Agriculture, Ecosystems and Environment 82 2000 261–271
Response and risk in rural ecosystems: from models and plots to defined universes
Jock R. Anderson
∗
Rural Development Department, World Bank, Washington, DC, USA
Abstract
This essay was prepared as an invited closure of a thematic session on “Scaling and Extrapolation” at the CGTE Conference on “Food and Forestry: Global Change and Global Challenges”. It is addressed to those who prognosticate at the global or
other large levels about food and forestry systems, and who naturally confront several problems, and inevitably also some risk. The problems range from conceptual and practical to measuremental and statistical. For other than simplistic models,
many constraints apply to procedures used to aggregate from small-scale to large-scale representations of agricultural systems, whether they be biophysical or socioeconomic, especially when uncertainty is explicitly recognized. Model-linking procedures
work well in some cases but by no means all. The risks encountered in such work are similarly wide-ranging, depending on the intrinsic uncertainties, context, analyst and audience. These spectrums of problems and risks, along with some suggestions for
what practically can be done about them largely involving ad hoc simulation modeling, are examined from a response-analysis perspective across a range of biophysical and social phenomena pertinent to terrestrial ecosystems. Attention is given to policy
applications of scaled-up models. © 2000 Elsevier Science B.V. All rights reserved.
Keywords: Aggregation; Agriculture; Modeling; Policy; Scaling; Uncertainty
1. Introduction
The author comes to this topic from a background in response analysis e.g., Dillon and Anderson, 1990,
risk analysis e.g., Anderson et al., 1977; Hardaker et al., 1997, and global analysisforecasting e.g.,
Anderson et al., 1988; Crosson and Anderson, 1992, 1994. In spite of the dual dangers of discovery of
personal inconsistency, and of possible delusions of self-citation, there is here an opportunity to review
some experiences germane to the topic of scaling up. Of the literature perused that seemed central to
this topic, Schneider 1994 was the most instructive, as well as the most entertaining.
∗
Tel.: +1-202-473-0437; fax: +1-202-614-0084. E-mail address: jandersonworldbank.org J.R. Anderson.
2. Context
The national and international policy agenda is in- creasingly encompassing global and regional issues,
as evidenced, for instance, for agriculture and forestry, by forums such as the present e.g., Committee on
Long-Run Soil and Water Conservation, 1993; OECD, 1998a,b and the diverse activities of the global envi-
ronment facility GEF e.g., GEF, 1998, 1999; Pagi- ola, 1999. This is to say that policy makers concerned
with agriculture, broadly defined, have rather lifted their horizons in recent times to seek to address much
broader issues than was their former, usually more na- tional, want. In the World Bank, analogous concerns
have led to changing my department from agricultural to rural World Bank, 1997a, and to a determination
for the rural staff to work beyond merely agricultural
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262 J.R. Anderson Agriculture, Ecosystems and Environment 82 2000 261–271
issues to ensure effective and relevant linkages across social and environmental as well as other more tradi-
tional spatial and investment considerations, in what the Bank calls Environmentally and Socially Sustain-
able Development.
Clearly it is not just the changing perception of the importance of supra-national issues that has facilitated
such broader purviews. The technology now avail- able to analysts has greatly expanded the opportuni-
ties, and these are being increasingly seized. GIS and GPS, electronic computers, contemporary software,
and modeling capability generally, have all surely led to significant expansion in the capacity for well-tuned
even inexperienced analysts to do so much more than their parents could ever have hoped to do at higher
levels of both resolution and aggregation.
And yet life is still not necessarily all so easy. The misleading nature of assessment of sustainability ques-
tions at crop-plot or field level, while ignoring other linked elements of the landscape, such as forests and
less-agriculturally managed areas Leach and Mearns, 1996, has given greater recognition of the need for
broad spatial scales of analysis, such as at the ecosys- tem Gregory and Ingram, 2000 or catchment Tinker
and Anderson, 1996 levels. This is overtly the case for global-level issues such as concerning the atmo-
sphere, but analogously pertains too to the geosphere and biosphere.
The problematic of this paper can now be stated. Many research workers have their hands-on inves-
tigative activities primarily at the level of field plots or process models, and yet are interested in saying
something sensible perhaps to policy makers about the behavior of some defined “universe”, at a wider
or more aggregate level of a system. To do this they must use a process such as addition, multiplication,
aggregation, magnification, transformation or general- ization. Within this unsettled set of procedures, there
are possibilities of combinations of method, and op- portunities for error, such as fallacy of composition;
in short, the challenge of the scaling-up problem.
For agricultural resource analysts, scaling up seems to be mainly concerned with the representativeness of
plot-level observations for making statements about the status of a resource such as soil in a patch-mozaic
agriculture Scoones and Toulmin, 1999, p. 29, 31, 41. Agricultural ecologists take this idea to a higher
level of generality Fresco and Kroonenberg, 1992. Engineers call scaling work dimensional analysis,
and there are well agreed procedures for particular classes of scale models. For yet others, the scaling-up
problem is more one of the difficulty of getting widespread adoption of worthy technical solutions
that seem to work well in local “islands of success” in developing agriculture Pretty, 1995, 1997. More
specifically, in the context of World Bank operations, it usually means handling the challenge of moving
from a pilot operation to a “full-scale” project. In- deed, the World Bank President has recently opined
that the most pressing problem facing Bank staff and their clients is that of scaling up from project-level
activities that work well enough at that typically more bounded level, to wider endeavors that really make a
difference in poverty alleviation at the national level and beyond; or else “the race” is being lost.
For the level of generality sought in this overview, it may be that there are no general fixes widely appli-
cable to diverse phenomena. To consider briefly one of the more general treatments observed, White et al.
1998, Table 19.3 offer tantalizing advice — tanta- lizing because there is no further discussion of these
“problem-solving” suggestions in the paper — about “scaling up” under three heads:
synthesis across sites — GIS and modeling these two data sourcesmethods for all the three, site
similarity studies; extrapolation of practices — extrapolation domain
definition; and links among system levels — watershed studies,
decision support systems. The sections pertaining to response and risk that
follow set out considerations that point to some pos- sibly useful procedures. Needless to say, adequate
scaling-of-model insight is a necessary but not a suf- ficient condition for good policy making at global
ecosystem levels, but the latter large topic is beyond the scope of this paper, covered herein by Norse and
Tschirley 2000.
3. Response and aggregation
