Wednesday, December 26, 2012

Are we moving towards global cooling or we are passing through major warming period?

Does the concept vary from season to season in the mind of the mass?


Dr. Nitish Priyadarshi


Total northern hemisphere is reeling under cold wave. Most part of the area is under thick cover of ice and snow. People are being killed due to severe cold waves. Lakes are freeze; leaves are drooping down due to the loads of the snow. Every where its white cover. Where there is no snow cold waves are showing impact on the population. Agriculture fields are under threat of frost bite. In India scores of people have been killed due to chilling wind and dropping of temperature. People like me are not able to understand whether we are moving towards global cooling or we are passing through major global warming period.  

When ever I talk about global warming concept today people are confused. They ask questions, why you are talking about global warming when it’s too cold. They are not easily accepting the concept of warming in chilling cold. It’s totally opposite in peak warm season. People put question mark on global cooling. They easily accept the concept of global warming. Does the concept vary from season to season in the mind of the mass? Every body can’t have scientific concept. Their thinking on the global warming or global cooling vary from hot to cold and cold to hot season. Even the media avoid doing the story on global warming in winter season.

Now a day’s media is also playing a big role in floating the concept, causes and effect of global warming. When I was in school I never heard of any such words like global warming or global cooling. We use to enjoy every season without any thought or any fear of climate change.

Every time a year is fixed to show that till that date or year there will be major changes on Earth ecosystem due to increasing green houses gases or global warming.  When the date passes without any major impact again other date is fixed.

It is not the question that how much we can believe on such predictions, but the question is can we predict the effects of global warming/cooling or climate change with accuracy? The way the increasing trend of global warming is shown or predicted, it seems that in coming 30 to 40 years earth will be totally devoid of any life and earth will die. I don’t think so.
Is really global warming is there or we are just exaggerating it? It is said that main cause of the global warming is due to increase in carbon dioxide level in the atmosphere.
Between 1940 and 1970, global temperatures went down slightly, even though carbon dioxide levels went up. This has been attributed to the cooling effect of sulphate aerosols.
Studies of ice cores show that carbon dioxide levels rise and fall with or after (as much as 1000 years) temperature variations. This argument assumes that current climate change can be expected to be similar to past climate change.
Most computer models suggest that the globe will warm up 1.5 degree centigrade to 4.5 degree centigrade if carbon dioxide reaches the predicted level of 600 ppm by the 2050. Although this may be largely true, there are other possible mechanisms that could act in the opposite direction. For instance the sulphate aerosols-the tiny bit of dust that are also added to the atmosphere when fossil fuels are burned by human activity, may cool the climate. The aerosols reflect away the sun’s radiation. Thus, they partially counter the warming that may be caused by the greenhouse gases. However, the degree to which these emissions might reduce the impact of greenhouse gases is not yet fully understood.
Other theory says that, in the past million years, the Earth experienced a major ice age about every 100,000 years. Scientists have several theories to explain this glacial cycle, but new research suggests the primary driving force is all in how the planet leans.

The Earth's rotation axis is not perpendicular to the plane in which it orbits the Sun. It's offset by 23.5 degrees. This tilt, or obliquity, explains why we have seasons and why places above the Arctic Circle have 24-hour darkness in winter and constant sunlight in the summer. Tilt varies between 21.5 and 24.5 degrees over a cycle of roughly 41,000 years. The greater the tilt, the more the seasonal imbalance in heat delivery from the Sun and the less the chance of ice remaining through the summer in temperate climates. At present we are near a neutral point between the extremes of this oscillation of tilt, thus neither favouring nor promoting an ice age.

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.

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.
Nature of the earth today is not fully understood. I am sure no one can say with accuracy what’s happening in the nature and also what’s going to happen in the future. It’s all the speculations and hypothesis.   

Monday, December 17, 2012

Groundwater exploitation is also raising sea levels.

By 2050, groundwater pumping will cause a global sea level rise of about 0.8 millimeters per year.

Dr. Nitish Priyadarshi

Slowly but surely, the sea level continues to rise. Recent research suggests this increase is also driven by the exploitation of underground water by humans that eventually flowed into the sea.
Climate change, with its associated melting ice caps and shrinking glaciers, is the usual suspect when it comes to explaining rising sea levels. But a recent study now shows that human water use has a major impact on sea-level change that has been overlooked.
Science community was shocked by the claim that 42% of the sea-level rise of the past decades is due to groundwater pumping for irrigation purposes. What could this mean for the future – and is it true?

Global warming is melting glaciers and causing sea levels to rise. The volume of water is also expanding because of heat. This ‘thermal expansion’ contributes significantly to the surge in the sea levels. But there is yet another important reason for the rising sea levels, as a team of hydrologists led by Yadu Pokhrel from Rutgers University (USA) has discovered for the first time.

Experts had already identified a flaw in existing models. If one takes ice melting and the expansion of water because of higher temperatures into account the oceans should have risen by 1.1 mm per year in the second half of the 20th century. However in reality, they rose by 1.8 mm.

Groundwater makes up about twenty percent of the world's fresh water supply, which is about 0.61% of the entire world's water, including oceans and permanent ice. Global groundwater storage is roughly equal to the total amount of freshwater stored in the snow and ice pack, including the north and south poles. This makes it an important resource which can act as a natural storage that can buffer against shortages of surface water, as in during times of drought.

Most of the Earth’s liquid freshwater is found, not in lakes and rivers, but is stored underground in aquifers. Indeed, these aquifers provide a valuable base flow supplying water to rivers during periods of no rainfall. The contribution from groundwater is vital; perhaps as many as two billion people depend directly upon aquifers for drinking water, and 40 per cent of the world’s food is produced by irrigated agriculture that relies largely on groundwater.

During the last 30 to 40 years there has been an enormous rise in food production in many countries through the increased use of irrigation. Much of this irrigation water has been drawn from groundwater as people realise the advantages to increased productivity of timely irrigation and security of application.

Due to human usage, groundwater reaches the ocean through the sewage system and rivers as well as the hydrological cycle in the atmosphere- and contributes about 42 per cent of the rise in the sea levels.

Because of population growth and increased irrigation, ground and drinking water consumption has doubled over the last few decades. 

A recent study from Yoshihide Wada and other researchers from Utrecht University attempted to assess the status of global groundwater depletion—that is, the amount of water that is being drawn out from underground reservoirs that is not being replaced by precipitation—and came up with some startling conclusions. Chief among them that depletion of groundwater may be contributing to as much as 25 percent of observed sea-level rise in recent years.

As people pump groundwater for irrigation, drinking water, and industrial uses, the water doesn’t just seep back into the ground — it also evaporates into the atmosphere, or runs off into rivers and canals, eventually emptying into the world’s oceans. This water adds up, and a new study calculates that by 2050, groundwater pumping will cause a global sea level rise of about 0.8 millimeters per year. Other than ice on land, the excessive groundwater extractions are fast becoming the most important terrestrial water contribution to sea level rise.
Taking into account the seepage of groundwater back into the aquifers, as well as evaporation and runoff, the researchers estimated that groundwater pumping resulted in sea level rise of about 0.57 mm in 2000 — much greater than the 1900 annual sea level rise of 0.035 mm.

The amount of groundwater pumped out by Delhiites and others across northern India is highest in the world and is contributing as much as 5% to the total rise in sea levels.

A new study using satellite data has found that the region - a swathe of over 2,000km from west Pakistan to Bangladesh along north India - extracts a mind boggling 54 trillion litres from the ground every year, a figure that's likely to cause serious concern over the future of water availability.


Thursday, December 6, 2012

How could the shape of plant leaves indicate temperature?

There is a general relationship between leaf shape and the climate.
Dr. Nitish Priyadarshi. 

Fig.1 Leaf of tropical areas having drip tip for water run off.

How could the shape of plant leaves indicate temperature, you ask? Surprisingly, they do so very well. There is a general relationship between leaf shape and the climate. In 1978 Jack Wolfe, of the United States Geological Survey, put the relationship on a quantitative footing. Using data for present –day forests in eastern Asia, he showed that there is a remarkable correlation between the mean annual temperature and the shapes of the leaves. The particular features of leaves that seem to be most distinctive in this regard is the nature of the leaf margin. In tropical areas, where temperatures and precipitation are high, leaves tend to be large and have smooth edges, without serrations, and they often have a narrow, elongated tip-sometimes referred to as a drip tip (Fig.1.)- that facilitates water runoff. In contrast, leaves in cooler regions are typically smaller, narrower, and usually have jagged edges. In today’s forests these characteristics are specific to climatic conditions through out the globe.

Warmer leaf temperatures promote both photosynthesis and transpiration; thus, plants in drier climates tend to have smaller leaves to reduce evaporative cooling, while in more humid climates larger leaves are common because the attendant water cost is less critical (Givnish, 1984).

Since plants are stationary they must respond developmentally and ultimately evolutionarily, to their environment. As a result, it's not surprising that leaf morphology (shape) has been shown to be related to climate. For example, some the following correlations have been reported (a) leaf length is directly related to the mean annual temperature (MAT), (b) leaf area is directly correlated to both MAT and mean annual precipitation (MAP); and (c)leaf width is directly correlated with MAP. Thus, leaves are longer and larger in climates with warmer temperatures and higher rainfall.

Another interesting observation that was first reported more than 100 year ago is that woody deciduous plants having leaves with toothed margins (termed serrate) predominate in temperate climates while species with smooth (termed entire) leaf margins predominate in frigid (arctic) and tropical climates.


Givnish TJ. 1984. Leaf and canopy adaptations in tropical forests. In: Medina E, Mooney HA, Vasquez-Yanes C, eds. Physiological ecology of plants of the wet tropics. The Hague, the Netherlands: Dr. W. Junk Publishers, 51–84. 

Macdougall,J.D. 1996. A short history of planet earth, mountains, mammals, fire, and ice. John Wiley & Sons, Inc. Canada.

Wednesday, October 31, 2012

Threat of Nuclear Waste Disposal.

The disposal of nuclear waste is a pressing problem for society worldwide.

Dr. Nitish Priyadarshi
76,circular road, Ranchi, India.

The nuclear disaster in Fukushima, Japan, caused many countries to rethink their appetite for nuclear power. It is also, in subtler ways, altering the fraught discussion of what to do with nuclear plants’ wastes.

Harnessing the power of the atom has propelled humanity forward at an astonishing rate since the dawn of the Nuclear Age. However, the proper disposal and storage of nuclear waste leaves an incomplete equation. Nuclear waste comes from nuclear power reactors and byproducts of military-grade bombs. This waste can come in the form of spent nuclear fuel rods or even toxic sludge. Perhaps the greatest danger of nuclear energy is the long-term investment in waste disposal that will be passed to future generations.

For more than 50 years, waste from nuclear power stations has been accumulating into what is now the most dangerous rubbish dump in the world. But we are still very far from coming up with a permanent, safe solution for the disposal of radioactive material.

Seven years ago, there were around 250,000 tonnes of highly radioactive waste worldwide. Towards the end of 2010, the International Atomic Energy Agency (IAEA) estimated it to be 345,000 tonnes, and in 2022, 450,000 tonnes. What  are we going to do with it all.

According to another report, a typical nuclear power plant in a year generates 20 metric tons of used nuclear fuel. The nuclear industry generates a total of about 2,000 - 2,300 metric tons of used fuel per year.

Over the past four decades, the entire industry has produced about 67,500 metric tons of used nuclear fuel. If used fuel assemblies were stacked end-to-end and side-by-side, this would cover a football field about seven yards deep. 

A recent study found that, on average, people in Britain live about 42km (26 miles) away from one of more than 30 radioactive waste sites, including power plants and military bases, in the UK.

Half-a-century after launching the nuclear programme, India has finally begun working on a “deep geological repository” to permanently store its nuclear waste.

Over the next five years, scientists are going to study a set of physical and geological parameters required for setting up the nuclear waste storage facility before zeroing in on its location.

The options vary from underground storage in rocky central India to plains where the storage may be housed inside layers of clay.

India's existing nuclear waste site is located at Tarapur where high-level radioactive waste is first converted into inert and stable materials which are kept inside stainless steel canisters sealed with lead covers. 

Sixteen nuclear reactors produce about 3% of India’s electricity, and seven more are under construction. Spent fuel is processed at facilities in Trombay near Mumbai, at Tarapur on the west coast north of Mumbai, and at Kalpakkam on the southeast coast of India. Plutonium will be used in a fast breeder reactor (under construction) to produce more fuel, and other waste vitrified at Tarapur and Trombay. Interim storage for 30 years is expected, with eventual disposal in a deep geological repository in crystalline rock near Kalpakkam.

In 1997, IAEA members proposed certain criteria for nuclear waste disposal. It should be done, “wherever possible”, in those countries that have produced the waste. Further, it should avoid “imposing undue burden on future generations”.

But at present, “no country has a geological site for the interim and permanent storage of spent fuel rods,” complain experts of the IAEA.

Radioactive wastes come in many different forms including the following:
1. protective clothing of people in contact with radioactive materials
2. the remains of lab animals used in experiments with radionuclides
3. cooling water, used fuel rods, and old tools and parts from nuclear power plants
4. mill tailings from uranium-enrichment factories
5. old medical radiation equipment from hospitals and clinics
6. used smoke detectors which contain radioactive americium-241 sensors

How does nuclear waste get to you?

The planet's water cycle is the main way radiation gets spread about the environment. When radioactive waste mixes with water, it is ferried through this water cycle. Radionuclides in water are absorbed by surrounding vegetation and ingested by local marine and animal life. Radiation can also be in the air and can get deposited on people, plants, animals, and soil. People can inhale or ingest radionuclides in air, drinking water, or food. Depending on the half life of the radiation, it could stay in a person for much longer than a lifetime. The half life is the amount of time it takes for a radioactive material to decay to one half of its original amount. Some materials have half-lives of more than 1,000 years!

On 26th June 1954, 110 km from Moscow, the first civil nuclear reactor of the world supplied current in the grid. At the end of 2011, in 31 countries where nuclear power is produced, there were 435 reactors in use, 104 in the US alone. They meet 15 per cent of the world’s electricity demand, though the national ratios vary. While France  generates almost three-quarters of its own electricity through nuclear power and also exports the surplus, India’s figure is 3 per cent, and even USA’s only 20 per cent. But however small the total amount of nuclear energy may be, the consequences are colossal.

Nuclear fission and decay not only produces radiation but also heat. This heat is used in power plants to generate electricity. The core of the fuel rods in the reactors must heat  up to about 1,200 degree centigrade. When they are worn out, they are lifted with a remote-controlled crane into a cooling pond, where they are stored for many years.

If the heat dissipation fails and the rods heat to over 2,500 degree centigrade, there is a risk of nuclear meltdown, which is what happened in March 2011 in Fukushima in Japan.

New ideas for repositories have kept cropping up, some as absurd as the one patented in 1956 by a physicist from Munich, who proposed that waste containers be airdropped  over Antarctica, which would then melt into the depths of the ice on their own. This proposal was discussed in trade conferences for many years.

For this option containers of heat-generating waste would be placed in stable ice sheets such as those found in Greenland and Antarctica. The containers would melt the surrounding ice and be drawn deep into the ice sheet, where the ice would refreeze above the wastes creating a thick barrier. Although disposal in ice sheets could be technically considered for all types of radioactive wastes, it has only been seriously investigated for high-level waste (HLW), where the heat generated by the wastes could be used to advantage to self-bury the wastes within the ice by melting.

The option of disposal in ice sheets has not been implemented anywhere. It has been rejected by countries that have signed the 1959 Antarctic Treaty or have committed to providing a solution to their radioactive waste management within their national boundaries. Since 1980 there has been no significant consideration of this option.

American scientists even considered shooting the waste into the Sun. the proposal was rejected as too unsafe and too expensive. To send a load of just half a kilo into the earth’s orbit would cost 10,000 dollars. And in USA, more than 70,000 tonnes of highly radioactive material is already in storage.

The objective of this option is to remove the radioactive waste from the Earth, for all time, by ejecting it into outer space. The waste would be packaged so that it would be likely to remain intact under most conceivable accident scenarios. A rocket or space shuttle would be used to launch the packaged waste into space. There are several ultimate destinations for the waste which have been considered, including directing it into the Sun.
The high cost means that such a method of waste disposal could only be appropriate for separated high-level waste (HLW) or spent fuel (i.e. long-lived highly radioactive material that is relatively small in volume). The question was investigated in the United States by NASA in the late 1970s and early 1980s. Because of the high cost of this option and the safety aspects associated with the risk of launch failure, this option was abandoned.

No doubt that’s why a final burial inside the earth is considered the safest option. Natural and technical barriers should ensure that no radiation leaks out. The waste can be sequestered in steel containers, embedded in a concrete sarcophagus, which is further surrounded by heat-resistant stone, and buried under hundreds of metres of rock.

Deep borehole concepts have been developed (but not implemented) in several countries, including Denmark, Sweden, Switzerland and USA for HLW and spent fuel. Compared with deep geological disposal in a mined underground repository, placement in deep boreholes is considered to be more expensive for large volumes of waste. This option was abandoned in countries such as Finland and USA. The feasibility of disposal of spent fuel in deep boreholes has been studied in Sweden, in order to check whether deep geological disposal remains the preferred option. The borehole concept remains an attractive proposition under investigation for the disposal of sealed radioactive sources from medical and industrial applications.

Although burial and long-term storage remain the best solutions for nuclear waste disposal, geologic processes pose a significant danger to these repositories. In reality, our limited ability to accurately predict moving fault lines, earthquakes, and volcanic eruptions is the true danger. The likelihood and possible location of future earthquakes is the initial concern when selecting a disposal site. On the other hand, flooding and groundwater pose their own geologic threat to underground disposal sites. Rising groundwater can erode away containment zones and spread radioactive waste into the water table.

Disposal at sea involves radioactive waste being shipped out to sea and dropped into the sea in packaging designed to either: implode at depth, resulting in direct release and dispersion of radioactive material into the sea; or sink to the seabed intact. Over time the physical containment of containers would fail, and radionuclides would be dispersed and diluted in the sea. Further dilution would occur as the radionuclides migrated from the disposal site, carried by currents. The amount of radionuclides remaining in the sea water would be further reduced both by natural radioactive decay, and by the removal of radionuclides to seabed sediments by the process of sorption.
This method is not permitted by a number of international agreements.
Researchers have short listed four kinds of rock for the construction of such a repository.

  1. In Germany, rock salt is preferred at present. Salt is very dry. As long as there’s no water nearby, it can tolerate heat well, which is important for storing radioactive substances. And its protective coating ensures that cracks are quickly closed. Its mobility, however, is a disadvantage because whatever’s inside the salt moves within it.
  2. Finland and Sweden have settled on granite, which is hard and immovable.
  3. In the US, tuff rock found in the Nevada desert was being used till now.
  4. In Switzerland and France, clay is being tested.  
A New Solution

The newest solution, sending the waste to the center of the earth, is the one solution combining safety, economy and permanence to nuclear waste disposal. At first glance, this seems impossible. There has never been a hole drilled in the earth's crust, so how can one be drilled to the center of the earth? The answer? Let the earth itself do the work through known subduction faults.
What is a subduction fault? This is an earthquake fault at the edge of a continental crust that is in collision with the adjoining oceanic crust. Since the continental crust is lighter than the oceanic crust, the latter deflects below the former when the two plates are colliding.
Permanent RadWaste Solutions has developed a process that utilizes a subduction fault for sending the waste to the center of the earth. This has the benefits of being permanent, no maintenance, much less expensive than other proposals, terrorist-proof, and no threat to people, fish, crabs or the environment.
To do this requires burying a specially designed pressure-and-temperature-compensating submersible transport vehicle (STV). It is to be buried in the sediments at a subduction fault.

 Ideas for disposal

Numerous options for long-term nuclear waste management have been considered in the past. The table below highlights a number of these.

·                                 Investigated in France, Netherlands, Switzerland, UK and USA.
·                                 Not currently planned to be implemented anywhere.

Disposal in outer space (proposed for wastes that are highly concentrated)
·                                 Investigated by USA.
·                                 Investigations now abandoned due to cost and potential risks of launch failure.

Deep boreholes
(at depths of a few kilometres)
·                                 Investigated by Australia, Denmark, Italy, Russia, Sweden, Switzerland, UK and USA.
·                                 Not implemented anywhere.

(proposed for wastes that are heat-generating)
·                                 Investigated by Russia, UK and USA.
·                                 Not implemented anywhere.
·                                 Laboratory studies performed in the UK.

·                                 Investigated by USA.
·                                 Not implemented anywhere.
·                                 Not permitted by international agreements.

·                                 Implemented by Belgium, France, Federal Republic of Germany, Italy, Japan, Netherlands, Russia, South Korea, Switzerland, UK and USA.
·                                 Not permitted by International agreements.

·                                 Investigated by Sweden and UK (and organisations such as the OECD Nuclear Energy Agency).
·                                 Not implemented anywhere.
·                                 Not permitted by international agreements.

Disposal in ice sheets (proposed for wastes that are heat-generating)
·                                 Investigated by USA.
·                                 Rejected by countries that have signed the Antarctic Treaty or committed to providing solutions within national boundaries.

Direct injection
(only suitable for liquid wastes)
·                                 Investigated by Russia and USA.
·                                 Implemented in Russia for 40 years and in USA (grouts).
·                                 Investigations abandoned in USA in favour of deep geological disposal of solid wastes.

Other countries are also looking at waste in new ways in the post-Fukushima world. Right now, worldwide, most spent fuel waste is stored on the site of the facility that produced it, in spent-fuel pools and, after it eventually cools, dry casks. Experts say dispersed storage is expensive and that central storage would be more secure.
Few countries , apart from Sweden and Finland, have moved forward on centralized disposal sites, deep in the earth, designed to hold the waste permanently.
France is evaluating a permanent disposal site for spent fuel , near the remote northeastern village of BureJapan also hopes to choose a site and build a geological disposal facility in the coming decades.

The disposal of nuclear waste is a pressing problem for society worldwide. Potential health and safety concerns require that nuclear waste be stored in a controlled and secure manner. The issue is further complicated by the extremely long half life of radioactive materials, some of which retain half of their dangerous properties 100,000 years after production. The disposal and storage of nuclear waste is one of the major factors limiting society's use of nuclear power as a widespread energy source.

There is no safe way of disposing of nuclear waste and one of the most important lessons is not to create any more, which means until and unless safe disposal method is identified we should not go for new nuclear power plants.


Kampe, J.A.D. and Bischoff, J. October 2012, Now What?. GEO, (Indian Ed.)

Sunday, October 21, 2012

Historic temple near Ranchi city of India.

Just a small experiment in my photography. This is a famous temple near Ranchi. Photo was taken by me on 21st October, 2012 evening. It seems that statue of the lions are trying to catch the moon.

Monday, September 24, 2012

Climate which changed the world 56 million years ago.

Are we heading towards the same disaster?
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.      


Tuesday, August 14, 2012

Climate change is increasing diseases.

They will be widespread and unpredictable.
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.

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.


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.