5 Conclusions
Broadly, climate change seems likely to lead to increases in yield potential at midand high mid-latitudes, and to decreases in the Tropics and Subtropics. But there
are many exceptions, particularly where increases in monsoon intensity or where
more northward penetration of monsoons leads to increases in available moisture.
Risk of hunger increases generally as a result of climate change, particularly in
southern Asia and Africa. However, this geographic distribution in some areas is
more the result of projected increase in number of poor people in these regions
(i.e. the exposed population) than of the regional pattern of climate change.
Much, of course, is uncertain. In particular, we are unclear about the
potentially beneficial effects of elevated CO
on crop growth. Current estimates
are based upon field experiments that have assumed near-optimal applications of
fertilizer, pesticide and water, and it is possible that the actual ‘fertilizing’ effect of
higher levels of CO
is less than we expect. Moreover, we have not taken into
account effects of altered climate on pests and weeds, which are likely to vary
greatly from one environment to another.
Although we have considered two levels of adaptation, these barely begin to
capture the range of options that is open to farmers. What is, however, initially
evident (and intuitively makes sense) is that the potential for adaptation is greater
in more developed economies and that this, together with the generally more
favourable effects of climate change on yield potential in higher rather than lower
latitude regions, is likely on balance to bring more positive effects to the North
and more negative effects to the South; in other words, to aggravate inequalities
in development potential.
Climate Change, Global Food Supply and Risk of Hunger
137
Broadly, climate change seems likely to lead to increases in yield potential at midand high mid-latitudes, and to decreases in the Tropics and Subtropics. But there
are many exceptions, particularly where increases in monsoon intensity or where
more northward penetration of monsoons leads to increases in available moisture.
Risk of hunger increases generally as a result of climate change, particularly in
southern Asia and Africa. However, this geographic distribution in some areas is
more the result of projected increase in number of poor people in these regions
(i.e. the exposed population) than of the regional pattern of climate change.
Much, of course, is uncertain. In particular, we are unclear about the
potentially beneficial effects of elevated CO
on crop growth. Current estimates
are based upon field experiments that have assumed near-optimal applications of
fertilizer, pesticide and water, and it is possible that the actual ‘fertilizing’ effect of
higher levels of CO
is less than we expect. Moreover, we have not taken into
account effects of altered climate on pests and weeds, which are likely to vary
greatly from one environment to another.
Although we have considered two levels of adaptation, these barely begin to
capture the range of options that is open to farmers. What is, however, initially
evident (and intuitively makes sense) is that the potential for adaptation is greater
in more developed economies and that this, together with the generally more
favourable effects of climate change on yield potential in higher rather than lower
latitude regions, is likely on balance to bring more positive effects to the North
and more negative effects to the South; in other words, to aggravate inequalities
in development potential.
Climate Change, Global Food Supply and Risk of Hunger
137