Friday, July 27, 2012

A hungrier world- blame it on climate change.

The impact of global warming on agriculture is going to be worse.
Dr. Nitish Priyadarshi

On the day you read this, the population of our planet will increase by 230,000 people. Hungry people.

In 2012 about 140 million human beings will be born and some 55 million of us will die. That amounts to a net population gain of 85 million – more than 230,000 additional residents of the earth every day of the year. Many of these newcomers will suckle their meals from a mother’s breast for a year or so, but after that it will be up to Mother Earth to provide them food and drink. Our fragile, over extended planet and its hard working human population will have to feed those 230,000hungry people day after day for the next 66 years.
A growing global food shortage has caused prices to double in recent years, and a growing consensus of scientists now blames climate change as one factor in an equation that includes a burgeoning population and increasingly scarce water supplies. More people around the planet are going hungry as a result. 

One in seven people go to bed hungry every night, according to the United Nations World Food Program. Hunger kills more people than AIDS, malaria and tuberculosis combined. The problem is worst in developing countries. 

Two hot spots has been identified —South Asia and southern Africa—where higher temperatures and drops in rainfall could cut yields of the main crops people grow there.

A variable agriculture needs a stable climate. If we cannot anticipate from one year to the next what and when to sow and what sort of harvest to expect because the climate is going through all sorts of unpredictable convulsions, then we are in serious trouble. According to current general circulation models, the worst impact on agriculture will be in Africa, the Middle East and the Indian sub-continent.

If we continue pumping greenhouse gases into the atmosphere and we fail to curb our destruction of the world’s forest, we can expect our crops to shrivel from increased heat-waves and droughts, get them washed away by unprecedented rainstorms and floods, and be ravaged by the spread of pests and weeds.

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, sunflowers can be affected by severe drought conditions in Australia.

Droughts caused by global climate change have led to a drop in wheat production, a worldwide shortage and high food prices around the world.

Scientists predict that climate change could result in food shortages and poverty for millions who rely on agriculture as a means of income in the Tropics.

Researchers found areas that are already experiencing food shortages due to climate changes could become “hotspots” in the next 40 years meaning the areas will have shorter, hotter or drier growing seasons which could devastate people in parts of Asia, Africa, China, India and South America.  

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. 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.

Due to global warming intensity and number of cyclones has increased. 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.

Drought like situation is also threatening most part of India where scanty and late arrival of monsoon this year is affecting crops and depletion of ground water.

Shortage of rainfall coupled with its erratic distribution during rainy season may cause severe water deficit conditions resulting in various intensities of droughts in India.

The total food grain production in India has to be stepped up from 212 million metric tons to 300 million metric tons by 2020 to meet the food demands of growing population. Therefore, there is a need for effective monitoring of agricultural drought, its onset, progression and impact on crops to minimize the damages. Shortage of drinking water and starvation for food may be the consequences in coming future. 

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%".

The Intergovernmental Panel on Climate Change (IPCC) has produced several reports that have assessed the scientific literature on climate change. The IPCC Third Assessment Report, published in 2001, 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. Marine life and the fishing industry will also be severely affected in some places.

IPCC projected that in drier areas of Latin America, productivity of some important crops would decrease and livestock productivity decline, with adverse consequences for food security.

Climate change could also trigger the growth of deserts in southern Africa. A report published in Nature today predicts that as greenhouse gases fuel global warming, the dunes of the Kalahari could begin to spread. By 2099, shifting sands could be blowing across huge tracts of Botswana, Angola, Zimbabwe and western Zambia.

Few years ago severe droughts has badly affected crops in Cuba, Cambodia, Australia, Afghanistan, Vietnam, Morocco, Guatemala, Honduras and Nicaragua. According to the UN's famine early warning system, 16 countries, including Peru, Ecuador and Lesotho, face "unfavourable prospects" with current crops.

In regions of South Asia and sub-Saharan Africa, an estimated 266 million people considered "food-insecure" live in areas that could experience a 5 percent decrease in the growing season over the next 40 years. That, in turn, could significantly affect food yields and food access for people.

Another 170.5 milion people in parts of West Africa, India and China could be "food-insecure" do to the impact of rising temperatures on many crops such as beans, maize and rice, according to the study.  

America's drought threatens a recurrence of the 2008 global food crisis, when soaring prices set off riots and unrest to parts of Africa, the Middle East, and Latin America. Americans face higher food prices at the supermarket because of a drought this summer.
Corn and soybean prices on the futures market have surged to record highs amid the worst drought in half a century, with new crop contracts for corn rising 50 percent since early June and soybeans increasing about 35 percent. More than 60 percent of the continental United States has been under drought and extreme heat conditions.

Sri Lanka banned rice exports until its harvest season next March aiming to stabilise local prices as its major rice-producing area struggles with a prolonged drought. Rice is the staple food in the island nation and any price increase could accelerate the $59 billion economy's inflation. 

The impact of global warming on agriculture is going to be worse. Indeed, all the indications are that our systems of agriculture will be in serious trouble if we follow a ‘business-as-usual’ strategy and do not take immediate measures to reduce our impact on the climate.


Bunyard, P. 1999. A hunger world. The Ecologist, v.29, no.2, pp.86-91.

Friday, July 20, 2012

Soil colour has been inferred as an indicator of past climate.

With special reference to Jharkhand State of India.

Dr. Nitish Priyadarshi.

Palaeoclimatology, the study of climates during the geological past, is one of the most topical areas research in the geoscience at present.

The threat of future climate change caused by higher levels of greenhouse gases, which would drastically alter many aspects of our environment, has prompted much research to try to understand how our complex climate system works. Only by understanding how climate has evolved over million of years can we identify important cycles with a frequency in excess of the short climate records we possess. These climate cycles have the potential to have a profound effect on our environment.

The determination of past climate parameters by the use of paleohydrologic conditions is an important phase of paleoclimatology. The present climate of any local area, on any continent, and around any lake basin, depends on the same factors which controlled Pleistocene climate. The study of present meteorological conditions is then a perfect application of the present being the “key to the past”.

The present climate for any area of the earth is controlled by innumerable and diverse variables, the same variables that undoubtedly controlled the paleoclimate of any particular area during any period of earth history. The earth’s temperatures and climates are basically controlled by the amount of solar radiation and the inclination of the earth to the sun.

Many methods exist which help in determining paleoclimatic conditions. The most popular probably concern the study of sand dunes, coal measures, soil studies, and spores and pollen although considerable attention is also devoted to the fossil plants, paleohydrologic conditions, and to the chemistry of lacustrine sediments.

Soil studies:

Much of the history of ancient lake basins, and particularly their past extent, may in many cases be quickly determined by soil studies.

Climate influences soil formation primarily through effects of water and solar energy. Water is the solvent in which chemical reactions take place in the soil, and it is essential to the life cycles of soil organisms. Water is also the principal medium for the erosive or percolative transport of solid particles. The rates at which these water-mediated processes take place are controlled by the amount of energy available from the sun.

On a global scale, the integrated effects of climate can readily be seen along a transect from pole to Equator. As one proceeds from the pole to cool tundra or forested regions, polar desert soils give way to intensively leached soils such as the Podzols (Spodosols) that exhibit an eye-catching, ash-coloured E horizon indicative of humid, boreal climates. Farther into temperate zones, organic matter accumulates in soils as climates become warmer, and eventually lime (calcium carbonate) also begins to accumulate closer to the top of the soil profile as evapotranspiration increases. Arid subtropical climate then follows, with desert soils that are low in organic matter and enriched in soluble salts. As the climate again becomes humid close to the Equator, high temperature combines with high precipitation to create red and yellow tropical soils, whose colours reveal the prevalence of residual iron oxide minerals that are resistant to leaching losses because of their low solubility.

The presence of specific minerals can also affect soil color. Manganese oxide causes a black color, glauconite makes the soil green, and calcite can make soil in arid regions appear white.

The development of a soil type depends greatly on climate, parent material, topography and time. Therefore, because parent material, time, and topography are well known for the Plistocene soils they are indicators of paleoclimate even though climate intensity still exists as an important variable. Basically pedalfer soils indicate temperate, forested areas, pedocal soils warm, dry grasslands, and the laterites a tropical environment.
Certainly red to yellow soils, because of their high concentration of iron oxides, suggest a warm, humid, oxidizing climate, and light gray to white, calcified soils indicate a warm, dry climate.

Red soils have been extensively developed in Singhbhum, Ranchi, Hazaribag, and Santhal Paraganas districts in Jharkhand State of India. The pH of the soils vary from 5 to 6.8. They are acidic in nature. The Jharkhand plateau consists of gneisses and schists. Many of these gneisses and schists contain a large proportion of biotite and hornblende and as they are highly ferruginous, the soils derived from them are deep red.  The red soils usually drain off quickly and can hardly retain moisture for any length of time.    

Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock. Tropical weathering (laterization) is a prolonged process of chemical weathering which produces a wide variety in the thickness, grade, chemistry and ore mineralogy of the resulting soils. The majority of the land areas with laterites was or is between the tropics of Cancer and Capricorn.

Laterites are formed from the leaching of parent sedimentary rocks (sandstones, clays, limestones); metamorphic rocks (schists, gneisses, migmatites); igneous rocks (granites, basalts, gabbros, peridotites); and mineralized proto-ores; which leaves the more insoluble ions, predominantly iron and aluminium. The mechanism of leaching involves acid dissolving the host mineral lattice, followed by hydrolysis and precipitation of insoluble oxides and sulfates of iron, aluminium and silica under the high temperature conditions of a humid sub-tropical monsoon climate. An essential feature for the formation of laterite is the repetition of wet and dry seasons. Rocks are leached by percolating rain water during the wet season; the resulting solution containing the leached ions is brought to the surface by capillary action during the dry season.

Laterite soils are found in the ‘Pat’ region of west Ranchi and south Palamau in Jharkhand State of India. The typical red colour is due to a high percentage of iron oxides. The soils are generally poor in nitrogen, phosphorous, potassium and organic matter, the pH ranging between 4.5 to 6.0.  

The location of the Jharkhand state is just near the Tropic of Cancer which has imparted to it a typical tropical climate. The average temperature is 22 degree C. As the area is situated in a zone of transition between Arabian Sea branches and Bay of Bengal branches of south-west monsoon a moderate rainfall of 1200 to 1400 mm. is experienced.  

However, caution must be exercised when using soils for the deduction of past climate events because development results from the intricate variability of innumerable factors such as topography, groundwater, time, rainfall, and temperature to mention only a few. Soil colour has been inferred by many investigators (Simonson, 1954; Carter, 1956) as an indicator of either past climate or soil age, the reds and yellows indicating a warm, dry climate with the soil becoming redder with age. Such generalizations may be adequate for local areas and restricted use, but are obviously dangerous for proper scientific evaluation.   


Carter, G.F.,1956. On soil color and time. Southern J. Anthropol., 12: 295-324.

Simonson,R.W., 1954. Identification and interpretation of buried soils. Am. J. Sci.,252:705-722.        

Wednesday, July 4, 2012

The poisonous Parthenium grass is covering the agricultural lands in Gaya district of Bihar state in India.

It is definitely going to affect the productivity of the soil and agricultural growth.
Dr. Nitish Priyadarshi 

Above photographs shows how the poisonous Parthenium grass is covering the agricultural lands in Gaya district of Bihar state in India. It is definitely going to affect the productivity of the soil and agricultural growth.

Gaya is already under the water stress zone which affects the irrigation. Growth of these herbaceous plants  will increase the problem many fold.

Lack of awareness among the local people and government agencies had helped these plants to grow rapidly on the vast areas of the district.

It will not only affect the agricultural products but also the health of the local villagers with asthma, Allergic, Trinities Sinusitis, dermatitis (type of skin disease) especially among the childrens, Eczema, Allergic papules and all types of Allergic reactions.

Parthenium weed's botanical name is Parthenium Hystrophorous. It is a herbaceous plant, and a native of Tropical America. It is an annual herb and has a deep taproot and erect stem, which becomes woody with age. Parthenium weed leaves are deeply lobed. It is pale green in colour and has soft hair. Parthenium weed flower is creamy white in color. The weed has a large number of stems. It has small (1-2mm long) black seeds with white scales. They are not visible to the naked eye. It has been declared noxious in America, Australia, India and many other countries especially those having tropical climates.

A single plant can produce 10,000 to 15,000 viable seeds that occupy roadsides, tank bunds, fence lines, waste lands, agricultural fields etc.

If it intrudes into the agricultural domain productivity is definitely going to be adversely affected.
It squeezes grasslands and pastures, reducing the fodder supply. Scientists describe it as a "poisonous, allergic and aggressive weed posing a serious threat to human beings and livestock."
The presence of parthenium in cropped lands results in yield reduction up to 40 per cent. It is also responsible for bitter milk disease in livestock fed on grass mixed with parthenium.
Probing biological pollutant, highly  successful in distribution. No species of the past   or the present century can ever match with this.  The reasons for its fast spread are: (l) High germination ability throughout the year, (2)  Large seed  production ability, (3) High survival rate, (4)  Extreme adaptability in a wide range of habitats.  (5) Easy dispersal of seeds.

From the day it was perceived as a menace, efforts are being made to control the weed by different  methods. But so far, no single method appears to be satisfactory, as each method suffers from one or more limitations, such as high cost, impracticability, environmental safety, tem and Mechanical Eradication It is observed that cutting or slashing of  parthenium enhances its regeneration. So uprooting manually is the finest option. During the rainy  season, the soil remains wet and hence manual or  mechanical removal can be done before the onset of flowering with people's participation. This  operation should be started before blooming as uprooting after fruit setting will be a sheer waste of time and money. As manual removal is not cost effective, it can be advocated only in limited situations. If it becomes imperative to use labour,  they should be equipped with protective measures including ascertaining their parthenium sensitiveness.

During the last few years much emphasis has been laid on controlling parthenium through various  biological agents like insects, pathogens and by creating competition that result in 'survival of  the fittest'.

In the recent past, this approach gained momentum to do away with unwanted plants. Experimentally, it was found that Cassia species can control parthenium. C.sericea(C.uniflora), a non-nitrogen fixing leguminous herb, colonizes more aggressively without giving scope for  Parthenium to manifest. Cassia can be encouraged either from wild source or by introducing it in targeted areas.

Problems associated with Parthenium:
  1. It is a vigorous species, which colonizes in grassy land . It grows rapidly in bare areas along roadsides and water points.
  2. It reduces the production of pasture.
  3. It is very expensive to control.
  4. It is a major health hazard to human beings.
  5. It emits carbon dioxide and hence, poses a problem to nitrogen fixation and becomes a parasite, dependent on standing crops and animals in its vicinity.
  6. Its pollens are a major cause of asthma, especially in children and elderly people.
  7. It is a major cause of Allergic, Trinities Sinusitis, affecting about ten percent of the people who live near it.
  8. It is a major cause of dermatitis, a skin disease, among animals and human being.
  9. It reduces yield of milk and weight of animals. 
  10. It causes irritation to eyes.
There is need for people and residents' welfare associations to put their heads together and declare a war on parthenium weed so that further growth in the area  could be checked. This will go a long way in the interest of the poor sufferers of asthma and other allergy-related disorders.