Impact of global warming on agricultural production

Prof Dr R D Gupta
As agricultural production is a function of climate, which is, now itself in unpredictable condition due to “Global Warming” effect, so the agricultural production of various crops will be affected badly. It is not only agricultural crops but the production of fruits and vegetables will also be influenced by the change of climate. Climate variability, in fact, has a great input on agricultural productivity both its magnitude and stability than does climate change. Extremes in weather rather than averages affect agriculture sector considerably. Both crops and livestock are very sensitive to weather over relatively short periods of time. Annual average of temperature and rainfall do not convey short time deficiencies. Such deficiencies have great impact both on the volume and stability of food output.
The history shows that for the food crops production, warmath is better than cooling. However too much warmth is quite injurious to the functioning of normal growth and development of the crops. Off all the natural climatic hazards, drought is that which hits the yield of many crops, particularly in dry land/rainfed agriculture. Drought situation, for instance, were observed in many parts of India since 1998 to 2003 due to monsoon failures. Because of paucity of water or moisture in soils many farmers of Kandi belt of Jammu, J&K State, Himachal Pradesh, Uttaranchal, Punjab and Haryana could not sow their crops during Kharif.
A report by Scientists from 23 countries found that warming of the earth due to “Global Warming” would reduce agricultural production in many developing countries, especially those belonging to the third world. The Scientists have found that production of wheat, rice, soybeans and maize would be more seriously damaged as temperature would rise. By the middle of the 21st Century there would be increase in atmospheric temperature to an extent of 1.5 to 4.0 degree Celsius if emissions of the gases that are trapping heat on the Earth are not curbed. At 4 degree Celsius level, production of cereals would be reduced to the order of 9 to 11 percent in the developing countries. However, in the developed countries farm production would generally increase if the Earth warms. This would happen for two reasons. Firstly the higher temperature would permit crops to be grown further north in the temperate zones and growing seasons would be lengthen. Secondly when warming would occur, the developed countries can take up large scale adaptive measures because of having much more resources to their credits for tackling such situation.
Impact of Carbon dioxide : The impacts of the rising levels of atmospheric carbon dioxide with respect to the agricultural production is narrated here under:
Elevated levels of atmospheric carbon dioxide are a decidedly beneficial effect on crop production through an enhancement of photosynthetic capacity and an increase in water use efficiency. Arrhenius (1896), The first author for describing the concept of “Global Warming”, suggested its possibilities over 100 years ago. He favoured the view that slow warming without doubling of the Earth’s atmospheric CO2 would result in better living conditions and higher crop yields.
Concerning with the changes in levels of atmospheric carbon dioxide, there are some well known facts. First, there is a documented increase. The isolated Test site at Mauna Loa in Hawaii shows more than a 12 percent increase in the mean and really Concentration from 316 ppm (by volume of dry air) during 1959 which at present is 370 ppm (Gupta, 2005). The current annual rate of increase is about 1.6 ppm. Carbon dioxide source sink models predict that the current level of atmospheric CO2 Will be doubled by the latter part of the twenty first Century (Witterwer, 1998). This was also supported by the scientists of Ohio State University, USA (Anonymous, 2002) according to whom the CO2 levels would become double by the end of twenty first Century. Second there is increase in truly global. The earth’s atmosphere is very effective in dispensing emissions from whatever the source, be it natural or man made.Third, with the average level of CO2 rising there is an annual oscillation of the Earth’s atmospheric CO2. The atmospheric CO2 level begins to fall in the spring and continues through the summer months. In the late autumn, there is resurgence of CO2 into the atmosphere. This results in new heights by mid winter. With an amplitude increasing by about 1.66 ppm each year, It seems that concentration amount of Earth’s biomass is either increasing or is steady.
A new study reveals that rising level of CO2 in the atmosphere could be a boon for agricultural crops, as this green house gas helps crop plants to grow and reproduce more (Anonymous, 2002). But this boon comes with a price, says Peter Curtis-a professor of evolution, ecology and organismal biology at Ohio State University (USA) as greater growth and reproduction may hurt the nutritional value of crops. According to Curtis, while crops may be more productive, but the resulting produce will be of lower nutritional quality. Nutritional quality decreases because when the plant yield more seeds under higher CO2 levels, the seeds contain less nitrogen. Less nitrogen means less proteins as the former is a critical component for building protein in animals after taking food.
Climate and floods
Changing climate could be leading to increased river flows in many parts of the world. Fast melting of the glaciers in the Himalayas and Hindukush ranges would affect half a million people in India alone because of excessive flooding in coastal areas, and can also increase the salinity of the ground water in the Sunder bans and Surface water in coastal areas.
Owing to increase in salinity the farmers of the area have to explore the changing crops suitable for saline/alkaline soils.
Melting of Glaciers
Geologists of Geological Survey of India have found that Himalayan Glaciers are reducing by 15m every year. According to Vasudeva (2007) Gangotri Glacier is receding by 25m every year, Pindari Glacier by 23m every year, Dokriani by 18m every year and Sonapani by 17m every year. According to Working Group-ll of Inter governmental Panel on climate change, the Himalayan glaciers are receding faster than any other part of the world. Himalayan glaciers are faced with the danger of receding and causing havoc with the regional ecology.India has taken up the matter with China for a joint solution to the problem of climatic change (Anonymous 2007). The melting of Himalayan glaciers is an important issue because it can have catastrophic effect on the ecology of not only of the region but whole of world also.
(The author is Ex-Associate Dean Cum Chief Scientist KVK-Jammu, SKUAST-J)