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Human population growth offsets climate-driven increase in woody vegetation in sub-Saharan Africa

Brandt, Martin; Rasmussen, Kjeld; Peñuelas, Josep; Tian, Feng LU ; Schurgers, Guy; Verger, Aleixandre; Mertz, Ole; Palmer, John R.B. and Fensholt, Rasmus (2017) In Nature Ecology and Evolution 1(4).
Abstract

The rapidly growing human population in sub-Saharan Africa generates increasing demand for agricultural land and forest products, which presumably leads to deforestation. Conversely, a greening of African drylands has been reported, but this has been difficult to associate with changes in woody vegetation. There is thus an incomplete understanding of how woody vegetation responds to socio-economic and environmental change. Here we used a passive microwave Earth observation data set to document two different trends in land area with woody cover for 1992-2011: 36% of the land area (6,870,000 km2) had an increase in woody cover largely in drylands, and 11% had a decrease (2,150,000 km2), mostly in humid zones.... (More)

The rapidly growing human population in sub-Saharan Africa generates increasing demand for agricultural land and forest products, which presumably leads to deforestation. Conversely, a greening of African drylands has been reported, but this has been difficult to associate with changes in woody vegetation. There is thus an incomplete understanding of how woody vegetation responds to socio-economic and environmental change. Here we used a passive microwave Earth observation data set to document two different trends in land area with woody cover for 1992-2011: 36% of the land area (6,870,000 km2) had an increase in woody cover largely in drylands, and 11% had a decrease (2,150,000 km2), mostly in humid zones. Increases in woody cover were associated with low population growth, and were driven by increases in CO2 in the humid zones and by increases in precipitation in drylands, whereas decreases in woody cover were associated with high population growth. The spatially distinct pattern of these opposing trends reflects, first, the natural response of vegetation to precipitation and atmospheric CO2, and second, deforestation in humid areas, minor in size but important for ecosystem services, such as biodiversity and carbon stocks. This nuanced picture of changes in woody cover challenges widely held views of a general and ongoing reduction of the woody vegetation in Africa.

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published
in
Nature Ecology and Evolution
volume
1
issue
4
external identifiers
  • scopus:85019844336
DOI
10.1038/s41559-017-0081
language
English
LU publication?
no
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1b6c93b9-e576-4618-aded-9e5fb14a5f71
date added to LUP
2018-06-08 14:31:36
date last changed
2018-08-19 04:43:16
@article{1b6c93b9-e576-4618-aded-9e5fb14a5f71,
  abstract     = {<p>The rapidly growing human population in sub-Saharan Africa generates increasing demand for agricultural land and forest products, which presumably leads to deforestation. Conversely, a greening of African drylands has been reported, but this has been difficult to associate with changes in woody vegetation. There is thus an incomplete understanding of how woody vegetation responds to socio-economic and environmental change. Here we used a passive microwave Earth observation data set to document two different trends in land area with woody cover for 1992-2011: 36% of the land area (6,870,000 km<sup>2</sup>) had an increase in woody cover largely in drylands, and 11% had a decrease (2,150,000 km<sup>2</sup>), mostly in humid zones. Increases in woody cover were associated with low population growth, and were driven by increases in CO<sub>2</sub> in the humid zones and by increases in precipitation in drylands, whereas decreases in woody cover were associated with high population growth. The spatially distinct pattern of these opposing trends reflects, first, the natural response of vegetation to precipitation and atmospheric CO<sub>2</sub>, and second, deforestation in humid areas, minor in size but important for ecosystem services, such as biodiversity and carbon stocks. This nuanced picture of changes in woody cover challenges widely held views of a general and ongoing reduction of the woody vegetation in Africa.</p>},
  articleno    = {0081},
  author       = {Brandt, Martin and Rasmussen, Kjeld and Peñuelas, Josep and Tian, Feng and Schurgers, Guy and Verger, Aleixandre and Mertz, Ole and Palmer, John R.B. and Fensholt, Rasmus},
  language     = {eng},
  month        = {03},
  number       = {4},
  series       = {Nature Ecology and Evolution},
  title        = {Human population growth offsets climate-driven increase in woody vegetation in sub-Saharan Africa},
  url          = {http://dx.doi.org/10.1038/s41559-017-0081},
  volume       = {1},
  year         = {2017},
}