated to livestock - either in the form of grazing land or cropland used for animal feed is equivalent to the area of the Americas (North, Central and South America combined); cropland (minus land used for the production of animal feed) is equivalent to the area of East Asia-Pacific, extending as far south as Thailand; forested area is equal to Africa (minus Libya), the Middle East and South Asia; global freshwater (inland water bodies) approximates to the area of Mongolia total build-up land (villages, towns, cities & infrastructure) would fit into an area the size of Libya; shrub land is equivalent to an area the size of East Asia-Pacific, from Malaysia southwards; barren land is equivalent to the size of Europe; glaciers (permanent ice & snow) approximates to an area of Antarctica & Greenland combined.

I.7 Global agricultural land use today We use roughly half of global habitable land for agriculture. But how much of total land area is utilised for agriculture across the world? In the map below we see the share of total (both habitable and non-habitable) land area used for agriculture from 1961-2014. There is large variability in the share of land a given country uses for agriculture. Allocation ranges from less than ten percent, particularly across countries in Sub-Saharan Africa and the Scandinavian region to close to 80 percent across most regions (including the UK, Uruguay, South Africa, Nigeria and Saudi Arabia). It's important to note that this metric includes both land used for arable (cropland) production and pasture land for livestock grazing; this means that agriculture can consume a large share of land area, even in arid and semi-arid regions where extensive arable farming is not possible. We will explore this difference in cropland and pastureland in the following section. If we view the map below in "chart" mode, we see how the allocation of land to agriculture has changed over time across the global regions. The share of land used for agriculture has been slowly increasing across most of the world's regions over the past few decades. However, land use across Europe and Central Asia- particularly within the European Union (EU) zone- and North America has been declining.

Share of land area used for agriculture, 2014

The share of land area used for agriculture, measured as a percentage of total land area. Agricultural land refers to the share of land area that is arable, under permanent crops, and under permanent pastures.

0%

No data

20%

10%

40%

30%

60%

50%

Source: World Bank – WDI

80%

70%

100%

90%

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Arable agriculture (cropland) There are two main uses of agricultural land: arable farming (which is land dedicated to growing crops), and pastureland (which includes meadows and pastures used for livestock rearing). In the chart below we see a global map of land used for arable agriculture (as a share of total land area). For most countries, as we will show in the section below, land use for livestock grazing is dominant relative to arable farming. For most countries, land dedicated to cropland is typically below 20 percent, with many countries dedicating less than 10 percent. There are some notable exceptions, however; countries in South Asia and Europe allocate a large share of land area to arable farming. India, Bangladesh, Ukraine and Denmark all dedicated more than half of total land area to cropland in 2014.

Share of land area used for arable agriculture, 2014

The share of land area used for arable agriculture, measured as a percentage of total land area. Arable land includes land defined by the FAO as land under temporary crops (double-cropped areas are counted once), temporary meadows for mowing or for pasture, land under market or kitchen gardens, and land temporarily fallow.

0%

No data

10% 5%

30%

20%

50%

40%

Source: World Bank – WDI

70% 80% 75%

60%

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Pastureland (permanent meadows and pasture) For most countries, the majority of agricultural land is used for livestock rearing in the form of pastureland. In the map below we see the share of permanent meadows and pasture as a percentage of total land area. As a contrast to arable farming, land use for livestock in Europe and South Asia, in particular, is typically less than 20 percent. However, most continental regions have countries where pastureland reaches close to half of total land area. In some countries (particularly in Central Asia, including Mongolia, Kazakhstan, and Turkmenistan) this can reach up to 70 percent. Livestock farming can take place across a range of diverse climatic and environmental regions (for example, ranging from cattle rearing in temperate regions to sheep farming in hilly and semi-arid terrain); meaning that this type of agriculture is potentially less geographically-constrained than arable farming.

Share of land area used for permanent meadows and pastures, 2014

The share of land area used for permanent meadows and pastures, measured as the percentage of total land area, 1961-2014. Permanent meadows and pastures is defined by the FAO as: "the land used permanently (five years or more) to grow herbaceous forage crops, either cultivated or growing wild (wild prairie or grazing land)."

0%

No data

10% 5%

30%

20%

50%

40%

Source: UN Food and Agricultural Organization (FAO)

70%

60%

>90%

80%

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

I.8 Arable land (cropland) use per person Cropland per person over the long-term The visualisation below shows the change in the average cropland use per person over the long-term (since 10,000 BC), measured in hectares per person.

Cropland per person over the long-term Total cropland per capita, measured in hectares per person.

3 hecatres

2.5 hecatres

2 hecatres

1.5 hecatres Canada

1 hecatres

United States Brazil Latin America and the Caribbean (excl. Brazil) Europe (excl. Russia) Africa World India China

0.5 hecatres

0 hecatres 10000 BCE

6000 BCE

2000 BCE

Source: Land Use Data - HYDE (2017)

0

2016

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Arable land use per person in the near-term Global population has more than doubled over the last 50 years. To meet the demands of a rapidly growing population on a planet with finite land resources, reducing our per capita land footprint is essential. In the chart below we have plotted trends of the average arable land use per person across the world's regions. Overall we see that the arable land use per capita has declined across all regions since 1961. Per capita land use is highest in North America-- more than double the land use of any other region. Land use in Asia-- both in South and East Asia is lowest (5-6 times less than in North America). Rates of reduction in South Asia have been the most dramatic; per capita land use in 2014 was roughly one-third of its value in 1961.

Arable land use per person

The per capita allocation of land to arable agriculture, measured as the are under arable cultivation divided by the national or regional population (hectares per person). Arable land includes land defined by the FAO as land under temporary crops (double-cropped areas are counted once), temporary meadows for mowing or for pasture, land under market or kitchen gardens, and land temporarily fallow.

1 hectares

0.8 hectares

0.6 hectares

North America

0.4 hectares

Europe & Central Asia

Sub-Saharan Africa World

0.2 hectares

South Asia East Asia & Pacific

0 hectares 1961

1970

1980

1990

Source: World Bank – WDI

2000

2010 2014

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

I.9 Agricultural land use per person Agricultural land per person over the long-term The visualisation below shows the change in the average agricultural land use (which is the sum of cropland and grazing area) per person over the long-term (since 10,000 BC), measured in hectares per person.

Total agricultural land use per person

Total agricultural land area (which is the combination of cropland and grazing land) use per person over the long-run, measured in hectares.

30

25

20

15 Oceania Latin America and the Caribbean (excl. Brazil) Canada Russia Brazil United States Africa Middle East China Europe (excl. Russia) India

10

5

0 10000 BCE 8000 BCE 6000 BCE 4000 BCE 2000 BCE

0

Source: Land Use Data - HYDE (2017)

2016

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Agricultural land per person over the near-term If we extend our land coverage above from arable land use to total agricultural land (which is the sum of arable, permanent crops and pastures and meadows), we still see overall declines in land per person but with different rates and patterns of reduction. Overall, we see that agricultural land per person is higher than that of arable land. At the global level, per capita agricultural land use is now less than half its value in 1961. Africa in particular has seen dramatic reductions in agricultural land per person - now less than one-third of per capita land 50 years ago. The Americas (North and South) and Africa have notably higher per capita agricultural land use relative to Europe and Asia.

Agricultural area per capita

Agricultural land area per capita, measured in hectares per person. The UN Food and Agricultural Organization define 'agricultural area' as the sum of arable land, permanent crops, permanent meadows and pastures.

3.5 hectares 3 hectares 2.5 hectares 2 hectares South America

1.5 hectares

Northern America Africa

1 hectares

World

0.5 hectares

Eastern Asia European Union Southern Asia

0 hectares 1961

1970

1980

1990

Source: Agricultural area per capita - FAO (2017)

2000

2013

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

I.10 Land projections to 2050-60: have we reached 'peak farmland'? Is the expansion of global agricultural land likely to continue in the coming decades? In the chart below we see the trends of global land under arable and permanent crops from 1961-2014, in addition to UN FAO projections of arable land use through to 2050. This projection is published in the FAO's World agriculture towards 2030/2050 Report.3 The FAO predicts that global arable land use will continue to grow to 2050, however, this is likely that this rate of expansion (towards eventual decline) will be at a slower rate than over the past 50 years. Most of this growth is projected to result from developing countries, meanwhile arable land use in developed countries is likely to continue its decline.

FAO projections of arable land to 2050

Global land allocated to arable production or permanent crops from 1961-2014, with the UN Food and Agricultural Organization's (FAO) projections to 2050. Land area is measured in hectares. FAO arable land projections (FAO (2017))

1.6 billion ha 1.4 billion ha 1.2 billion ha 1 billion ha

800 million ha 600 million ha 400 million ha 200 million ha 0 ha 1961

1980

2000

2020

Source: FAO 2030-50 Projections of Arable Land (FAO (2017))

2040

2050

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

This FAO projection of continued arable land expansion through to 2050 was disputed by Ausubel, Wernick & Waggoner in a widelydiscussed paper in 2013 which predicted we had reached a global peak in farmland use in 2009.4 The authors, which only had land use data available to 2009 predicted we had reached 'peak farmland', with continued decline in arable land use of around 0.2 percent per year from 2010-2060. In the chart below we have plotted this 'peak and decline' projection but have extended actual land use trends through to the year 2014. As we see, over the period 2009-2014, arable land use has continued to increase, diverging from Ausubel's earlier projection. Whilst premature, the authors' model for estimating arable land requirements provides a useful explanation of the variables which will determine at what date we reach this peak. We discuss these determinants, and where Ausubel's predictions diverge from actual trends in the Correlates, Determinants & Consequences section of this entry.

Peaking farmland: global arable and permanent crop area and Ausubel (2013) projections of peak farmland

Global area used for arable and permanent crops from 1961-2014 based on UN Food and Agricultural Organization (FAO) data, measured in hectares. Ausubel et al. (2013) projected peak farmland in 2009, with a 0.2 percent reduction in farmland area per year to 2060; this projection is also shown.

1.4 billion ha

Ausubel et al. (2013) Projection

1.2 billion ha 1 billion ha 800 million ha 600 million ha 400 million ha 200 million ha 0 ha 1961

1980

2000

2020

2040

2060

Source: FAOstats (1961-2014); and Ausubel et al. (2013) projections (2010-2060) OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

I.11 Land projections to 2050: when will we reach peak agricultural land? The projections of farmland above are limited in scope to land used for crop production (i.e. arable land plus land under permanent crop production). These estimates do not include land used for grazing and livestock production. The chart below maps a range of published estimates of total agricultural area over time (which is the sum of arable land and permanent crops, plus permanent meadows and pastures for grazing). You can note that the areal extent of our agricultural land is significantly larger than that of the farmland analysed above (about three times larger). These estimates come from a range of sources, including the UN FAO, OECD and Millennium Ecosystem Assessment (MEA). Also shown is the actual agricultural areal extent from 1980 onwards, as reported by the UN Food and Agricultural Organization. Some projections vary significantly - for example, the MEA scenario 1 suggests that the world will not peak in agricultural land prior to 2050. However, most projections suggest a peaking of land expansion in the timespan between 2020 and 2040. Our measured agricultural area appears to be most closely aligned to the FAO/IMAGE projection, which is characterised by a very slow increase in areal extent over the coming decades before peaking around 2040.

Projections for global peak agricultural land

Projected trends in global agricultural area extent by various sources, measured in hectares. Projections include those from the UN Food and Agricultural Organization (FAO), International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD); OECD, and scenarios from the Millennium Ecosystem Assessment (MEA). Also shown is the actual agricultural area to 2014, as reported by the UN FAO. MEA Scenario 1 MEA Scenario 3 IAASTD OECD Outlook MEA Scenario 4 MEA Scenario 2 FAO/IMAGE

5 billion ha

4 billion ha

3 billion ha

2 billion ha

1 billion ha

0 ha 1980

1990

2000

2010

2020

2030

2040

2050

Source: Projections of peak agricultural land - FAO (2006), OECD (2012), MEA (2005)

OurWorldInData.org • CC BY-SA

I.12 Land use by crop type In the chart below we see the global area of land use in agriculture by major crop types, from 1961 to 2014. Overall, we see that the majority of our arable land is used for cereal production; this has grown from around 650 to 720 million hectares (an area roughly twice the size of Germany) over this period. The total land area used for coarse grains has remained approximately constant over this 50 year period, and is the 2nd largest user of arable land. The most dramatic increase in land allocation is in the production of oilcrops. Total land area used for oilcrop production has increased almost 3-fold since 1961-- an area just short of the size of Mexico. All other crop types take up less than 100 million hectares of global area.

Global agricultural land use by major crop type

Global land area used for agricultural production, by major crop category, measured in hectares. Cereals

700 million

600 million

500 million

400 million Coarse Grain

300 million

Oilcrops

200 million Pulses Roots and Tubers Vegetables Fruit Treenuts Citrus Fruit Jute

100 million

0 1961

1970

1980

1990

2000

2010 2014

Source: Global agricultural land by crop - FAO (2017)

OurWorldInData.org • CC BY-SA

I.13 Land use by food type The amount of land required to produce food has wide variations depending on the product--this is especially true when differentiating crops and animal products. In the chart below we have plotted the average land required (sometimes termed the "land footprint") to produce one gram of protein across a range of food types. At the bottom of the scale, we see that cereal crops typically have a small land impact per unit of protein (although such protein is often lacking in some essential amino acids). At the upper end of the spectrum we find meat products, with the land required for beef or mutton up to 100 times larger than cereals. However, it's important to note the differences in land required across the meat products: poultry and pork have a land footprint 8-10 times lower than that of beef. This means individuals can make notable reductions in the environmental impact of their diets simply by substituting lower-impact meat products for beef or mutton.

Land use per gram of protein, by food type

Average land use area needed to produce one unit of protein by food type, measured in metres squared (m²) per gram of protein over a crop's annual cycle or the average animal's lifetime. Average values are based on a meta-analysis of studies across 742 agricultural systems and over 90 unique foods. Beef/Mutton

1.02 m²

Pork

0.13 m²

Fresh Produce

0.1 m²

Poultry

0.08 m²

Eggs

0.05 m²

Dairy

0.04 m²

Wheat

0.04 m²

Rice

0.02 m²

Maize

0.01 m²

Pulses

0.01 m²

0 m²

0.2 m²

0.4 m²

0.6 m²

0.8 m²

1 m²

Source: Environmental footprint by food type (protein) - Clark & Tilman (2017) OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

II. Correlates, Determinants & Consequences

II.1 Determinants of crop yields Modern inputs – irrigation, improved varieties of cereal & fertilizer – have expanded rapidly around the world but have lagged in SubSaharan Africa, as seen in the following graph.

Fertilizer use and yields

Cereal crop yield vs. fertilizer application, 2014

Average cereal crop yield (measured in kilograms per hectare) versus fertilizer application (measured in kilograms of fertilizer used per hectare of arable land) Africa Asia Europe North America Oceania South America

United Arab Emirates Kuwait

Cereal yield (kg per hectare)

10,000 kg

Belgium

United States

Madagascar Myanmar Bhutan Russia Fiji

Uganda

1,000 kg

China

New Zealand

Japan Italy Indonesia South Africa Poland Colombia Mexico India Ecuador

Malaysia

Nepal Pakistan Lebanon El Salvador Australia Guatemala

Hong Kong

Rwanda Iran Honduras Nigeria Mali Central African Republic Benin Jordan Algeria Guinea Burkina Faso Togo Jamaica Syria Yemen Brunei Democratic Republic of Congo Libya Eritrea Namibia Oman Zimbabwe Niger Botswana

1 kilograms

10 kilograms

Qatar

Cyprus

100 kilograms

1,000 kilograms 10,000 kilograms

Fertilizer application (kg per hectare arable land) Source: World Bank – WDI

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Tractor use (per 100 square km) and yields

Cereal yields vs. tractor inputs in agriculture, 1961 to 2009

Cereal yields, measured in kilograms per hecatre versus the number of tractors used per 100 square kilometres of arable land. Africa Asia Europe North America Oceania South America

United Arab Emirates

16,000 kg Saint Vincent and the Grenadines

Cereal yield (kilograms per hectare)

14,000 kg

1961

12,000 kg 10,000 kg

Belgium Netherlands

8,000 kg

United States Denmark

Egypt

Switzerland

South Korea

Germany

6,000 kg

Chile

Japan

Austria Italy

Malta

Slovenia

China

Greece Brazil Poland Lithuania Colombia Norway Pakistan Spain

4,000 kg 2,000 kg

India

New Caledonia

Trinidad and Tobago

Lebanon

Kenya

0 kg

2009

Cyprus

Sudan

1,000

2,000

3,000

4,000

5,000

6,000

Tractors per 100 sq km arable land Source: World Bank – WDI

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

II.2 Determinants of arable land use in agriculture The quantity of land required for arable agriculture is determined by a range of factors relating to population, dietary consumption, and food system dynamics/productivity. As we discussed earlier in the entry, Ausubel, Wernick & Waggoner (2013) applied a simplified model of these variables to predict when the world would reach 'peak farmland'.6 Ausubel defines it as the IMPACT model, where land use is determined by five key variables: 1. P = Population (number of people to feed) 2. A = Affluence (in GDP per capita) 3. C1 = Consumption 1 (in kcal/GDP), where kcal refers to the annual national or global food supply in kilocalories from both vegetal and animal sources. C1 provides a measure of how much our kilocalorie (i.e. food) intake increases (or decreases) as we get richer or poorer. 4. C2 = Consumption 2 (in Crop Production Index [PIN]/kcal) using the FAO Crop Production Index, which measures the relative level of aggregate volume of agricultural crop production indexed to a base year. C2 tracks the ratio of crop production for food, feed, fuel, fiber, and tobacco to the supply of food calories. This means it provides a measure of how much food is produced relative to how much food is eaten (i.e. the efficiency of the system in delivering food from the field to peoples' plates). If we reallocate more food towards feed and fuel, for example, we would have to continue increasing agricultural output to ensure food supplies remain adequate. 5. T = Technology (in hectares/Crop PIN) tracks how much land farmers use relative to total crop value. This is a measure of agricultural yield/productivity. We are therefore left with the equation, where: Im (arable land in hectares) = P * A * C1 * C2 * T Or the rate of change in arable land is equal to the sum of the rates of change in these variables (in percent per year): im = p + a + c 1 + c 2 + t

How did Ausubel's predictions differ from reality? In order to assess why Ausubel et al. (2013) predicted we would reach 'peak farmland' prematurely, we assessed how their predicted values for each of the variables differed from actual values over the period 2009-2014. It should be noted that the authors derived their rate of decline (at 0.2 percent per year) based on an average prediction over the period 2010-2060; therefore a divergence from this value over the first 5-year period does not necessarily confirm these averaged predictions to be false. In the table below, we provide a comparison of the values used in Ausubel's projection, and our own analysis of changes in these variables from 2009-2014 (measured in percent change per year). Whilst Ausubel predicted a 0.2 percent decline in arable land area per year, our analysis suggests a 0.37 percent increase per year over this 5-year period. This correlates very closely to the actual land in land use; FAO figures suggest this also grew at 0.37 percent per year. Ausubel prediction

Variable

OWID analysis (2009-

Actual change in land (2009-

2014)

2014)

(2010-2060) Population (p)

0.90%

1.2%

Affluence (GDP per capita)

1.80%

1.8%

Food supply/GDP (kcal/GDP)

-1.60%

-1.4%

Crop PIN/kcal

0.40%

0.50%

Technology (yield)

-1.70%

-1.8%

Total change in arable land (per year)

-0.20%

0.37%

0.37%

II.3 The trade-off between higher yields and land use Agricultural Production Index: land needed per unit of crop production The following graph shows that to produce an equivalent aggregate of crop production in 2012 required only about 32% of the land needed in 1961. The agricultural production index (PIN) use here is the sum of agricultural commodities produced (after deductions of quantities used as seed and feed). It is weighted by the commodity prices. The FAO explains the construction of the PIN in detail here. The idea for this chart is taken from Ausubel, Wernick, and Waggoner (2013).7 The authors write: 'A combination of agricultural technologies raised yields, keeping downward pressure on the extent of cropland, sparing land for nature. Countering the global rise of population and affluence by parents and workers, consumers and farmers restrained the expansion of arable land by changing tastes and lifting yields. The noticeable shrinkage in the extent of cropland as a function of the Crop Production index since 1990 (Figure below) provides encouragement that farmers will continue sparing land.'

Production, yield and land use changes over time In the chart below we see index trends in cereal production, yield, land use and population measured from 1961 (i.e. 1961 = 100). From 1961 to 2014, global cereal production has increased by 280 percent. If we compare this increase to that of total population (which increased only 136 percent over the same period), we see that global cereal production has increased at a much faster rate than that of population. If distributed equally, cereal production per person has increased despite a growing population. Have we achieved this through land expansion or improved yields? A bit of both. In 2014, we used 16% more land for cereal production than we did in 1961 (approximately equivalent to double the area of Germany). Overall, this means we use less land per person than we did fifty years ago. Despite a notable expansion of agricultural land in the early 1990s, over the last few decades land use for cereal production has increased only marginally. Most of our improvements in cereal production have arisen from improvements in yield. The average cereal yield has increased by 175 percent since 1961. Today, the world can produce almost three-times as much cereal from a given area of land as it did in 1961.

Index of cereal production, yield and land use, 1961-2014, World

The index of total cereal production (measured in metric tonnes), cereal yield (kilograms per hectare), and land used for cereal production (hectares). The index is calculated as the production, yield and land use in any given year divided by that in the year 1961 (i.e. 1961 = 100). The index of total population (all ages and genders) relative to 1961 is also shown. Trends for individual countries can be viewed using the "change country" wheel. Cereal production index

350 300 Cereal yield index

250

Population index

200 150 Land under cereal production index

100 50 0 1961

1970

1980

1990

2000

2014

Source: OWID based on World Bank, World Development Indicators (WDI) OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Yields vs. Land Use There is therefore an important relationship between yields improvements and land use. In order to grow more food, we can increase the output from a given area of land (called 'intensification'), or expand the area over which we grow our food (called 'extensification'). Increasing yields reduces the pressure of expanding agricultural land. In the chart below, we see the indexed change in land area used for cereal production from 1961-2014 (on the y-axis), measured against the indexed change in cereal yield over the same period (on the x-axis). In these trends we see large regional differences in this yieldland use trade-off. Most European, American (both North and Latin American), Asian and Pacific countries have seen a much larger increase in cereal yields relative to area used for production. For many, changes in the arable land have been minimal (or have declined). This is an important contrast to Africa where results are more mixed. Some countries, including Ethiopia, Nigeria and Algeria have followed the rest of the world in yield increases. However, a failure to increase agricultural productivity in many Sub-Saharan countries has led to large increases in land used for cereal production.

Land use vs. yield change in cereal production, 1961 to 2014 Indexed change in land used for cereal production versus cereal yields, from 1961 to 2014. Both indexes are measured relative to values in 1961 (i.e. 1961 = 100).

Africa Asia Europe North America Oceania South America

Oman

Change to land area used for cereal production since 1961

2,500

2,000

1961

1,500

2014

Solomon Islands Paraguay

1,000 Guinea Sudan Niger

500

Papua New Guinea Tanzania Congo Mauritius Belize

Democratic Republic of Congo Nepal Burkina Faso Haiti Nigeria

0

Lesotho Japan

0

Italy

India

200

China

South Africa Portugal

Greece

400

Bahamas

600

800

1,000

1,228

Cereal yield index Source: Cereal Yield Index - World Bank (2017) & OWID, Land under cereal production index - World Bank (2017) OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Different approaches to growing food: South Asia vs. Sub-Saharan Africa This trade-off between land use for agriculture and yields is very clearly exemplified in a comparison between cereal production in Asia and Sub-Saharan Africa. Expansion of cereal production has followed very different paths in Sub-Saharan Africa and Asia. Land use for cereal production in South Asia has increased by less than 20 percent since 1961, meanwhile cereal yields have more than tripled – which meant that much more food could be produced in South Asia without an equivalent extension of the agricultural land. This is in strong contrast to Sub-Saharan Africa where the area of land used for cereal production has more than doubled since 1961 and yields have only increased by 80 percent.

The change of cereal yield vs. land used for cereal production, 1961 to 2014

The index of cereal yield (kilograms per hectare) versus and land used for cereal production (hectares). The index is calculated as the yield and land use in any given year divided by that in the year 1961 (i.e. 1961 = 100).

350

East Asia & Pacific

1961

2014

Latin America & Caribbean South Asia

Index of cereal yield (1961 = 100)

300

250

200 Sub-Saharan Africa

150

100

1961 1961

97

120

140

160

180

200

221

Index of land under cereal production (1961 = 100) Source: OWID Based on World Bank & UN FAO

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

Land sparing from improvements in cereal yields Although there are a few exceptions--notably across Sub-Saharan Africa, the continued increase in cereal yields across the world has been the major driver of total cereal production. This has inevitably allowed us to 'spare' land we would have otherwise had to convert for cereal production. In the chart below we see that the global area under cereal production (in blue) has increased from 625 to 721 million hectares from 1961-2014. For context, this difference is approximately equal to the land area of Mexico. However, if global average cereal yields were to have remained at their 1961 levels, we see the amount of additional land (in red, below) which we would have had to convert to arable land if we were to achieve the same levels of cereal production. This 'spared' land amounts to 1.26 billion hectares in 2014-- roughly equal to the area of Mexico and Europe combined. We currently use approximately 50 percent of global habitable land for agriculture; without cereal yield increases, this may have risen to 62 percent. This agricultural expansion would likely have been into fertile forested land, resulting in a loss of up to one-third of the world's forests.

Global land spared as a result of cereal yield improvements

Global area of land spared from agricultural production as a result of improvements in cereal yield, measured in hectares. This has been calculated as the area of land which would have been necessary to maintain global cereal production at actual output rates, assuming average cereal yields had remained constant since 1961.

1.5 billion Land spared by yield gains (hectares)

1 billion

500 million Land under cereal production

0 1961

1970

1980

1990

Source: Land sparing from cereal yields - World Bank (2017)

2000

2010 2014

OurWorldInData.org/yields-and-land-use-in-agriculture/ • CC BY-SA

III. Data Quality & Definition

III.1 Yields The definition for 'crop yield' given by the FAO is 'Harvested production per unit of harvested area for crop products. In most of the cases yield data are not recorded but obtained by dividing the production data by the data on area harvested. Data on yields of permanent crops are not as reliable as those for temporary crops either because most of the area information may correspond to planted area, as for grapes, or because of the scarcity and unreliability of the area figures reported by the countries, as for example for cocoa and coffee.'8

III.2 Agricultural Land Use The Land Area of the World is 13,003 million ha. 4,889 million ha are classified as 'agricultural area' by the FAO (this is 37.6% of the Land Area). The agricultural area use is divided into 3 categories: arable land (28% of the global agricultural area), permanent crops (3%) and permanent meadows and pastures (69%) which account for the largest share of the world's agricultural area.9 What do these words mean? The agricultural area is the sum of arable land, permanent crops, permanent meadows and pastures. The FAO definition for arable land is land under temporary agricultural crops (multiple-cropped areas are counted only once), temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporarily fallow (less than five years). The abandoned land resulting from shifting cultivation is not included in this category. Data for “Arable land” are not meant to indicate the amount of land that is potentially cultivable.'10 The same source defines permanent crops as follows: 'Permanent crops are divided into temporary and permanent crops. Permanent crops are sown or planted once, and then occupy the land for some years and need not be replanted after each annual harvest, such as cocoa, coffee and rubber. This category includes flowering shrubs, fruit trees, nut trees and vines, but excludes trees grown for wood or timber. And again from the same source the definition for permanent meadows and pastures is 'land used permanently (five years or more) to grow herbaceous forage crops, either cultivated or growing wild (wild prairie or grazing land).' The FAO definition for fallow land is 'the cultivated land that is not seeded for one or more growing seasons. The maximum idle period is usually less than five years.'

IV. Data Sources

FAO Statistical Database (FAOstat) Data: Many indicators relating to food production, yields and land use – the full list is here. Geographical coverage: Global – by country and world region. Time span: Since 1961. Available at: Available for download here.

World Development Indicators – World Bank Data: Cereal yields, production and land use data Geographical coverage: Global – by country and world region Time span: 1961-2014 Available at: online here.

Inter-American Development Bank (IDB) Agrimonitor Data: Agricultural output, policy and support Geographical coverage: Latin America - by country Time span: 2004-2014 Available at: online here.

Footnotes 1. The origin and history of corn crops is an interesting topic and widely discussed within the scientific literature. Am accessible overview of the history of corn can be found here. 2. Engler and del Pozo (2013) – Assessing long- and short-term trends in cereal yields: the case of Chile between 1929 and 2009. Ciencia e investigación agraria. Vol.40 no.1 Santiago Apr. 2013. Pontificia Universidad Católica de Chile. Available online. Data from 1961 onwards is taken from FAOstat; database online here. 3. Alexandratos, N. and J. Bruinsma. 2012. World agriculture towards 2030/2050: the 2012 revision. ESA Working paper No. 12-03. Rome, FAO. Available online. 4. Jesse H. Ausubel, Iddo K. Wernick, Paul E. Waggoner (2013) – Peak Farmland and the Prospect for Land Sparing. Population and Development Review, Volume 38, Issue Supplement s1, pages 221–242, February 2013. DOI: 10.1111/j.1728-4457.2013.00561.x. Available online. 5. This is taken from World Bank (2008) – World Development Report (2008): Agriculture for Development. Washington, DC: World Bank. Online here. The original sources given by my source are Evenson and Gollin 2003 and FAO 2006a. 6. Although proven to be premature in their projection, the model remains useful in estimating future demands for arable land.[ref]Jesse H. Ausubel, Iddo K. Wernick, Paul E. Waggoner (2013) – Peak Farmland and the Prospect for Land Sparing. Population and Development Review, Volume 38, Issue Supplement s1, pages 221– 242, February 2013. DOI: 10.1111/j.1728-4457.2013.00561.x. Available online. 7. Jesse H. Ausubel, Iddo K. Wernick, Paul E. Waggoner (2013) – Peak Farmland and the Prospect for Land Sparing. Population and Development Review, Volume 38, Issue Supplement s1, pages 221–242, February 2013. DOI: 10.1111/j.1728-4457.2013.00561.x. Online here. 8. This is the definition given by the UN's Food and Agricultural Organization (FAO) in their glossary that is online here. 9. These numbers are taken from FAO (2013) – Statistical Yearbook. Table 4. Online here. For comparison: The area of the USA, Canada and China are all short of 1,000 million ha (USA 963 million ha, China 932 million ha, Canada 909 million ha). 10. This is the definition given by the UN's Food and Agricultural Organization (FAO) in their glossary that is online here.

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