Deforestation, carbon emissions, and land-use displacement in the Chaco. Tobias Kuemmerle

Transcription

1 Deforestation, carbon emissions, and land-use displacement in the Chaco Tobias Kuemmerle

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3 The South American soybean boom Massive increase in soybean production since the 1980s Soybean area [Mha) Argentina Bolivia Brazil Paraguay Uruguay Source: FAOSTAT Photo: T. Kuemmerle 3

4 The South American soybean boom How has the soybean boom directly and indirectly affected deforestation and environmental impacts? Source: 4

5 Land-use change in the Gran Chaco Largest South American forest outside the Amazon Rich in biodiversity, but sparse protected area network Hotspot of land-use change globally Photos: T. Kuemmerle 5

6 Land-use change in the Gran Chaco Soybean expansion in Argentina between 1975 and 2005 Source: Clarin 6

7 Overarching research questions What were the rates and spatial pattern of land-use conversion in the Chaco since 1985? What were the carbon emissions associated with these losses? What is the evidence that deforestation and its emissions are driven by land-use displacement? Recently deforested plot in the Argentine Chaco Photo: T. Kuemmerle 7

8 Mapping land-use conversions Image composites based on ~15,000 Landsat images for the years 1985, 2000 and 2013 Map woodlands, grassland, savannas and croplands - and the transitions between these categories Baumann et al., 2017 Global Change Biology 8

9 Baumann et al., 2017 Global Change Biology Deforestation for cropland Deforestation for pasture 9

10 Massive loss of natural vegetation Rapid and accelerating woodland loss between (~140,000 km², >20%) Cattle ranching most dominant post-deforestation land use, especially after 2000 Baumann et al., 2017 Global Change Biology 10

11 Major differences among countries In terms of rates of land-use change In terms of post-deforestation land use Forest to grazing land Forest to cropland Baumann et al., 2017 Global Change Biology 11

12 Distinct frontiers Le Polain de Waroux et al. 2017, Annals Am. Assoc. Geogr. 12

13 Carbon Carbon emissions intro from land use change? Photo: T. Kuemmerle 13

14 Carbon book-keeping modelling Parameterized using extensive field data on carbon stocks Regionalized parameterization Land conversions from the remote sensing data Baumann et al., 2017 Global Change Biology 14

15 Carbon emissions Total emissions from the Chaco between due to habitat loss about 824 Tg C Annual emissions of up to 46 Tg C (2013) Emissions mainly from forest loss, but post-deforestation land-use change matters Emissions [Tg C] from Forest to cropland Forest to grazing land Baumann et al., 2017 Global Change Biology Grazing land to cropland 15

16 Carbon emissions Annual emissions comparable to Kalimantan, yet much higher deforestation rates Chaco as a whole a low carbon density fast deforestation frontier 16

17 Econometric modelling intro What drives these land use changes? Photo: T. Kuemmerle 17

18 What is the role of displacement? Soybean expansion pushes cattle ranching into more marginal areas, such as the Chaco? Displacement within countries and across country boundaries Source: 18

19 Land-use change driven by profits? Net returns model to estimate land conversion probabilities for the Argentinean Pampas and Chaco: Land-use changes from RS maps Estimate average profits to cropland as cropprofit = Σ (% ) [( ) ] Environmental and structural control variables Multinomial framework to estimate conversion probabilities for (1) forest pasture, (2) forest cropland, (3) pasture cropland Piquer-Rodriguez et al., under review a,b 19

20 Land-use change driven by profits? Pasture to cropland conversions well-explained by marginal changes in profits In both ecoregions, but especially in the Pampas Agricultural expansion into forests (pastures or cropland) much less sensitive to profit changes Piquer-Rodriguez et al., under review a,b 20

21 Drivers of land use change in the Chaco For grazing land cropland conversions: predicted vs actual land-use change patterns match well Piquer-Rodriguez et al., under review a,b 21

22 Drivers of land use change in the Chaco For woodland conversions: differences in predicted vs actual land-use change patterns Important non-profit related variables seems to drive these land-use transitions Woodland to cropland Woodland to pastures Piquer-Rodriguez et al., under review a,b 22

23 Soybean boom as an underlying driver? Correlation between soybean expansion and deforestation only high in some parts of Argentina Fehlenberg et al. 2017, Global Environmental Change 23

24 Soybean boom as an underlying driver? District-level panel regression models for all of the Chaco Inputs: deforestation (Y) and time series of soybean area and yields, cattle heads, environmental control variables Results: Soybean expansion only a direct driver of deforestation in Argentina Argentinean soybean expansion indirectly linked to deforestation in the Paraguayan and Bolivian Chaco Only weak link between changes in soybean area in Paraguay and deforestation in the Chaco Substantial time-delayed effects Fehlenberg et al. 2017, Global Environmental Change 24

25 Soybean boom as an underlying driver? Fits well to local-scale research (e.g., Le Poulain de Waroux et al.) and anecdotal evidence Fehlenberg et al. 2017, Global Environmental Change 25

26 Summary Rapid and accelerating land-use transitions in the Chaco The Chaco now a globally relevant source of carbon emissions related to deforestation Deforestation partly driven by soybean displacing cattle ranching - but evidence not very strong at the moment Linking fine-scale land-use change data with on consumption and trade would help to Characterize Chaco frontiers (and possibly to find the right policy mix for them) to better quantify indirect emissions embodied in soybean and beef traded from the region 26

27 Thanks to man collaborators! Matthias Baumann, Van Butsic, Verena Fehlenberg, Phillip Gärtner, Gregorio Gavier Pizarro, Ignacio Gasparri, Leandro Macchi, Daniel Müller, Robert Müller, Patrick Meyfroidt, Maria Piquer-Rodriguez, Yann le Poulain de Waroux, Fabrizio Vázquez, José Volante and many more 27

28 Thank you for listening! 28