According to the American Heritage dictionary (1) global warming is defined as a rise in the mean temperature in the atmosphere of the earth, and mostly the rise held at particular level enough to cause a variation in climate. Temperatures together with rainfall are the basic climatic features. Atmospheric temperature can be defined as the level of heat which results from the solar energy from the sun. On the other hand, rainfall is the condensed water vapor in the atmosphere. Global warming or rather variation in the atmospheric temperature affects rainfall. Production in agriculture is completely dependent on both the atmospheric temperature and rainfall. Recent researches show that the global climate is being altered by the green house effect. This paper is going to look at the effect of global warming on agricultural production.
Global warming effect on temperature and agriculture
People have believed, over a long period of time, that global warming is going to be very much favorable for agriculture production and food supply. The belief has stemmed from the very fact that the increasing amount of carbon (IV) oxide resulting in climatic change will play major role in photosynthesis translating into increased agricultural productivity and supply of food. This belief was supported when prove came out that there was an increased level of barley production in Iceland which had never been realized ever before.
However, the very recent investigations and experiments have shown that these changes in the climatic conditions are not as favorable as people may expect. UNEP reported in 2001 in form of a prediction that there will be more floods, storms, and droughts. Over time, winter will become shorter as summer grows longer becoming even more severe. More problems will arise including big storms, high sea level, heavy rain, and heavy snowfall among other problems (Catesson, 4).
The argument goes further to indicate that the overall supply of food will go up in the USA due to these effects of climatic change. However, more droughts will be realized in the Great Plains due to these changes. There are current cases in the North eastern part of the USA where maple syrup production has gone down by one tenth (Catesson, 7).
On the issue of increase in the level of carbon dioxide concentration in the atmosphere, Bhushan (6) suggests that the research that has been carried out in the past about the justifying carbon fertilization effects may have been overvalued, a case in which it is believed that the high levels of carbon (IV) oxide increases the rate of photosynthesis and in turn brings up the level of agricultural productivity. He concurs with the current researchers that the figure is to be estimated at 15 percent. This particular estimate is considerate about the fact that plants’ response to the increase in carbon dioxide concentration, of course in most positive way, varies from plant to plant with some responding while others do not show any response at all.
Bhushan (8) further reports that most recent research forecasts that agricultural yields will decrease by between 10 and 20 percent in the developing countries even as the justifying carbon dioxide effect is being put in to consideration. This is considered to be causing very much worry especially when it is realized that most of these developing countries have agriculture as the backbone of their countries’ economy.
Another contribution towards this issue of agriculture being affected by global warming is made by Nash (19). He indicates his consent on the issue of the effect of increased level of carbon dioxide in the atmosphere on the agricultural productivity. He reveals the belief of the scientists that the agricultural yields will actually increase with the increase in the carbon dioxide level though by only a small fraction. But this suggestion is keen to point out that although the increase in the carbon dioxide level will increase the agricultural yields, this fact will only hold if the temperature does not increase beyond a particular limit. The increase in temperature beyond this limit will bring about a decline in the agricultural production. Therefore, from this point there is likelihood that the current ever increasing temperatures will drastically affect the crop yields in the farming regions. More so, he goes ahead and expresses his fears that there will be many problems in the dry areas that rely upon irrigation. These problems will stem from the fact that there will be less supply of water for irrigation because of the higher temperatures. In addition to this, there is a cooling effect from evaporating water in the areas that relies on irrigation and this effect moderates temperatures which in turn facilitate survival of crops from withering during summer. Therefore, the absence of water in these will bring about absence of these benefits. Researchers at the University 0f California suggest that that global warming can also be fought by introducing new crop varieties that reflect back more sunlight to take the place of the existing ones (Anonymous, Super-hairy plants may help fight global warming ).
Tungate, Israel, Watson & Rufty (1) suggest that global climate variations that come as result of the rise in temperatures could possibly have an impact on competition in weeds and the relationship between crops and weeds. The factors that play a role in how different plants respond to the increase in temperature consist of the inborn restrictions of the species and their capability to get water and food resources.
In their study, they had an intention to determine how the selected species of plants in the southeast of the United States of America respond to temperature. The plant species involved in this study included priddy sida, soybean and siddle pod. They also determined how temperature affected colonization of mycorrhizal and how the system of soybean nitrogen-fixation developed. They grew the crop species at 23/18°C (day/night), 28/23°C, 32/27°C,36/31°C, or 42/37°C for a period of one month ( 30 days) in a soil that was having low fertility. They found that the weeds grew to the maximum at a higher temperature of 36/31°C as opposed to that of soybean of 32/27 °C. This is possibly an indication of the difference in their agroecological origins. The ratio of the root mass to the mass of shoot was higher for the weeds than for the soybean and a higher colonization of mycorrhiza at the optimum temperature. The weight of nodules, their number, and the whole nitrogenaze enzyme action in the soybean were very high at optimum temperature for growth but in turn declined in considerable terms at the point where the temperatures were higher. From these results, they drew a conclusion that this was an indication that the rise in temperatures beyond 32 °C would improve weed competitiveness. From this, it is seen that a rise in the level of interference with growth of the soybean plant and its yields is likely.
According to Erda, Xiu, ShiMing, Hui, LiPing, Wei, Yue & YinLong (15), global warming has brought about a favorable environment for agricultural production in the northeast part of China by causing a longer period for crop growing, moving accumulated temperature belts towards the north and by decreasing the cold stress. However, they do not exhibit absolute optimism in this matter. They as well point out to the fact that there exist other problems that come along with these increases in the temperature. They cite among these problems as water shortage and urbanization. These have put much stress on production in the agriculture field and even on the ecosystems. This indicates the very much complicated nature of the effects caused by the current changes in the climate.
They went ahead and suggested that the positive impacts that come along with the change in the climate can not just come about in direct and obvious way. It requires the communities to be given such support as bringing in new varieties of crops, giving them extension services, setting up adequate research centers, and promoting agricultural production as a business. As time goes by and the temperatures get higher and higher, the potential benefits that may accrue from the increase in temperatures may decrease or even be reversed by the unfavorable impacts such as increased water shortage and severe events. This fact to support agriculture in relation to the effect of global warming is also supported by the chief scientific adviser for the United Kingdom, Sir David king in the Farmers’ Weekly, (Anonymous, Global warming could see European agriculture increase its production ). He points out that in order to deal with the problems that are associated with global warming, tax incentives are required together with a change in culture.
Considering the situation in Europe, a change in the agricultural production was forecast in the northeast (Anonymous, Global warming could see European agriculture increase its production )). A prediction was made that by the year 2050, the temperatures would have gone up by about 3 °C. This will cause a reduction in water availability by about 30 percent in the southern part of Europe but in the north, the water supply will increase by between 5 percent and 10 percent. This will offer significant gains in the field of agricultural production in the northern part of Europe. More crops such as Soya, sunflower, and maize will be grown. It is further reported that the yields of crops will be on the rise as a consequence of the increased level of carbon dioxide concentration as well. Research done in Denmark showed that the benefits arising from the high carbon dioxide level would go up by 20 percent but still this report pointed out that this could be realized since this was too high an estimate and a realistic estimate could only possibly stand at 10 percent.
These benefits could be only enjoyed in the northern part of Europe but the southern side will require more money to counter the effects of global warming in order to improve agricultural production. However, in overall terms, the effects of global warming will not be felt so much in Europe as a continent as compared to other continents in the world.
From the discussion above, it has been established that the effects of global warming has much negative effects than it could bring about benefits in relation to agricultural production. Only a few areas could benefit especially in the northern part of Europe and Asia but the rest of the many parts of the world will experience more and more severe conditions, especially water shortages as time goes by. The result of this is a reduction in agricultural productivity. It is quite vital that drastic measures be taken by all nations globally to curb these negative impacts in order to realize high production in agriculture.
American Heritage Dictionary. “Global warming” The free dictionary. 2009. Web.
Anonymous, “Global warming could see European agriculture increase its production”. Farmers Weekly, 2009. Web.
Anonymous, “Super-hairy plants may help fight global warming”. Thaindian News. 2008. Web.
Bhushan Ambika, “World agriculture may suffer under global warming”. Yale Daily News. 2007. Web.
Catesson Christophe. “Effects of Global Warming on Agriculture and Food Supply – Implication for the USA”. Ezine articles. 2009. Web.
Erda Lin, Xiu Yang, ShiMing Ma, Hui Ju, LiPing Guo, Wei Xiong, Yue Li and YinLong Xu. “China Benefiting from Global Warming”: Agricultural Production in Northeast China. IDS BULLETIN. 2005, VOL 36, Pages 15 – 32.
Nash James. “Effects of global Warming on Agriculture”. Global Warming Info. 2009. Web.
Tungate D. Kimberley, Israel W. Danile, Watson M. Dorothy & Rufty W. Thomas. “Potential changes in weed competitiveness in an agro ecological system with elevated temperatures”. Department of Soil Science, North Carolina State University, Raleigh. 2006. Web.