Mapping the world's degraded lands

May combine two claims.

Global estimates of total degraded area vary from less than 1 billion ha to over 6 billion ha, with equally wide disagreement in their spatial distribution.

“Global estimates of total degraded area vary from less than 1 billion ha to over 6 billion ha, with equally wide disagreement in their spatial distribution.”

May combine two claims.

No clear consensus exists as to the extent of degraded land, not only globally, but even within a particular country.

“Indeed, no clear consensus exists as to the extent of degraded land, not only globally, but even within a particular country (Bindraban et al., 2012;FAO, 2008;Lepers et al., 2005).”

• cites Bindraban et al., 2012 sourceNot checked yet

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• cites FAO, 2008Not checked yet

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• cites Lepers et al., 2005 sourceNot checked yet

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May combine two claims.

The areas affected by at least moderate degradation comprise 9 percent and 47 percent of the land surface, according to GLASOD and TerraSTAT, respectively.

“The areas affected by at least moderate degradation comprise 9 percent and 47 percent of the land surface, according to GLASOD and TerraSTAT, respectively (Table 2), highlighting the high degree of interpretability of these data sets.”

May combine two claims.

The greatest disagreement occurs in Asia where only two data sets show agreement and standard deviation among the data sets is greater than 30 percent of cell area for large areas of China and Southeast Asia.

“The greatest disagreement occurs in Asia where only two data sets show agreement and standard deviation among the data sets is greater than 30 percent of cell area for large areas of China and Southeast Asia.”

May combine two claims.

This discrepancy leads to only three data sets agreeing in these regions and standard deviations of about 30 percent of cell area.

“This discrepancy leads to only three data sets agreeing in these regions and standard deviations of about 30 percent of cell area.”

May combine two claims.

GLADA alone observed degradation in several areas, leading to patches of disagreement in Eastern Argentina, Quebec and Ontario in Eastern Canada, much of Central Africa, the Northern Territory in Australia, and the Central Siberian Plateau.

“GLADA alone observed degradation in several areas, leading to patches of disagreement in Eastern Argentina, Quebec and Ontario in Eastern Canada, much of Central Africa, the Northern Territory in Australia, and the Central Siberian Plateau.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Where three data sets indicate a similar degree of degradation, but one set diverges, there are three data sets in agreement and the standard deviation reflects the degree of divergence.

“Where three data sets indicate a similar degree of degradation, but one set diverges, there are three data sets in agreement (light green in Fig. 2) and the standard deviation reflects the degree of divergence.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Where all four values indicate degradation of similar extent (up to 20 percent of cell area), there are four data sets in agreement and the standard deviation is low.

“Where all four values indicate degradation of similar extent (up to 20 percent of cell area), there are four data sets in agreement (dark green in Fig. 2) and the standard deviation is low (yellow or green in Fig. 3).”

May combine two claims.

Where all four data sets indicate different states of degradation, there is only one data set in agreement and the standard deviation is high.

“Finally, where all four data sets indicate different states of degradation, there is only one data set in agreement (red in Fig. 2), and the standard deviation is high (red in Fig. 3).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Where two data sets indicate a similar state of degradation, and the other two indicate different degrees of degradation, there are two data sets in agreement and the standard deviation reflects how far the two differing sets diverge from the two in agreement.

“Similarly, where two data sets indicate a similar state of degradation, and the other two indicate different degrees of degradation, there are two data sets in agreement (yellow in Fig. 2), and the standard deviation reflects how far the two differing sets diverge from the two in agreement.”

May combine two claims.

Yield increases on existing croplands will be an essential component to increased food production, but by themselves will not suffice.

“Yield increases on existing croplands will be an essential component to increased food production, but by themselves will not suffice (Godfray et al., 2010;Hubert, Rosegrant, van Boekel, & Ortiz, 2010;Ray, Mueller, West, & Foley, 2013).”

• cites Godfray et al., 2010 sourceNot checked yet

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• cites Hubert, Rosegrant, van Boekel, & Ortiz, 2010Not checked yet

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• cites Ray, Mueller, West, & Foley, 2013 sourceNot checked yet

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May combine two claims.

The potential of degraded lands is often estimated using highly uncertain data sets and tends to be overstated, with little attention given to the current status and use of these degraded lands.

“However, this potential is often estimated using highly uncertain data sets (Field, Campbell, & Lobell, 2008;Goldewijk & Verburg, 2013;Hoogwijk et al., 2003;Meiyappan & Jain, 2012;Nijsen, Smeets, Stehfest, & Vuuren, 2012;Ramankutty, Heller, & Rhemtulla, 2010;vanVuuren, Vliet, & Stehfest, 2009), and tends to be overstated, with little attention given to the current status and use of these degraded”

• cites Field, Campbell, & Lobell, 2008Not checked yet

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• cites Goldewijk & Verburg, 2013Not checked yet

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• cites Lambin et al., 2013 sourceNot checked yet

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May combine two claims.

During the 1980s and 1990s, more than half of newly expanding agricultural areas in the tropics came at the expense of closed forests, with an additional third from disturbed forests.

“For example, Gibbs et al. (2010) found that during the 1980s and 1990s more than half of newly expanding agricultural areas in the tropics came at the expense of closed forests, with an additional third from disturbed forests.”

• cites Gibbs et al. (2010) sourceNot checked yet

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Probably not a substantial claim: may not pass S2 (checkable).

The risk of overestimating the availability and productive potential of degraded lands is severe, as it may divert attention from efforts to reduce food and agricultural waste or the demand for land-intensive commodities.

“The risk of overestimating the availability and productive potential of these areas is severe, as it may divert attention from efforts to reduce food and agricultural waste or the demand for land-intensive commodities.”

• Also stated in: § Introduction · hedged

  “The risks of overestimating the availability and productive potential of these areas is severe, as it may divert attention from efforts to reduce waste or the demand for land-intensive commodities such as beef.”

Classified as probably not a substantial claim. May combine two claims.

Studies focus on temporal and spatial scales of degradation that differ, which leads to much confusion when interpreting the results.

“Yet studies focus on temporal and spatial scales of this process that differ, which leads to much confusion when interpreting the results.”

May combine two claims.

The Global Assessment of Soil Degradation (GLASOD) was the first attempt to map human-induced degradation around the world and is still used today.

“The Global Assessment of Soil Degradation (GLASOD) commissioned by the United Nations Environment Program was the first attempt to map human-induced degradation around the world (Oldeman, 1994;Oldeman et al., 1990) and is still used today (e.g., Nijsen et al., 2012).”

• cites Oldeman, 1994Not checked yet

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• cites Oldeman et al., 1990Not checked yet

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• cites Nijsen et al., 2012 sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Lands with naturally low productivity, such as heathlands or naturally saline soils, may also be described as degraded.

“Another challenge is that lands with naturally low productivity, such as heathlands or naturally saline soils, may also be described as degraded.”

May combine two claims.

There is disagreement between degradation data that include natural processes and those that have been induced solely through human activity, and it is often difficult to distinguish between these causes.

“In addition, there is disagreement between degradation data that include natural processes and those that have been induced solely through human activity (Weigmann, Hennenberg, & Fritsche, 2008), and it is often difficult to distinguish between these causes.”

• cites Weigmann, Hennenberg, & Fritsche, 2008Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Due to its dependence upon local experts, the GLASOD assessment is considered subjective and has been open to disparagement.

“Due to this dependence upon local experts, the GLASOD assessment is considered subjective and has been open to disparagement (e.g., Rey, Scoones, & Toulmin, 1998, chap. 1;Thomas, 1993).”

• cites Rey, Scoones, & Toulmin, 1998, chap. 1Not checked yet

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• cites Thomas, 1993 sourceNot checked yet

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May combine two claims.

Solicitation of expert opinion was the first approach used to map and quantify degraded lands and maintains a leading role in assessments despite its subjective nature and inconsistencies.

“Solicitation of expert opinion was the first approach used to map and quantify degraded lands and maintains a leading role in assessments despite its subjective nature and inconsistencies (Dregne & Chou, 1992;Oldeman, 1994;Oldeman, Hakkeling, & Sombroek, 1990).”

• cites Dregne & Chou, 1992Not checked yet

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• cites Oldeman, 1994Not checked yet

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• cites Oldeman, Hakkeling, & Sombroek, 1990Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

The GLASOD study estimated that nearly 2 billion ha (22.5 percent) of agricultural land, pasture, forest and woodland had been degraded since mid-twentieth century.

“The GLASOD study estimated that nearly 2 billion ha (22.5 percent) of agricultural land, pasture, forest and woodland had been degraded since mid-twentieth century.”

• cites Oldeman et al., 1990Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Most seminal efforts have focused on soil degradation, while more recent efforts have investigated the broader issue of land degradation from an ecosystem approach, which encompasses both soils and vegetation.

“Finally, while most seminal efforts have focused on soil degradation (Nijsen et al., 2012;Oldeman et al., 1990), more recent efforts have investigated the broader issue of land degradation from an ecosystem approach, which encompasses both soils and vegetation.”

• cites Nijsen et al., 2012 sourceNot checked yet

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• cites Oldeman et al., 1990Not checked yet

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May combine two claims.

GLASOD estimates are uniform in the sense that they are based upon defined mapping units and carefully structured definitions, but they rely on local knowledge rather than measurements.

“The estimates are uniform in the sense that they are based upon defined mapping units and carefully structured definitions but they rely on local knowledge rather than measurements.”

May combine two claims.

GLASOD was designed to generate continental scale estimates, and the sampling procedure is not adequate to draw conclusions at the national scale.

“GLASOD was designed to generate continental scale estimates, and the sampling procedure is not adequate to draw conclusions at the national scale (Bruinsma, 2003;Scherr & Yadav, 1996).”

• cites Bruinsma, 2003Not checked yet

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• cites Scherr & Yadav, 1996Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The FAO TerraSTAT interpretation of GLASOD by Bot et al. (2000) finds that over 6 billion ha, 66 percent of the world's land, has been affected by degradation, leaving roughly only a third of the world's surface in good condition.

“The FAO TerraSTAT interpretation of GLASOD by Bot et al. (2000), on the other hand, finds that over 6 billion ha, 66 percent of the world's land, has been affected by degradation, leaving roughly only a third of the world's surface in good condition.”

• cites Bot et al. (2000)Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Dregne and Chou (1992) found very extensive degradation covering roughly 3.6 billion ha (70 percent) of Earth's drylands.

“They found very extensive degradation covering roughly 3.6 billion ha (70 percent) of Earth's drylands.”

• cites Dregne and Chou (1992)Not checked yet

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May combine two claims.

There are few if any routine assessments of degradation at the country level that keep track of pre-existing or changing conditions, nor is there any agreement on how to conduct such assessments.

“There are few if any routine assessments of degradation at the country level that keep track of pre-existing or changing conditions, nor is there any agreement on how to conduct such assessments (Bruinsma, 2003).”

• cites Bruinsma, 2003Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Many degradation studies focus only on drylands, so their results are difficult to compare with broader studies that include temperate and humid domains.

“For example, many degradation studies focus only on drylands, so their results are difficult to compare with broader studies that include temperate and humid domains.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

GLASOD has been criticized for the coarse spatial resolution of mapping units and the qualitative judgments whose consistency was untested.

“Others have criticized GLASOD for the coarse spatial resolution of mapping units and the qualitative judgments whose consistency was untested.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Dregne and Chou (1992) concluded that in their study region 73 percent of rangelands, 47 percent of rainfed croplands, and 30 percent of irrigated croplands were degraded.

“Indeed, they concluded that in their study region 73 percent of rangelands, 47 percent of rainfed croplands, and 30 percent of irrigated croplands were degraded.”

• cites Dregne and Chou (1992)Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Some estimates of degradation have focused on the end condition of the land, others consider the ongoing process of degradation itself, and even the perceived risk of degradation, adding more confusion to the term.

“Indeed, while some estimates of degradation have focused on the end condition of the land, others consider the ongoing process of degradation itself (e.g., Bai, Dent, Olsson, & Schaepman, 2008;Cai, Zhang, & Wang, 2011), and even the perceived risk of degradation, adding more confusion to the term.”

• cites Bai, Dent, Olsson, & Schaepman, 2008Not checked yet

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• cites Cai, Zhang, & Wang, 2011 sourceNot checked yet

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May combine two claims.

Each of the four approaches offers a glimpse into the conditions on the ground but none capture the complete picture.

“Each offers a glimpse into the conditions on the ground but none capture the complete picture (Tables 1 and 2; Fig. 3).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Despite its limitations, GLASOD remains the only complete, globally consistent information source on land degradation and has been widely used and interpreted.

“Despite its limitations, GLASOD remains the only complete, globally consistent information source on land degradation and has been widely used and interpreted (e.g., Bot, Nachtergaele, & Young, 2000;Crosson, 1995Crosson, , 1997;;Pimentel et al., 1995;Sonneveld & Dent, 2007).”

• cites Bot, Nachtergaele, & Young, 2000Not checked yet

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• cites Crosson, 1995Not checked yet

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• cites Pimentel et al., 1995 sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Expert judgments will continue to play a role, regardless of improvements in other methods, because degradation will remain a subjective quality whose benchmarks vary among locations.

“Such expert judgments will continue to play a role, regardless of improvements in other methods, because degradation will remain a subjective quality whose benchmarks vary among locations (Sonneveld & Dent, 2007).”

• cites Sonneveld & Dent, 2007Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The benefit of focusing on abandoned agricultural lands is that it captures the longer time frame of the expert opinion approach but quantifies the actual conditions rather than estimating potential risk.

“The benefit of focusing on these lands is that it captures the longer time frame of the expert opinion approach but quantifies the actual conditions rather than estimating potential risk.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Wessels, Van Den Bergh, and Scholes (2012) were highly critical of the Bai et al. (2008) publication of GLADA results, especially in the humid tropics where results were described as fatally flawed and misleading.

“Indeed, Wessels, Van Den Bergh, and Scholes (2012) commented on the Bai et al. (2008) publication of GLADA results, and was highly critical of their methods, especially in the humid tropics where results were described as fatally flawed and misleading.”

• cites Wessels, Van Den Bergh, and Scholes (2012)Not checked yet

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• cites Bai et al. (2008) sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

Satellite data are only available from the 1980s in most cases, so we have only a short time frame to observe changes in the land surface.

“Satellite data are only available from the 1980s in most cases, so we have only a short time frame to observe changes in the land surface.”

May combine two claims.

Early GLADA results reveal a declining trend in NPP across 21 percent of the global land area, 2.7 billion ha, mainly in tropical Africa, Southeast Asia, China, north central Australia, the Pampas, and swaths of the boreal forest in Siberia and North America.

“Early GLADA results reveal a declining trend in NPP across 21 percent of the global land area, 2.7 billion ha, mainly in tropical Africa, Southeast Asia, China, north central Australia, the Pampas, and swaths of the boreal forest in Siberia and North America.”

• cites Bai et al., 2008 sourceNot checked yet

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Classified as probably not a substantial claim.

Remotely-sensed data provide a major opportunity to improve our spatial representation of the locations of degraded lands in a globally consistent manner, as well as the process of degradation.

“Remotely-sensed data provide a major opportunity to improve our spatial representation of the locations of degraded lands in a globally consistent manner, as well as the process of degradation.”

May combine two claims.

Bai et al. (2008) found that nearly one-fifth of degraded land is cropland, an area equivalent to more than 20 percent of all cultivated areas.

“Bai et al. (2008) also found that nearly one-fifth of this degraded land is cropland, an area equivalent to more than 20 percent of all cultivated areas.”

• cites Bai et al. (2008) sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Another way to identify degraded lands is to look for areas that were once croplands but have since been abandoned because of decreased productivity, or due to political and economic reasons.

“Another way to identify degraded lands is to look for areas that were once croplands but have since been abandoned because of decreased productivity, or due to political and economic reasons.”

May combine two claims.

Many land-use mapping efforts employ expert opinion successfully but are generally limited by issues of consistency and bias.

“Many land-use mapping efforts employ expert opinion successfully (e.g., Achard et al., 2002;FAO, 2000) but are generally limited by issues of consistency and bias.”

• cites Achard et al., 2002 sourceNot checked yet

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• cites FAO, 2000Not checked yet

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May combine two claims.

The Cai et al. (2011) study assesses the extent of degradation due to over-utilization of lands of marginal productivity, and focuses on capturing the process of degradation, rather than the cumulative result.

“Thus, the study assesses the extent of degradation due to over-utilization of lands of marginal productivity, and focuses on capturing the process of degradation, rather than the cumulative result.”

• cites Cai et al. (2011) sourceNot checked yet

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May combine two claims.

The Cai et al. (2011) study focuses on lands of marginal productivity currently being cropped, so it excludes previously abandoned lands, lands that were experiencing full productivity when the data were developed, and non-agricultural degradation.

“As the Cai et al. (2011) study focuses on lands of marginal productivity currently being cropped, it excludes previously abandoned lands, lands that were experiencing full productivity when the data were developed, and non-agricultural degradation.”

• cites Cai et al. (2011) sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Cai et al. (2011) results asserted that Asia (China and India only) contained most of the land degradation, 490 million ha.

“Results asserted that Asia (China and India only) contained most of the land degradation, 490 million ha (Table 2).”

• cites Cai et al. (2011) sourceNot checked yet

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May combine two claims.

Roughly 23 percent of forests are improving along with more than 43 percent of rangelands.

“Roughly 23 percent of forests are also improving along with more than 43 percent of rangelands.”

• cites Bai et al., 2008 sourceNot checked yet

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May combine two claims.

Recent satellite advances have enabled new global scale datasets of agricultural land cover, which have been developed by merging satellite derived land cover maps with ground level agricultural inventory data sets.

“Recent satellite advances have enabled new global scale datasets of agricultural land cover, which have been developed by merging satellite derived land cover maps with ground level agricultural inventory data sets (Cardille, Foley, & Costa, 2002;Goldewijk, 2001;Ramankutty & Foley, 1999).”

• cites Cardille, Foley, & Costa, 2002Not checked yet

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• cites Goldewijk, 2001 sourceNot checked yet

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• cites Ramankutty & Foley, 1999 sourceNot checked yet

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Classified as probably not a substantial claim.

Deviations from normal NDVI may indicate land degradation once other factors that may be responsible, such as rainfall, climate, and land use, are taken into account.

“Deviations from normal NDVI may indicate land degradation once other factors that may be responsible, such as rainfall, climate, and land use are taken into account.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Extensive ground data, currently unavailable, will be required to produce reliable estimates of degraded areas from remote sensing at broad scales.

“Still, extensive ground data, currently unavailable, will be required to produce reliable estimates of degraded areas from remote sensing at broad scales (Kniivila, 2004).”

• cites Kniivila, 2004Not checked yet

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May combine two claims.

The vast majority (78 percent) of degrading lands are found in humid regions, which is contrary to the popular belief that most degradation occurs in drylands.

“The vast majority (78 percent) of degrading lands are found in humid regions, which is contrary to the popular belief that most degradation occurs in drylands.”

• cites Bai et al., 2008 sourceNot checked yet

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May combine two claims.

Satellite data will struggle to distinguish the fine gradients that exist between degraded and non-degraded grasslands and may be further limited by potentially confounding biophysical conditions.

“Satellite data will also struggle to distinguish the fine gradients that exist between degraded and non-degraded grasslands and may be further limited by potentially confounding biophysical conditions (e.g., seasonality in drylands and environmental trends; Wesselset al., 2012).”

• cites Wesselset al., 2012Not checked yet

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May combine two claims.

The accuracy of the biophysical approach will be influenced by the quality of the data used for calibration and the suitability of the model selected, which can be especially challenging when trying to manage conditions that vary locally at the global scale.

“Thus, the accuracy of the biophysical approach will be influenced by the quality of the data used for calibration and the suitability of the model selected, which can be especially challenging when trying to manage conditions that vary locally at the global scale.”

May combine two claims.

Bai et al. (2008) found that 16 percent of global land area is increasing in NPP, with 20 percent of total cropland area on an upward swing.

“But at the same time, they also found that 16 percent of global land area is increasing in NPP, with 20 percent of total cropland area on an upward swing.”

• cites Bai et al. (2008) sourceNot checked yet

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May combine two claims.

It is unlikely that remote sensing will be able to map all cases of land degradation unequivocally, but the approach does provide valuable clues and has the potential to identify hotspots of ongoing degradation.

“Thus, it is unlikely that remote sensing will be able to map all cases of land degradation unequivocally, but the approach does provide valuable clues and has the potential to identify hotspots of ongoing degradation (Alcantara, Kuemmerle, Prishchepov, & Radeloff, 2012;Prince, Becker-Reshef, & Rishmawi, 2009;Wessels, Prince, & Reshef, 2008).”

• cites Alcantara, Kuemmerle, Prishchepov, & Radeloff, 2012Not checked yet

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• cites Prince, Becker-Reshef, & Rishmawi, 2009Not checked yet

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• cites Wessels, Prince, & Reshef, 2008Not checked yet

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May combine two claims.

Roughly 40 percent of the degraded lands were found to be in forests, with another quarter in rangelands.

“Roughly 40 percent of the degraded lands were found to be in forests, with another quarter in rangelands.”

• cites Bai et al., 2008 sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Biophysical modeling has been broadly used to assess the potential vegetative productivity of global land areas.

“Biophysical modeling has been broadly used to assess the potential vegetative productivity of global land areas (e.g.Fischer, van Velthuizen, Shah, & Nachtergaele, 2002).”

• cites Fischer, van Velthuizen, Shah, & Nachtergaele, 2002Not checked yet

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Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

Others posit that Dregne and Chou (1992) have greatly overestimated degradation.

“However, others posit that Dregne and Chou (1992) have greatly overestimated degradation (Helld en & Tottrup, 2008).”

• cites Helld en & Tottrup, 2008Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

The spatial and temporal extent, as well as the type of degradation considered, is dependent upon the input data sets for the modeling process.

“The spatial and temporal extent, as well as the type of degradation considered, is dependent upon the input data sets for the modeling process.”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

Modeling approaches that rely on models will inevitably be influenced by any inherent error.

“Unfortunately, however, modeling approaches that rely on models will inevitably be influenced by any inherent error.”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

The expert opinion approach will continue as a mainstay until satellite-based measurements can provide more accurate and detailed information for both vegetation and soils.

“The expert opinion approach will continue as a mainstay until satellite-based measurements can provide more accurate and detailed information for both vegetation and soils.”

May combine two claims.

The vast majority of the agricultural abandonment occurred in Latin America, where over 56 million ha of land became 'idle' during the 1990s.

“The vast majority of the agricultural abandonment occurred in Latin America, where over 56 million ha of land became 'idle' during the 1990s.”

• cites FAO, 2001Not checked yet

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• cites Gibbs et al., 2010 sourceNot checked yet

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May combine two claims.

Tropical Asia accounts for 12 million ha and Africa for the remaining 9 million ha of abandoned land.

“Tropical Asia accounts for 12 million ha and Africa for the remaining 9 million ha of abandoned land.”

• cites FAO, 2001Not checked yet

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• cites Gibbs et al., 2010 sourceNot checked yet

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May combine two claims.

A significant limitation of the abandonment approach is that it excludes degradation other than agricultural abandonment, so the numbers should be considered extremely conservative estimates of degradation.

“A significant limitation of this approach is that it excludes degradation other than agricultural abandonment, so the numbers should be considered extremely conservative estimates of degradation.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The HYDE database also provides information on pastures not captured by Ramankutty and Foley (1999).

“The HYDE database also provides information on pastures not captured by Ramankutty and Foley (1999).”

• cites Ramankutty and Foley (1999) sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The magnitude of reported changes are relatively similar, suggesting some degree of confirmation.

“However, it is important to note that the magnitude of reported changes are relatively similar, suggesting some degree of confirmation.”

May combine two claims.

Most cropland abandonment occurred in eastern North America during the early 1900s but expanded to China, southern South America and Europe by mid-century.

“Most cropland abandonment occurred in eastern North America during the early 1900s but expanded to China, southern South America and Europe by mid-century.”

• cites Ramankutty and Foley (1999) sourceNot checked yet

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May combine two claims.

The analysis of the HYDE database by Campbell, Lobell, and Field (2009) found that over the last three centuries, 269 million ha of cropland and 479 million ha of pastureland were abandoned.

“The analysis of the HYDE database by Campbell, Lobell, and Field (2009) found that over the last three centuries, 269 million ha of cropland and 479 million ha of pastureland were abandoned.”

• cites Campbell, Lobell, and Field (2009) sourceNot checked yet

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May combine two claims.

Ramankutty and Foley (1999) found that the extent of cropland abandonment increased greatly from roughly 65 million ha in the 1950s to 225 million ha in 1990, and the rate of abandonment increased as well.

“They found that the extent of cropland abandonment increased greatly from roughly 65 million ha in the 1950s to 225 million ha in 1990, and the rate of abandonment increased as well.”

• cites Ramankutty and Foley (1999) sourceNot checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Degradation in one area may have ripple effects on other areas that are not readily evident from observations (e.g., siltation, chemical contamination).

“Degradation in one area may have ripple effects on other areas that are not readily evident from observations (e.g., siltation, chemical contamination).”

May combine two claims.

To grow crops or animals on lands with reduced productivity will be a low profit-high cost enterprise that is unlikely to happen without strong economic incentives to farmers and agroindustry.

“To grow crops or animals on lands with reduced productivity will be a low profitehigh cost enterprise that is unlikely to happen without strong economic incentives to farmers and agroindustry.”

Classified as probably not a substantial claim.

Lambin et al. (2013) emphasize that the physical availability of degraded land is only part of the story.

“Lambin et al. (2013) emphasize that the physical availability of degraded land is only part of the story.”

• cites Lambin et al. (2013) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

The GAEZ data set does not indicate the cause of salinization, but it could suggest more about the improvability of the land than the more general term 'degraded.'

“Though this data set does not indicate the cause of salinization, it could yet suggest more about the improvability of the land than the more general term 'degraded.'”

May combine two claims.

The two global agricultural databases are difficult to compare because Ramankutty and Foley (1999) do not consider abandonment of pastureland, which is part of the Campbell et al. (2009) estimate.

“The two global agricultural databases are also difficult to compare because Ramankutty and Foley (1999) do not consider abandonment of pastureland, which is part of the Campbell et al. (2009) estimate.”

• cites Ramankutty and Foley (1999) sourceNot checked yet

  Not checked in the free run.

• cites Campbell et al. (2009) sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The number of data sets in agreement revealed places where the majority of data sets diverged in their appraisal of degradation effects.

“The number of data sets in agreement revealed places where the majority of data sets diverged in their appraisal of degradation effects.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The FAO/IIASA analysis of Global Agro-EcoZones (GAEZ) estimates that 1.39 billion ha are affected by excess salts, leading to moderate, severe, or very severe constraints.

“The FAO/IIASA analysis of Global Agro-EcoZones (GAEZ) estimates that 1.39 billion ha are affected by excess salts, leading to moderate, severe, or very severe constraints (FAO/IIASA 2012).”

• cites FAO/IIASA 2012Not checked yet

  Not checked in the free run.

May combine two claims.

Restoration of degraded lands does offer a lower-carbon expansion pathway, and could provide some respite for forest conversion or increase food production in key locales.

“Restoration of degraded lands does offer a lower-carbon expansion pathway, and could provide some respite for forest conversion or increase food production in key locales (Gibbs et al., 2008).”

• cites Gibbs et al., 2008 sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

Our uncertain knowledge of degraded lands is not surprising given the significant measurement challenges of capturing a dynamic and subjective condition.

“Our uncertain knowledge of degraded lands is not surprising given the significant measurement challenges of capturing a dynamic and subjective condition.”

• AssumptionRests on an assumption: Degradation is a dynamic and subjective condition.

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Efforts to map degraded lands often aim to identify regions that could be converted to uses deemed more productive, particularly biofuel production.

“Efforts to map degraded lands often aim to identify regions that could be converted to uses deemed more productive, particularly biofuel production.”

May combine two claims.

Some degraded lands were once forests or savannas and may be better suited to restoration to those ecosystems, and their associated carbon sinks, rather than undergoing further development for agriculture.

“Some degraded lands were once forests or savannas and may be better suited to restoration to those ecosystems, and their associated carbon sinks, rather than undergoing further development for agriculture (Houghton & Hackler, 2006;Piñeiro, Jobb agy, Baker, Murray, & Jackson, 2009).”

• cites Houghton & Hackler, 2006Not checked yet

  Not checked in the free run.

• cites Piñeiro, Jobb agy, Baker, Murray, & Jackson, 2009Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Standard deviation, calculated independently for each 20 km cell, indicated the spread of the values that the four mapping methods ascribe to degraded area.

“Standard deviation, calculated independently for each 20 km cell, indicated the spread of the values that the four mapping methods ascribe to degraded area.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Linear regression indicated the presence or absence of any relationships between specific pairs of degradation mapping methods.

“Linear regression indicated the presence or absence of any relationships between specific pairs of degradation mapping methods (e.g.expert opinion versus abandoned agriculture).”

Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

In many ways our focus on using degraded lands is a distraction; it lulls us into complacency by implying that we can easily continue meeting global demands for agricultural commodities.

“In many ways our focus on using degraded lands is a distraction; it lulls us into complacency by implying that we can easily continue meeting global demands for agricultural commodities.”

Probably not a substantial claim: may not pass S4 (based). May combine two claims.

Leakage may occur as communities evicted from such degraded areas are pushed into the forest frontier, or they could face reduced livelihoods if pushed onto even lower quality lands.

“Leakage may also occur as communities evicted from such degraded areas are pushed into the forest frontier, or they could face reduced livelihoods if pushed onto even lower quality lands.”

May combine two claims.

Emphasizing and mapping these vulnerable regions may also facilitate large-scale economic land acquisitions, as countries perceived to have more cultivable land are likely to be more attractive to investment by others.

“Emphasizing and mapping these vulnerable regions may also facilitate largescale economic land acquisitions, as countries perceived to have more cultivable land are likely to be more attractive to investment by others (Deininger & Byerlee, 2011).”

• cites Deininger & Byerlee, 2011Not checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

Visual comparison was useful in identifying large differences between maps at the global scale.

“Visual comparison was useful in identifying large differences between maps at the global scale.”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

The estimates provided here provide a starting point for considering the potential of degraded land.

“The estimates provided here provide a starting point for considering the potential of degraded land.”

Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

Despite uncertainties in these estimates of degraded areas and their ideal uses, improved understanding of our global land base is necessary to address worldwide land scarcity, and to develop policies around bioenergy and large-scale land acquisitions.

“Despite uncertainties in these estimates of degraded areas and their ideal uses, improved understanding of our global land base is necessary to address worldwide land scarcity, and to develop policies around bioenergy and large-scale land acquisitions (Lambin & Meyfroidt, 2011;Lambin et al., 2013).”

• cites Lambin & Meyfroidt, 2011 sourceNot checked yet

  Not checked in the free run.

• cites Lambin et al., 2013 sourceNot checked yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S2 (checkable).

They emphasize the urgency for new approaches that will likely require a combination of innovative satellite data analysis and extensive field inventories.

“they emphasize the urgency for new approaches that will likely require a combination of innovative satellite data analysis and extensive field inventories.”