Term Paper Topics on Global Warming | Geography

Here is a compilation of term paper topics on ‘Global Warming’ especially written for school and college students.

Term Paper Topics on Global Warming

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Contents:

1. Term Paper on Global Warming and Greenhouse Effect
2. Term Paper on Global Warming and Oceans
3. Term Paper on Global Warming and Species Extinction
4. Term Paper on Global Warming and Water Resources
5. Term Paper on Global Warming and Carbon Dioxide Emissions
6. Term Paper on Global Warming and Nuclear Power
7. Term Paper on Global Warming and Freshwater

Term Paper Topic # 1. Global Warming and Greenhouse Effect:

Global warming results from the effect of what is called the ‘greenhouse effect’. Carbon dioxide (CO₂), methane, water vapor, nitrous oxide and ozone are the main greenhouse gases. The main purpose of a greenhouse is to allow sun’s radiation (heat) to enter the enclosure easily, however, does not allow the heat to be radiated back to the atmosphere. Similar to a greenhouse, our atmos­phere allows the sun’s radiation to heat the Earth and slows down the radiated heat to go back into the space. This greenhouse effect is essential to sustain life on Earth.

The greenhouse effect is a natural warming process of the earth. The theory is that when the sun’s energy reaches the earth, some of it is reflected back to space while the rest is absorbed. The absorbed energy warms the earth’s surface which then emits heat energy back toward space in the form of long wave radiation. This outgoing radiation is partially trapped by greenhouse gases such as carbon dioxide, methane and water vapor which then radiate the energy in all directions, warming the earth’s surface and atmosphere.

Troubling facts about the greenhouse effect include that the increasing amounts of greenhouse gases intensify the greenhouse effect. Higher concentrations of CO₂ and other greenhouse gases trap more infrared energy in the atmosphere than what occurs naturally.

The additional heat further warms the atmosphere and Earth’s surface. Climate models suggest this natural warming is being enhanced by human activities that increase concentrations of greenhouse gases in the atmosphere and thus, in turn, intensify the greenhouse effect. The increase in atmospheric concen­tration of greenhouse gases, accentuating the natural greenhouse effect globally, results in global warming.

Now, due to the increased level of greenhouse gases, the atmosphere’s ability to trap and hold the heat increases more than required. As a result, the average temperature of the Earth increases and this natural phenomenon is known as ‘global warming’. It is also defined as a sustained increase in the atmosphere that causes abnormal climate change. In the following description about global warming and carbon dioxide, a brief explanation regarding effects of global warming and CO₂ emission in the atmosphere, has been provided.

Term Paper Topic # 2. Ocean and Global Warming:

Marine regions cover about three-fourths of the Earth’s surface and include oceans, coral reefs, and estuaries. Ocean covers 97 percent of marine regions while rest 3% belongs to freshwater. The world’s oceans have an even greater effect on global climate than forests do.

The total amount of carbon in the ocean is about 50 times greater than the amount in the atmosphere, and is exchanged with the atmosphere on a time-scale of several hundred years. At least 1/2 of the oxygen we breathe come from the photosynthesis of marine plants. Currently, 48% of the carbon emitted to the atmosphere by fossil fuel burning is sequestered into the ocean.

But the future fate of this important carbon sink is quite uncertain because of potential climate change impacts on ocean circulation, biogeochemical cycling, and ecosystem dynamics. In addition to fresh water, ocean stores heat, salt and carbon dioxide, and circulates these necessities around the planet’s surface. The water, carbon dioxide and the heat in the ocean – all play important role in global warming.

Heat Storing and Transport by Ocean:

Ocean’s fundamental role in climate is based largely on their storage and transport of heat around the globe, thus keeping atmospheric temperature fairly constant. The oceans store vast amounts of heat, much more than the heat stored by the atmosphere, because water is 1000 times denser and has a heat holding capacity (heat capacity) four times that of air. The ocean can store about thousand times more heat than the atmosphere.

Ocean currents are primary highways for the transport of heat around the globe. The atmosphere, with less heat content moves faster and thus can heat around the world much more quickly. Without the warm ocean currents transferring heat to the atmosphere, certain parts of the globe, such as northern European countries including Britain, would not have the temperate climate.

The carbon and hydrologic cycles are the two natural processes regulating the global warming and climate changes. The carbon cycle involving natural exchange of carbon by ocean water with the atmosphere, determines the quantum of extra carbon in the atmosphere and thus the extent of global warming.

The hydrologic cycle determines the humidity of the atmosphere and precipitation (rainfall) and thus has a significant effect on global temperature and climate. Both the natural processes are affected by anthropogenic emissions making the cycle unbalanced. To cope up with the excess emissions it is essential to retain and improve the carbon absorption capacities of oceans.

To preserve the carbon exchange capacity it is necessary to prevent pollution detrimental to marine life and to stop eliminating already ‘endangered species’. In addition to these measures, cultivation of phytoplankton can cause an increase in the capacity to absorb carbon. The carbon cycle and the hydro cycle are interrelated and thus both play important role in global warming.

The ocean contains 97% of the fresh water on Earth, experiences 86% of evaporation, and directly receives 78% of precipitation. The evaporation of water from ocean surface and return by precipitation complete the hydrologic cycle. Together, the atmosphere and ocean maintain a global balance in the distribution of fresh water.

Evaporation rates should increase as the surface ocean heats up. Also, because water vapor pressure rises exponentially as temperature increases, a warmer atmosphere will hold more water vapor. Since water vapor is itself a potent greenhouse gas (much more so than carbon dioxide), increased water vapor concentrations will trap additional heat and cause the surface temperatures to rise even faster. Therefore the higher evaporation rate in hydrologic cycle would result because of global warming, and that this will, in turn shall accelerate global warming.

Ocean-Atmosphere Carbon Cycle:

In the long term, the ocean plays the dominant role in the natural regulation of CO₂ in the atmosphere and thus exerts a powerful influence on the climate.

The natural carbon exchange of ocean with atmosphere takes place by following three processes:

i. By physical pump which is driven by gas exchange at the air-sea interface and the physical processes that transport CO₂ to the deep ocean.

ii. By biological pump i.e. phytoplankton taking up nutrients and CO₂ through the process of photosynthesis.

III. The ocean “breathes” i.e., ocean uptake and out gassing of CO₂ across the sea surface. Hot water gives up CO₂ while cool water absorbs CO₂.

Ocean plays a vital role in the Earth’s carbon cycle and currently sequesters up to 48% of the carbon by burning fossil fuel.

A recent report indicates the quantum of carbon pool and fluxes in ocean as follows:

Carbon Pools in Ocean:

Carbon dioxide uptake by ocean can be improved by keeping the normal activities of the nature’s physical and biological pumps.

Physical Pump:

Atmospheric CO₂ enters the ocean by gas exchange depending on wind speed and the differences in partial pressure across the air- sea interface. The amount of CO₂ absorbed by seawater is also a function of temperature through its effect on solubility. Solubility increases as temperatures fall so that cold surface waters pick up more CO₂ than warm waters. The solubility of carbon dioxide in the sea water can be increased by limiting the rise of global temperature.

Biological Pump:

The rate at which photosynthesis process occurs is called the primary productivity. Some of the organic matter created is cycled through the food web in the upper ocean and some sinks to the bottom. Some of this carbon is rematerialized back to CO₂ while a tiny fraction is buried in the sediments of the sea floor.

Biological pump is run by planktons through photosynthesis. They are capable of making the process self-sustaining with the help of sunlight. Phytoplankton’s convert water, minerals, and carbon dioxide under sunlight into carbohydrates and oxygen.

For photosynthesis it is necessary to have sun light and minerals. Physical processes such as upwelling, hydrographic fronts, eddies and cyclones bring nutrients from deeper waters to the ocean surface. The top 100-150 m of the ocean surface (photic or euphotic zone) as well as shallow water zones in the coastal areas gets the required level of light intensity for photosynthesis.

These zones are thus favorable for producing phytoplankton. Tropical and sub-tropical oceans with abundant light have low primary production because of poor availability of nutrients. In such regions, primary production occurs at greater depth, although at a reduced level (because of reduced light).

Recently there has been a growing commercial interest in the seeding process, because of the possibilities of selling carbon credits worth millions of dollars. Much of the Southern Ocean is depleted of iron and experiments have shown even a small amounts of nutrient can trigger phytoplankton blooms that can last for up to two months. Some entrepreneurs have started iron seeding on commercial scale in icy seas between Australia and Antarctica for producing plankton which could become a money spinner.

Oceans are naturally alkaline, or basic, with a pH of about 8.2. When carbon dioxide dissolves in sea water it forms carbonic acid (H₂CO₃), making it more acidic. The high acidity can be harmful for planktons to grow. Iron seeding can increase the growth of phytoplankton and thus speed up absorption of carbon dioxide by phytoplankton instead of sea water. By ‘fertilizing’ the ocean with iron would also prevent ocean acidification.

Human Activities Destroying Ocean Biome:

Oceans for centuries have been considered as resource to provide inexhaustible supply of food, useful transport route, and a convenient dumping ground. But human activity, particularly over the last few decades, has finally pushed oceans to their limit. Pollution, habitat destruction, unsustainable fishing, tourism development, oil and gas extraction, shipping, and aquaculture are all taking their toll on marine habitats, marine species and people.

These factors would also affect hydrologic cycle and eventually the climate. Ocean water circulation systems, which controls excessive temperature rise depends on the density and salinity of the water get badly affected by pollution. Pollution affects density and salinity thus carbon dioxide sinking ability. This would have not only an adverse effect on conveyor belt type circulation but also spread of pollution.

Prevent Marine Pollution:

Over 80% of marine pollution comes from land-based activities. Most of the waste produced on the land eventually reaches the oceans, either through deliberate dumping or from run-off through drains and rivers. These include, oil, fertilizers, solid garbage, sewage, and toxic chemicals.

Oil spills include releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, and heavier fuels used by large ships such as bunker fuel, or the spill of any oily white substance refuse or waste oil. Oil spills cause huge damage to the marine environment. An estimated amount of around 12% of the oil enters the seas each year.

According to a study by the US National Research Council, 36% comes down drains and rivers as waste and runoff from cities and industry. Fertilizer runoff from farms and lawns is a huge problem for coastal areas. The extra nutrients cause eutrophication – flourishing of algal blooms that deplete the water’s dissolved oxygen and suffocate other marine life. Eutrophication has created enormous dead zones in several parts of the world, including the Gulf of Mexico and the Baltic Sea. Sewage disposal flows untreated, or under-treated, in many parts of the world into the ocean. For example, 80% of urban sewage discharged into the Mediterranean Sea is untreated.

Plastic garbage, which decomposes very slowly, is often mistaken for food by marine animals. High concentrations of plastic material, particularly plastic bags, have been found blocking the breathing passages and stomachs of many marine species, including whales, dolphins, seals, puffins, and turtles. Plastic six-pack rings for drink bottles can also choke marine animals.

Toxic chemicals dumping at sea include material such as pesticides, chemical weapons, and radioactive waste. Toxic waste gets into seas and oceans by the leaking of landfills, dumps, mines, and farms. Farm chemicals and heavy metals from factories can have a very harmful effect on marine life and humans.

Harmful chemicals in the ocean are lead & mercury. Mercury in the oceans has increased 5 times since the industrial revolution and is getting worse, with an estimated 2% rise in mercury per year. Top ocean predators like sea mammals and tuna have high levels of mercury in their meat, ranging from 5 to 3500 times the amount allowed by Japanese law.

Mercury originates mainly from the burning of fossil fuels (coal and gasoline). The releases mercury from combustion of coal accounts for 70 percent of this pollutant’s presence in the atmosphere. To reduce the mercury in the oceans it is essential to reduce use of coal as a source of energy.

The man-made pollution of ocean is controllable. Several countries have taken steps to reduce pollution of the sea.

Term Paper Topic # 3. Global Warming and Species Extinction:

Many biologists are of the opinion that species are disappearing between 100 and 1000 times as fast as they were before man arrived on earth. Our impact is different from the event of mass extinction that happened in the past. They wiped out whole group of animals, as happened with dinosaurs, whereas humans are picking off individual species.

In the past, biodiversity recovered as species spread into ecological niches, but humans are wiping out niches as well as organisms. One in four mammal species and one in eight bird species face a high risk of extinction in the near future. The population of each species is expected to fall by at least a fifth in the next 10 years.

Almost all are endangered by human activity. The invertebrates are tipped to dominate the new world order. Only around 0.1 percent of the 1.6 million known species are thought to be threatened, though many undiscovered species are likely to be dying out before we even know of their existence.

As global climate change shifts temperatures across the planet, species may not be able follow fast enough. According to UNEP, they will have to migrate 10 times as fast as they did after the last ice age. Many would not make it. There are several reports suggesting that global warming is driving species like butterflies and birds to expand their territories in Europe.

It is just a part of and emerging worldwide trend that is seeing animals on the move in response to changing climate. According to Professor Chris Thomas of the University of Leeds, a quarter of butterfly species had begun to move north in Europe, where once it would have been too cold for them to live.

An analysis of the bird habitats over the past 20 years also showed an expansion north-word, with bird species in Britain moving an average of 18.9 km north. The scientists have sought to weed out other factors that might have contributed to the species expansion, and were left only with climate change as the possible cause. A study of satellite data shows that the northern hemisphere is becoming greener with denser vegetation and a longer growing season now than 20 years ago.

The study conducted by NASA and Boston University, found that most places north of 40° latitude—such as New York, Madrid, London and Beijing—show plants growing more vigorously now than in 1981. This warming is also being noted in the vegetation of Scotland, with many trees leafing earlier—some of them as much as three weeks earlier than in the 1940s.

Species that migrate due to warming will move at different rates, breaking up existing communities. At high altitudes, entire forest types are expected to disappear, to be replaced by new ones. During this transition, carbon will be lost to the atmosphere faster than it can be replaced by new growth, accelerating climate change.

Lee Hannah at Conservation International in Washington DC found that human activity has displaced the natural habitat over two-thirds of the habitable surface of the planet. Much of the undisturbed land is mainly rock, ice and blowing sand, already shunned by wildlife.

After habitat destruction, the biggest threat to biodiversity is invasion by alien species. These have arrived mainly through trade, tourism and bio-control. Invasive plant species already cover 400,000 sq. kms. of the US, and are spreading at 12,000 square kilometres a year. For millennia, the natural barriers of oceans, mountains, rivers and deserts provided the isolation essential for unique species and ecosystems to evolve.

In a just few hundred years these barriers have been rendered ineffective by major global forces that combined to help alien species travel vast distances to new habitats and become alien invasive species. The globalization and growth in the volume of trade and tourism, coupled with the emphasis on free trade, provide more opportunities than ever before for species to be spread accidentally or deliberately.

Customs and quarantine practices, developed in an earlier time to guard against human and economic diseases and pests, are often inadequate safeguards against species that threaten native biodiversity. The scope and cost of biological alien invasions is global and enormous, in both ecological and economic terms.

Here are some examples:

i. Native to the dry, desert regions of the America, the Prickly Pear Cactus was imported by Australian ranches in 1839 for use as living cattle fences. Soon the hardy, drought resistant cactus covered some 16 million acres of land. Impenetrable as well as inedible by cattle, the invited guest quickly became an unwelcome guest in the land down under.

ii. The giant African snail is a serious agricultural pest, known to attack more than 500 plant species. It can also carry and spread a form of meningitis. In 1966, a boy visiting Hawaii brought two or three of the giant snail home to his grandmother in Miami, USA, where she released them in her garden.

The snails, each capable of laying 1,200 eggs each year of their nine yearlong lives, rapidly reproduced. Within three years, some 42 city blocks of Miami were infested with more than 18,000 snails and millions of eggs. Twenty-five miles north of Miami, another infestation broke out in Florida. By the late 1970s, after a four-year, $1 million campaign, Florida was finally free of this invasive species.

iii. A relative of the sunflower, the poisonous Eurasian weed, tansy ragwort, thrives in coastal Washington, Oregon and northern California in USA. Likely brought to both coasts of the United States in ship’s ballast, tansy ragwort has spread eastward from the Pacific coast. First documented in Oregon in 1922, the ragwort’s eastward progression was probably aided by human transportation of contaminated hay and straw.

Since a single specimen of this prolific weed can produce up to 150,000 seeds, which can remain viable for three to fifteen years, tansy ragwort can quickly establish a foothold in a given pasture. In Oregon, a biological control programme reduced the tansy ragwort population by 90% over 17 years. The reduction has saved an estimated five million dollars per year.

The degradation of natural habitats, ecosystems and agricultural lands that has occurred throughout the world has made it easier for alien species to establish and become invasive. Many alien invasive are colonizing species that benefit from the reduced competition that follows habitat degradation. Global climate change is also a significant factor assisting the spread and establishment of alien invasive species.

For example, increased temperatures may enable alien, disease-carrying mosquitoes to extend their range. Biodiversity is good for humans. By destroying it, we could bring the axe down on our own heads. Rural communities in more than 60 countries get much of their meat from wild animals.

Over population, famine and the spread of arms and ammunitions are killing off these creatures. In many areas local people are going hungry. In the Congo basin, conflict has forced people to sell wild meat, putting the squeeze on creatures such as large antelopes, gorillas and chimpanzees.

A variety of species is considered best for ecosystem. The health of an ecosystem depends on the variety of species that inhabit it, suggests new research. A recent study shows that when several species of caddis-fly larvae live together in a stream, they get more food from the stream and as a result are likely to be more productive than when only a single species inhabits the same area.

When species help each other in capturing food, ecologists call facilitation. The study found that increasing the diversity of species in a stream increases the likelihood of facilitation. The team’s findings raise new concerns about the ecological consequences of species extinction.

While all continental areas have suffered from biological alien invasions, and lost biological diversity as a result, the problem is especially acute on islands in general, and for small island countries in particular. Problems also arise in other isolated habitats and ecosystems, such as in Antarctica. The physical isolation of islands over millions of years has favoured the evolution of unique species and ‘ ecosystems.

As a consequence, islands and other isolated areas usually have a high proportion of endemic species and are centers of significant biological diversity. The evolutionary processes associated with isolation have also meant island species are especially vulnerable to competitors, predators, pathogens and parasites from other areas.

Term Paper Topic # 4. Water Resources and Global Warming:

All of us rely for our water on the weather to produce rainfall to replenish our aquifers and to provide us with water in our rivers. The demand for water is expected to grow strongly due to population growth and urbanization. World water resources are expected to diminish due to pollution of sources and over-abstraction of groundwater.

Recently, concern has developed that man’s action on the planet is changing the climate. World temperature has risen by about 0.5°C over the last one and half centuries. This change is primarily due to the burning of fossil fuels for heat and power and this result in CO₂ emissions to the atmosphere.

In turn, this CO₂ acts as a greenhouse, trapping more of the heat of the sun’s rays and raising the temperature. Emissions of CO₂ are currently increasing atmospheric concentrations of CO₂ at about 1% per year. Some actions are being taken but World Energy Council predicts that world temperature rises are bound to happen for several decades ahead.

Climate change is likely to have the following effects on water resources:

i. A small increase in demand for municipal and industrial water.

ii. Appreciable increase in demand for irrigation water.

iii. Most southern Asian countries could have reduced water resources.

iv. Greater climatic variability and more frequent droughts.

v. Changes could occur non-linearly as a climate flip.

vi. Sea level rise could have some effect on coastal aquifers and tidal intakes.

The results of some models for 50 years’ time indicate a rise in temperature from the 19th century to 2050 of about 1.5°C. However, the spread across the globe is not uniform. The oceanic regions with their greater thermal absorption capacity warm least and the Polar Regions the most. Under this scenario the mean annual temperature of Hong Kong would rise by about 1°C with parts of India, Australia and South East Asia rising by about 1.5°C.

Most important for us is ‘how would this change rainfall patterns? All models produce an increase in global mean evaporation and rainfall consistent with increased heating of the surface and enhanced long-wave cooling from the warmer atmosphere. During the next few decades there is expected to be increased rainfall in mid and high latitude regions, especially in winter, and in parts of the Inter-tropical Convergence Zone. Decreases in rainfall are likely in many parts of the subtropics.

Increased temperature means increased evaporation and less of the rainfall would become run-off. The process will change the mean annual soil moisture, and a reduction in annual soil moisture might reduce annual run-off and annual river flow. Predictions show that almost all of Asia south of a line from the Himalayas to Beijing having overall less soil moisture available on an average year and may be less river flow. In much of Asia, the greatest use of water is for irrigating agricultural crops.

Where the mean annual soil moisture decreases, irrigators will use more water on their crops. As quantities of water are finite, this would result in more conflict between users of water for municipal or agricultural purposes. Irrigation need is driven greatly by evapotranspiration which, in turn, is driven by temperature.

Many models predict that all of Asia, except north and east China, would get hotter during December to February. India, Vietnam, Malaysia and the Philippines would get drier and much of the rest of Asia would get wetter. Work on run-off change is not yet available, but most of India, Thailand, Vietnam and the Philippines would have less soil moisture and hence probably less river flow at this time of year.

During June to August, the period of South West Monsoon, there may be appreciable temperature increase. Some models show a 5°C increase in the temperature of Delhi during this period. Most of the rest of Asia would warm by 1-2°C. The rainfall scenario shows significant rainfall reductions over India, Pakistan and China.

Unfortunately not much work has been done on the impact of global warming on the run-off in Asia. Such detailed study was conducted for England. In December, January and February, England would get up to 10% more rainfall. However, the winter temperatures would go up by about 1.5°C and the potential evaporation would, in the south, more than double. This would mean proportionally less run-off.

In June, July and August the rainfall would increase in the north but decrease in the south of England. There is also a worrying gradient from +10% to -10% in as little as 500 miles. This could indicate greater instability and great variation from year to year.

Mean summer temperature could increase by 1.5°C. This would result in increased potential evaporation of up to 40%. The result is that in the north of England mean summer flows would be similar but the increased winter rainfall would result in increased run-off.

In the middle of England mean winter flow would be similar but in summer the small decrease in rainfall, coupled with increased evaporation, would decrease flow significantly. In the south of England there would be reduced winter flows and summer flows would be about halved.

This would have a serious effect on surface water resources. This shows the sensitivity of water resources to what appear to be modest changes of climate. If a similar effect were to occur in Asia on a regional scale then surface water resources could also be seriously affected.

Many aquifers depend on wet season recharge to provide sustainable water supplies. Because of the increased temperature and evapotranspiration, many aquifers will have a shorter recharge season and hence lower groundwater yields. This includes much of southern and eastern Asia.

It has been suggested by some that climate change would occur over such a long period that it would not be noticeable. However, many models show that likely changes in rainfall might occur by 2030 over a substantial portion of the globe. Some now believe that the effects are non-linear and a slight change in global temperature could trigger a disproportionately large effect on climate. Increased temperature will result in increased domestic demand for water for personal washing, cloths washing, gardening and irrigation.

Owing to the increase temperature the glaciers and ice-sheets will melt and sea will expand thermally. It has been estimated that by 2050 the sea level rise could be about 300 mm. For some Asian countries such as Bangladesh this could be serious affecting large areas of low-lying coastal land. Climate change could have an appreciable effect on water resources available for municipal supply and this need to be considered when preparing long-term water resource planning.

Term Paper Topic # 5. Global Warming and Carbon Dioxide Emissions:

Power Plants:

Power plants are the major contributors to the increased level of carbon dioxide emissions in the atmosphere. The plants work for generating electricity by burning fossil fuels in a massive scale, which produces large amounts of CO₂. Coal is known to be responsible for about 93% of the emis­sions in the power plants. Natural gas produces 80% less carbon per unit of energy than coal, and hence so much of impact on the environment results in the ever-increasing pace of global warming.

Vehicles:

Gasoline-burning engines produce about 20% of carbon dioxide emitted in the atmosphere. In the United States, 33% of emissions is from vehicles. Sports bikes and vehicles result in more emission than general vehicles designed for normal roads.

CO₂ due to Deforestation:

The ever-increasing deforestation is also one of the main culprits of global warming. As we are all aware of the fact that, trees take in huge amount of CO₂ from the atmosphere and releases oxygen. So, if there are no trees, there will be no absorption of this global warming gas and thus, the situation worsens further.

This fact is important when it comes to the reason as to why one of the global warming causes is carbon dioxide? As the world is progressing its way towards develop­ment, forests are vanishing away from the face of the Earth. More urbanization results in more deforestation for land and timber requirements, and all these factors boil down to one ‘dead end’, called global warming.

Term Paper Topic # 6. Nuclear Power for Curbing Global Warming:

Two years back, during the Indian Science Congress, Dr. R. Chidambaram, Principal Scientific Advisor to Government of India, had hinted that nuclear power holds the key of curtailing the emissions of greenhouse gases. He also informed that at present India is producing 250 MW of electricity through nuclear power plants, but during the next 20 years, we will be able to produce 20,000 MW of electricity through this mode.

The generation of electric power around the world remains largely dependent on the burning of fossil fuels—oil, gas and coal—which are heavily polluting. One of the most serious threats to the global environment comes from such pollution—the rapidly rising emissions of so-called “greenhouse” gases, especially carbon dioxide (CO₂) which many scientists believe is principally responsible for global warming.

Indeed, various reports from the Intergovernmental Panel on Climate Change (IPCC) warn that unless the world community takes immediate and drastic steps to stabilize and reduce the emissions of such heat-trapping gases, global temperatures may rise by at least 1.5°C by the middle of this century—a rate of increase that would be comparable to the warming that ended the last Ice Age, and with’ perhaps equally profound effects on sea levels and climate.

Among the most alarming predictions of the report entire ecosystems could vanish as rainfall and temperature patterns shift; rising seas could inundate huge swaths of densely populated land; and droughts, floods and storms could become more severe.

In an effort to reduce emissions of greenhouse gases, some countries are turning to natural gas, which is economically competitive with oil and coal. However, natural gas consumption also produces carbon dioxide (though less than coal or oil) and, moreover, methane leakage from extraction, transmission and distribution of natural gas are globally in the 5 to 10% range, a level which more than offsets the gains from lower CO₂ emissions.

Given the prospects of ever rising consumption of fossil fuels for electricity production and an increasing threat to the global environment, nuclear power can play an important part for countries that need increasing energy supplies without increasing greenhouse gas emissions.

Nuclear power plants produce virtually no sulphur dioxide, particulate, nitrogen oxides, volatile organic compounds and greenhouse gases. The complete nuclear power chain from resource extraction to waste disposal, including reactor and facility construction, emits only 2-6 grams of carbon equivalent per kilowatt-hour (gCeq/kW.h). This is about the same as wind and solar power including construction and component manufacturing. All three are two orders of magnitude below coal, oil and natural gas (100-360 gCeq/kW.h).

Globally nuclear power currently avoids approximately 600 Million Tonnes of Carbon (MtC) emissions annually, about the same as hydropower. The 600 MtC avoided by nuclear power equals 8% of current global greenhouse gas emissions. In the OECD countries, nuclear power has for 35 years accounted for most of the reductions in the carbon intensity per unit of delivered energy.

Nuclear power plants already provide about 17% of the world’s total supply of electricity. At least five countries, including France, Sweden and Belgium, rely on nuclear power for more than 50% of their total electrical supplies. Another ten countries, including Finland, Japan, Republic of Korea, Spain and Switzerland rely on nuclear plants to provide 30% or more of their total supplies.

And a large number of developing nations, including Argentina, Brazil, China, India, Mexico and Pakistan, have operational nuclear power plants. Worldwide there are more than 430 reactors currently in operation producing about as much electricity as obtained from hydropower.

The increasing uses of nuclear power since the 1960s, combined with steady increases in hydropower, have helped curb worldwide carbon dioxide output. If the world were not employing nuclear power today, global carbon dioxide emissions would be at least 8 percent greater every year. Nuclear power is more environmentally friendly from a waste management perspective as well.

In addition to the large quantities of greenhouse gases and sulfuric acid generated, a 1000 M W (e) coal-burning plant produces some 300,000 tonnes of ash per year, containing among other things radioactive material and heavy metals which end up in landfill sites and in the atmosphere.

On the other hand, the radioactive waste arising from a nuclear plant of the same capacity amounts only to some 800 tonnes of low and medium level wasted and some 30 tonnes of high level waste per year, which can be isolated from the biosphere.

While a global trend toward reducing the amounts of CO₂ produced for each unit of energy consumed has been espoused by Governments, relatively few countries have succeeded in reducing output of greenhouse gases through a switch to non-fossil fuels.

France, Japan, India, Republic of Korea and Sweden have all markedly reduced their CO₂ emissions per unit of energy output by up to 30 percent over the past 30 years. Countries with no nuclear power (such as Ireland, Italy and Denmark) have seen their energy-related emissions drop by less than 10 percent.

Term Paper Topic # 7. Global Warming and Freshwater

Whenever we talk of problems associated with water, always we discuss either pollution or water scarcity. But, plenty of water may also create severe problems. The global warming and associated melting of glaciers and icebergs hardly makes news these days. But, scientists observing the impacts of glacier melting are telling that these freshwater may change the climate and also may cause massive floods.

According to an international team of scientists the six largest Eurasian rivers are dumping a lot more freshwater into the Arctic Ocean now than they were several decades ago. Climate models have long predicted that as global temperatures warm, evaporation of surface water will increase and more moisture will be held in the atmosphere. This moisture will lead to more precipitation at high altitudes, such as Arctic, and subsequently more river runoff.

If these models are correct the 1°F rise in temperature over the last century should have caused a corresponding increase in Arctic river discharge. According to the researchers’ analysis, the average annual discharge from these six rivers is currently about 128 cubic kilometres greater than it was when routine measurements of discharge began in the 1930s.

According to the Intergovernmental Panel on Climate Change, which was established in 1988 to assess the risk of human-induced climate change, global surface air temperature is expected to rise between 2.5 to 10.4°F by 2100. This would represent an 18 to 70 percent increase in Eurasian Arctic river discharges over the present conditions. The report further tells that if the current rate of freshwater influx into the oceans continues to rise, it could have a large-scale impact on ocean circulation patterns in the North Atlantic, which governs the global climate.

Scientists are particularly interested in the potential impacts of this increase in freshwater on thermohaline circulation. The circulation is driven by differences in density of seawater, which is controlled by temperature and salinity. The traditional thermohaline circulation brings warm, salty water to the North Atlantic, where it is cooled and sinks.

The influx of freshwater could slow down or shut off the North Atlantic Deep Water (NADW) formation, the driving factor behind the conveyor belt current, which brings large amounts of warm water to the North Atlantic region. This ocean circulation, which brings warm waters northward and ships cooler water south, is thought to be responsible for the warming of Northern Europe by several degrees.

Scientists predict that stoppage of NADW could cause temperatures in continental Europe to drop by 3.6 to 9°F. However, most of the rest of world gets warmer when NADW is shut down. “In fact, a shutdown of the NADW would probably enhance global warming because it will also reduce the ocean’s uptake of carbon dioxide, so that more of our emissions remain in the air,” says Rahmstorf, an ocean current modeling expert with the Marine Biological Laboratory in Woods Hole, Massachusetts.

In recent past, two separate teams of scientists had predicted more extreme rainfall and greater flooding in this century. Both teams, one from the United States and the other from Europe, attribute the expected pattern to global warming accelerated by human activities. According to their projections, it will be particularly striking at northern latitudes—across Canada, Alaska, northern Europe, northern Asia, regions that already receive the most precipitation. But the equatorial tropics and Southeast Asia are also likely to have increased rainfall and flooding.

Although people may adapt to gradual climate change, the effects of extreme rain and flooding are often broad, devastating, and costly to society. Landslides, avalanches, and flooding damage infrastructure such as roads, bridges, buildings and hurt agricultural productivity.

Christopher Milly, an atmospheric scientist at the US Geological survey, and his colleagues reviewed data on 100-year floods that occurred in the last century for 29 major river basins around the world. They combined a climate model with a river model, tied them together, and examined different scenarios to identify trends.

The trends for the 20th century, particularly at high altitudes and in equatorial regions, closely mirrored what had actually happened. Based on model’s projections, it is reasonable to assume that increased flooding over the past century was related to global warming, and the increase is likely to continue. The models suggest that instead of chances of a 100-year flood occurring once every 100 years, the risk will increase in the 21st century to somewhere between 3 to 6 chances in 100.

In another study, Tim Palmer of the European Center for Medium Range Weather Forecasts in the United Kingdom studies increased rainfall due to global warming. Analyzing data from 19 climate models, they concluded that much of the central and northern Europe will be five times more likely to suffer very wet winters during this century. They also predict the Asian monsoon region will experience a five-fold increase of very wet summer.

“Dozens of mountains lakes in Nepal and Bhutan are so swollen from melting glaciers that they could burst their seams in the next five years and devastate many Himalayan villages,” warns a report published by the United Nations Environment Programme (UNEP).

The lives of tens of thousands of people who live high in the mountains and in downstream communities could be at severe risk as the mud walls of the lakes collapse under the pressure of extra water. Major loss of land and other property would aggravate poverty and hardship in the region.

The warning is based on three years of research involving site visits and studies of topographical maps, satellite images and aerial photography. The team assessed the conditions of about 4,000 glaciers and 5,000 glacial lakes in Nepal and Bhutan.

The findings indicate that 20 glacial lakes in Nepal and 24 in Bhutan have become potentially dangerous as a result of climate change. Data from 49 meteorological monitoring centers in Nepal indicate that temperatures have been rising about 0.06°C each year since the mid-1970s, with the average temperature now a degree higher.

Glacial melting associated with the temperature warming has expanded the size of many lakes in the region. In less than a decade, the Raphstreng Tsho Lake in the Pho Chu River sub-basin of Bhutan swelled from 1.6 kilometres to 1.94 kilometres in length, from 0.96 kilometres to 1.13 kilometres in width and from 80 to 107 meters in depth. Another lake deemed at critical risk of bursting is Tsho Rolpa in the Dolakha District of Nepal, as its area has extended from 0.23 sq. km. nearly a century ago to 1.4 sq. km. today.

Studies conducted by the Geological Survey of India have revealed that on average glaciers in India have been receding at the rate of about 15 meters every year. Although, the largest of Himalayas lies within India, almost nothing is known about glacial lake outburst floods from this country. UNEP is planning to take up India, Pakistan and China in the second phase of its study.