Global Warming Effects on Agriculture

Global Warming Effects on Agriculture

Climate is the most significant factor in determining plant growth and productivity. 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.Without intervention to reduce emissions of greenhouse gases, global average surface temperature is projected to increase by about 0.2°C per decade during the 21st century. This swift change in climate will have major implications for agriculture around the globe.

Moisture and water availability will be affected by a temperature increase, regardless of any change in rainfall. Higher temperatures increase the evaporation rate, thus reducing the level of moisture available for plant growth, although other climatic elements are involved. Warming of the earth's atmosphere will significantly affect the wheat and maize yields across the globe. Reduced moisture availability would only add to the existing problems of infertile soils, soil erosion and poor crop yields.

Although climate changes may have some adverse impacts on agricultural production around the world, the increase in atmospheric carbon dioxide concentrations could be beneficial. Plants grow as a result of photosynthesis - the mechanism whereby the plant converts carbon dioxide from the atmosphere into food. With higher levels of carbon dioxide stimulating the rate of photosynthesis, the growth rate and productivity of plants could be expected to increase. This would be beneficial for global food stocks. Most crops grown in cool, temperate regions respond positively to an increased concentration of carbon dioxide, including some of the current major food staples such as wheat, rice and soybean. Some studies have shown that growth rate in these crops may increase up to 50% if carbon dioxide in the atmosphere is doubled. Crops grown in the tropical regions of the world, including sorghum, maize, sugar cane and millet, which combined, account for about one fifth of the world's food production, do not respond as well to increases in carbon dioxide.

In order to maintain agricultural output to meet the demand for a growing world population, farmers will have to adjust and adapt to compensate for a changing climate. Higher temperatures would increase the demand for irrigation of agricultural land. Unfortunately, in many arid and semi-arid regions of the world the demand for water already exceeds supply. Increased spread of pests and disease may also place additional demands on the need for fertilizers, pesticides and herbicides which are costly and unhealthy. The ability to adapt to the effects of climate change will vary greatly between regions. Economic and technological constraints will limit the rate of adaptability, with poorer economies lagging behind. Without planning and intervention, climate change will likely widen the gap between the rich and deprived areas of the world.