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46
Projected changes in agricultural productivity to 2080 due to
climate change, incorporating the effects of carbon fertilization
-50%
-15% 0
+15% +35% No data
maize in the absence of any agricultural adaptation to cli-
mate change have been projected by Lobell
et al.
(2008).
The effects of extreme weather are not included in these
estimates. In addition, these effects are projected to 2030
only, when the impacts of climate change would be only
just emerging. Increasing our understanding how crops
may be impacted under climate change conditions may
provide alternatives for adaptive strategies in the most vul-
nerable regions of the world (Lobell
et al
., 2008).
Based on a consensus estimate of 6 climate models and
two crop modelling methods, Cline (2007) concluded that
by 2080, assuming a 4.4° C increase in temperature and
a 2.9% increase in precipitation, global agricultural output
potential is likely to decrease by about 6%, or 16% without
carbon fertilization. Cline suggested a range of output po-
tential decline between 10 and 25% among regions. As cli-
mate change increases, projections have been made that by
2080 agricultural output potential may be reduced by up
to 60% for several African countries, on average 16–27%,
dependent upon the effect of carbon fertilization (Figures
18 and 19). These effects are in addition to general water
scarcity as a result of melting glaciers, change in rainfall
patterns, or overuse.
Figure 18: Projected losses in food production due to climate change by 2080.
(Source: Cline, 2007).