Socio-economic and climate change impacts on agriculture: an integrated assessment, 1990-2080

Abstract

A comprehensive assessment of the impacts of climate change on agro-ecosystems over this century is developed, up to 2080 and at a global level, albeit with significant regional detail. To this end an integrated ecological-economic modelling framework is employed, encompassing climate scenarios, agro-ecological zoning information, socio-economic drivers, as well as world food trade dynamics. Specifically, global simulations are performed using the FAO/IIASA agro-ecological zone model, in conjunction with IIASAs global food system model, using climate variables from five different general circulation models, under four different socio-economic scenarios from the intergovernmental panel on climate change. First, impacts of different scenarios of climate change on bio-physical soil and crop growth determinants of yield are evaluated on a 5' X 5' latitude/longitude global grid; second, the extent of potential agricultural land and related potential crop production is computed. The detailed bio-physical results are then fed into an economic analysis, to assess how climate impacts may interact with alternative development pathways, and key trends expected over this century for food demand and production, and trade, as well as key composite indices such as risk of hunger and malnutrition, are computed. This modelling approach connects the relevant bio-physical and socio-economic variables within a unified and coherent framework to produce a global assessment of food production and security under climate change. The results from the study suggest that critical impact asymmetries due to both climate and socio-economic structures may deepen current production and consumption gaps between developed and developing world; it is suggested that adaptation of agricultural techniques will be central to limit potential damages under climate change.

Figure 1

Graphic description of the AEZ–BLS modelling framework. Socio-economic SRES scenarios determine both climatic and market conditions under which AEZ and BLS are run. Climatic impacts on agricultural production—computed with AEZ, are passed on to the agricultural economics and trade model, BLS, to determine overall impacts on world food systems.

Figure 2

GCM-predicted mean annual temperature change over land, as a function of corresponding CO₂ concentrations (a proxy for time from 1990 to 2080) and against GCM-predicted mean annual precipitation change. Graphs show results for all 14 scenarios considered in this study, computed for all land in (a) developed world and (b) developing world.

Figure 3

Changes in potentially attainable cereal-production predicted by AEZ under different GCM climate change scenarios, versus CO₂ concentration. Projections are for either current cultivated land (right), or all available under future climates (left), and pooled into developed (top) and developing (bottom) countries. Results are expressed against an index of climate change (=100 in 1990), a proxy for time from 1990 to 2080.

Figure 4

Changes in potentially attainable wheat production predicted by AEZ under different GCM climate change scenarios, versus CO₂ concentration. Projections are for either current cultivated land (right), or all available under future climates (left), and pooled into developed (top) and developing (bottom) countries. Results are expressed against an index of climate change (=100 in 1990), a proxy for time from 1990 to 2080.

Figure 5

AEZ-simulated distribution of climate impacts on cereal productivity in the 2080s, under HadCM3-A1FI climate projections. The diagrams show the distribution of land with respect to cereal suitability changes under climate change. Bars shown to the right of the red line indicate land pixels where suitability increased; bars to the left denote negative changes. SI=suitability index for potential cereal-production computed by AEZ.

Figure 6

Impacts of climate change on rainfed cereal-production potential of developing countries, for currently cultivated land in the 2080s, according to HadCM3 and CSIRO climate projections.

Figure 7

Geographic distribution of percentage changes of AEZ-simulated potentially attainable cereal output per grid cell in the 2080s, SRES A2, and different GCM climate projections, relative to current climate.

Figure 8

BLS-based estimation of the percent share of undernourished people in the total population of any given country, based on food balances, based on domestic production as well as on international trade.

Figure 9

BLS-projected number of people undernourished, under all four SRES scenarios and no climate change, computed for (a) all developing countries and (b) African developing countries.

Figure 10

Additional number of people at risk of hunger in 2080, plotted against different levels of atmospheric CO₂ concentrations and associated climate change, for SRES A2 development path and simulation results with HadCM3 and CSIRO climate projections.