Climate which changed the world 56 million years ago.

Are we heading towards the same disaster?

By

Dr. Nitish Priyadarshi

The Eocene was much like the garden of Eden.

56 million years ago a mysterious surge of carbon into the atmosphere sent global temperatures soaring. In a geologic eyeblink life was forever changed.

Climate change is changing the world. Either it is in the form of temperature rise or in the form of severe floods. Many times question arises in my mind whether this climate change is the out come of present human activities on the earth or it has happened in early geological ages too. Answer is “yes” climate change has occurred several times from the beginning of the earth formation. Evidences are preserved in from of rocks, sediments, and fossils.

Studying the records of past climate change will fill you like reading thriller novel in which every chapter is full of suspense and thrill. Every chapter of this novel denotes different geological periods with different stories of climate change.

My article is about the chapter which covers the story of climatic conditions around 56 million years ago.

The Atlantic Ocean had not fully opened, and animals, including perhaps our primate ancestors, could walk from Asia through Europe and across Greenland to North America. They wouldn’t have encountered a speck of ice; even before the events we’re talking about, earth was already much warmer than it is today. But as the Paleocene epoch gave way to the Eocene, it was about to get much warmer still-rapidly, radically warmer.

The cause was a massive and geologically sudden release of carbon. Just how much carbon was injected into the atmosphere during the Paleocene-Eocene Thermal Maximum, or PETM, as scientists now call the fever period, is uncertain. But they estimate it was roughly that amount that would be injected today if human beings burned through all the earth’s reserves of coal, oil and natural gas. The PETM lasted more than 150,000 years, until the excess carbon was reabsorbed. It brought on drought, floods, insect plagues, and a few extinctions. Life on earth survived-indeed, it prospered- but it was drastically different. Climate zones shifted toward the poles, on land and at sea, forcing plants and animals to migrate, adapt or die. Some of the deepest realms of the ocean became acidified and oxygen-starved, killing off many of the organisms living there. It took nearly 200,000 years for the earth’s natural buffers to bring the fever down. Today the evolutionary consequences of that distant carbon spike are all   around us; in fact they include us. Now we ourselves are repeating the experiment.

The PETM is significant because it marks the beginning of a 20+ million year warming trend that takes place in the Eocene, and continues on through the Oligocene. That isn't to say that the PETM lasted for 20+ million years, and was responsible for the warm balmy weather in the Eocene, but it did have an effect on the creatures living at the time, especially microscopic ocean organisms.

30-40% of foraminifera species went extinct during this time. Foraminifera are microscopic plankton-like organisms that feed much of the rest of the food chain.

According to a recent study led by Goethe University and the Biodiversity and Climate Research Centre (BIK-F) in Frankfurt, Antarctica had a much warmer climate during the Eocence Epoch (56-34 million years ago), enough to support subtropical flora and fauna.

Published in Nature, the study looked at sediment from cores dating back between 55 and 46 million years ago drilled off the coast of Antarctica near Wilkes Land (part of Antarctica located south of Australia) in 2010 as part of the Integrated Ocean Drilling Programme.

Scientists believe that global atmospheric carbon dioxide (CO2) concentrations were significantly higher (as much as 1,000 parts per billion) than present (which are just under 400 parts per billion). They don’t yet know what caused the major surge in CO2 levels at the start of the Eocene and exactly why they began to abate.

Hundreds of scientific papers have been published on the PETM, but because of the scarcity of paleo-data from this time, there has been no clear scientific agreement over what initiated this warming, or where all the CO2 came from.  

Where did all the carbon come from? We know the source of the excess carbon now pouring into the atmosphere: us. But there were no humans around 56 million years ago, no cars no power plants. Many sources have been suggested for PETM carbon spike, and given the amount  of carbon, it likely came from more than one. At the end of the Paleocene, Europe and Greenland were pulling apart and opening the North Atlantic, resulting in massive volcanic eruptions that could have cooked carbon dioxide out of organic sediments on the seafloor. Wildfires might have burned through Paleocene peat deposits, although so far soot from such fires has not turned up in sediment cores. A giant comet smashing into carbonate rocks also could have released a lot of carbon very quickly, but as yet there is no direct evidence of such an impact.

The oldest and still the most popular hypothesis is that much of the carbon came from large deposits of methane hydrate, a peculiar, ice like compound that consists of water molecules forming a cage around a single molecule of methane. Hydrates are stable only in a narrow band of cold temperatures and high pressures; large deposits of them are found today under the Artic tundra and under the sea floor, on the slopes that link the continental shelves to the deep abyssal plains. At the PETM an initial warming from somewhere –perhaps the volcanoes, perhaps slight fluctuations in Earth’s orbit that exposed parts of it to more sunlight- might have melted hydrates and allowed methane molecules to slip from their cages and bubble into the atmosphere.

Many of the other climate feedbacks that we either already observe today or expect to experience probably took place during the PETM warming, as well. Severe drought would have led to increased wildfires, injecting more carbon into the atmosphere. Some research shows that permafrost on a then glacier-free Antarctica thawed, which would have also released carbon dioxide and methane. Another interesting source of carbon that some scientists hypothesize is the burning of peat and coal seams. Peat is decayed vegetation and has a very high carbon content. Peat, which is found in the soil beneath the surface, can be ignited by something like a wildfire and continue to smolder for as long as centuries. Coal seams can be ignited in a similar way, and burn for decades to centuries, releasing huge amounts of carbon into the atmosphere.

The consequences of the PETM were significant in magnitude and truly global in scope:

1. Global warming; atmospheric temperatures warmed by 5°-9°C globally (6°-9°C warming of southern high latitude sea surface temperatures, 4°-5°C warming of the deep-sea, tropical sea surface temperatures, and Arctic Ocean, and ~5°C warming mid-latitude continental interiors).

2. Perhaps the most staggering result was that at times during the early Eocene warm episode the Arctic sea surface temperature soared to 24°C. The evidence suggests that the PETM marked possibly the warmest time at the North Pole for over 100 million years—certainly it has not been as warm since. Today's circum-polar ecosystems could not exist in such a climate regimen.

3. Ocean acidification (the carbonate compensation depth [CCD] rapidly shoaled by more than 2 km [<10 and="and" gradually="gradually" recovered="recovered" years="years">100,000 years)).

4. Sudden onset of anoxic conditions in deep ocean waters..

5. Increased intensity of the hydrologic cycle and erosion rates (based in part on changes in clay mineral assemblages).

6. Major extinctions of benthic foraminifera in the deep-sea (30-50% of species). Turnover and evolution of calcareous plankton (calcareous nannofossils and planktic foraminifers).

7. Migration of terrestrial organisms to the high latitudes.

8. Turnover and evolution of terrestrial animals and plants. New mammal lineages first appear in the earliest Eocene, including the earliest horse in North America.

The hypothesis is alarming. Methane in the atmosphere warms the earth over 20 times more per molecule than carbon dioxide, then after a decade or two, it oxidizes to C02 and keeps on warming for a long time. Many scientists think just that kind of scenario might occur today: The warming caused by the burning of fossil fuels could trigger a runway release of methane from the deep sea and the frozen north.      

References:

http://www.wunderground.com/climate/PETM.asp#petm

http://www.scientificamerican.com/article.cfm?id=the-last-great-global-warming

http://www.theresilientearth.com/?q=content/could-human-co2-emissions-cause-another-petm

http://ngm.nationalgeographic.com/print/2011/10/hothouse-earth/kunzig-text

http://geology.fullerton.edu/whenderson/Fal201L2005/EoceneWarming/index.htm

http://www.sciencepoles.org/news/news_detail/antarctica_had_much_warmer_climate_some_50_million_years_ago_according_to_s/

Climate change is increasing diseases.

They will be widespread and unpredictable.

By

Dr. Nitish Priyadarshi

An outbreak of the Ebola virus has killed 14 people in western Uganda last month. There is no treatment and no vaccine against Ebola, which is transmitted by close personal contact and, depending on the strain, kills up to 90 per cent of those who contract the virus. In recent years, Uganda has been hit with three Ebola outbreaks, the worst of which was in 2000, when more than half of the 425 people infected died.

Cases of Japanese Encephalitis (JE) has gone up to 50 in the Assam State in Eastern India. The areas mostly affected by Japanese Encephalitis are Kamrup, Sivasagar, Dhubri, Morigaon, Darrang and Nalbari. More than 400 people in northern India have died last year from encephalitis, a rare condition that causes inflammation of the brain. Around 347 people have died in Uttar Pradesh, while 54 children have died in the neighbouring state of Bihar. Cases of malaria is increasing every year in the state of Jharkhand, Assam, Orissa, Maharashtra etc.

With over 2,50,000 people testing positive for malaria last year, Orissa topped the chart for reporting the highest number of malaria cases. This was followed by 95,000 cases reported from Chhattisgarh and over 61,000 registered in Madhya Pradesh.

A 1996 report from the London School of Hygiene and Tropical Medicine calculated that, of ten of the world’s most dangerous vector-borne diseases (malaria, schistomiasis, dengue fever, lymphatic filariasis, sleeping sickness, guinea worm, leishmaniasis, river blindness, chagas’ disease and yellow fever), all but one were likely to increase, or in some way change their range as a result of climate change.

In recent years, vector-borne diseases (VBD) have emerged as a serious public health problem in countries of the South-East Asia Region, including India. Many of these, particularly dengue fever, Japanese Encephalitis (JE) and malaria now occur in epidemic form almost on an annual basis causing considerable morbidity and mortality. Dengue is spreading rapidly to newer areas, with outbreaks occurring more frequently and explosively. Chikungunya has re-emerged in India after a gap of more than three decades affecting many states.

Asia spans tropical and temperate regions. Plasmodium falciparum and P. vivax malaria, dengue fever, dengue haemorrhagic fever, and schistosomiasis are endemic in parts of tropical Asia. In the past 100 years, mean surface temperatures have increased by 0.3–0.8 °C across the continent and are projected to rise by 0.4–4.5 °C by 2070.

An increase in temperature, rainfall and humidity in some months in the Northwest Frontier Province of Pakistan has been associated with an increase in the incidence of  P. falciparum malaria. In north-east Punjab, malaria epidemics increase fivefold in the year following an El Niño event, while in Sri Lanka the risk of malaria epidemics increases fourfold during an El Niño year. In Punjab, epidemics are associated with above-normal precipitation, and in Sri Lanka, with below-normal precipitation.

According to WHO, many countries in Asia experienced unusually high levels of dengue and/or dengue haemorrhagic fever in 1998, the activity being higher than in any other year. Changes in weather patterns, such as El Niño events, may be major contributing factors, since laboratory experiments have demonstrated that the incubation period of dengue 2 virus could be reduced from 12 days at 30 °C to 7 days at 32–35 °C in Aedes aegypti .

Public health officials often use the term tropical diseases to refer collectively to a list of infectious diseases that are found primarily in developing countries. These include malaria, schistosomiasis, dengue, trypanosomiasis, leprosy, cholera, and leishmaniasis, among others. Many of these diseases are spread by insect vectors, and all of them disproportionately affect the world's poor. Malaria is the most severe of these, with the World Health Organization estimating that the disease causes about 250 million episodes of acute illness and perhaps 880,000 deaths annually.

The most widespread and severe climate-sensitive vector-borne disease in South America is malaria. Studies have shown that unusually dry conditions (for example, those caused by weather related to the El Niño–Southern Oscillation phenomenon in the northern part of the continent) are accompanied or followed by increases in the incidence of the disease. This has been documented in Colombia and Venezuela.

In Asia, dengue fever  and malaria  have been associated with positive temperature and rainfall anomalies, while in Australia arboviral disease outbreaks are most frequently associated with flooding. Urban developments in Asia and the surrounding regions may have a substantial impact on trends in the transmission of dengue fever. In some areas, such as Viet Nam, effects of past civil instability and slow economic growth may also be implicated.

Climate change would directly affect disease transmission by shifting the vector's geographic range and increasing reproductive and biting rates and by shortening the pathogen incubation period. Climate-related increases in sea surface temperature and sea level can lead to higher incidence of water-borne infectious and toxin-related illnesses, such as cholera and shellfish poisoning. Human migration and damage to health infrastructures from the projected increase in climate variability could indirectly contribute to disease transmission. Human susceptibility to infections might be further compounded by malnutrition due to climate stress on agriculture and potential alterations in the human immune system caused by increased flux of ultraviolet radiation.

Of the many scientists who have projected, predicted and warned of the likely health effects of climate change, almost all agree on the basics: they will be widespread and unpredictable, they are likely to be severe, and many, many people across the world will die as a result.

New Scientist magazine reported that ‘human disease is emerging as one of the most sensitive, and distressing indicators of climate change. “It is accepted by virtually all climate scientists that the likely increase in and spread of, potentially fatal diseases is likely to be the single most dangerous threat that climate change poses to human health.

Among the ten most dangerous diseases Malaria is the world’s most prevalent mosquito- borne disease. All experts seem to agree that one effect of climate change will be to increase the range of the malarial mosquito. Destruction of forests to create new human settlements can increase local temperatures by 3–4 °C and at the same time create breeding sites for malaria vectors. These phenomena can have serious consequences on malaria transmission in India, African highlands and other parts of the world.

And it is not just vector-borne diseases that are likely to take advantage of the changing climate. Other infectious killers are likely to enjoy a resurgence too, particularly diseases associated with water supply and sanitation. Climate change could have a major impact on water resources and sanitation by reducing water supply. This could in turn reduce the water available for drinking and washing, and lower the efficiency of local sewerage systems, leading to increased concentration of pathogenic organisms in raw water supplies.

More than 100 pathogens can cause illness if you drink or swim in water contaminated by sewage, including norovirus Norwalk and hepatitis A viruses and bacteria such as E. coli and campylobacter.

Several studies have shown that shifts brought about by climate change make ocean and freshwater environments more susceptible to toxic algae blooms and allow harmful microbes and bacteria to proliferate.

Global Warming will also increase rainfall intensity. Rainfalls will be heavier, triggering sewage overflows, contaminating drinking water and endangering beachgoers. Higher lake and ocean temperatures will cause bacteria, parasites and algal blooms to flourish. Warmer weather and heavier rains also will mean more mosquitoes, which can carry the West Nile virus, malaria and dengue fever. Fresh produce and shellfish are more likely to become contaminated.

Heavier rainfalls are one of the most agreed-upon effects of climate change. The frequency of intense rainfalls has increased notably in the Eastern India, China, Philippines, Korea and Japan.

Flooding may follow heavy rainfall. For developing nations there is evidence of outbreaks following floods. Outbreaks of leptospirosis in Rio de Janeiro (Barcellos and Sabroza 2001) and in the Philippines (Easton 1999) have followed floods. Hepatitis E, malaria and diarrhoeal disease have followed floods in Khartoom (Homeida et al. 1988; Novelli et al. 1988 ). Both acute diarrhoea and acute respiratory disease increased in Nicaragua following Hurricane Mitch and the associated flooding (Campanella 1999).

Temperature can affect both the distribution of the vector and the effectiveness of pathogen transmission through the vector. Gubler et al. (2001) list a range of possible mechanisms whereby changes in temperature impact on the risk of transmission of vector-borne disease:

1. Increase or decrease in survival of vector
2. Changes in rate of vector population growth
3. Changes in feeding behaviour
4. Changes in susceptibility of vector to pathogens
5. Changes in incubation period of pathogen
6. Changes in seasonality of pathogen transmission

By 2100 it is estimated that average global temperatures will have risen by 1.0–3.5 °C, increasing the likelihood of many vector-borne diseases in new areas. The greatest effect of climate change on transmission is likely to be observed at the extremes of the range of temperatures at which transmission occurs. For many diseases these lie in the range 14–18 °C at the lower end and about 35–40 °C at the upper end. Malaria and dengue fever are among the most important vector-borne diseases in the tropics and subtropics; Lyme disease is the most common vector-borne disease in the USA and Europe. Encephalitis is also becoming a public health concern. Health risks due to climatic changes will differ between countries that have developed health infrastructures and those that do not.

Human settlement patterns in the different regions will influence disease trends. While 70% of the population in South America is urbanized, the proportion in sub-Saharan Africa is less than 45%. Climatic anomalies associated with the El Niño–Southern Oscillation phenomenon and resulting in drought and floods are expected to increase in frequency and intensity. They have been linked to outbreaks of malaria in Africa, Asia and South America. Climate change has far-reaching consequences and touches on all life-support systems. It is therefore a factor that should be placed high among those that affect human health and survival.

Conclusion:

Analyzing the role of climate in the emergence of human infectious diseases will require interdisciplinary cooperation among physicians, climatologists, biologists, and social scientists. Increased disease surveillance, integrated modeling, and use of geographically based data systems will afford more anticipatory measures by the medical community. Understanding the linkages between climatological and ecological change as determinants of disease emergence and redistribution will ultimately help optimize preventive strategies.

References:

Barcellos, C. and Sabroza, P.C. (2001) The place behind the case: leptospirosis risks and associated environmental conditions in a flood-related outbreak in Rio de Janeiro. Cadernos de Saude Publica 17(suppl), 59–67.

Bouma MJ, Dye C, van der Kaay HJ. (1996) Falciparum malaria and climate change in the northwest frontier province of Pakistan. American Journal of Tropical Medicine and Hygiene,  55: 131–137

Bouma MJ et al. (1997) Predicting high-risk years for malaria in Colombia using parameters of El Niño–Southern Oscillation. Tropical Medicine and International Health, 2: 1122–1127.       

Campanella, N. (1999) Infectious diseases and natural disasters: the effects of Hurricane Mitch over Villanueva municipal area, Nicaragua. Public Health Reviews 27, 311–319.

Dengue in the WHO Western Pacific Region.(1998) Weekly epidemiological record, 73(36): 273–277.        

Easton, A. (1999) Leptospirosis in Philippine floods. British Medical Journal 319, 212.

Gubler, D.J., Reiter, P., Ebi, K.L., Yap, W., Nasci, R. and Patz, J.A. (2001) Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases. Environmental Health Perpectives 109(suppl 2), 223–233.

Homeida, M., Ismail, A.A., El Tom, I., Mahmoud, B. and Ali, H.M. (1988) Resistant malaria and the Sudan floods. Lancet 2, 912.

Novelli, V., El Tohami, T.A., Osundwa, V.M. and Ashong, F. (1988) Floods and resistant malaria. Lancet 2, 1367.

Poveda, G et al.(1999) Climate and ENSO variability associated with vector-borne diseases in Colombia. In: Diaz HF, Markgraf V, eds. El Niño and the Southern Oscillation, multiscale variability and regional impact. Cambridge, Cambridge University Press. 

Watts DM et al. (1987) Effect of temperature on the vector efficiency of Aedes aegypti for dengue 2 virus. American Journal of Tropical Medicine and Hygiene, 1987, 36: 143–152.        

http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2672.94.s1.5.x/full

http://jama.jamanetwork.com/article.aspx?articleid=394508

http://www.searo.who.int/LinkFiles/CDS_vector-borne_diseases_in_India.pdf

http://www.scielosp.org/scielo.php?pid=S0042-96862000000900009&script=sci_arttext&tlng=e

A hungrier world- blame it on climate change.

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

By

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.

References:

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

http://www.dailytimes.com.pk/default.asp?page=2012%5C07%5C25%5Cstory_25-7-2012_pg5_24

http://www.brecorder.com/agriculture-a-allied/183/1207604/

http://www.livescience.com/14447-global-food-shortage-urgent-climate-global-warming.html

http://www.guardian.co.uk/world/2005/jun/30/science.famine

http://news.medill.northwestern.edu/chicago/news.aspx?id=187175

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

With special reference to Jharkhand State of India.

By

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.   

Reference:

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.        

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.

by

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.