Identifying potential synergies and trade-offs for meeting food security and climate change objectives in sub-Saharan Africa.
Potential interactions between food production and climate mitigation are explored for two situations in sub-Saharan Africa, where deforestation and land degradation overlap with hunger and poverty. Three agriculture intensification scenarios for supplying nitrogen to increase crop production (mineral fertilizer, herbaceous legume cover crops--green manures--and agroforestry--legume improved tree fallows) are compared to baseline food production, land requirements to meet basic caloric requirements, and greenhouse gas emissions. At low population densities and high land availability, food security and climate mitigation goals are met with all intensification scenarios, resulting in surplus crop area for reforestation. In contrast, for high population density and small farm sizes, attaining food security and reducing greenhouse gas emissions require mineral fertilizers to make land available for reforestation; green manure or improved tree fallows do not provide sufficient increases in yields to permit reforestation. Tree fallows sequester significant carbon on cropland, but green manures result in net carbon dioxide equivalent emissions because of nitrogen additions. Although these results are encouraging, agricultural intensification in sub-Saharan Africa with mineral fertilizers, green manures, or improved tree fallows will remain low without policies that address access, costs, and lack of incentives. Carbon financing for small-holder agriculture could increase the likelihood of success of Reducing Emissions from Deforestation and Forest Degradation in Developing Countries programs and climate change mitigation but also promote food security in the region.
Palm
Cheryl A
CA
Tropical Agriculture and Rural Environment Program, The Earth Institute, Columbia University, P.O. Box 1000, Palisades, NY 10964, USA. cpalm@ei.columbia.edu
Smukler
Sean M
SM
Sullivan
Clare C
CC
Mutuo
Patrick K
PK
Nyadzi
Gerson I
GI
Walsh
Markus G
MG
D017954:Africa South of the Sahara; D000383:Agriculture / Q000379:methods*; D002244:Carbon / Q000032:analysis; D058572:Carbon Footprint; D057231:Climate Change; D005523:Food Supply; D057232:Global Warming; D009609:Nitrous Oxide / Q000032:analysis; D003313:Zea mays / Q000254:growth & development
D002244:Carbon; D009609:Nitrous Oxide
Science. 2002 Mar 15;295(5562):2019-20
11896257
Philos Trans R Soc Lond B Biol Sci. 2008 Feb 12;363(1491):495-515
17656343
Proc Natl Acad Sci U S A. 2009 Dec 8;106(49):20675-80
19955435
Science. 2000 Sep 15;289(5486):1922-5
10988070
PLoS Biol. 2009 Jan 27;7(1):e23
19175292
Proc Natl Acad Sci U S A. 2007 Oct 23;104(43):16757-62
17942698
Science. 1998 Apr 3;280(5360):112-5
9525856
Science. 2009 Sep 4;325(5945):1209-10
19729642
Proc Natl Acad Sci U S A. 2007 Oct 23;104(43):16775-80
17942701