Climate change has been the norm through out the earth’s history. Ice ages have been interspersed with interglacial periods with warmer temperatures. Although the causes of these previous natural changes are not completely understood, there is a growing consensus that human activities are contributing to the current period of climate change. In 1996, the World Meteorological Office/ United Nations Environmental Program’s Inter- governmental Panel on Climate Change (IPCC) cautiously stated: ‘ The balance of evidence suggests a discernible human influence on global climate. In spite of the nay-sayers, by 2001, new evidence and improved understanding led the IPCC to state unequivocally in its Third Assessment Report that, in its Judgement, ‘most of the warming observed over the last 50 years is attributed to human activities.
Climate change is the outcome of the “Global Warming”. It has now started showing its impacts worldwide. Either it is in the form of floods, heavy rain or in a form of drought.
Climate change induced by increasing greenhouse gases is likely to affect crops differently from region to region. For example, average crop yield is expected to drop down to 50% in Pakistan according to the UKMO scenario whereas corn production in Europe is expected to grow up to 25% in optimum hydrologic conditions.
Crops such as these sunflowers can be affected by severe drought conditions in Australia.
Between 1996 and 2003, grain production has stabilized slightly over 1800 millions of tons. In 2000, 2001, 2002 and 2003, grain stocks have been dropping, resulting in a global grain harvest that was short of consumption by 93 millions of tons in 2003.
The earth's average temperature has been rising since the late 1970s, with nine of the 10 warmest years on record occurring since 1995. In 2002, India and the United States suffered sharp harvest reductions because of record temperatures and drought. In 2003 Europe suffered very low rainfall throughout spring and summer, and a record level of heat damaged most crops from the United Kingdom and France in the Western Europe through Ukraine in the East. Bread prices have been rising in several countries in the region.
The 2001 IPCC Third Assessment Report concluded that the poorest countries would be hardest hit, with reductions in crop yields in most tropical and sub-tropical regions due to decreased water availability, and new or changed insect pest incidence. In Africa and Latin America many rainfed crops are near their maximum temperature tolerance, so that yields are likely to fall sharply for even small climate changes; falls in agricultural productivity of up to 30% over the 21st century are projected.
The impacts of global warming have been truly global and extraordinarily varied. The average rise in global temperatures may seem small- 0.76 degrees C since the Industrial Revolution in roughly the mid-18th century, the earth’s average temperature reaching 14.5 degree C in 2005- but this is only an average. The farther one goes from the equator, in northern latitudes in particular, the rise is much higher than the average.
In this article my emphasis will be more on impact on agriculture due to climate change, with special reference to India and its Jharkhand State. India’s agriculture is more dependent on monsoon from the ancient periods. Any change in monsoon trend drastically affects agriculture. Human interference has certainly made the Indian monsoon fickle. Even the increasing temperature is affecting the Indian agriculture. A recent study by the Indian Agriculture Research Institute found that increase in temperature by about 2 degrees C “reduced potential (wheat) grain yields in most regions”, and that “overall, temperature increases are predicted to reduce rice yields”, the impact on rice yields being most in eastern India. even the IPCC, scarcely alarmist, says 0.5 degree C rise in winter temperature would reduce wheat yield by 0.45 tons per hectare in India. And this when Indian agriculture has already pushed into crisis, and 1.5 lakh farmers have committed suicide since 1995.
There has been a major shift in the pattern of rainfall during the south-west monsoon season (from June to September) in recent years. This is one of the findings of an analysis by scientists at the India Meteorology Department’s National climate Centre at Pune.
Another is that rainfall over Kerala, Chhattisgarh and Jharkhand has been showing a significant decreasing trend, while that over coastal Andhra Pradesh, Rayalaseema, north interior Karnataka, Madhya Maharashtra, Konkan, Goa and Gangetic West Bengal is showing a significant increasing trend. While the contribution of July rainfall to the overall monsoon exhibit a significant increasing trend. The contribution in June and August exhibited a significant increasing trend. The findings are significant in the context of the global phenomenon of climate change. Due to global warming intensity and number of cyclones has increased. In the cyclone seasons of 2006, the number of depressions and cyclonic storms over Bay of Bengal were almost twice the annual average. This is damaging coastal agriculture and livelihoods. Due to global warming there is high influx of water in the Himalayan rivers flowing through Assam, Bihar and West Bengal in eastern India in the form of floods due to melting of Himalayan glaciers associated with heavy rains in the Himalayas. These floods annually destroy millions of tons of crops. This year the world's largest river island Majuli in Assam State of India has been severely hit by flood and erosion. Floodwaters have inundated over 87 villages of the island causing tremendous difficulty to the inhabitants and due to rapid erosion many fertile paddy fields have also been washed away by gushing water.
In year 2008 more than two million people have been marooned by late monsoon floods in 15 of the country's 64 districts, according to the Bangladesh Water Development Board (BWDB). According to a report by the Department of Agricultural Extension (DAE), crops such as Aman (the mainstay of the country's rice production and a staple component of the population's diet), t-Aman (a locally developed hybrid paddy), Aush (a secondary rice crop whose volume is less than half of Aman), jute and vegetables on more than 100,000 hectares of land in the 15 flood-hit districts were submerged. More than 20,000 hectares of Aman and Aus crops in Companiganj, Golapganj, Jaintapur, Kanaighat, Gowainghat, Fenchuganj and Beanibazar Sub-districts have been destroyed in Sylhet and Sunamganj districts, according to agriculture officials.
Few years ago, there were reports coming in of massive forced migration due to persistent droughts in Bundelkhand area in Central India. large lakes had completely dried, water in wells that people use for their daily needs had run down, rivers and tributaries had dried up, thousands of hand pumps had become useless because the groundwater levels had fallen. People had abandoned their cows and other cattle to a dusty death, as they were unable to provide them fodder and water.
Global warming intensifies drought conditions in regions that already face dry conditions, particularly in [ Sub] continental interiors. The IPCC’s report in 2007 says that “increased continental temperatures are expected to lead to greater evaporation and drying, particularly important in dry regions where surface moisture is limited… drought has become more common, especially in the tropics and subtropics, since the 1970s … more intense and larger drought have been observed.
Drought like situation is also threatening Jharkhand State of India where scanty and late arrival of monsoon this year is affecting crops and depletion of ground water. Drought is a recurrent phenomenon in Jharkhand. It affects the livelihoods of the majority of its people, particularly tribals and dalits living in rural areas. Twelve of the 22 districts of the state, covering 43% of the total land area, are covered under the Drought Prone Areas Programme (DPAP).Hunger and starvation deaths are reported almost every year. Jharkhand is one of the richest states in the country in terms of natural resources. However, the rate of growth in agriculture has been one of the slowest in the country both in terms of production and productivity. Almost 90% of the cultivated area is monocropped. Only 9% of the total cropped area is irrigated. Hence the rural population is very vulnerable to rainfall fluctuations.
Jharkhand receives almost 1200-1300 mm of rainfall every year but from last few years the rains are erratic in many areas. The probability of rainfall failures and coefficient of variations is quite high in the last weeks of June-July and in the last weeks of September-October. Hence, drought in the state primarily occurs at the start or end of the kharif season.
This year there was less rain in the month of July. In July, upland crops grow to maturity and seedlings for transplanted rice are established. If there is deficient rain, the upland crop—mainly paddy and maize, which provides food security in August-September— is affected.
This year most of the vegetables have been destroyed either due to uneven rainfall or due to intense un-seasonal hailstorms that damaged the standing crops and vegetables and led to huge losses to farmers. In year 2007 and 2008 also hailstorms destroyed crops. This year situation worsened as most of the green vegetables vanished from the local markets or was too costly to be purchased by the common and poor people.
Palamau district in Jharkhand State of India is reeling under drought due to scanty rainfall. Crops have been destroyed and the region is facing a famine-like situation. It has not only affected the crops but also depleted the ground water and well water forcing people to drink contaminated water.
The Indian Irrigation Commission described Palamau as the driest and probably the poorest district of the province. The frequent draughts and famines or scarcity conditions that have visited this district within the last century support this observation. The district falls within the retreating range of the south-west monsoon and as such rainfall is wholly dependent upon local conditions and local winds which are seldom favourable to the district.
The rainfall in Palamau is not only scanty but very capricious in its distribution. There are, it is true, a large number of rivers and streams in the district, but in most of them the supply of water diminishes rapidly or fails entirely soon after the end of the scanty rains.
It is not only Palamau but other districts are also under threat of drought like conditions including Ranchi district. It is not only the scanty rain but rise in temperature and short period of winter has also affected the crops and vegetables of the state.
Jharkhand is one of the most food-insecure and malnourished states in the country. NSSO (55th round) data reveal that 10.46% of all households in Jharkhand face seasonal food insecurity. Around 2.5% of households face chronic food shortages. Of the families facing food insecurity, 64% face food shortages for two to three months while as many as 28% do not have sufficient food for four to five months. Almost 6% of the food-deficient
households have to go hungry for more than half the year. The incidence of food insecurity is higher among ST and SC families. Assured food supplies exist for only three to four months of the year, after the harvest in late October-early November. Food supplies tend to run short by the end of winter. The starvation period begins by mid-summer (June) and in many cases, continues till the end of October.
Entire Jharkhand has been now declared drought-hit following scanty rainfall. The decision was taken at the meeting of the Advisory Council of the Governor. Earlier, the Council had announced 11 of the 24 districts as drought-hit. In the face of severe drought, it was decided to distribute grains free of cost to BPL (below poverty line) families, besides setting up of grain godowns at district and block headquarters.
If the same condition prevails in coming years situation will be worse as the state lacks proper irrigation facilities and proper storage facilities for grains.
A dry spell has led the Uttar Pradesh government to declare 20 of the state's 70 districts as "drought-hit". According to weather reports, Uttar Pradesh has received only about 128 cm of rainfall since June 1 as against the expected normal rainfall of about 307 cm. In the 20 drought-hit districts, the recorded rainfall was barely 60 cm.
Scanty rainfall in most parts of Uttar Pradesh, will hit agricultural production leading to a shortage of rice in the state, says a government report. According to the report prepared by the state agriculture department, the worst hit would be paddy yield, which is expected to decline by about 60 percent this year. Maize production is also expected to fall 1.15 million tonnes to 900,000 tonnes.
The districts where rainfall has been lowest include Chitrakoot (81 percent below normal), Etah (84 percent below normal) and Rampur (85 percent below normal).
Twenty six of Bihar’s 38 districts were declared drought-hit this year in view of scanty rainfall that has badly hit transplanting of paddy seedlings and affected millions of farmers.
Bihar has recorded a 42 percent rainfall deficit so far this monsoon season. This has hit the transplanting of paddy seedlings.
The state during the period between June 1 and Aug 6 had received just 331.7 mm of rainfall against the average 568.5 mm — a deficiency of 42 percent. It has resulted in 58 percent decline in paddy transplantation. Bihar had targeted sowing of paddy in 8,772,241 acres this year, but the crop could only be planted in only 3,822,967 acres so far.
Uttarakhand State is under drought-like conditions for last six months. 50 per cent of crops damaged in 3216 villages of five districts alone. Rainfall in the months of December, January, February and March has been far below normal, severely affecting winter crops in the hilly areas.
Madhya Pradesh state of central India is going to witness the worst drought of the century due to the scanty rainfall in as many as 37 districts following which it has declared them drought-affected.
Due to scanty rainfall, as many as 37 districts of the state were declared drought-affected. The districts which were declared drought-affected are Alirajpur, Ashok Nagar, Anuppur, Barwani, Bhind, Balaghat, Burhanpur, Chhatarpur, Dewas, Dindori, Datia, Damoh, Guna, Gwalior, Jhabua, Jabalpur, Katni, Khandwa, Morena, Mandla, Narsinghpur, Panna, Ratlam, Raisen, Rewa, Satna, Sidhi, Singrauli, Shahdol, Sagar, Sehore, Shivpuri, Sheopur Kalan, Shajapur, Tikamgarh, Umaria and Vidisha.
Drought like conditions is prevailing in most parts of Northern India. According to William Cline, a senior fellow at the Center for Global Development (CGD) and the Peterson Institute for International Economics, “India is among the most adversely affected with losses of 30-40% (in agriculture productivity) depending upon whether higher carbon dioxide provides a significant fertilization effect.”He noted that in the southern parts of India, damage will be substantial and similar to that in other countries also located close to equator. In these locations, where temperatures are already at high levels, an increase in temperature will surpass crop tolerance levels. In North India, the unusual increase in rainfall combined with higher temperature could result in a higher decline in productivity than one would expect from where it is located relative to equator. Cline finds that agricultural production in developing countries may fall between 10 and 25 percent, and if global warming progresses unabated, India's agricultural capacity could fall as much as 40 percent.
Poverty in South Asia is still largely rural. About 70% of South Asia’s population lives in rural areas, and it accounts for about 75% of the poor. Most of the rural poor depend on agriculture for their livelihood. Agriculture employs about 60% of the labor force in South Asia and contributes 22% of regional GDP. The Green Revolution of 1970s and 1980s substantially increased food grain productivity and increased rural wages. Recent agricultural growth in South Asia, however, is less than 3% and is far below the growth rates of other economic sectors.
Prime Minister of India Manmohan Singh said that the country was facing a drought threat. India's vital monsoon rains have been 29 percent below normal since the beginning of the June-September season, hurting crops such as rice and sugarcane and triggering a sharp rise in food prices. "We are staring at the prospect of an impending drought,".
Since agriculture constitutes a much larger fraction of GDP in developing countries, even a small percentage loss in agricultural productivity would impose a larger proportionate income loss in a developing country than in an industrial country.
A study published in Science suggest that, due to climate change, "southern Africa could lose more than 30% of its main crop, maize, by 2030. In South Asia losses of many regional staples, such as rice, millet and maize could top 10%".
Drought obviously leads to water stress in plants. Heat waves, on the other hand, are acute episodes which, if the temperature is high enough, above 40 degree C for instance, lead to wilting and death, because of structural damage to essential proteins. The problem is that plants react by closing their stomata when subjected to water stress, so shutting down on transpiration and conserving water. But rather as the body would overheat dangerously if it shut its pores to prevent sweating, so in a plant the shutting of the stomata will cause internal temperatures to rise and may well cause permanent damage, if not death. According to a report temperatures above 45 degree C will damage most plants if lasting for half-an-hour or more. High soil temperatures will also damage roots and prevent nutrient uptake.
David Pimental from the college of Agriculture and Life Sciences, Cornell University, points out that each crop has its optimum temperature and length of growing season for maximum yields. Rice generally grows best when temperatures are between 30 degree C and 33 degree C, yet it will still ‘fruit’ and generally produce as long as temperatures do not fall below 18 degree C. Some varieties will tolerate temperatures rising to as high as 40 degree C. In contrast potatoes do badly if temperature rise above 28 degree C and do best when they lie between 15 and 20 degree C. higher soil temperatures will increase the rate of oxidation and hence loss of nutrients and organic matter. Less organic matter means less soil organisms such as earthworms and insects that do so much to improve the ground. Hence global warming and temperature rises could have a deleterious effect on the main cereal crops.
In temperate latitudes crops need at least 250 millimeters of rain a year and in the tropics 500 millimeters. However, it is not just the amount of precipitation, but when the bulk of it occurs that is important. Global warming will undoubtedly play havoc with a crop’s specific needs, both through increasing surface temperatures, which itself will lead to a greater likelihood of water stress on vegetation because of enhanced evaporation from soils and through distorting rainfall patterns. A failure of the monsoon spells disaster for India as does just a small decline in the amount of rain over the semi-arid countries of the Sahel.
Global warming is not only affecting the production of the crops but also making some of the crops toxic. According to an Australian scientist, Staples such as cassava on which millions of people depend become more toxic and produce much smaller yields in a world with higher carbon dioxide levels and more drought.
A team of Monash University in Melbourne tested cassava and sorghum under a series of climate change scenarios, with particular focus on different CO2 levels, to study the effect on plant nutritional quality and yield. Both species belong to a group of plants that produce chemicals called cyanogenic glycosides, which break down to release poisonous cyanide gas if the leaves are crushed or chewed.
Around 10 percent of all plants and 60 percent of crop species produce cyanogenic glycosides.
The team grew cassava and sorghum at three different levels of CO2; just below today's current levels at about 360 parts per million in the atmosphere, at about 550 ppm and about double at 710 pm.
It was found that at double current CO2 levels, the level of toxin was much higher while protein levels fell.
The ability of people and herbivores, such as cattle, to break down the cyanide depends largely on eating sufficient protein.
Anyone largely reliant on cassava for food, particularly during drought, would be especially at risk of cyanide poisoning.
The group looked at a type of sorghum commonly fed to cattle in Australia and Africa and found it became less toxic at the highest CO2 level. But under drought conditions, leaf toxin levels rose.
Within the context of the modern industrialized farming, global warming and warmer temperatures with mild winters in temperate zones will lead to a surge in pathogens and pests. Not only will some pests be able to take advantage of rising temperatures to spread to higher latitudes and altitudes, but also to increase their rate of reproduction by adding an additional generation. During the growing season some insect pests can produce 500 progeny per female every two weeks and as many as 3,000 in a single generation. In general, losses to insects and mites are higher in warmer regions of the world.
According to the United Nations, agricultural mismanagement has damaged more than 552 million hectares – 38 percent of today’s cultivated area- since World War 2 and that overall, between 5 and 10 million hectares a year are currently being lost. Just 100 years at that rate would leave the world with but a patch of the land for agriculture that it has today.
Bunyard, P. 1999. A hunger world. The Ecologist, v.29, no.2, pp.86-91.
Runeckles, V.C. 2002. Air pollution and climate change. In air pollution and plant life, second edition, eds. J.N.b. Bell and M. Treshow. Wiley, USA.
“The roots of Global Warming” a report published by Delhi Platform in year 2008.