reconciling conservation of tropical forests and food...
TRANSCRIPT
Thank you!
Reconciling Conservation of Tropical Forests and Food
Production: Challenges and Opportunities
Third Annual International Food Security SymposiumTuesday, April 4th, 2017
University of Illinois at Urbana-Champaign
Paulo [email protected]
The world’s largest agriculture frontier
Agriculture and forests
• Can the expansion of cropping systems influence deforestation rates?
• What’s the role of agriculture expansion in altering forest disturbance regimes?
Cattle ranching
60-70% of deforested areas
Mechanized agriculture
12% direct deforestation
Why deforestation decreased?
Nepstad et al. 2014
Agriculture will lower deforestation if it…
• Decreases demand for new deforestation.
• Increases risks to those engaged in deforestation.
• Reduces the supply of undesignated claimed forestland – target of land speculators.
Production x Deforestation
Mato Grosso
Macedo et a. (2012)
Sparing land or buying out time?
Displacing deforestation?
650
700
750
800
850
2004 2008 2012 2016
Year
Cu
mu
lative
lo
ss (
tho
usa
nd k
m2)
BiomeAmazonCerrado
Agriculture x disturbance regimes
• Climate (precipitation and warming)
• Fragmentation (edges)
• Fire (ignition)
Environ. Res. Lett. 3 (2008) 044006 R B Jackson et al
A B
C D
Figure 1. Examples of various biophysical factors in a grassland or cropland (A) and forest (B). Because of a grassland or cropland’s higherreflectivity (albedo), it typically reflects more sunlight than the forest does, cooling surface air temperatures relatively more. In contrast, theforest often evaporates more water and transmits more heat to the atmosphere (latent and sensible heat, respectively), cooling it locallycompared to the grassland or unirrigated cropland. More water vapor in the atmosphere can lead to a greater number and height of clouds aswell as to increased convective rainfall. In addition, the forest has a more uneven canopy (surface roughness) that increases mixing andupwelling of air. ((C) and (D)) Comparison of shortwave albedo and surface skin temperature for 215 grassland and forest stands acrossArgentina and Uruguay. The satellite data were assessed using 180 km × 180 km Landsat images (2000–2005) on seven dates for theCorrientes and Concordia regions of Argentina and three dates for the Rivera region of Uruguay. The Landsat scenes were geometrically andatmospherically corrected and correspond to images 226/80 (path and row) for Corrientes, 225/82 for Concordia, and 223/82 for Rivera. Ingeneral, measurements at sites within a region compared adjacent grassland, pine, and eucalypt stands.
albedo, but they are fire-prone [24] and often use more
water than native vegetation [19]. Because forestry projects
can appropriate scarce water resources, they may be poor
choices in semi-arid regions [19, 25]. Applying fertilizers in
forest sequestration projects helps trees grow more quickly
but also increases the emissions of nitrous oxide, a potent
greenhouse gas [26]. Finally and perhaps most importantly,
forests provide a wide range of important services, including
preserving biodiversity, wildlife habitat, and freshwater supply.
Policies focused solely on managing vegetation to cool local
or global temperatures may jeopardize other key ecosystem
services.
In the coming decades, policies for forest carbon
sequestration and offset activities will create a multi-billion-
dollar industry. The biophysical consequences of forest
cover change and other co-effects of these activities can
be large at regional scales [27, 28] and may sometimes
reduce or even cancel the benefits of carbon sequestration.
Biophysical interactions should therefore be factored into
climate mitigation strategy in at least two ways—in designing
carbon sequestration projects to achieve the greatest climate
benefit and in comparing the costs and benefits of terrestrial
carbon sequestration with those of other mitigation activities.
Successful policy should account for the different ways that
3
Costa et al. 2007
Amazon edges
- Demand to comply with the Forest Code and restore large tracts of deforested areas
- Between 2004 and 2008, IPAM-WHRC provided science-based guidance to Amaggi in this process.
12-16% of Amazonforests near an edge
Brando et al. 2014
Trumbore et al. 2015
Tanguro
Testing the limits of Amazon forests
Brando et al. 2013
Brando et al. 2014 PNAS21
Fire-induced tree mortality
3ºC Warmer
20% DrierControl
Burned Annually
Burned 3yrs
Tanguro
Since 2004 IPAM/WHRC have studied the impacts of drought-fires on forest dynamics stability
Cropping and fire ignition
NYT
Cropping and fire ignition
Discussion points
• Can agriculture intensification lead to land sparing in tropical regions?
• Are the climatic changes caused by agriculture intensification/expansion large enough to accentuate a large-scale forest dieback?
• Multiple disturbances can lead to rapid forest degradation, but it is still unclear how much of the region is exposed to such disturbances.