Effects of Global warming and Climate change on agricultural production

a. Soil processes:

• Increase in soil water deficits i.e. dry soils become drier, therefore increased need for irrigation but: Could improve soil workability in wetter regions and diminish poaching and erosion risk.

b. Crops:

• The range of current crops will move northward
• New crop varieties may need to be selected
• Horticultural crops are more susceptible to changing conditions than arable crops
• Field vegetables will be particularly affected by temperature changes
• Phaselous bean, onion and sweetcorn are most likely to benefit commercially from higher temperatures
• Water deficits will directly affect fruit and vegetable production.

c. Crop Impacts

• Horticultural crops are likely to be more sensitive to climate change than grains and oilseeds.
• Climate change is likely to lead to the northern migration of weeds. Weeds respond positively to CO2 and the commonly used herbicide glyphosate loses its ability in to kill weeds in a higher CO2 environment.
• This is particularly troublesome because the use of continuous no-till, which necessitates high applications of glyphosate, is seen as a means to offset GHG emissions.
• With increased CO2 and temperature rises there may be an initial expansion of grain and oilseed production. With continued rising temperatures this initial expansion may be short lived, particularly if precipitation patterns become more variable.

d. Grasslands and livestock

• There is unlikely to be a significant change in suitability of livestock for systems
• Pigs and poultry could be exposed to higher incidences of heat stress, thus influencing productivity
• Increase in disease transmission by faster growth rates of pathogens in the environment and more efficient and abundant vectors (such as insects)
• Consequences for food quality and storage.

e. Weeds, pests and diseases:

• Global warming would cause an increase in rainfall in some areas, which would lead to an increase of atmospheric humidity and the duration of the wet seasons.
• Combined with higher temperatures, these could favor the development of fungal diseases.
• Similarly, because of higher temperatures and humidity, there could be an increased pressure from insects and disease vectors.
• Rate of evolution will increase in hotter, drier conditions and in ‘extreme years’, could lead to some types of herbicide tolerance becoming more common.
• Possible increase in the range of many native pests, and species that at present are not economically important may become so.
• Surveillance and eradication processes for other significant pests, such as the Colorado beetle will become increasingly important.

f. Erosion and fertility:

• The warmer atmospheric temperatures observed over the past decades are expected to lead to a more vigorous hydrological cycle, including more extreme rainfall events.
• Erosion and soil degradation is more likely to occur. Soil fertility would also be affected by global warming.
• However, because the ratio of carbon to nitrogen is a constant, a doubling of carbon is likely to imply a higher storage of nitrogen in soils as nitrates, thus providing higher fertilizing elements for plants, providing better yields.
• The average needs for nitrogen could decrease, and give the opportunity of changing often costly fertilization strategies.

In the long run, the climatic change could affect agriculture in several ways :

a) Productivity, in terms of quantity and quality of crops

b) Agricultural practices, through changes of water use (irrigation) and agricultural inputs such as herbicides, insecticides and fertilizers environmental effects, in particular in relation of frequency and intensity of soil drainage (leading to nitrogen leaching), soil erosion, reduction of crop diversity

c) Rural space, through the loss and gain of cultivated lands, land speculation, land renunciation, and hydraulic amenities.

d) Adaptation, organisms may become more or less competitive, as well as humans may develop urgency to develop more competitive organisms, such as flood resistant or salt resistant varieties of rice.