GLOBAL WARMING AND ITS IMPACT ON CANE PRODUCTION UNDER PAKISTAN CONDITIONS

Abstract

Global warming is a long term universal challenge being faced in Agricultural sectors in all contents of the world. It is directly associated with increasing atmospheric CO2 and other greenhouse gases like nitrous oxide and methane. It results in climatic change with change in rainfall pattern and the frequency of extreme high and low temperature events, floods, drought and other abiotic stresses. The global surface mean temperature was reported to increase from 0.550 to 0.670 C in the last century and are projected to rise from 1.10 to 2.90 C (low emission) or 2.50 to 3.40 C (high emission) by the year 2100, relative to 1980-1999 period, depending on GHG emission level, regions and geographic locations (IPCC, 2014). Climatic changes have been observed in all the regions of the world, but divergent reports are available on their impact on agricultural productivity. According to Moorthy etal (2012) the temperature and precipitation trends did not have measurable impact on cotton, rice, sorghum and wheat, however cane yields were improved by 1%, over last 60 years (1951-2010). An increase in maximum temperature had adverse effect on crop yields, and wheat yields were worst hit (Birthal etal (2014); it was further stipulated that rice yields would be reduced by 15% and wheat by 22% towards 2100 century. Kumar and Parikh (2001) projected large scale changes in climate would lead to significant reduction in wheat and rice yield by 2060; However there is no linear relationship between climatic factors and sugarcane productivity in India. Sugarcane crop would get benefit from increased winter temperature and rainfall. Comparing area and yield of five top leading countries for the period 1977-2013, impact of change is not conspicuous and increase in yield is still feasible in current environment. (zhao and Li, 2015).
Pakistan is not exception to this climate change that is threatening agricultural productivity. Pakistan is one of the most vulnerable countries to the consequence of climatic change, because of adverse geographical and climatic features. Pakistan is confined between huge series of high mountain ranges laden with glaciers in the North, hyper desert in South, and Arabian Sea in SouthWest. The sub-continent faces extreme variation in temperatures and precipitation in upstream and downstream of river Indus and its tributaries with extreme variation in frequency and intensity of hydrological events. Climatically most parts of Pakistan are arid to semi-arid with significant spatial variability in climatic parameters. Coastal climate is confined within a narrow strip along the coast.