Geoscience Reference
In-Depth Information
only increase crop production in colder regions due to a longer
growing season (Smith et al., 2005a,b) but also could accelerate
decomposition of soil organic matter, releasing stored soil car-
bon into the atmosphere (Fang et al., 2005; Knorr et al., 2005;
Smith et al., 2005b). Moreover, changes in precipitation pat-
terns could change the adaptability of crops or cropping sys-
tems selected to reduce GHG emissions (Smith et al., 2007a).
Agriculture will have a two-sided effect: an increased CO
2
climate change, first, directly by the fertilising effect creating a
higher level of ambient CO
2
(both positively and negatively) in
the atmosphere and, second, indirectly by the effect of change
in climate on crop, livestock, insect pests, diseases, weeds, soils
and water supplies (Easterling et al., 1989; Parry et al., 1989,
1990). These impacts classified as both direct (positive and
negative) and indirect are listed in Tables 1.1 through 1.3.
The effects of climate change on agriculture vary by region
and by crop (Adams et al., 1998). Higher growing season tem-
peratures can significantly impact agricultural productivity,
farm incomes and food security (Battisti and Naylor, 2009).
In mid and high latitudes, the suitability and productivity of
table 1.1
Positive impacts on agriculture
Impact on agricultural
production
S. no.
Evidence of climate change
1
Longer frost-free periods
Use of higher-yielding
genetics
2
Lower daily maximum
temperature in summer
Reduced plant stress
3
More freeze/thaw cycles in
winter
Increased soil tilt and
water infiltration
4
More summer precipitation
Reduced plant stress
5
More soil moisture
Reduced plant stress
6
Higher dew point temperatures
Reduced moisture stress
7
Higher intensity of solar output
Increased degree days
8
More diffuse light (increased
cloudiness)
Reduced plant stress
9
Higher water-use efficiency
Higher yields
10
Warmer spring soil
temperatures
Use of higher-yielding
genetics
11
Reduced risk of late spring or
early fall frosts
Use of higher-yielding
genetics
12
Increased atmospheric CO
2
levels
Increased photosynthesis
and yields
