Tuesday, December 29, 2009

Arsenic alarm in Bihar and Jharkhand Villages of India.

Bihar and Jharkhand is facing one of the gravest natural disasters in the form of arsenic contamination of ground water.
Dr. Nitish Priyadarshi

Thousands of people living in over hundreds of villages in different district of Bihar and Sahebganj district of Jharkhand state in India are facing serious threat to their health due to alarmingly high quantity of arsenic present in the underground water.

Bihar is facing one of the gravest natural disasters in the form of arsenic contamination of ground water. In the first detailed study of ground water quality, the Department of Environment and Water Management, A.N.College, Patna, has already submitted Interim Reports to PHED and UNICEF about the alarming findings on arsenic poisoning cases in the districts of Patna, Bhojpur, Vaishali and Bhagalpur. The study was conducted from April 2004 to May 2006, the study area being confined to 10 kms. wide belt along the Ganga river as per the instructions of PHED and UNICEF.

According to Dr.Ashok Ghosh, Principal Investigator of Project Arsenic, Dept. Of EWM, A.N.College, these findings are just the tip of the iceberg, as more contaminated aquifers are waiting to be detected in the remaining parts of the state. The water quality testing was done initially by Field Test Kits and then confirmed by AAS or UV Spectrophotometric tests. Epidemiological studies indicate that drinking water having more than permissible arsenic levels of 10 ppb. increases the mortality rates as arsenic is a bio-accumulative toxin.

Persons suffering from arsenicosis have not yet responded to known treatment procedures. The high the intake of arsenic, along with under nourishment and lack of medical help have worsened the lives of the population in the arsenic affected rural areas. Arsenic can also contaminate standing food crops if it is present in the soil and soil water. As Bihar Plains are highly fertile and its crops are marketed to many distant places, apart from being locally consumed, it becomes imperative to test the levels of arsenic in the food chain too. What is worrisome is that arsenic contaminated ground water tables have abrupt occurrences both over time and space. This explains why a public hand pump in village Ramnager in Maner tested 30 ppb. in the post monsoon period and more than 60 ppb. in the month of May. Also arsenic manifestation exists at different levels in different areas. In north-west Maner, arsenic contaminated hand pumps have a shallow depth of between 60 to 80 feet in the diara belt.

In Bhojpur, the depth of contaminated aquifers goes down to 150 feet away from new diara land, while in Vaishali, arsenic is found in the shallow and middle aquifers at an average distance of 5 km. away from the river bank. Regular monitoring of drinking water from hand pumps is immediately required as a part of the mitigation strategy. Patna, the first district to be covered, revealed pockets of high arsenic contamination, above the acceptable limit of 10 ppb., in 171 villages in Maner, Danapur, Sampatchak, Barh, Bakhtiarpur, , Fatuha, Khusrupur, Phulwari, Mokama, Pandarak and Patna City.

1060 village hand pumps were arsenic contaminated The highest AAS reading of arsenic level in government hand pump water is 724 ppb. in village Naikatola in Maner, 450 ppb. in Kasimchak village in Danapur, 553 ppb. in Ghiaspur Mahazi and 538 ppb. in Kala Diara, Bakhtiarpur,, and 484 ppb. in Malahi Banda village in Barh. Sampatchak Block has low contamination levels of below 50 ppb. over a larger area in most of the villages. In Bhojpur, the highest AAS test readings are 1861 ppb. and 1064 ppb. in Pandey tola, Barhara Block, a situation far more serious than the one represented by the much-touted village Ojhapatti of Shahpur Block. Out of the 6292 hand pumps tested, 47.70 % were arsenic contaminated hand pumps. In Barhara, 62.84%, in Udwantnagar 59.39%, in Shahpur 40.41%, in Behea 37.17%, in Koilwar, 29.20%, and in Ara 25.88% of Block level hand pumps were arsenic contaminated. In Vaishali, all the Blocks covered within 10 km. along the Ganga banks, has low level arsenic contamination at present.
In Bhagalpur district most affected areas are Kahalgaon, Pirpainti, Sabaur and Sultanganj. A detailed study has been presented on groundwater metal contents of Sahebgunj district in the state of Jharkhand, with special reference to arsenic. Both tubewell and well waters have been studied separately with greater emphasis on tubewell waters. Groundwaters of all the nine blocks of Sahebgunj district have been surveyed for iron, manganese, calcium, magnesium, copper and zinc in addition to arsenic. Groundwaters of three blocks of Sahebgunj, namely, Sahebgunj, Rajmahal and Udhawa have been found to be alarmingly contaminated with arsenic present at or above 10 ppb.
Rivers flowing through the coal fields of Jharkhand have been reported to carry arsenic responsible for arsenic poisoning in downstream areas of West Bengal. The coal fields of Bachara and Piprawar areas of Jharkhand have contaminated the waters of the Damodar and its tributary, the Safi. According to author, arsenic contamination arises mainly due to the dumping of waste from the coal mines along the river bed. Coals of the area mentioned contains sufficient amount of arsenic.
Arsenic upto 608 parts per billion (ppb) was detected against the permissible limit of 10 ppb in some villages of Kahalgaon block in Bhagalpur district in 2005. Work was carried out by Dr. Sunil Chaudhary of TM Bhagalpur University.
A detailed work was carried out by Dr. Ashok Ghosh, Professor-in-charge, department of environment and water management, A.N. College Patna, in the arsenic affected areas of Bihar State. He found that out of 27,061 hand pumps, 7,218 pumps tested had arsenic contaminated water greater than 10 ppb (26.67%). Highest arsenic value recorded was 1861 ppb. Study also revealed that 87% of the Trivalent arsenic was found in the groundwater of Bihar State.
The study by Bihar's Public Health and Engineering Department (PHED) reveals that the average arsenic content in drinking water in the 12 districts is 500 parts per billion (ppb). The state capital, Patna, is among the affected areas.
According to Dr. Ghosh, a total of 16 Bihar districts (57 blocks) are affected by high level of arsenic in the groundwater. Worst-affected districts are Bhojpur, Buxar, Vaishali, Bhagalpur, Samstipur, Khagaria, Katihar, Chapra, Munger and Dharbanga.
A very alarming recent finding by the research group is the detection of high arsenic content (more than 50 ppb) in the water of River Jaminia – flowing parallel to River Ganga in Bhagalpur district of Bihar.This river merges with Ganga and water from this river is being supplied to urban Bhagalpur without any treatment, alarmed Dr. Ghosh.
Alarmed by the severity of arsenic’s impact on human body in these villages, the team also collected samples of hair and nail of affected persons for detail medical examination to ascertain the level of damage, said Principal Investigators Dr. Ashok Kumar Ghosh and Nupur Bose of A.N. College Patna. The findings indicated that a wider area, including the fertile irrigational lands, was under the grip of arsenic.
According to another research report done by Mr. Dipanka Chakraborti in Semria Ojha Patti village in the Middle Ganga Plain, Bihar, where tube wells replaced dug wells about 20 years ago, analyses of the arsenic content of 206 tube wells (95% of the total) showed that 56.8% exceeded arsenic concentrations of 50 micro g/L, with 19.9% greater than 300 micro g/L, the concentration predicting overt arsenical skin lesions.



Mayon Volcano in the Phillipines may errupt.

Tens of thousands of people living within the danger zone of Mayon Volcano in the Philippines were forced to evacuate to emergency shelters in mid-December 2009 as small earthquakes, incandescent lava at the summit and minor ash falls suggested a major eruption was on the way. On the evening of Dec. 14, the local volcano observatory raised the alert level to Level 3, which means "magma is close to the crater and hazardous explosive eruption is imminent."This natural-color image of Mayon was captured on Dec. 15, 2009, by the Advanced Land Imager on NASA's Earth Observing-1 (EO-1) satellite. A small plume of ash and steam is blowing west from the summit. Dark-colored lava or debris flows from previous eruptions streak the flanks of the mountain. A ravine on the southeast slope is occupied by a particularly prominent lava or debris flow.The Phillipine Star said on Dec. 22 that "ashfall blanketed at least three towns in Albay, raising new health fears for thousands already bracing for an eruption that could come at any time ... Health officials warned the tiny particles could cause respiratory problems or skin diseases, and could affect the thousands of people crammed into evacuation centers.Also on Dec. 22, CNN reported that "tens of thousands of people have already fled their homes. More than 9,000 families -- a total of 44,394 people -- are being housed in evacuation camps after authorities raised the alert status of the country's most active volcano" as "fountains of red-hot lava shot up from the intensifying Mayon volcano."
Image Credit: NASA/Jesse Allen

Wednesday, December 23, 2009

More population more global warming.

Population Explosion may trigger Global Warming.
Dr. Nitish Priyadarshi
Image credit: http://webecoist.com/wp-content/uploads/2008/11/population-explosion1.jpg
The earth’s population has nearly doubled since World War II. More babies than ever than ever have been born, but this is only part of the reason for the increase. More and better food and medical care have kept alive many people who would otherwise have died. This enormous increase in the number of people is called ‘population explosion.’ Many experts believe it is the greatest danger facing mankind. A doubled population means a greater drain on the world’s limited resources.

Increasing in population size, age and distribution is affecting climate by producing more green house gases, either in the form of automobile or in the form of thermal energy to meet increasing electricity demand. A larger global population means a larger demand for everything--most urgently, energy. The world population is growing by 75 million people each year. That’s almost the size of Germany. Today we are nearly 7 billion people. At this rate we will reach 9 billion people by 2040. According to other report, if current fertility rates continued, in 2050 the total world population would be 11 billion, with 169 million people added each year. Almost all growth will take place in the less developed regions, where today’s 5.3 billion population of underdeveloped countries is expected to increase to 7.8 billion in 2050.

More people means more food, and more methods of transportation. That means more carbon and methane because there will be more burning of fossil fuels. If we take the case of Jharkhand state of India, to meet the demand of electricity more and more coal mines are being opened which has thrust more carbon dioxide and methane to the atmosphere.

Life on Earth is dependent on carbon dioxide (CO2) to regulate the temperature of our planet, but too much can create a heat-trapping blanket over our atmosphere. In the last century, unsustainable population growth and excessive consumption have raised levels of CO2 so dramatically that the earth's climate has been altered in ways never experienced before. Agricultural expansion and forest depletion have multiplied emissions of greenhouse gases like CO2, but it is our dependence on fossil fuels that propels monumental atmospheric change. When we burn fossil fuels such as coal, oil, and gas, we release unsustainable levels of CO2—the primary global warming culprit. Those of us living in the developed world bear a majority of the responsibility for reversing this disturbing trend.

The relationships among humans, their activities and global temperature can be assessed by making the appropriate measurements and analyzing the data in a way that shows the connections and their magnitudes. Human population can be closely estimated and the consequences of their activities can be measured. For example, the volume of carbon dioxide, methane and nitrous oxide emissions is an indicator of human's energy and resource consumption.

Population does appear to be a vital factor in the increase in carbon dioxide emissions. According to an estimate, over a third of the doubling of fossil fuel emissions in developed countries between 1960 and 1988 was due to increased population. The significance of this change is its potential for raising the temperature of the earth through the process known as the Greenhouse Effect. Carbon dioxide in the atmosphere prevents the escape of outgoing long wave radiation from the earth to outer space. As more heat is produced and less escapes, the temperature of the earth increases.

The threat of climate change and global warming has therefore, been heavily influenced by population growth. As developing countries, with rapidly increasing populations follow the Western path of development, it is likely to add greatly to the problem. A country like China, for example, which has rapid industrialization and has the largest population in the world is projected to increase its population further, and is expected to become the leading source of global- warming gas emission by 2050.

Increasing population is decreasing forest cover, which happens to be major absorbent of carbon dioxide. Experts agree that population pressure contributes directly to the continuing loss of forest cover. Based on UN Food and Agriculture Organization (FAO) land use estimates, it would appear that in the past three decades or so 59% of the forests cleared in developing countries were for human settlements, roads and other non-agricultural developments- almost entirely related to population growth.

The act of cutting trees to generate farmland, has a great impact on global warming. The cutting of trees is mainly done for paper production, livestock farming etc. Deforestation is responsible for about 20% emission of global warming. Experts opine that deforestation has greater impact on global warming than emissions from factories and automobiles.

Each day the average person breathes in about 15,000 liters, or approximately 35 pounds, of air. (http://www2.envmed.rochester.edu/envmed/TOX/faculty/frampton.html) Since air is 21% oxygen (molecular weight 16) and 78% nitrogen (molecular weight 14) by volume, oxygen is 23.5% by weight and nitrogen is 76.5% by weight in air. So the amount of oxygen breathed in per day by the average person is about 35*0.235 = 8.2 lbs.

Humans breath out about 16% oxygen by volume, so about 5% of the air by volume is converted to CO2, which is about (5/21)x8.2 = about 2 lbs of CO2 every day.

The molecular weight of O2 is 32 and the molecular weight of CO2 is 12+32=44. Therefore, humans emit 44x2x/32 lbs = about 2.8 lbs of CO2 breathed out every day or about 1005 lbs = about 0.5 tons per person per year.

In 2005 the Earth population was about 6.66x109. So the emitted CO2 per year by their breathing was about 3.3x109 tons.
In 2002 CO2 emissions due to human activities were about 25x109 tonnes = 27.6x109 tons (http://www.unep.org/geo/yearbook/yb2006/077.asp). Breathing comprises about 3.3x109 tons of that amount, or about 12% of it.

Globally, annual average emissions of carbon dioxide per capita due to human activities (other than breathing) have been fairly stable since 1990. For 2002, this figure was up to 3.93 tonnes from 3.85 tonnes in 2001 (http://www.unep.org/geo/yearbook/yb2006/077.asp).

Scientists have predicted that the day is not far when nations would fight for drinking water and people would perish due to floods and climate changes. Population explosion, though undeniably the root cause of global warming, has so far been largely overlooked.

UN estimates forecast around 8 to 10 billion population on the planet by 2050 — a galloping 50 per cent increase from the present world population, which is estimated to be 6.5 billion. Scientists have proved that human activities do influence climatic conditions. Therefore, any long-term planning to combat the threat of climate change would not succeed without first finding solutions to rectify the demographic trends.

While industrial nations have been primarily responsible for high emissions levels in the recent past, the rapidly growing population of the developing world will be a major factor in future emissions levels. As we look to the developed world to curb and reduce emissions, many in developing countries need to increase their energy use to meet basic needs and improve their quality of life. Countries such as India and Brazil are looking for solutions to balance the needs of people and the planet. Therefore, all national policies and international agreements on global warming must take population growth into account.

Wednesday, December 16, 2009

High levels of black carbon likely to impact Tibetan Plateau's temperature.

The Dark Side of Black Carbon
Dr. Nitish Priyadarshi
Image Credit: NASA

As interest in Earth's changing climate heats up, a tiny dark particle is stepping into the limelight: black carbon. Commonly known as soot, black carbon enters the air when fossil fuels and biofuels, such as coal, wood, and diesel are burned. Black carbon is found worldwide, but its presence and impact are particularly strong in Asia. Black carbon, a short-lived particle, is in perpetual motion across the globe. The Tibetan Plateau's high levels of black carbon likely impact the region's temperature, clouds and monsoon season.

Black soot deposited on Tibetan glaciers has contributed significantly to the retreat of the world's largest non-polar ice masses, according to new research by scientists from NASA and the Chinese Academy of Sciences. Soot absorbs incoming solar radiation and can speed glacial melting when deposited on snow in sufficient quantities.
Temperatures on the Tibetan Plateau -- sometimes called Earth's "third pole" -- have warmed by 0.3°C (0.5°F) per decade over the past 30 years, about twice the rate of observed global temperature increases. New field research and ongoing quantitative modeling suggests that soot's warming influence on Tibetan glaciers could rival that of greenhouse gases.

Since melt water from Tibetan glaciers replenishes many of Asia's major rivers -- including the Indus, Ganges, Yellow, and Brahmaputra -- such losses could have a profound impact on the billion people who rely on the rivers for fresh water. Areas going to most affected in India would be Uttrakhand, Uttar Pradesh, Bihar, Jharkhand, West Bengal and Assam. While rain and snow would still help replenish Asian rivers in the absence of glaciers, the change could hamper efforts to manage seasonal water resources by altering when fresh water supplies are available in areas already prone to water shortages.
Researchers led by Baiqing Xu of the Chinese Academy drilled and analyzed five ice cores from various locations across the Tibetan Plateau, looking for black carbon (a key component of soot) as well as organic carbon. The cores support the hypothesis that black soot amounts in the Himalayan glaciers correlate with black carbon emissions in Europe and South Asia.
Black carbon or BC is formed through the incomplete combustion of fossil fuel, biofuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot. Black carbon warms the planet by absorbing heat in the atmosphere and by reducing albedo, the ability to reflect sunlight, when deposited on snow and ice. Black carbon stays in the atmosphere for only several days to weeks, whereas CO2 has an atmospheric lifetime of more than 100 years. The term black carbon is also used in soil sciences and geology, referring either to deposited atmospheric BC or to directly incorporated BC from vegetation fires. Especially for the tropics, BC in soils significantly contributes to fertility as it is able to adsorb important plant nutrients .

Black carbon is a potent climate forcing agent, estimated to be the second largest contributor to global warming after carbon dioxide (CO2). Because black carbon remains in the atmosphere only for a few weeks, reducing black carbon emissions may be the fastest means of slowing climate change in the near-term.

Black carbon emissions from northern Eurasia, North America, and Asia have the greatest absolute impact on Arctic warming.

In some regions, such as the Himalayas, the impact of black carbon on melting snowpack and glaciers may be equal to that of CO2.Warmer air resulting from the presence of black carbon in South and East Asia over the Himalayas contributes to a warming of approximately 0.6°C. An “analysis of temperature trends on the Tibetan side of the Himalayas reveals warming in excess of 1°C.

Black carbon sources vary by region. For example, the majority of soot emissions in South Asia are due to biofuel cooking, whereas in East Asia, coal combustion for residential and industrial uses plays a larger role.

Black carbon can be controlled in developing countries through the implementation of cleaner fuels, new cooking technologies, and changing crop management practices.



Monday, December 14, 2009

क्या है समुद्र के नीचे लेमुरिया महाद्वीप का रहस्य?

क्या है समुद्र के नीचे लेमुरिया महाद्वीप का रहस्य ? क्या बदलते तापमान ने इन्हे डुबाया ?
झारखण्ड की मुंडा जाती भी शायद इसी महाद्वीप से होते हुए भारत पहुँची।
डा। नितीश प्रियदर्शी

आज सारे विश्व के वैज्ञानिक इस बात पर सहमत हैं की आने वाले समय में पृथ्वी पर कई विनाशकारी बदलाव होंगे। कारन है ग्लोबल वार्मिंग । कई छोटे द्वीप समुद्र में समां जायंगे । कहीं सूखे की मार होगी तो कहीं अतिवृष्टि । कई नए जगह भूकंप प्रभावित होंगे जो पहले नही थे । यानि विनाश का एक नया रूप सामने आएगा।

कुछ खोजकर्ता इस बात का दावा कर रहें हैं की माया सभ्यता के कैलेंडर मे इस बात का जिक्र है की सन २०१२, २१ दिसम्बर को पृथ्वी का विनाश हो जाएगा।ऐसी बात नही हे की आने वाले समय में ही विनाश होगा । विनाश अगर होगा भी तो अचानक नही । विनाश की प्रक्रिया धीरे धीरे होती है जैसे पहले हुई थी । जब से पृथ्वी बनी है विनाश के कई चरण हुए है जब कई प्रजातियाँ विलुप्त हुई तथा नई आई हैं। विश्व के सभी जातिओं एवं धर्मो में प्राचीन महाप्रलय का उल्लेख मिलता है । केवल धर्मं ही नही भूवैज्ञानिक साक्ष्य भी पृथ्वी पर कई प्राचीन विनाशकारी हलचल को दर्शाता है। चाहे वो भूकंप के रूप मे हो या ज्वालामुखी के रूप मे या ग्लोबल वार्मिंग या हिमयुग के रूप मे हो। विश्व के सभी धर्मो में जल को ही महाप्रलय का कारण माना गया है। यहाँ तक की सभी आदिम जन जातिओं मे भी जल महाप्रलय का उल्लेख कहानिओं के रूप में हुआ है।इसी क्रम में दो महाद्वीपों का नाम उभर कर आता है जो आज महासागर के नीचे है। इनका नाम है "लेमुरिया एवं मु”। वेसे इन द्वीपों का अभी तक वेज्ञानिक पुष्टि नही हो पाई है। लेकिन विश्व के खोजकर्ताओं का दावा है की यह दोनों महाद्वीप पर सभ्यता काफी विकसित थी। कुछ खोजकर्ताओं, जिनमे प्रमुख थे फिलिप स्कोल्टर , का यह भी कहना था की मनुष्य की उत्पत्ति इन्ही महाद्वीपों पर हुई थी। ये दोनों महाद्वीप किसी भूवैज्ञानिक हलचल के वजह से समुद्र के भीतर समां गए।

एक रोचक तथ्य यह सामने उभर कर सामने आया है की हमलोग की आगे की पीढ़ी शायद फिर लेमुरिया द्वीप पर वास करे। खोजकर्ताओं का मानना है की जिस तरीके से लेमुरिया द्वीप समुद्र के अन्दर समां गया शायद भविष्य मैं किसी प्लेट टेक्टोनिक या किसी भूगर्भीय हलचल की वजह से यह द्वीप समुद्र के ऊपर आ जाए। एक और रोचक तथ्य सामने यह आया है की लेमुरिया द्वीप के लोग काफ़ी लंबे होते थे। उनके पास तीसरा आँख भी था जो सर के पीछे होता था। यही आँख आज के मनुष्य मैं pineal eye के नाम से जाना जाता है। इसका अब कोई कम नही है। लेकिन इसपर अभी कोई खोज नही हुआ है।एसा माना जाता है की लेमुरिया महाद्वीप हिंद महासागर के नीचे एवं मु महाद्वीप प्रशांत महासागर के नीचे समा गया। खोजकर्ताओं की माने तो "मु" महाद्वीप ५०,००० वर्ष पहले तक था एवं "लेमुरिया द्वीप" की उत्पत्ति एक लाख साल पहले हुई थी।ऐसा लगता है जिस वक्त ये दोनों महाद्वीप समुद्र के नीचे समाये उस वक्त पृथ्वी का तापमान आज के तुलना में ज्यादा रहा होगा जिसके चलते हिमनदों के पिघलने से समुद्र का जलस्तर ऊँचा उठा एवं इन दोनों महाद्वीपों को धीरे धीरे अपने भीतर समां लिया। वेसे भी आज के बढ़ते तापमान की वजह से विश्व के कई छोटे छोटे द्वीप खतरें मैं आ गए है।
पहले भी हमारे पृथ्वी पर कई बदलाव हुए आज जहाँ पर सुखी जमीन है वहां पहले समुद्र हुआ करता था। आज जहाँ रेगिस्तान है वहां पहले हरियाली हुआ करती थी। पृथ्वी पर प्राचीन काल के जिओलोजिकल विनाश के अवशेष आज भी मिलते है । एल्फ्रेड रसेल एवं एर्नेस्ट हेकेल का मानना था की मनुष्य की उत्पत्ति इन महाद्वीपों पर हुई थी। लेमुरिया शब्द लेमूर नामक जीव से आया जो बन्दर एवं गिलहरी का मिश्रित रूप है। लेमूर का मूल स्थान मेडागास्कर है लेकिन यह भारत एवं मलाया मे भी पाया जाता है। इसलिये यह माना गया की ये जीव तभी भारत पहुंचें होंगे जब कोई विशाल महाद्वीप हिंद महासागर में रहा होगा एवं जो भारत एवं मेडागास्कर के बिच में सेतु का काम किया।

वैज्ञानिक मानते हैं की भारत उप महाद्वीप में किसी नर-वानर की उत्पत्ति नही हुई थी। अतः जितनी भी जातियां भारत की धरती पर जीवित हैं या लुप्त हो चुकीं हैंउनका मूल स्थान कहीं न कहीं भारत से बाहर रहा था। झारखण्ड के मुंडाओं के मूल स्थान तथा उनके आव्रजन मार्ग की खोग में लेमुरिया सिद्धांत का उल्लेख हुआ है।एस सी रॉय ने इस सिद्धांत का प्रतिपादन किया है। श्री रॉय ने दक्षिण अफ्रीका एवं दक्षिण भारत के बिच एक लेमुरिया द्वीप की कल्पना की है जो अब जलमग्न हो चुका है। उन्होंने संभावना व्यक्त की है की मुंडा जाती लेमुरिया द्वीप से होती हुए भारत आई थी। इस प्रसंग में दक्षिण अफ्रीका के मेडागास्कर का नाम उल्लेखित हुआ है। इस मत के अनुसार मुंडाओं का मूल स्थान मेडागास्कर है और भारत आव्रजन "लेमुरिया द्वीप" से होते हुए हुआ है।अब सवाल यह उठता है की अगर यह दोनों महाद्वीप थे तो ये समुद्र में कैसे समा गए। क्या समुद्र के बढ़ते जलस्तर ने इनको अपने अन्दर समा लिया या किसी भुवेज्ञानिक हलचल के चलते यह महासागर के अन्दर चले गए । अभी भी इसपर खोज जारी है।सवाल लेमुरिया या मु का नहीं है । सवाल यह है की अगर पृथ्वी का तापमान यूँ ही बढ़ता रहा तो आने वाले समय में कोई दूसरा लेमुरिया या मु जैसी घटना होने से इंकार नही किया जा सकता।

Saturday, December 12, 2009

Varves are the best indicators of ancient climate change.

Varves has the similarity with the regular, annual rings of the trees.
Dr. Nitish Priyadarshi

The study of climates during the geological past, is one of the most topical areas of research in the geosciences at present. The threat of future climate change caused by higher levels of green house gases, which would drastically alter many aspects of our environment, has prompted much research to try to understand how our own complex climate system works. Only by understanding how climate has evolved over million of years can we identify important climate 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.

Understanding our climate history in the geological past is also important for climatologists trying to construct accurate numerical computer models of our present climate system to use for predicting future climate change. It is obviously not possible to check the accuracy of models that are predicting the future so climatologists must turn to the past to see if their models can accurately simulate ancient climates. It is therefore the role of the geoscientists to collect as many data as possible from the rock record.

There are many rocks/minerals whose formations are controlled by climate, such as bauxite, coal and varves.
This article aims to introduce the formation of varves and how they can be used to determine ancient climate conditions.
What is Varve?

A varve is any sedimentary bed or lamination deposit within the period of one year, or any pair of contrasting laminae representing seasonal sedimentation (as summer and winter) within the period of one year.

In its broadest sense the term is applied to the layer of sediment deposited in a single year. In practice, however, the use of the term is almost always confined to sediments deposited in glacial melt-water lakes. These consist of coarser layer, representing summer deposition, and a finer layer, representing winter deposition. Counting and correlation of these varves has led to the development of a detailed Pleistocene chronology for the Northern Hemisphere.

Varves form distinctive layers. A varve consists of two layers; a thick light colored layer of silt and fine sand which forms in the spring and summer and a thin dark colored layer of clay forming in the fall and winter. Since low temperatures are necessary in delaying the settling of clay particles, it is assumed that varve formation can occur only in glacial waters, particularly lakes on the margins of glaciers. The salt and electrolytes in seawater cause a homogenous mass, preventing the formation of varves.
The deposition of varved sediments is either caused by seasonal variations in the glacial melt-water discharge (glacial varves) or by seasonal variations in the river discharge (postglacial varves).

The study of varved clays goes back to about 1880, when De Geer, working in the Stockholm area in Sweden, “was struck by the marked cyclical banding of the varved clay. From the obvious similarity with the regular, annual rings of the trees. Geer got at once the impression that both ought to be annual deposits”.
According to Sauramo (1923), there are four characteristics of varve: the grain size, the colour, the plasticity, and the chemical composition. The dominating rhythemic arrangement of a varve is alteration between coarse and lighter summer units and finer and darker winter units. These granulometrically graded varves are termed diatactic varves. There are also non graded varves, with the seasonal rhythm expressed only in the colour ranges (darker winter units). These varves are known as symmict varves and are common in brackish water environment.
Of the many rhythmites found in the geological record, varves are one of the most important and illuminating to studies of past climate change. Varves are amongst the smallest-scale events recognised in stratigraphy. Varves form only in fresh or brackish water, because the high levels of salt in normal sea water coagulates the clay into coarse grains.

Varve analysis is the process of counting varves or annually laminated sediments to determine the rates of change in climate and various ecosystems. Varves form when glacial advances come in contact with bodies of water such as lakes. When this process occurs, layers of sediment form on the floor of the body of water. This technique provides an opportunity to acquire detailed chronological information about the composition, displacement, and climate of that region, at that time.
Doyle, P. and Bennett, M. R. 1999. Unlocking the Stratigraphical Record, advances in Modern Stratigraphy. John Wiley & Sons, New York.

Fairbridge, R. W. and Bourgeois, J. 1978. The Encyclopedia of Sedimentology. Dowden, Hutchinson Ross, Inc. Pennsylvania.

Sauramo, M., 1923. Studies of the Quaternary varve sediments in southern Finland, bull. Comm.. Geol. Finlande, 60, 164p.


Tuesday, December 8, 2009

Tree rings and Pollen helps in measuring global temperature.

For a scientist studying climate change, “eureka” moments are unusually rare.

Dr. Nitish Priyadarshi
photo credit:http:// boojum.as.arizona.edu

In 1938, British meteorologist Guy Stewart Callendar made the first proper measurement of global temperature. He gathered data from weather stations worldwide and found that the average temperature of the earth has increased between 1880 and 1930. Sadly, no one took his findings seriously. In 1957, two scientists set up instruments on the Mauna Kea Volcano in Hawaii to measure the level of carbon dioxide in the atmosphere. Its records show that the level of carbon dioxide has been increasing steadily since that time and that the earth is slowly warming up.

For a scientist studying climate change, “eureka” moments are unusually rare. Instead progress is generally made by a painstaking piecing together of evidence from every new temperature measurement, satellite sounding or climate-model experiment. Data get checked and rechecked, ideas tested over and over again.

Evidence for climatic change is taken from a variety of sources that can be used to reconstruct past climates. Reasonably complete global records of surface temperature are available beginning from the mid-late 1800s. For earlier periods, most of the evidence is indirect—climatic changes are inferred from changes in indicators that reflect climate, such as vegetation, pollen, ice cores, dendrochronology, sea level change, and glacial geology.

Pollen in fossils provides important clues to prehistoric global climates. Pollen falls from trees and plants into the soil and can be preserved for thousands of years. Each plant species produces a unique pollen type. By identifying the type of pollen found in a place, scientists can tell which trees grew there. In tropical regions like Indonesia, scientists have found pollen from plants, such as pine, that can grow in temperate climates. This means that the temperature in the world’s tropical areas may have been lower in the past, allowing temperate plants to grow there. Pollen is widely distributed, produced in vast quantities (one pine branch can produce 350 million pollen grains), easily recognisable and very resistant to decay (some pollen in East Africa goes back 3 million years). The fluctuating type and distribution of pollen assists in interpreting local and regional histories of vegetation and climate.

Scientists also study tree rings to learn about the earth climate in the past. Tree rings are a good place to start thinking about how climate researchers get information about past climates. In certain cases, trees can live for many hundreds of years and in an extraordinary case, like the bristlecone pine, thousands of years! Each year trees add growth rings, which can indicate what sort of growing season the tree experienced. Interestingly these rings are more than a temperature indicator, they also tell the researcher about moisture and cloudiness as well. Trees grow faster in warmer climates than in cooler environments. Each year, the trunk of a tree grows wider. If you can chop a tree down, you will see rings in the cross-section of the trunk. A tree produces a new ring each year. Scientists measure the width of individual rings to estimate climate conditions at the time each ring was formed. Tree rings grow during warmer years are thicker than those produced in colder years. In other words wide and thick rings indicate a fertile, well-watered growing period, whilst thin, narrow rings indicate a time of lower rainfall and less-than-ideal growing conditions.

In this way, scientists can calculate which were the warmer and colder years.

Tree-ring measurements can help to distinguish anthropogenic from natural environmental change. These data can be used to determine whether recent climatic changes are unusual and possibly due to anthropogenic effects (specifically, increasing CO2 and other trace gases) or are still within the range of natural climate variability.

Saturday, December 5, 2009

Some scientists disagree with Global Warming Theory.

They say it is natural.


Dr. Nitish Priyadarshi

Rising temperature are already the clearest sign of climate change. So far, according to the IPCC, global average temperatures have risen 0.60 C above the pre-industrial average. Nine of the hottest years on record have occurred since 1988; six of the first eight months of 1998 were the warmest since records began in 1866; and July 1998 was the hottest month ever.

Scientists who assess the planet’s health see indisputable evidence that earth has been getting warmer, in some cases rapidly. Most believe that human activity, in particular the burning of fossil fuels and the resulting buildup of green house gases in the atmosphere, have influenced this warming trend. In the past decades scientists have documented record-high average annual surface temperatures and have been observing other signs of change all over the planet: in the distribution of ice, and in the salinity, levels, and temperatures of the oceans.

Everywhere on earth ice is changing. The famed snows of Kilimanjaro have melted more than 80 percent since 1912. Glaciers in the Garhwal Himalayas in India are retreating so fast that researchers believe that most central and eastern Himalayan could virtually disappear by 2035. Artic sea ice has thinned significantly over the fast half century, and its extent has declined by about 10 percent in the past 30 years.

This is one of the aspect of the global warming which most of scientists believe is man made. There is small minority of atmospheric and other scientists who disagree with this general scientific consensus. According to these scientists we still know too little about natural climate variables that could change the assessment (up or down). In addition, computer models used to predict climate change are improving but still are not reliable.

They also point out that some signs of global warming may not necessarily be caused by human activities. For example, while many glaciers are shrinking, others are growing. Also, glaciers shrink and grow naturally over long periods of time for reasons that are largely unknown.

Finally, they contend that global warming may be a lot less damaging than many people think and can be beneficial for some regions. For example, some countries may be able to increase crop productivity because of more rainfall and longer growing seasons.

They also claim that more carbon dioxide in the atmosphere could increase the rate of photosynthesis in areas with adequate amounts of water and other soil nutrients. This would remove more carbon dioxide from the atmosphere and help slow atmospheric warming.

However recent studies cast doubt on such a generalization for two reasons. First, this effect would slow as the plants reach maturity and take up less carbon dioxide. Second, it is a temporary effect. When the plants die and are decomposed or burned, the carbon they stored is returned to the atmosphere as carbon dioxide.

Are we heading towards major disaster or it is a simply a natural shifting of climate as it happened in the geological past. During the last 2 billion years the Earth's climate has alternated between a "Ice House", like today's world, and a steaming "Hot House", like the world of the dinosaurs. Jurassic climate stayed warm and became more humid. The polar areas were ice-free during this Period.

The history of earth’s climate is characterized by change. Times of glaciations on the earth have been followed by warm intervals and the duration in years of both cold and warm intervals has varied by several orders of magnitude.

What ever may be the truth we have no options but we have to opt wait and watch theory if we don’t stop carbon emission recklessly. But it is also true that the climate of the earth is changing from the time of its birth from hot to cold and cold to hot. Earlier too the earth has passed through global warming due to natural causes, but this time we the humans are culprits for the changes. When man-made factors are added to the natural ones, the ecosystem may be damaged beyond repair.