Water crises :: Effect on Rice - INDIA

Water crises :: Effect on Rice - INDIA

Temperature :: Temperature rise will negatively impact rice and wheat yields in tropical parts of South Asia where these crops are already being grown close to their temperature tolerance threshold. While direct impacts are associated with rise in temperatures, indirect impacts due to water availability and changing soil moisture status and pest and disease incidence are likely to be felt. IPCC(2001) Temperature rise of 1.5 degree and 2mm increase in precipitation could result in decline in rice yield by 2 to 15%

Agriculture and aquaculture will be threatened by a combination of thermal and water stresses, sea level rise, increased flooding, and strong winds associated with intense tropical cyclones. Freshwater availability and biodiversity, which are already under pressure due to population growth and land use change, will be further impacted by climate change. 

 Groundwater : :The major foodgrain producing regions of Haryana, Punjab and western Uttar Pradesh experience the most negative effects, along with the coastal districts of Tamil Nadu. Punjab and Haryana are significant from the perspective of food security in India, but they also face severe depletion of groundwater resources due to intensive cultivation techniques introduced in the Green Revolution in the 1970s coupled with populist free power policies.

Groundwater is being depleted in many important ricegrowing areas such as the Punjab in India. Tube-well irrigation, which has boomed in India and Bangladesh, has become much less profitable because of the increased cost of fuel. Demand is also growing for nonagricultural water use, such as for clean drinking water from wealthier and larger urban populations.

2009 study by NASA on Northern India that found it is losing about one foot of its groundwater each year and studies showing that groundwater levels in Punjab will fall to below 100 feet by 2020 so that the existing pumps and irrigation will stop working.

Natural water storage capacity and long-term annual river flows are also declining, especially in the Northern Hemisphere, due to glacial/snowcap melting. Glacial melting is one of the reasons that many of Asia’s largest rivers are projected to recede in coming decades. Available records suggest that Gangotri glacier is retreating by about 30 m yr-1. A warming is likely to increase melting far more rapidly than accumulation. Glacial melt is expected to increase under changed climate conditions, which would lead to increased summer flows in glacier fed river systems for a few decades, followed by a reduction in flow as the glaciers disappear. India, Bhutan and Nepal are concerned about the reduction in flow of snow-fed rivers. The vulnerability of India’s coastal areas is highlighted in Jagatsingpur, where loss of mangroves due to biotic and abiotic pressures in the past few decades has left the coast exposed to the fury of cyclones and storm surges. Household surveys in Orissa, indicate fall in production levels due to floods by 67 % in the kharif season. The flood also manifests itself in a breakdown of livelihoods and the ensuing economic compulsions have a direct bearing on the education of children. 40% school dropouts were recorded in Sunadiakandha village of Orissa. the supercyclone of 1999 badly affected Jagatsingpur district of Orissa. One of the villages in this district, Sunadiakandha, which is located close to the main coast, has experienced increasing salinity and dwindling agricultural productivity.

It takes 3,000–5,000 liters to produce 1 kilogram of rice, which is about 2 to 3 times more than to produce 1 kilogram of other cereals such as wheat or maize. In Asia, 17 million ha of irrigated rice areas may experience “physical water scarcity” and 22 million ha “economic water scarcity” by 2025.

Population growth and economic development are driving significant increases in agricultural and industrial demand for water. Agriculture accounts for more than two-thirds of global water use, including as much as 90 percent in developing countries.  Freshwater consumption worldwide has more than doubled since World War II and is expected to rise another 25 percent by 2030. Much of the growth is the result of expected increases in the world population from 6.6 billion currently to about 8 billion by 2030 and over 9 billion by 2050.

Water is already over-appropriated in many regions of the world. More than one-third of the world’s population – roughly 2.4 billion people – live in water-stressed countries and by 2025 the number is expected to rise to two-thirds.10 Groundwater tables and river levels are receding in many parts of the world due to human water use. In India, for example, farmers are now using nearly 80 percent of the country’s available water, largely from groundwater wells; at current rates, the World Bank estimates that India will have exhausted available water supplies by 2050.