Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC
AR4) projected that mean annual precipitation will increase in the tropical regions
and at high northern latitudes, and decrease in the subtropics. Meanwhile, precipitation may increase in one season, while it may decrease in another one. Over
most parts of the globe, the mean annual runoff will increase; however, there are
still some significant areas where runoff will decrease such as middle-east Europe,
northern Africa, Central America, Southern Africa, major parts of southern and
western Australia, and various areas of South America (Parry 2007).
Climate variability is one of the most significant factors influencing yearto-year crop production, even in high-yield and high-technology agricultural areas
(Kang et al. 2009). Investments aimed at improving agricultural adaptation to
climate change inevitably favor some crops and regions over others. Crop yields
affected by climate change are projected to be different in various areas. Studies
done to date show that negative and positive effects will occur both within
countries and across the world and agricultural regions will be affected quite
differently. In some areas crop yields will increase, and in other areas it will
decrease depending on the latitude of the area and irrigation application (Kang
et al. 2009). For example, some regions will experience increases in production
and some will experience declines (Reilly et al. 2003). Also, developing countries
are more vulnerable than developed countries. This is because most developing
countries are located in lower latitude regions (some of which are indeed semiarid), while most developed countries are located in the more humid mid to high
latitudes. Thus, higher temperatures will intensify the evaporative demand of the
atmosphere, leading to greater water stress, especially in semi-arid regions and as a
result many crops will be pushed beyond their limits of optimal growth and yield.
This suggests a divergence in vulnerability between these groups of nations
(Rosenzweig 2007).
Farmers have dealt with climatic fluctuations since the advent of agriculture,
and improving strategies for dealing with present climate extremes such as
droughts, floods, and heat waves is an important way to prepare for climate change
(Rosenzweig et al. 2001). The crop yield can be increased with irrigation application and precipitation increase during the crop growth; meanwhile, crop yield is
more sensitive to the precipitation than temperature. If water availability is
reduced in the future, soil of high water holding capacity will be better to reduce
the frequency of drought and improve the crop yield (Kang et al. 2009). With
climate change, the growing period will reduce, and the planting date also needs to
change for higher crop production. Climate change can decrease the crop rotation
period, so farmers need to consider crop varieties, sowing dates, crop densities,
and fertilization levels when planting crops (Cuculeanu et al. 2002). So adaptation
is a key factor that will shape the future severity of climate change impacts on food
production. Although relatively inexpensive changes, such as shifting planting
dates or switching to an existing crop variety, may moderate negative impacts, the
biggest benefits will likely result from more costly measures including the
development of new crop varieties and expansion of irrigation (Lobell et al. 2008).
1 Strategies for Sustainable Plant Food Production
21
AR4) projected that mean annual precipitation will increase in the tropical regions
and at high northern latitudes, and decrease in the subtropics. Meanwhile, precipitation may increase in one season, while it may decrease in another one. Over
most parts of the globe, the mean annual runoff will increase; however, there are
still some significant areas where runoff will decrease such as middle-east Europe,
northern Africa, Central America, Southern Africa, major parts of southern and
western Australia, and various areas of South America (Parry 2007).
Climate variability is one of the most significant factors influencing yearto-year crop production, even in high-yield and high-technology agricultural areas
(Kang et al. 2009). Investments aimed at improving agricultural adaptation to
climate change inevitably favor some crops and regions over others. Crop yields
affected by climate change are projected to be different in various areas. Studies
done to date show that negative and positive effects will occur both within
countries and across the world and agricultural regions will be affected quite
differently. In some areas crop yields will increase, and in other areas it will
decrease depending on the latitude of the area and irrigation application (Kang
et al. 2009). For example, some regions will experience increases in production
and some will experience declines (Reilly et al. 2003). Also, developing countries
are more vulnerable than developed countries. This is because most developing
countries are located in lower latitude regions (some of which are indeed semiarid), while most developed countries are located in the more humid mid to high
latitudes. Thus, higher temperatures will intensify the evaporative demand of the
atmosphere, leading to greater water stress, especially in semi-arid regions and as a
result many crops will be pushed beyond their limits of optimal growth and yield.
This suggests a divergence in vulnerability between these groups of nations
(Rosenzweig 2007).
Farmers have dealt with climatic fluctuations since the advent of agriculture,
and improving strategies for dealing with present climate extremes such as
droughts, floods, and heat waves is an important way to prepare for climate change
(Rosenzweig et al. 2001). The crop yield can be increased with irrigation application and precipitation increase during the crop growth; meanwhile, crop yield is
more sensitive to the precipitation than temperature. If water availability is
reduced in the future, soil of high water holding capacity will be better to reduce
the frequency of drought and improve the crop yield (Kang et al. 2009). With
climate change, the growing period will reduce, and the planting date also needs to
change for higher crop production. Climate change can decrease the crop rotation
period, so farmers need to consider crop varieties, sowing dates, crop densities,
and fertilization levels when planting crops (Cuculeanu et al. 2002). So adaptation
is a key factor that will shape the future severity of climate change impacts on food
production. Although relatively inexpensive changes, such as shifting planting
dates or switching to an existing crop variety, may moderate negative impacts, the
biggest benefits will likely result from more costly measures including the
development of new crop varieties and expansion of irrigation (Lobell et al. 2008).
1 Strategies for Sustainable Plant Food Production
21