Figure 8. Median projected changes in rainfed rice yields with low fertilizer use, 2000–2050 in 2030 to a decline of 2.2–4.3 percent in 2050. The negative impact on corn yields is even wider, ranging from a decline of 0.1– 12.6 percent in 2030 to decline of 3.2–23.8 percent SUMMARY | APRIL 2010 in 2050. ADAPTATION STRATEGIES Rosegrant et al. (2014) studied the potential benefits of developing a variety of agricultural technologies based on a global analysis at a half-degree resolution using a similar methodology to GCM crop modeling already discussed, but using two models from IPCC’s AR4—from Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) and MIROC—using the A1B scenario, which represents high-emissions, but not as high as under RCP 8.5. The results are useful not only in illustrating the magnitude of potential benefits of various technology interventions, but also in highlighting regional differences in those benefits. One limitation of their analysis, however, is that, although they calculated each technology’s benefits, they did not calculate the costs, which makes it difficult to determine the overall economic benefit of any one technology over any other. Source: Constructed by authors based on DSSAT model simulation results THE FULL EFFECT OF CLIMATE CHANGE ON AGRICULTURE Direct productivity effects are only one aspect of the impact of climate change, which also catalyzes indirect impacts across the globe. If climate change reduces the supply of an agricultural commodity, for example, prices will rise. For this reason, the effect of reduced production and productivity on the accessibility of agricultural commodities is not trivial. Under climate change, the prices of agricultural food commodities are projected to be considerably higher in 2030 and 2050 than they otherwise would be. Unsurprisingly, the impact of higher food prices is disproportionately higher on poor people. The technology that provided the highest projected increase in maize productivity was integrated soil fertility management (ISFM), at just over 32 percent nationwide (Table 9). The second-highest increase resulted from no-till agriculture, at just over 24 percent. ISFM includes the use of both organic inputs and synthetic fertilizers to maximize soil fertility. Both technologies ultimately increase soil organic matter, which in turn enhances other soil fertility indicators, such as nutrient and water retention (Rosegrant et al. 2014). Analyses based on the International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) project substantial consumer price increases by 2050 for cereals (38 percent), roots and tubers (34 percent), and fruits and vegetables (27 percent) compared with baseline values. Similarly, meat prices are projected to increase by 4 percent despite only a 0.7 percent decline in production. Among cereals, the prices of corn, rice, and wheat are projected to increase by 45, 26, and 15 percent, respectively. Depending on the climate model used, the impact of climate change on the productivity of rice ranges from a decline of 0.9–2.2 percent Unlike the case for rainfed maize, nitrogen-efficient varieties seem to offer large potential benefits for irrigated rice (Table 10). The projected increase in productivity was 53 percent nationally, and 61 percent for CAR. It should be noted, however, that—although this is a very encouraging result— the simulation was based on the potential to develop a crop that is not currently cultivated in the Philippines, so investment decisions should not be based on that statistic alone. 6