- Created on Sunday, 16 September 2012 19:33
Climate change is any long-term significant change in the “average weather” that a given region experiences. Average weather may include average temperature, precipitation and wind patterns. It involves changes in the variability or average state of the atmosphere over durations ranging from decades to millions of years. These changes can be caused by dynamic processes on earth, external forces including variations in sunlight intensity, and more recently by human activities.
Related to climate change is Global warming. This is the increase in the average measured temperature of the earth's near-surface air and oceans since the mid-20th century. Global surface temperature increased 0.74 ± 0.18 °C during the 100 years ending in 2005. The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations". Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C during the twenty-first century. This range of values results from the use of differing scenarios of future greenhouse gas (GHG) emissions as well as models with differing climate sensitivity.
Increasing global temperature is expected to cause sea levels to rise, an increase in the intensity of extreme weather events, and significant changes to the amount and pattern of precipitation, likely leading to an expanse of tropical areas and increased pace of desertification. Other expected effects of global warming include changes in agricultural yields, modifications of trade routes, glacier retreat, mass species extinctions and increases in the ranges of disease vectors.
Climate change and agriculture are interrelated processes, both of which take place on a global scale. The agricultural sector is a significant user of land and consumer of fossil fuel, agriculture contributes directly to GHG emissions through crop production and the raising of livestock; according to the Intergovernmental Panel on Climate Change, two of the main causes of the increase in greenhouse gases observed over the past 250 years have been fossil fuels and agriculture.
A study published in Science suggest that, due to climate change, "southern Africa could lose more than 30% of its main crop, maize, by 2030. In South Asia losses of many regional staples, such as rice, millet and maize could top 10%".
Five main climate change related drivers: temperature, precipitation, sea level rise, GHG emissions and incidence of extreme events, may affect the agriculture sector in the following ways:
Reduction in crop yields and agriculture productivity: There is growing evidence that in the tropics and subtropics, where crops have reached their maximum tolerance, crop yields are likely to decrease due to an increase in the temperature.
Increased incidence of pest attacks: An increase in temperature is also likely to be conducive for a proliferation of pests that are detrimental to crop production.
Limit the availability of water: It is expected that the availability of water in most parts of Africa would decrease as a result of climate change. Particularly, there will be a severe down trend in the rainfall in Southern African countries and in the dry areas of countries around Mediterranean Sea.
Exacerbation of drought periods: An increase in temperature and a change in the climate throughout the continent are predicted to cause recurrent droughts in most of the region.
Reduction in soil fertility. An increase in temperature is likely to reduce soil moisture, moisture storage capacity and the quality of the soil, which are vital nutrient for agricultural crops.
Low livestock productivity and high production cost: Climate change will affect livestock productivity directly by influencing the balance between heat dissipation and heat production and indirectly through its effect on the availability of feed and fodder.
Availability of human resource: Climate change is likely to cause the manifestation of vector and vector born diseases, where an increase in temperature and humidity will create ideal conditions for malaria, sleeping sickness and other infectious diseases that will directly affect the availability of human resources for the agriculture sector.
Sub-Saharan Africa, the world’s poorest region and the one most dependent on agriculture, brings the problem into sharp focus. An estimated 500 million hectares of its agricultural land are already degraded, say soil scientists. Moreover, 95% of the region’s cropland is rainfed, according to the Food and Agriculture Organization (FAO), and rainfall patterns are already quite erratic. The Intergovernmental Panel on Climate Change predicts that in some African countries yields from rain-fed agriculture could be reduced by 50% by 2020
With more “heavy weather” on the horizon, how will farmers in Africa and elsewhere keep pace with the demand for food, which is expected to at least double in the developing world over the next 40 years? And what hope do they have of creating better livelihoods for themselves and their children?
Specifically, they seek ways to protect water and other natural resources under extreme weather conditions and other pressures. Biotechnology has a significant role to play when meeting the challenges of climate change. With the development of crop varieties that are adapted to harsh climates such as drought and heat tolerant crops. As well as reducing GHG emissions with the use of biofuels.