Page 74 - FAO-IPCC Expert meeting on climate change

Appendix 01: Speakers’ summary notes
52
Synergies and trade-offs between forestland management and food system
ARILD ANGELSEN1
PLENARY SESSION 3:
HUMAN-DIRECTED DRIVERS OF LAND USE AND LAND USE CHANGE, LAND DEGRADATION AND IMPLICATIONS FOR FOOD SECURITY
Introduction
A long-standing debate concerns the impact of improved agricultural technologies and higher yield on agricultural land expansion into natural habitats (including forests) with subsequent biodiversity loss and greenhouse gas (GHG) emissions. Is higher yield (i) land saving, as growing demand for food and other agricultural outputs can be met by the same acreage (the Borlaug hypothesis, based on a simple global food equation), or (ii) does the potentially higher profitability of crop and livestock production stimulate land expansion (the Jevons paradox)? The answer to the question depends on the technology in question, the farm and farmer characteristics, the biophysical and institutional/ policy environment, the market conditions, as well as the scale of adoption and of the analysis (Angelsen and Kaimowitz, 2001a).
The potential of achieving win-win outcomes formed part of the basis for the promotion of Green Revolution technologies and – more recently – of climate smart agriculture (CSA), and – as a subset of that – conservation agriculture (CA). CSA and CA has gained prominence among donors, NGOs, national ministries, international research centres and agricultural extension agencies as a potentially viable means to increase agricultural productivity and food security while delivering climate benefits, both on-site and off-site by reducing pressure on natural habitats. They
are also linked to the call for sustainable intensification (SI) of agriculture, to avoid “the risk that land is cleared for agricultural production elsewhere to compensate for locally lower yields” (Garnett et al., 2013, 33).
The AR5 IPCC also points to CA principles and sustainable intensification as a major avenue for both climate mitigation and adaptation in agriculture (Niang et al., 2014; Smith et al., 2014). This debate is also linked to the question on land sharing vs. land sparing, that is, whether optimal production and conservation benefits are achieved by integrating the two objectives at the same land or by landscape specialization (Phalan et al., 2011; Kremen, 2015).
These linked concepts of CSA, CA and SI raise at least three major issues: (i) adoption; (ii) impact on yield, farm incomes and food security; and (iii) impact on GHG emissions and other environmental outcomes. This note focusses on the latter. There is, however, a lively debate on adoption rates, e.g., of CA in Sub-Saharan Africa. Despite almost two decades of sustained CA promotion among small-scale farmers in SSA, the extent of its adoption among smallholders remains mixed and contested (Giller et al., 2009)2009. Ngoma et al. (2016) find, using nationally representative data, for Zambia that less than 5% of the smallholders (on less than 3% of total cultivated land) practice minimum tillage, while other estimates have reported as high as 71% uptake. CA practices tend to be labour intensive, and family labour supply is limited and farmers often cannot afford to hire in labour. The investments in CA can pay dividends over the medium-long term in terms of higher crop yield, but the high initial costs – including own labour – make some reluctant.
The yield effects from CA and other forms of SI are, in general favourable. Evidence from experimental plots suggests that CA may improve maize yields in the medium to long term but that short term benefits are variable and negative on average (Thierfelder et al., 2015)2015. A meta-analysis of CA yield impact points that the effect depends on a number of factors, such as rainfall and drainage and the level of inputs (including fertilizers) (Rusinamhodzi et al., 2011).
The impact on GHG emissions can be split into on-site and off-site emission, the latter being linked to direct and indirect land cover change. Improved soil carbon sequestration resulting from reduced tillage and enhanced build-up of soil organic matter can reduce emissions and enhance removals. According to some estimates, improved practices, such as minimum tillage, can reduce emissions by as much as 1.1-4.3 GtCO2e y-1 by 2020 (UNEP, 2013). Others questions, however, the methods used and argue that the estimates are overstated (Powlson et al., 2014; Powlson et al., 2016). The remainder of this note deals with the impact of new technologies and higher yield on agricultural land expansion,
I am grateful for very useful comments and literature suggestions from Tobias Kümmerle, Hambulo Ngoma, Ben Phalan and the expert
1
meeting participants to the first draft of this summary.
FAO-IPCC Expert meeting on climate change, land use and food security