Global warming

What is Global Warming ?What is Global Warming ?

• In vague terms Global Warming may be described as the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation.

Understanding Global WarmingUnderstanding Global Warming

Causes.

Effects.

Prevention

Causes Of Global WarmingCauses Of Global Warming

There are 3 main causes of global warming,namely :

* Greenhouse gases in the atmosphere.

* Feedback.

* Solar Variation.

Greenhouse GasesGreenhouse Gases The greenhouse effect was discovered by Joseph Fourier in 1824 and was first investigated

quantitatively by Svante Arrhenius in 1896. It is the process by which absorption and emission of infrared radiation by atmospheric gases warm a planet's atmosphere and surface.

Existence of the greenhouse effect as such is not disputed. Naturally occurring greenhouse gases have a mean warming effect of about 33 °C (59 °F), without which Earth would be uninhabitable. Rather, the issue is how the strength of the greenhouse effect is changed when human activity increases the atmospheric concentrations of some greenhouse gases.

On Earth, the major greenhouse gases are water vapor, which causes about 36–70% of the greenhouse effect (not including clouds); carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone, which causes 3–7%.Some other naturally occurring gases contribute very small fractions of the greenhouse effect; one of these, nitrous oxide (N2O), is increasing in concentration owing to human activity such as agriculture. The atmospheric concentrations of CO2 and CH4 have increased by 31% and 149% respectively above pre-industrial levels since 1750. Molecule for molecule, methane is a more effective greenhouse gas than carbon dioxide, but its concentration is much smaller so that its total radiative forcing is only about a fourth of that from carbon dioxide. These levels are considerably higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from ice cores. From less direct geological evidence it is believed that CO2 values this high were last attained 20 million years ago.[20] Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. Most of the rest is due to land-use change, in particular deforestation.

FeedbackFeedbackThe effects of forcing agents on the climate are complicated by various feedback processes.

One of the most pronounced feedback effects relates to the evaporation of water. In the case of warming by the addition of long-lived greenhouse gases such as CO2, the initial warming will cause more water to be evaporated into the atmosphere. Since water vapor itself acts as a greenhouse gas, this causes still more warming; the warming causes more water vapor to be evaporated, and so forth until a new dynamic equilibrium concentration of water vapor is reached with a much larger greenhouse effect than that due to CO2 alone. Although this feedback process involves an increase in the absolute moisture content of the air, the relative humidity stays nearly constant or even decreases slightly because the air is warmer. This feedback effect can only be reversed slowly as CO2 has a long average atmospheric lifetime.

Feedback effects due to clouds are an area of ongoing research. Seen from below, clouds emit infrared radiation back to the surface, and so exert a warming effect; seen from above, clouds reflect sunlight and emit infrared radiation to space, and so exert a cooling effect. Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud. These details are difficult to represent in climate models, in part because clouds are much smaller than the spacing between points on the computational grids of climate models. Nevertheless, cloud feedback is second only to water vapor feedback and is positive in all the models that were used in the IPCC Fourth Assessment Report.[25]

Another important feedback process is ice-albedo feedback. When global temperatures increase, ice near the poles melts at an increasing rate. As the ice melts, land or open water takes its place. Both land and open water are on average less reflective than ice, and thus absorb more solar radiation. This causes more warming, which in turn causes more melting, and this cycle continues.

Positive feedback due to release of CO2 and CH4 from thawing permafrost, such as the frozen peat bogs in Siberia, is an additional mechanism contributing to warming.A massive release of CH4 from methane clathrates could cause rapid warming, according to the clathrate gun hypothesis.

Solar VariationSolar VariationA few papers suggest that the Sun's contribution may have been underestimated. Two researchers

at Duke University, Bruce West and Nicola Scafetta, have estimated that the Sun may have contributed about 45–50% of the increase in the average global surface temperature over the period 1900–2000, and about 25–35% between 1980 and 2000. A paper by Peter Stott and other researchers suggests that climate models overestimate the relative effect of greenhouse gases compared to solar forcing; they also suggest that the cooling effects of volcanic dust and sulfate aerosols have been underestimated. They nevertheless conclude that even with an enhanced climate sensitivity to solar forcing, most of the warming since the mid-20th century is likely attributable to the increases in greenhouse gases.

A different hypothesis is that variations in solar output, possibly amplified by cloud seeding via galactic cosmic rays, may have contributed to recent warming. It suggests magnetic activity of the sun is a crucial factor which deflects cosmic rays that may influence the generation of cloud condensation nuclei and thereby affect the climate.

One predicted effect of an increase in solar activity would be a warming of the stratosphere; however, the observed effect since at least 1960 has been a cooling of the lower stratosphere, which is one of the predicted results of greenhouse gas warming.] Reduction of stratospheric ozone also has a cooling influence, although substantial ozone depletion did not occur until the late 1970s. Solar variation combined with changes in volcanic activity probably did have a warming effect from pre-industrial times to 1950, but a cooling effect since. In 2006, Peter Foukal and other researchers from the United States, Germany, and Switzerland found no net increase of solar brightness over the last thousand years. Solar cycles led to a small increase of 0.07% in brightness over the last 30 years. This effect is far too small to contribute significantly to global warming.A paper by Mike Lockwood and Claus Fröhlich found no relation between global warming and solar radiation since 1985, whether through variations in solar output or variations in cosmic rays.Henrik Svensmark and Eigil Friis-Christensen, the main proponents of cloud seeding by galactic cosmic rays, disputed the findings of Lockwood and Fröhlich. Another recent study speculates that other bodies within the Solar System may influence the climate in a complex manner.

FactFactAverage temperatures have climbed 1.4 degrees Fahrenheit (0.8 degree Celsius) around the world since 1880, much of this in recent decades, according to NASA's Goddard Institute for Space Studies.

FactFactAn upsurge in the amount of extreme weather events, such as wildfires, heat waves, and strong tropical storms, is also attributed in part to climate change by some experts.

Effects Of Global WarmingEffects Of Global WarmingAn Overview:

Projected climate changes due to global warming have the potential to lead to future large-scale and possibly irreversible effects at continental and global scales. The likelihood, magnitude, and timing is uncertain and controversial, but some examples of projected climate changes include significant slowing of the ocean circulation that transports warm water to the North Atlantic, large reductions in the Greenland and West Antarctic Ice Sheets, accelerated global warming due to carbon cycle feedbacks in the terrestrial biosphere, and releases of terrestrial carbon from permafrost regions and methane from hydrates in coastal sediments.

The probability of one or more of these changes occurring is likely to increase with the rate, magnitude, and duration of climate change. Additionally, the United States National Academy of Sciences has warned, "greenhouse warming and other human alterations of the earth system may increase the possibility of large, abrupt, and unwelcome regional or global climatic events. . . . Future abrupt changes cannot be predicted with confidence, and climate surprises are to be expected."[1]

The IPCC finds that the effects of global warming will be mixed across regions. For smaller values of warming (1 to 3 °C), changes are expected to produce net benefits in some regions and for some activities, and net costs for others. Greater warming is very likely to produce net costs (or to reduce the benefits from smaller warming) in all regions. Developing countries are expected to be especially vulnerable to reduced economic growth as a result of warming.[2]

Most of the consequences of global warming would result from one of three physical changes: sea level rise, higher local temperatures, and changes in rainfall patterns. Sea level is generally expected to rise 18 to 59 cm (7.1 to 23.2 inches) by the end of the century.[3]

5 Deadliest Effects Of Global 5 Deadliest Effects Of Global WarmingWarming

-Spread Of Disease.-Warmer waters and more hurricanes.-Increased probability and intensity of draught .-Economic Consequences. -Polar Ice Caps Melting.

Spread Of DiseaseSpread Of Disease

As northern countries warm, disease carrying insects migrate north, bringing plague and disease with them.

Warmer Winters And More Warmer Winters And More HurricanesHurricanes

As the temperature of oceans rises, so will the probability of more frequent and stronger hurricanes. We saw in this in 2004 and 2005.

Droughts And heat WavesDroughts And heat Waves

Although some areas of Earth will become wetter due to global warming, other areas will suffer serious droughts and heat waves. Africa will receive the worst of it, with more severe droughts also expected in Europe. Water is already a dangerously rare commodity in Africa, and according to the Intergovernmental Panel on Climate Change, global warming will exacerbate the conditions and could lead to conflicts and war.

Economic ConsequencesEconomic Consequences

Most of the effects of anthropogenic global warming won’t be good. And these effects spell one thing for the countries of the world: economic consequences. Hurricanes cause do billions of dollars in damage, diseases cost money to treat and control and conflicts exacerbate all of these.

Polar Ice Caps MeltingPolar Ice Caps Melting

Global warming will lead to the polar ice caps and glaciers of the earth to start melting due to an increase in world temperature. This will result in rise in sea levels and flooding of coastal regions

Prevention Of Global WarmingPrevention Of Global Warming

We can prevent global warming by the following :

*Reduce electricity usage around the home.

*Improve vehicle and fuel efficiency.

*Conserve energy in the yard.

Reduce Electricity Usage Around Reduce Electricity Usage Around The HomeThe Home

• The largest source of greenhouse gases is electric power generation. The average home actually contributes more to global warming than the average car. This is because much of the energy we use in our homes comes from power plants which burn fossil fuel to power our electric products.

• To reduce the amount of electricity used in our homes:• switch to energy-efficient lighting - Replace the familiar incandescent light bulbs with compact fluorescent

bulbs. For each CFL bulb replacement, you'll lower your energy bill and keep nearly 700 pounds of carbon dioxide out of the air over the bulb's lifetime. CFL bulbs last much longer and use only a quarter of the energy consumed by conventional bulbs. LED bulbs are also energy-saving, but have a narrower range of application. Advances in LED bulb technology, however, are leading to more applications for these bulbs in the home. LEDs are more efficient than CFLs and do not have issues surrounding disposal, as do the CFLs. more info

• improve the efficiency of home appliances - Home appliances vary greatly in terms of energy-efficiency and operating costs. The more energy-efficient an appliance is, the less it costs to run. You can lower your utility bill and help protect the environment. here's how

• buy energy-efficient appliances - When shopping for a new appliance - especially a major appliance such as a refrigerator, dishwasher, or air-conditioner - select the one with the highest energy efficiency rating. By opting for a refrigerator with the Energy Star label -- indicating it uses at least 15 percent less energy than the federal requirement -- you can reduce carbon dioxide pollution by nearly a ton in total. more info

• reduce energy needed for heating - According to the U.S. Department of Energy, heating and cooling systems in the U.S. emit over a half billion tons of carbon dioxide into the atmosphere each year. Much of the energy used for heating our homes is wasted, and yet the prevention is, in many cases, simple and inexpensive. here's how

• reduce energy needed for cooling - Air conditioners alone use up to 1/6th of the electricity in the U.S. and, on hot summer days, consume 43% of the U.S. peak power load. You can reduce much of the need for air conditioning, and enjoy a cost savings benefit, by using 'passive' techniques to help cool your home. here's how

Improve Vehicle And Fuel Improve Vehicle And Fuel EfficiencyEfficiency

practice fuel-efficient driving - Every gallon of gasoline burned puts 26 pounds of carbon dioxide into the atmosphere. You can boost the overall fuel-efficiency of your car as much as 30% by simple vehicle maintenance and attention to your style of driving.

read these tips for fuel-efficient driving.

buy a fuel-efficient car - Even more important is the choice of car or truck you buy. If you buy a new car that gets 10 more miles per gallon than your old car, the amount of carbon dioxide reduction realized in one year will be about 2,500 pounds. The new hybrid cars, using efficient gas-electric engines, can cut global warming pollution by 30% or more.

learn more about hybrid cars.

recycle air conditioner coolant - If your car has an air conditioner, make sure you recycle its coolant whenever you have it serviced. You can save thousands of pounds of carbon dioxide each year by doing this.

drive less - You'll save energy by taking the bus, riding a bike, or walking. Try consolidating trips to the mall or longer routine drives. Encourage car-pooling.

Conserve Energy In The Yardreduce lawn size - Lawn size can be reduced by adding shrubs, beds, ground covers and mulched

areas. Try creating a lawn area small enough to be mowed using an efficient reel (push) mower. Lawn edging can be set low enough to mow over, reducing or eliminating the need for a weed-eater. more info

recycle whenever possible - aluminum cans, newspapers, magazines, cardboard, glass - anything recycled reduces the energy needed to create new products. To find the recycling center nearest you, call: 1 800-CLEANUP. For ideas on home recycling, click here for more info.

eat locally produced food - Today, the food choices available in supermarkets come from all over the world. All of this 'traffic' in food requires staggering amounts of fuel - generally by refrigerated airplanes or transport trucks. Food transportation is one of the fastest growing sources of greenhouse gas emissions. more info

paint your home a light color if you live in a warm climate, or a dark color in a cold climate. This can contribute saving up to 5000 pounds of carbon dioxide per year.

choose clean energy options - If you can choose your electricity supplier, pick a company that generates at least half its power from wind, solar energy and other renewable sources.

buy clean energy certificates and carbon offsets - Help spur the renewable energy market and cut global warming pollution with "wind certificates" or "green tags," which represent clean power you can add to the nation's energy grid in place of electricity from fossil fuels. more info

A “carbon offset” is an emission reduction credit which can be purchased by individuals, businesses and governments to reduce their net greenhouse gas emissions. more info

PollutionPollution

• Pollution is the introduction of contaminants into an environment that cause harm to human health, other living organisms, and the environment.Pollution can be in the form of chemical substances, or energy such as noise, heat, or light. Pollutants can be naturally occurring substances or energies, but are considered contaminants when in excess of natural levels. Pollution is often categorized into point source an nonpoint source pollution.

Pollution controlPollution controlPollution control devices

* Dust collection systems o Cyclones o Electrostatic precipitators o Baghouses * Scrubbers o Baffle spray scrubber o Cyclonic spray scrubber o Ejector venturi scrubber o Mechanically aided scrubber o Spray tower o Wet scrubber * Sewage treatment and Wastewater treatment o API oil-water separators[2][3] o Sedimentation (water treatment) o Dissolved air flotation (DAF) o Activated sludge biotreaters o Biofilters o Powdered activated carbon treatment * Vapor recovery systems

Major forms of pollution and major Major forms of pollution and major polluted areaspolluted areas

The major forms of pollution are listed below along with the particular pollutants relevant to each of them:

* Air pollution, the release of chemicals and particulates into the atmosphere. Common examples include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs), and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight.

* Water pollution via runoff, leaching to groundwater, liquid spills, wastewater discharges, eutrophication and littering.

* Soil contamination occurs when chemicals are released by spill or underground storage tank leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE[4], herbicides, pesticides and chlorinated hydrocarbons.

* Radioactive contamination, added in the wake of 20th century discoveries in atomic physics. (See alpha emitters and actinides in the environment.)

* Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar.

* Light pollution, includes light trespass, over-illumination and astronomical interference. * Visual pollution, which can refer to the presence of overhead power lines, motorway billboards,

scarred landforms (as from strip mining), open storage of trash or municipal solid waste. * Thermal pollution, is a temperature change in natural water bodies caused by human influence,

such as use of water as coolant in a power plant.

The Blacksmith Institute issues annually a list of the world's worst polluted places. In the 2007 issues the ten top nominees are located in Azerbaijan, China, India, Peru, Russia, Ukraine and Zambia.

Sources and causesSources and causesMotor vehicle emissions are one of the leading causes of air pollution. China, United States, Russia,

Mexico, and Japan are the world leaders in air pollution emissions; however, Canada is the number two country, ranked per capita. Principal stationary pollution sources include chemical plants, coal-fired power plants, oil refineries,petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.), PVC factories, metals production factories, plastics factories, and other heavy industry.

Some of the more common soil contaminants are chlorinated hydrocarbons (CFH), heavy metals (such as chromium, cadmium--found in rechargeable batteries, and lead--found in lead paint, aviation fuel and still in some countries, gasoline), MTBE, zinc, arsenic and benzene. Ordinary municipal landfills are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU. There have also been some unusual releases of polychlorinated dibenzodioxins, commonly called dioxins for simplicity, such as TCDD.

Pollution can also be the consequence of a natural disaster. For example, hurricanes often involve water contamination from sewage, and petrochemical spills from ruptured boats or automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produce widespread and potentially hazardous releases when accidents occur.

In the case of noise pollution the dominant source class is the motor vehicle, producing about ninety percent of all unwanted noise worldwide.

EffectsEffectsHuman health

Adverse air quality can kill many organisms including humans. Ozone pollution can cause respiratory disease, cardiovascular disease, throat inflammation, chest pain, and congestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of drinking water by untreated sewage in developing countries. Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood pressure, stress, and sleep disturbance.

Ecosystems

* Sulfur dioxide and oxides of nitrogen can cause acid rain which reduces the pH value of soil.

* Soil can become infertile and unsuitable for plants. This will affect other organisms in the food web.

* Smog and haze can reduce the amount of sunlight received by plants to carry out photosynthesis.

* Invasive species can out compete native species and reduce biodiversity. Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species competitiveness.

* Biomagnification describes a situation where toxins may be pass through trophic levels, becoming exponentially more concentrated in the process.

Media On Air PollutionMedia On Air Pollution

Media On Water PollutionMedia On Water Pollution

Media On Land PollutionMedia On Land Pollution

Bibliography:

www.wikipedia.orgwww.google.co.inBritanica Encyclopedia Online Edition.www.climatehotmap.orgwww.epa.gov