Wind Power

Photograph by Mefford Taylor

An Ancient Source of Energy

Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives.

Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives.

Ancient mariners used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are using wind turbines to wring electricity from the breeze. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small fraction of the world's energy.

Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These contraptions look like giant airplane propellers on a stick. The wind spins the blades, which turn a shaft connected to a generator that produces electricity. Other turbines work the same way, but the turbine is on a vertical axis and the blades look like a giant egg beater.

The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines erected in a backyard can produce enough electricity for a single home or small business.

Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments offer tax incentives to spur wind-energy development.

Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also variable: If it's not blowing, there's no electricity generated.

Nevertheless, the wind energy industry is booming. Globally, generation more than quadrupled between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China.

Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind.

for more detail go to National Geographic web
(source: http://environment.nationalgeographic.com)

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Solar Energy

Photograph by Otis Imboden

A Surging Energy Source

Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand.

Every hour the sun beams onto Earth more than enough energy to satisfy global energy needs for an entire year. Solar energy is the technology used to harness the sun's energy and make it useable. Today, the technology produces less than one tenth of one percent of global energy demand.

Many people are familiar with so-called photovoltaic cells, or solar panels, found on things like spacecraft, rooftops, and handheld calculators. The cells are made of semiconductor materials like those found in computer chips. When sunlight hits the cells, it knocks electrons loose from their atoms. As the electrons flow through the cell, they generate electricity.

On a much larger scale, solar thermal power plants employ various techniques to concentrate the sun's energy as a heat source. The heat is then used to boil water to drive a steam turbine that generates electricity in much the same fashion as coal and nuclear power plants, supplying electricity for thousands of people.

In one technique, long troughs of U-shaped mirrors focus sunlight on a pipe of oil that runs through the middle. The hot oil then boils water for electricity generation. Another technique uses moveable mirrors to focus the sun's rays on a collector tower, where a receiver sits. Molten salt flowing through the receiver is heated to run a generator.

Other solar technologies are passive. For example, big windows placed on the sunny side of a building allow sunlight to heat-absorbent materials on the floor and walls. These surfaces then release the heat at night to keep the building warm. Similarly, absorbent plates on a roof can heat liquid in tubes that supply a house with hot water.

Solar energy is lauded as an inexhaustible fuel source that is pollution and often noise free. The technology is also versatile. For example, solar cells generate energy for far-out places like satellites in Earth orbit and cabins deep in the Rocky Mountains as easily as they can power downtown buildings and futuristic cars.

But solar energy doesn't work at night without a storage device such as batteries, and cloudy weather can make the technology unreliable during the day. Solar technologies are also very expensive and require a lot of land area to collect the sun's energy at rates useful to lots of people.

Despite the drawbacks, solar energy use has surged at about 20 percent a year over the past 15 years, thanks to rapidly falling prices and gains in efficiency. Japan, Germany, and the United States are major markets for solar cells. With tax incentives, solar electricity can often pay for itself in five to ten years.

for more detail go to National Geographic web
(source: http://environment.nationalgeographic.com)

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http://loveearth-dk.blogspot.com

Hydropower

Photograph by Dorling Kindersley/Getty Images

Going With the Flow

Hydropower is electricity generated using the energy of moving water. Rain or melted snow, usually originating in hills and mountains, creates streams and rivers that eventually run to the ocean. The energy of that moving water can be substantial, as anyone who has been whitewater rafting knows.

Hydropower is electricity generated using the energy of moving water. Rain or melted snow, usually originating in hills and mountains, create streams and rivers that eventually run to the ocean. The energy of that moving water can be substantial, as anyone who has been whitewater rafting knows.

This energy has been exploited for centuries. Farmers since the ancient Greeks have used water wheels to grind wheat into flour. Placed in a river, a water wheel picks up flowing water in buckets located around the wheel. The kinetic energy of the flowing river turns the wheel and is converted into mechanical energy that runs the mill.

In the late 19th century, hydropower became a source for generating electricity. The first hydroelectric power plant was built at Niagara Falls in 1879. In 1881, street lamps in the city of Niagara Falls were powered by hydropower. In 1882 the world’s first hydroelectric power plant began operating in the United States in Appleton, Wisconsin.

A typical hydro plant is a system with three parts: an electric plant where the electricity is produced; a dam that can be opened or closed to control water flow; and a reservoir where water can be stored. The water behind the dam flows through an intake and pushes against blades in a turbine, causing them to turn. The turbine spins a generator to produce electricity. The amount of electricity that can be generated depends on how far the water drops and how much water moves through the system. The electricity can be transported over long-distance electric lines to homes, factories, and businesses.

Hydroelectric power provides almost one-fifth of the world's electricity. China, Canada, Brazil, the United States, and Russia were the five largest producers of hydropower in 2004. One of the world's largest hydro plants is at Three Gorges on China's Yangtze River. The reservoir for this facility started filling in 2003, but the plant is not expected to be fully operational until 2009. The dam is 1.4 miles (2.3 kilometers) wide and 607 feet (185 meters) high.

The biggest hydro plant in the United States is located at the Grand Coulee Dam on the Columbia River in northern Washington. More than 70 percent of the electricity made in Washington State is produced by hydroelectric facilities.

Hydropower is the cheapest way to generate electricity today. That's because once a dam has been built and the equipment installed, the energy source—flowing water—is free. It's a clean fuel source that is renewable yearly by snow and rainfall.

Hydropower is also readily available; engineers can control the flow of water through the turbines to produce electricity on demand. In addition, reservoirs may offer recreational opportunities, such as swimming and boating.

But damming rivers may destroy or disrupt wildlife and other natural resources. Some fish, like salmon, may be prevented from swimming upstream to spawn. Technologies like fish ladders help salmon go up over dams and enter upstream spawning areas, but the presence of hydroelectric dams changes their migration patterns and hurts fish populations. Hydropower plants can also cause low dissolved oxygen levels in the water, which is harmful to river habitats.

for more detail go to National Geographic web
(source: http://environment.nationalgeographic.com)

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Geothermal Energy

Photograph by Mefford Taylor

Tapping the Earth's Heat

Geothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.This thermal energy is contained in the rock and fluids beneath Earth's crust. It can be found from shallow ground to several miles below the surface, and even farther down to the extremely hot molten rock called magma.

Geothermal EnergyGeothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.This thermal energy is contained in the rock and fluids beneath Earth's crust. It can be found from shallow ground to several miles below the surface, and even farther down to the extremely hot molten rock called magma.

These underground reservoirs of steam and hot water can be tapped to generate electricity or to heat and cool buildings directly.

A geothermal heat pump system can take advantage of the constant temperature of the upper ten feet (three meters) of the Earth's surface to heat a home in the winter, while extracting heat from the building and transferring it back to the relatively cooler ground in the summer.

Geothermal water from deeper in the Earth can be used directly for heating homes and offices, or for growing plants in greenhouses. Some U.S. cities pipe geothermal hot water under roads and sidewalks to melt snow.

To produce geothermal-generated electricity, wells, sometime a mile (1.6 kilometers) deep or more, are drilled into underground reservoirs to tap steam and very hot water that drive turbines linked to electricity generators. The first geothermally generated electricity was produced in Larderello, Italy, in 1904.

There are three types of geothermal power plants: dry steam, flash, and binary. Dry steam, the oldest geothermal technology, takes steam out of fractures in the ground and uses it to directly drive a turbine. Flash plants pull deep, high-pressure hot water into cooler, low-pressure water. The steam that results from this process is used to drive the turbine. In binary plants, the hot water is passed by a secondary fluid with a much lower boiling point than water. This causes the secondary fluid to turn to vapor, which then drives a turbine. Most geothermal power plants in the future will be binary plants.

Geothermal energy is generated in over 20 countries. The United States is the world's largest producer, and the largest geothermal development in the world is The Geysers north of San Francisco in California. In Iceland, many of the buildings and even swimming pools are heated with geothermal hot water. Iceland has at least 25 active volcanoes and many hot springs and geysers.

There are many advantages of geothermal energy. It can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces. Binary plants release essentially no emissions. Unlike solar and wind energy, geothermal energy is always available, 365 days a year. It's also relatively inexpensive; savings from direct use can be as much as 80 percent over fossil fuels.

But it has some environmental problems. The main concern is the release of hydrogen sulfide, a gas that smells like rotten egg at low concentrations. Another concern is the disposal of some geothermal fluids, which may contain low levels of toxic materials. Although geothermal sites are capable of providing heat for many decades, eventually specific locations may cool down.

for more detail go to National Geographic web
(source: http://environment.nationalgeographic.com)

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Fuel Cells

Energy Source of the Future According to many experts, we may soon find ourselves using fuel cells to generate electrical power for all sorts of devices we use every day. A fuel cell is a device that uses a source of fuel, such as hydrogen, and an oxidant to create electricity from an electrochemical process. Photograph by Michael Klinec/Alamy

According to many experts, we may soon find ourselves using fuel cells to generate electrical power for all sorts of devices we use every day. A fuel cell is a device that uses a source of fuel, such as hydrogen, and an oxidant to create electricity from an electrochemical process.

Much like the batteries that are found under the hoods of automobiles or in flashlights, a fuel cell converts chemical energy to electrical energy.

All fuel cells have the same basic configuration; an electrolyte and two electrodes. But there are different types of fuel cells, based mainly on what kind of electrolyte they use.

Many combinations of fuel and oxidant are also possible. The fuel could be diesel or methanol, while air, chlorine, or chlorine dioxide may serve as oxidants. Most fuel cells in use today, however, use hydrogen and oxygen as the chemicals.

Fuel cells have three main applications: transportation, portable uses, and stationary installations.

In the future, fuel cells could power our cars, with hydrogen replacing the petroleum fuel that is used in most vehicles today. Many vehicle manufacturers are actively researching and developing transportation fuel cell technologies.

Stationary fuel cells are the largest, most powerful fuel cells. They are designed to provide a clean, reliable source of on-site power to hospitals, banks, airports, military bases, schools, and homes.

Fuel cells can power almost any portable device or machine that uses batteries. Unlike a typical battery, which eventually goes dead, a fuel cell continues to produce energy as long as fuel and oxidant are supplied. Laptop computers, cellular phones, video recorders, and hearing aids could be powered by portable fuel cells.

Fuel cells have strong benefits over conventional combustion-based technologies currently used in many power plants and cars. They produce much smaller quantities of greenhouse gases and none of the air pollutants that create smog and cause health problems. If pure hydrogen is used as a fuel, fuel cells emit only heat and water as a byproduct. Hydrogen-powered fuel cells are also far more energy efficient than traditional combustion technologies.

The biggest hurdle for fuel cells today is cost. Fuel cells cannot yet compete economically with more traditional energy technologies, though rapid technical advances are being made. Although hydrogen is the most abundant element in the universe, it is difficult to store and distribute. Canisters of pure hydrogen are readily available from hydrogen producers, but as of now, you can't just fill up with hydrogen at a local gas station.

Many people do have access to natural gas or propane tanks at their houses, however, so it is likely that these fuels will be used to power future home fuel cells. Methanol, a liquid fuel, is easily transportable, like gasoline, and could be used in automobile fuel cells. However, also like gasoline, methanol produces polluting carbon dioxide.

for more detail go to National Geographic web
(source: http://environment.nationalgeographic.com)

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Alternative Energy

Biofuels

Biofuels have been around as long as cars have. At the start of the 20th century, Henry Ford planned to fuel his Model Ts with ethanol, and early diesel engines were shown to run on peanut oil.

But discoveries of huge petroleum deposits kept gasoline and diesel cheap for decades, and biofuels were largely forgotten. However, with the recent rise in oil prices, along with growing concern about global warming caused by carbon dioxide emissions, biofuels have been regaining popularity.

Gasoline and diesel are actually ancient biofuels. But they are known as fossil fuels because they are made from decomposed plants and animals that have been buried in the ground for millions of years. Biofuels are similar, except that they're made from plants grown today.

Much of the gasoline in the United States is blended with a biofuel—ethanol. This is the same stuff as in alcoholic drinks, except that it's made from corn that has been heavily processed. There are various ways of making biofuels, but they generally use chemical reactions, fermentation, and heat to break down the starches, sugars, and other molecules in plants. The leftover products are then refined to produce a fuel that cars can use.

Countries around the world are using various kinds of biofuels. For decades, Brazil has turned sugarcane into ethanol, and some cars there can run on pure ethanol rather than as additive to fossil fuels. And biodiesel—a diesel-like fuel commonly made from palm oil—is generally available in Europe.

On the face of it, biofuels look like a great solution. Cars are a major source of atmospheric carbon dioxide, the main greenhouse gas that causes global warming. But since plants absorb carbon dioxide as they grow, crops grown for biofuels should suck up about as much carbon dioxide as comes out of the tailpipes of cars that burn these fuels. And unlike underground oil reserves, biofuels are a renewable resource since we can always grow more crops to turn into fuel.

Unfortunately, it's not so simple. The process of growing the crops, making fertilizers and pesticides, and processing the plants into fuel consumes a lot of energy. It's so much energy that there is debate about whether ethanol from corn actually provides more energy than is required to grow and process it. Also, because much of the energy used in production comes from coal and natural gas, biofuels don't replace as much oil as they use.

For the future, many think a better way of making biofuels will be from grasses and saplings, which contain more cellulose. Cellulose is the tough material that makes up plants' cell walls, and most of the weight of a plant is cellulose. If cellulose can be turned into biofuel, it could be more efficient than current biofuels, and emit less carbon dioxide.

for more detail go to National Geographic web

(source: http://environment.nationalgeographic.com)

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Global Warming: How Hot? How Soon?

A broad scientific census says that Earth is already experiencing significant global warming. So how hot will it get, how soon, and to what effect? Some climate scientists warn that the pace of global warming could be much more rapid than that predicted even a few years ago.

"Any time you get into projections, you get into a lot of uncertainties. But the [climate] models are getting a lot stronger," said Jay Gulledge, a senior research at the Pew Center on Global Climate Change in Arlington, Virginia.

Gulledge says some current projections point to a rise in average global temperature of 0.5°C (slightly less than 1°F) by the year 2030.

The estimates are based on greenhouse gasses already in the atmosphere. While the temperature increase is small, it would be significant. Over the past century Earth has warmed about 1°F (0.6°C). (See our fast facts on global warming.)

Gulledge cautions, however, that warming rates depend on many factors, some of which have yet to be discovered.

"One of the big unknowns is how society will react," said Antonio Busalacchi, a University of Maryland meteorologist who chairs the climate research committee for the National Academy of Sciences. "Are we going to change?

Meadow Offers Glimpse of Warmer Future

John Harte, an ecosystem sciences professor at the University of California, Berkeley, is already seeing possible future outcomes of global warming.

For 15 years, he has artificially heated sections of a Rocky Mountain meadow by about 3.6°F (2°C) to study the projected effects of global warming.

Harte has documented dramatic changes in the meadow's plant community. Sagebrush, though at the local altitude limit of its natural range, is replacing alpine flowers.

More tellingly, soils in test plots have lost about 20 percent of their natural carbon. This effect, if widespread, could dramatically increase Earth's atmospheric CO2 levels far above even conventional worst-case models.

Soils around the world hold about five times more carbon than the atmosphere in the form of organic matter," Harte noted. If similar carbon loss was repeated on a global scale, it could double the amount of carbon in the atmosphere.

"Now, [the test plot] is just one ecosystem, and you can't make global claims from one alpine meadow," Harte cautioned. "But bogs, prairie, and tundra ecosystem studies are beginning to show similar results."

Vanishing Ice

Elsewhere real-life signs of global climate change blanket the globe.

When Montana's Glacier National Park was established in 1910, it held some 150 glaciers. But now fewer than 30 glaciers remain and they are greatly reduced.

In Tanzania the legendary snows of Mount Kilimanjaro have melted by some 80 percent since 1912 and could be gone by 2020.

"We know that most of the world's small glaciers are shrinking," said Mark Serreze of the National Snow and Ice Data Center at the University of Colorado at Boulder.

"A few are still advancing. But if you want to see Kilimanjaro or go to Glacier National Park to see glaciers, you'd better go soon. Because they're on their way out."

Arctic regions are feeling even more heat and will be among the most altered over the next few decades.

Temperatures there have already increased as much as 4° to 7°F (3° to 4°C) in the past 50 years—nearly twice the global average.

They're projected to rise 7° to 13°F (4° to 7°C) over the next hundred years, according to the Arctic Climate Impact Assessment, a multinational study.

Some Arctic coastal communities are already pondering relocation. Thawing permafrost poses an infrastructure disaster, as homes, roads, and pipelines that were built on once-frozen ground begin to shift or sink.

Shrinking Arctic sea ice is melting some three weeks earlier than it did three decades ago, and the trend is expected to continue. (See "Arctic Melting Fast; May Swamp U.S. Coasts by 2099.")

This spells bad news not only for Arctic peoples but for species like the polar bear, which hunts seals on the sea ice.

Global polar bear populations are likely to decline 30 percent over the next 35 to 50 years, according to a recent study issue by the polar bear specialist group of the World Conservation Union.

The bears are not alone. Animals and ecosystems across the planet are likely to be affected by global warming. (See "By 2050 Warming to Doom Million Species, Study Says." )

Adapting to a Warmer Planet

"The one surprise for me is how rapidly [warming] is happening, how sensitive ecological resources are to climate change," said ecologist Hector Galbraith, of Galbraith Environmental Sciences and the University of Colorado at Boulder.

Galbraith expects that over the next two decades, the Earth will see an acceleration of ecosystem changes already under way. Such alterations will include different migration and breeding seasons for some animals and new flowering seasons for plants.

"We're also seeing changes in species distribution. Things like trees can't react too quickly" to climate change, Galbraith said.

"But mobile organisms, like birds, can simply move. We're already seeing major range extensions of species like Acadian flycatchers and red-bellied woodpeckers."

Such adaptations could mean major and unpredictable ecosystem changes.

"A lot of the northern forests are very susceptible to insect attacks, and songbirds are a major [source of] control," Galbraith continued.

"If the birds move north, forests may be more susceptible to insect attacks, which means more dead wood, which means more fire. The whole nature of the forest can change fairly quickly."

Fires can also be outgrowths of droughts and severe weather, which many scientists expect to increase as the Earth warms.

One such scientist is Sir John Houghton, former chairman of the Intergovernmental Panel on Climate Change's scientific assessment.

In testimony last week to the United States Senate's Energy and Natural Resources Committee, Houghton referenced the unusually extreme heat wave that killed some 20,000 central Europeans during the summer of 2003.

"Careful analysis shows that it is very likely that a large part of the cause of this event is due to increases in greenhouse gases and projects that such summers are likely to be the norm by the middle of the 21st century and cool by the year 2100," Houghton told the committee.

Busalacchi, the University of Maryland meteorologist, cautions that it is difficult to attribute any single extreme weather event to global warming. "But that episode is a very good example of what we expect to see more of in the future," he said. (See "Global Warming Unstoppable for 100 Years, Study Says.")

Like severe weather, many of global warming's near-term effects will be felt regionally, resulting in relative "winners" and "losers."

"There's likely to be a very large disparity of impact between the developed and developing world," said Anthony Janetos, director of the Heinz Center for Science, Economics, and the Environment's global change program.

"We know that there's a large disparity in the capacity to deal with that impact, which creates some challenges for the policy community."

source from National Geographic

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Global Warming Fast Facts

hai all long time not posting again, now I (dony konig) have information from National Geographi about the earth.
the information is about why it's happening, what's causing it, and how it might change the planet.
ok now I (dony Konig) and loveearth-dk will give you the information,,,
enjoy it and think what should you do to save the earth!!!

Global warming, or climate change, is a subject that shows no sign of cooling down. Here's the lowdown on why it's happening, what's causing it, and how it might change the planet.

Is It Happening?

Yes. Earth is already showing many signs of worldwide climate change.

• Average 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.

• The rate of warming is increasing. The 20th century's last two decades were the hottest in 400 years and possibly the warmest for several millennia, according to a number of climate studies. And the United Nations' Intergovernmental Panel on Climate Change (IPCC) reports that 11 of the past 12 years are among the dozen warmest since 1850.

• The Arctic is feeling the effects the most. Average temperatures in Alaska, western Canada, and eastern Russia have risen at twice the global average, according to the multinational Arctic Climate Impact Assessment report compiled between 2000 and 2004.

• Arctic ice is rapidly disappearing, and the region may have its first completely ice-free summer by 2040 or earlier. Polar bears and indigenous cultures are already suffering from the sea-ice loss.

• Glaciers and mountain snows are rapidly melting—for example, Montana's Glacier National Park now has only 27 glaciers, versus 150 in 1910. In the Northern Hemisphere, thaws also come a week earlier in spring and freezes begin a week later.

• Coral reefs, which are highly sensitive to small changes in water temperature, suffered the worst bleaching—or die-off in response to stress—ever recorded in 1998, with some areas seeing bleach rates of 70 percent. Experts expect these sorts of events to increase in frequency and intensity in the next 50 years as sea temperatures rise.

• An 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.

Are Humans Causing It?

he report, based on the work of some 2,500 scientists in more than 130 countries, concluded that humans have caused all or most of the current planetary warming. Human-caused global warming is often called anthropogenic climate change.

• Industrialization, deforestation, and pollution have greatly increased atmospheric concentrations of water vapor, carbon dioxide, methane, and nitrous oxide, all greenhouse gases that help trap heat near Earth's surface. (See an interactive feature on how global warming works.)

• Humans are pouring carbon dioxide into the atmosphere much faster than plants and oceans can absorb it.

• These gases persist in the atmosphere for years, meaning that even if such emissions were eliminated today, it would not immediately stop global warming.

• Some experts point out that natural cycles in Earth's orbit can alter the planet's exposure to sunlight, which may explain the current trend. Earth has indeed experienced warming and cooling cycles roughly every hundred thousand years due to these orbital shifts, but such changes have occurred over the span of several centuries. Today's changes have taken place over the past hundred years or less.

• Other recent research has suggested that the effects of variations in the sun's output are "negligible" as a factor in warming, but other, more complicated solar mechanisms could possibly play a role.

What's Going to Happen?

A follow-up report by the IPCC released in April 2007 warned that global warming could lead to large-scale food and water shortages and have catastrophic effects on wildlife.

• Sea level could rise between 7 and 23 inches (18 to 59 centimeters) by century's end, the IPCC's February 2007 report projects. Rises of just 4 inches (10 centimeters) could flood many South Seas islands and swamp large parts of Southeast Asia.

• Some hundred million people live within 3 feet (1 meter) of mean sea level, and much of the world's population is concentrated in vulnerable coastal cities. In the U.S., Louisiana and Florida are especially at risk.

• Glaciers around the world could melt, causing sea levels to rise while creating water shortages in regions dependent on runoff for fresh water.

• Strong hurricanes, droughts, heat waves, wildfires, and other natural disasters may become commonplace in many parts of the world. The growth of deserts may also cause food shortages in many places.

• More than a million species face extinction from disappearing habitat, changing ecosystems, and acidifying oceans.

• The ocean's circulation system, known as the ocean conveyor belt, could be permanently altered, causing a mini-ice age in Western Europe and other rapid changes.

• At some point in the future, warming could become uncontrollable by creating a so-called positive feedback effect. Rising temperatures could release additional greenhouse gases by unlocking methane in permafrost and undersea deposits, freeing carbon trapped in sea ice, and causing increased evaporation of water.

source from National Geographic

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dk-loveearth change the name to loveearth-dk

hi all long time not posting again, I change my blog name from http://dk-loveearth.blogspot.com to http://loveearth-dk.blogspot.com
I change my blog name for make every body easier to search my blog.
and I will add more than just issue or problem about earth but I will add something like poster about earth and another think that have relation about earth.

it's coming soon!!!!

love earth
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Fact About Global Warming

PARIS (Feb. 2) - A panel of international scientists predicted Friday that global warming will continue for centuries no matter how much people control pollution, in a bleak report that blamed humans for killer heat waves, devastating droughts and stronger storms.

The report said people were "very likely" the cause of global warming - the strongest conclusion to date - and placed the burden on governments to take action.

"It's later than we think," said Susan Solomon, co-chair of Intergovernmental Panel on Climate Change.

Man-made emissions of greenhouse gases are to blame for fewer cold days, hotter nights, heat waves, floods and heavy rains, droughts and stronger storms, particularly in the Atlantic Ocean, the 21-page report said.

It highlighted "increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level."

Authors of the report called it conservative: It used only peer-reviewed published science and was edited by representatives of 113 governments who had to agree to every word. It was a snapshot of where the world is with global warming and where it is heading, but does not tell governments what to do.

Yet if nothing is done, the world is looking at billions of dollars in costs adapting to a warmer world over the next century, co-author Kevin Trenberth said in an interview. He also warned of at least 1 million deaths in droughts, floods and hurricanes.

The study said no matter how much civilization slows or reduces its greenhouse gas emissions, global warming and sea-level rise will continue for centuries.

"This is just not something you can stop. We're just going to have to live with it," said Trenberth, the director of climate analysis at the U.S National Center for Atmospheric Research. "We're creating a different planet. If you were to come back in 100 years' time, we'll have a different climate."

Scientists fear world leaders will take that message in the wrong way and throw up their hands, Trenberth said. Instead, the scientists urged leaders to reduce emissions and adapt to a warmer world with wilder weather.

"The point here is to highlight what will happen if we don't do something and what will happen if we do something," said another author, Jonathan Overpeck of the University of Arizona. "I can tell you if you decide not to do something the impacts will be much larger than if we do something."
The next step is up to public officials, scientists said.

"It is critical that we look at this report ... as a moment where the focus of attention will shift from whether climate change is linked to human activity, whether the science is sufficient, to what on earth are we going to do about it," U.N. Environment Program Executive Director Achim Steiner said.

The strongly worded report put pressure on the Bush administration to reduce the United States' growing share of gases that trap heat in the atmosphere.

The White House issued a statement less than four hours after the report's release defending President Bush's six-year record on climate change.

It said Bush and his budget proposals have devoted $29 billion to climate-related science, technology, international assistance and incentive programs - "more money than any other country."
Bush has called for slowing the growth rate of U.S. greenhouse gas emissions, which averages 1 percent a year, but has rejected government-ordered reductions.

Since 1990, U.S. greenhouse gas emissions have gone up 16 percent. The Bush administration has rejected the Kyoto Protocol, which calls for cuts in emissions of greenhouse gases.

Sharon Hays, White House associate science adviser, called the study "a significant report. It will be valuable to policy makers."

Another report by the panel later this year will address the most effective measures for slowing global warming.

If it looks bad now, the harmful effects during the 21st century "would very likely be larger than those observed during the 20th century," the report said.

The panel predicted temperature rises of 2-11.5 degrees Fahrenheit by the year 2100. It said its best estimate was for temperature rises of 3.2-7.1 degrees.

On sea levels, the report projects rises of 7-23 inches by the end of the century. An additional 3.9-7.8 inches are possible if recent, surprising melting of polar ice sheets continues.
The panel, created by the United Nations in 1988, releases its assessments every five or six years, though scientists have been observing aspects of climate change since as far back as the 1960s. The reports are released in phases - this is the first of four this year.

The projected effects of global warming would vary in different parts of the globe. The closer to the poles, the higher the temperature spikes, the study said.

Dramatic temperature spikes are likely to be seen within 22 years in most of the Northern Hemisphere, the report showed. Northern Africa and other places will see dramatically less rainfall.

The United States could see a 10-degree temperature rise by the end of the century and a more arid south and west, Overpeck said.

And that's just average temperature increases and rainfall amounts, something that doesn't affect people much. The harshest consequences of global warming are the heat waves, droughts, floods, and hurricanes, said study co-author Philip Jones of Britain's University of East Anglia. And those have increased dramatically in the past decade and will get worse in the future, he said.

Global warming could eventually lead to an "ice-free Arctic," warned Gerry Meehl, an official with the U.S National Center for Atmospheric Research.

And when that happened 125,000 years ago, seas rose between 13 and 20 feet. That is looking like a real possibility for the 22nd Century, the report said, though some scientists fear much of it could happen before the end of the century.

Trenberth said the world is paying more attention to scientists now than to previous warnings in 1990, 1995 and 2001. "The tension is more now," he said.

As the IPCC report was being released, environmental activists rappelled off a Paris bridge and draped a banner over a statue used often as a popular gauge of whether the Seine River is running high.

"Alarm bells are ringing. The world must wake up to the threat," said Catherine Pearce of Friends of the Earth.

Associated Press writer Angela Charlton contributed to this report.

Copyright 2007 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewritten or otherwise distributed without the prior written authority of The Associated Press. All active hyperlinks have been inserted by AOL.

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Top 12 Ways To Reduce Global Warming

Save Energy, Money and the Environment

According to the Natural Resources Defense Council, the two biggest offenders in the global warming problem are cars and power plants. In particular, coal-burning power plants are the largest U.S. source of carbon dioxide pollution, producing 2.3 billion tons every year. Cars, the second largest source, are responsible for generating almost 1.1 billion tons of carbon dioxide emissions a year. Carbon dioxide and other air pollution collect in the atmosphere and trap heat from the sun causing the planet to warm up.

The good news is we don't have to wait for technical solutions to reduce the impact of these big offenders. Solutions exist now to allow us to reduce our dependence on power plants and use cleaner transportation options. We just have to start using them. Here are 12 simple ways to do your part to start making a difference now. By saving energy, you’ll also save money.

(Note: According to the EPA, a typical U.S. household generates 45,000 pounds of greenhouse gas emissions each year.)

1. Change Five Lights Replace your five most frequently used lights or the bulbs in them with ones that have earned the Energy Star and you’ll use less energy, which means less pollution from power plants. Your household will also be saving about 700 pounds of carbon dioxide a year and save $90 a year in energy costs (If every household in the country did it -- we would save a trillion pounds of greenhouse gases.) Take the "Change a Light Pledge" and change at least one light in your home.
2. Heat and Cool Smartly
About half the energy we use in our homes goes to heating and cooling. Changing air filters annually, having your system checked annually and useing a programmable thermostat are all easy things you can do. Just by using a programmable thermostat, you can save about 1,800 pounds of carbon dioxide a year and about $100 a year in energy costs. If you want to go the extra mile, see "Bonus Tips" below for how to purchase green power.

3. Put the Freeze on Inefficient Appliances
Get rid of old, energy inefficient appliances and replace with newer energy-efficient models. For example a high-efficiency refrigerator will save you $100 per year and reduce carbon dioxide emissions by 500 pounds a year.

If you replace your current washing machine with a low-energy, low-water-use machine you will be able to reduce your carbon dioxide emissions by 440 pounds per year. For even more savings wash your laundry in warm or cold water, instead of hot. That will bring in a reduction of carbon dioxide emissions of about 500 pounds per year.

4. Reduce and Recycle
Reducing your garbage by 25 percent will reduce carbon dioxide emissions by 1,000 pounds per year. Recycle aluminum cans, glass bottles, plastic, cardboard and newspapers can reduce your home's carbon dioxide emissions by 850 pounds per year.

5. Don't Give Energy Away
If you caulk and weather-strip around doors and windows to plug up leaks you can reduce carbon dioxide emissions by 1,700 pounds per year.

6. Take the Green Way
Leave your car at home two days a week (walk, bike, take public transit or telecommute) and you can reduce your carbon dioxide emissions by 1,590 pounds per year.

7. Buy Products That Have Earned the Energy Star
Over 40 different kind of products now carry the Energy Star -- the government-backed symbol for energy efficiency -- including lighting, home electronics, heating and cooling equipment and appliances. With Energy Star products you can save 30 percent on your energy bills (about $450 a year). For information on high efficiency appliances and other products, visit the Energy Star Web site (www.energystar.gov).

8. Slow the Flow
When purchasing a new vehicle, consider finding a car that gets more miles to the gallon than your current vehicle, and match the vehicle to your needs. The potential carbon dioxide reduction for a car that gets 32 miles per gallon is 5,600 pounds per year. To get more information about finding and buying a fuel-efficient car visit AOL Autos.

9. Make the Right Move
If you spend hours on the road every day to get to work you could save some significant time and money by moving closer to work and reducing your commute. The carbon dioxide emissions you save are icing on the cake.

10. Be a Turnoff
Turn off your TV, video player, stereo and computer when you aren't using them. Turn off your lights when you don't need them and you start saving within a minute or two. Prevent "phantom" energy losses by plugging these devices into a power strip and turning the power strip off when the devices are not in use.

11. Trim Your Load
When you do drive, keep your car tuned up and its tires properly inflated to save on fuel costs as well as reducing carbon dioxide emissions. A tune-up could boost your miles per gallon anywhere from four to 40 percent; a new air filter could get you 10 percent more miles per gallon. Take your roof rack off your car when you aren't using it for more savings.

12. Keep Your Water Heater Cozy
For a water heater more than five years old, wrapping it in an insulating jacket will result in a 1,000 pounds per year reduction of carbon dioxide emissions. Keep your water heater thermostat no higher than 120 degrees F and you can reduce carbon dioxide emissions by 550 pounds per year.


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22 Ways To Help The Earth

Most people want to help the earth, but very few actually go out and do something (If you are one of those few, GREAT JOB!!). To help the earth, you don't have to restore a river or clean up ten miles of highway. You can do those things, but here are some easier ways to help out. For even more ideas, read 50 Simple Things You Can Do To Save The Earth, 50 Simple Things Kids Can Do To Save The Earth, or 50 Simple Things Your Business Can Do To Save The Earth. These are great books all by the EarthWorks Group. Try them!

1. Put a bleach bottle in your toilet. Fill it with water, put on the cap tightly, and put it in the back part of your toilet. A brick inside a plastic bag to contain all the crumbs would also work. Since the average toilet uses 3 to 7 gallons of water per flush, the brick or bottle will displace some water, so your toilet will use ½ - 1 gallon less each time someone uses it!
2. Plant a tree. There are two ways to do this old idea. You could find a tree (like a maple) that produces seeds every spring, collect a few, and plant them. Start them in pots until they're at least a foot tall, then put them in the yard. The other way is, of course, to go out and buy a young tree to plant. The price may vary from $20 to over $200, depending on the size or type of tree. We know that because of the cost, not everyone can plant a tree, but it's a great way to save the earth's oxygen!

   

3. Re-use your plastic sandwich bags. Plastic takes over 100 years to biodegrade, so the less plastic we throw out, the better. After using a plastic bag, wash it out with soapy water and let it dry. Then you can use it over and over again, and it works just as well as a new bag! This will also save you some money when you don't have to buy as many new bags!
4. Make your meals earth-friendly. When packing a lunch, put sandwiches, chips, etc. in reusable plastic containers instead of sandwich bags. Carry your drink in a washable thermos bottle, and your lunch in a reusable lunch container. For meals at home, put leftover food in hard plastic washable and reusable containers. (You could save glass jars and deli containers for this!)
5. Use both sides of paper. If you have to scribble down directions or make a quick math calculation, don't just throw the paper away when you're done! Save it for the next time you need to jot something down quickly. Having a few pages of "scrap" paper around is a good way to keep yourself from wasting new sheets each time.
6. Don't give kids nice packaged computer paper to color on. Little kids seem to love to make one line on a piece of paper and then get a new one. Because of this, don't use packaged printer paper (which can be $6 for 500 sheets) when cheaper notebook or recycled paper will work. If you work in an office, bring home scrap paper that is still blank on one side! Many network printers print out title sheets with every printout, telling who printed it. One-sided "junk" flyers are good too--sometimes they even come in colors. Use these for kids' coloring paper.
7. Make your house energy efficient. One visitor to our site mentioned that after installing compact flourescent light bulbs and other energy-efficient appliances, his electricity bill went down 75%. Compact flourescant bulbs last ten times longer than regular incandescent bulbs, plus they don't produce nearly as much wasted heat.
8. If you don't need a light on, don't use one! If it's 1:00 on a bright sunny day, don't turn on a light that you don't need. If you're going to be in a room for only a minute, try to go without any electric lights at all. Most houses have enough windows that you won't need to use lights for most of the daytime. And if you do have to turn on a light, turn on only as many as you need.
9. If you have a leaky faucet, catch the drips. If your faucet is leaking, of course you should get it fixed. But, what about the time before it's fixed? Put a pan, bowl, or cup underneath to catch the water, and use it for something else like watering a plant, cooking, making Kool-Aid, or drinking! There's nothing wrong with the water; it came out of the tap just like normal. Be careful! A leaking faucet can fill a coffee cup in 10 minutes, so watch the size of your container and how fast it fills up.
10. "Recycle" your clothes. Once your kids grow out of their clothes, or you no longer like or fit into something, DON'T THROW IT AWAY! If you want to make money, try having a garage sale. Too much work? The Salvation Army or other clothing donation stores offer tax refunds for donated clothes. Resale shops will pay you for clothes you give them. Feeling moral? Donate your clothes to the needy or to other clothing drives for the poor.
11. Open windows instead of using air conditioning. When the temperature outside is right around the temperature inside, then save some money, electricity, and the earth by opening some windows. If you do that at night, then your house will cool down without costing you a cent!
12. Donate to an ecological organization. If you don't feel like doing anything for the earth, pay someone else to! If you have extra cash, the groups would greatly benefit from your donation. The more money they have, the more ways they can reach out to help our earth!
13. Buy organically-grown foods. Some grocery stores now have organic sections where you can purchase all kinds of fruits, vegetables, and cereals that have had no chemical fertilizer, pesticides, or herbicides. Show the stores you care by buying these things! They'll be better for you and for the earth because no chemicals are going into the soil or water.
14. Snip your 6-pack holders. Countless animals and birds die from uncut 6-pack holders and other ringed packages each year. They get caught in the holes and are choked to death. Make it a habit to cut all the rings apart when you throw away a 6-pack holder!
15. Buy recycled products! Paper, packaging, plastic containers, cardboard, and other products are being sold that have been recycled. By all means, buy these products, but be carful when reading the labels. Don't confuse "recycled" with "recyclable"! Lots of companies will put the recycling symbol or "100% recyclable" on their products to appeal to ecologists. While that is all fine and good, "made from recycled waste" or "post-consumer waste" is what you really want. If you buy recycled notebook paper for school, no one will really care if your paper is a s hade greyer than the non-recycled kind.

    

16. Use permanent silverware and dishes instead of paper ones. Not only will you save the earth, you'll save money! Why use disposable plastic silverware when you can buy regular ones? The last thing we need is extra garbage in landfills, and this is a great way to cut down on some of it. Use permanent kitchenware unless you absolutely have to use disposable stuff!
17. In general, don't use disposable products at all. Diapers, pens, razors, towels; they're all disposable, so there are many ways to do help the earth this way. Use cloth diapers instead of disposable plastic ones. Don't use paper towels--old t-shirts or towels work fine as messy-use rags. Those multi-use paper towels that claim to be strong enough to use again may be, but it's still cheaper to use an old rag, and the rag will probably work better! What's the use of using disposable razors if you have to buy a new bag every other week? It will save you money just to get a good one to keep using! In other words, don't get sucked into the world of simple disposable items because "it's easy and convenient."
18. Buy in bulk. One 32-ounce bottle will use less packaging than two 16-ounce ones, even though the total size is the same. Plus, the larger bottle will probably cost less per ounce than the other two combined! For an example, let's look at pop. A 2-liter bottle of pop costs $1, or about 1.5¢ per ounce (there's 67 ounces). The packaging comes to about 163 square inches. Opposing this is the 12-pack of cans. The cost is about $3 for 144 ounces, or 2.1¢ per ounce. The total packaging here comes to 600 square inches! The 2-liter is much better! Less cost per ounce, and a lot less garbage in the landfill!
19. Don't buy products with lots of packaging. As you can see from above, the more packaging, the more cost. If you see a small product (for example, a toothbrush) wrapped in five layers of plastic with a flashy cardboardy thing, all in a box made of a foam-like plastic, chances are most of the price is because of the packaging. Find a similar product with less packaging. Wouldn't a plastic wrapper or cardboard box be just as good? Also, stay away from individually wrapped candy and other products. Also, select fresh produce from display bins instead of the pre-packaged variety. The more packaging, the more price, and (more importantly) the more garbage in the landfills.
20. Buy dolphin-safe tuna and other eco-safe products. Every day, dolphins get caught in tuna nets. You can do something about it! Check the label of the tuna you buy to make sure it it dolphin-safe, that is, catching the tuna doesn't harm dolphins. There will be a special logo on the label to tell you if it is dolphin-safe.
21. Spread the word about conservation. Any way you can, get people to think about the earth. There are almost 6,000,000,000 people on this earth, and every one of them needs to take care of it! Always look for environment-safe products and encourage others to do the same. From recycling to buying less packaging to planting trees to saving water to conserving energy, keep the environment in mind. Posters can be a great way to spread the word, so drop by our Poster Page to look at some, print them out, or get your own ideas.
22. Use rechargable batteries. Although they may cost more to buy, rechargable batteries will save you 10 or 20 times the original cost (by not buying new batteries over and over again), and not get thrown in the trash. Prolong the life of any batteries by using a cord (and AC adapter, if necessary) for radios and other appliances when possible.

Earth is Beautiful

Earth is Beautiful

by www.loveearth.com

by dk-loveearth

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Plastic Bag Caused Seriously Polution

Plastic solid waste is one of MANY significant pollutants in ocean world (and freshwater systems as well). In the North Pacific, currents have accumulated floating plastic waste en masse. The flotilla is estimated to be roughly the size of Texas.

This plastic waste has a penchant for finding its way into the mouths of seabirds, turtles, marine mammals and other already-threatened ocean life. Death or some degree of morbidity ensues.

How can this problem be averted or at least mitigated? A top-down approach, directed at waste management, ocean dumping, etc.? Or a bottom-up attack, looking at plastic-use in products, or even eco-friendly polymers? What do you guys think?

Maybe the solution is using paper bag or bring your own shopping bag.

Water Pollution

Water pollution is largely caused by human activity and has had a major impact on our local waterways and their ability to be healthy and function naturally.

Water pollution comes from two sources - point sources or diffuse sources:

• Point source pollution is any pollution that originates from a single location. It is often associated with intensive production activities including farming, manufacturing and service sectors such as sewage treatment plants, on-site sewage management systems, industrial activities and discharges from urban stormwater drains. Point sources are largely regulated through the Protection of the Environment Operations Act, 1997. The Act permits Council and the NSW Department of Environment and Conservation to regulate various polluting issues, including issuing clean up or prevention notices. Nonetheless, point sources can discharge a variety of pollutants to aquatic environments and have the potential to cause severe long-term impacts.

• Diffuse sources are generated mainly by run-off after rain, which collects pollutants from across a wide area. Diffuse sources in urban areas include roads, industrial and commercial premises, parks, gardens and households. Stormwater typically contains litter, nutrients, bacteria, pathogens pesticides, heavy metals, sediment, oils, grease and other pollutants. In rural areas diffuse sources include agricultural activities, such as cropping, irrigation, livestock grazing and intensive livestock industries as well as unsealed roads. Rural run-off can increase the levels of sediment, nutrients, pesticides and chemicals in waterways.

The ability of these pollutant sources to cause a decline in water quality depends on the amount of vegetation cover, intensity of land use and the loss of vegetation along creek banks. All of these factors effect the ability of our waterways to cope with increased nutrients, sediment and changes in flows which causes changes to the health of the waterways through decline in water quality, native plant and animals.

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Air Pollution

Air Pollution is the human introduction into the atmosphere of chemicals, particulates, or biological materials that cause harm or discomfort to humans or other living organisms, or damage the environment.[1] Air pollution causes deaths[2] and respiratory disease.[3] Air pollution is often identified with major stationary sources, but the greatest source of emissions is actually mobile sources, mainly automobiles.[4] Gases such as carbon dioxide, which contribute to global warming, have recently gained recognition as pollutants by climate scientists, while they also recognize that carbon dioxide is essential for plant life through photosynthesis.

The atmosphere is a complex, dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems.

There are many substances in the air which may impair the health of plants and animals (including humans), or reduce visibility. These arise both from natural processes and human activity. Substances not naturally found in the air or at greater concentrations or in different locations from usual are referred to as pollutants.

Pollutants can be classified as either primary or secondary. Primary pollutants are substances directly emitted from a process, such as ash from a volcanic eruption or the carbon monoxide gas from a motor vehicle exhaust.

Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone - one of the many secondary pollutants that make up photochemical smog.

Note that some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants.

Major primary pollutants produced by human activity include:

• Sulfur oxides (SOx) especially sulfur dioxide are emitted from burning of coal and oil.

• Nitrogen oxides (NOx) especially nitrogen dioxide are emitted from high temperature combustion. Can be seen as the brown haze dome above or plume downwind of cities.

• Carbon monoxide is colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.

• Carbon dioxide (CO2), a greenhouse gas emitted from combustion.

• Volatile organic compounds (VOC), such as hydrocarbon fuel vapors and solvents.

• Particulate matter (PM), measured as smoke and dust. PM10 is the fraction of suspended particles 10 micrometers in diameter and smaller that will enter the nasal cavity. PM2.5 has a maximum particle size of 2.5 µm and will enter the bronchies and lungs.

• Toxic metals, such as lead, cadmium and copper.

• Chlorofluorocarbons (CFCs), harmful to the ozone layer emitted from products currently banned from use.

• Ammonia (NH3) emitted from agricultural processes.

• Odors, such as from garbage, sewage, and industrial processes

• Radioactive pollutants produced by nuclear explosions and war explosives, and natural processes such as radon.

Secondary pollutants include:

• Particulate matter formed from gaseous primary pollutants and compounds in photochemical smog, such as nitrogen dioxide.

• Ground level ozone (O3) formed from NOx and VOCs.

• Peroxyacetyl nitrate (PAN) similarly formed from NOx and VOCs.

Minor air pollutants include:

• A large number of minor hazardous air pollutants. Some of these are regulated in USA under the Clean Air Act and in Europe under the Air Framework Directive.

• A variety of persistent organic pollutants, which can attach to particulate matter.

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Evolution on Earth

The history of the Earth's atmosphere prior to one billion years ago is poorly understood and an active area of scientific research. The following discussion presents a plausible scenario.

The modern atmosphere is sometimes referred to as Earth's "third atmosphere", in order to distinguish the current chemical composition from two notably different previous compositions. The original atmosphere was primarily helium and hydrogen. Heat from the still-molten crust, and the sun, plus a probably enhanced solar wind, dissipated this atmosphere.

About 4.4 billion years ago, the surface had cooled enough to form a crust, still heavily populated with volcanoes which released steam, carbon dioxide, and ammonia. This led to the early "second atmosphere", which was primarily carbon dioxide and water vapor, with some nitrogen but virtually no oxygen. This second atmosphere had approximately 100 times as much gas as the current atmosphere, but as it cooled much of the carbon dioxide was dissolved in the seas and precipitated out as carbonates. The later "second atmosphere" contained largely nitrogen and carbon dioxide. However, simulations run at the University of Waterloo and University of Colorado in 2005 suggest that it may have had up to 40% hydrogen.[7] It is generally believed that the greenhouse effect, caused by high levels of carbon dioxide and methane, kept the Earth from freezing.

One of the earliest types of bacteria was the cyanobacteria. Fossil evidence indicates that bacteria shaped like these existed approximately 3.3 billion years ago and were the first oxygen-producing evolving phototropic organisms. They were responsible for the initial conversion of the earth's atmosphere from an anoxic state to an oxic state (that is, from a state without oxygen to a state with oxygen) during the period 2.7 to 2.2 billion years ago. Being the first to carry out oxygenic photosynthesis, they were able to produce oxygen while sequestering carbon dioxide in organic molecules, playing a major role in oxygenating the atmosphere.

Photosynthesising plants would later evolve and continue releasing oxygen and sequestering carbon dioxide. Over time, excess carbon became locked in fossil fuels, sedimentary rocks (notably limestone), and animal shells. As oxygen was released, it reacted with ammonia to release nitrogen; in addition, bacteria would also convert ammonia into nitrogen. But most of the nitrogen currently present in the atmosphere results from sunlight-powered photolysis of ammonia released steadily over the aeons from volcanoes.

As more plants appeared, the levels of oxygen increased significantly, while carbon dioxide levels dropped. At first the oxygen combined with various elements (such as iron), but eventually oxygen accumulated in the atmosphere, resulting in mass extinctions and further evolution. With the appearance of an ozone layer (ozone is an allotrope of oxygen) lifeforms were better protected from ultraviolet radiation. This oxygen-nitrogen atmosphere is the "third atmosphere". 200 – 250 million years ago, up to 35% of the atmosphere was oxygen (as found in bubbles of ancient atmosphere were found in an amber).

This modern atmosphere has a composition which is enforced by oceanic blue-green algae as well as geological processes. O2 does not remain naturally free in an atmosphere, but tends to be consumed (by inorganic chemical reactions, and by animals, bacteria, and even land plants at night), and CO2 tends to be produced by respiration and decomposition and oxidation of organic matter. Oxygen would vanish within a few million years due to chemical reactions and CO2 dissolves easily in water and would be gone in millennia if not replaced. Both are maintained by biological productivity and geological forces seemingly working hand-in-hand to maintain reasonably steady levels over millions of years (see Gaia theory).

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Aerosol

An aerosol is a collection of microscopic particles, solid or liquid, suspended in a gas.

In the context of air pollution, an aersol refers to fine particulat matter (Sum of all microscopic solid and liquid particles, of human and natural origin, that remain suspended in a medium such as air for some time. These particles vary greatly in size, composition, and origin, and may be harmful.Particulate matter may be in the form of fly ash, soot, dust, fog, fumes etc.), that is larger than a molecule, but small enough to remain suspended in the atmosphere

for at least several hours.

The term aerosol is also commonly used for a pressurized container (aerosol can) which is designed to release a fine spray of a material such as paint. It has also come to be associated, erroneously, with the gas (propellant) used to expel materials from an aerosol can.

Natural sources of aerosols include salt particles from sea spray, dust and clay particles from the weathering of rocks. Aerosols can also originate as a result of human activities and are often considered pollutants.

Aerosols play an important role in the atmosphere namely in the condensation of water droplets and ice crystals, various chemical cycles, and the absorption of solar radiation.

Source: based on EPA Glossary of Climate Change and GreenFacts

Greenhouse gas

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth’s surface, the atmosphere and clouds.

This property causes the greenhouse effect.

Water vapour (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH₄), and ozone (O3) are the primary greenhouse gases in the Earth’s atmosphere. Moreover there are a number of entirely human-made greenhouse gases in the atmosphere, such as the halocarbons and other chlorine and bromine containing substances, dealt with under the Montreal Protocol. Beside CO2, N2O and CH₄, the Kyoto Protocol deals with the greenhouse gases sulphur hexafluoride (SF₆), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs).

What makes the climate change?

The Earth’s climate is influenced by many factors, such as the amount of greenhouse gases and aerosols in the atmosphere, the amount of energy coming from the sun or the properties the Earth’s surface. Changes in those factors, through human-related or natural processes, have a warming or a cooling effect on the planet because they alter how much of this solar energy is retained or reflected back to space.

The concentrations in the atmosphere of greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) have all increased markedly since 1750, and now exceed by far their pre-industrial levels.

Carbon dioxide is the most important anthropogenic greenhouse gas. Its concentration in the atmosphere (379 ppm in 2005) is now far higher than the natural range over the last 650 000 years (180 to 300 ppm) and is growing faster than ever since the beginning of its continuous direct measurement in 1960, mainly due to fossil fuel use and to a lesser extent to land use change. For instance, emissions of carbon dioxide from fossil fuel use increased from 6.4 Gt per year in the 90s to 7.2 Gt of carbon per year over the period 2000-2005. Concentrations of methane and nitrous oxide in the atmosphere have also greatly increased since pre-industrial times, and those increases are mostly due to human activities such as agriculture and fossil fuel use.

The effect on climate of each of the different drivers is expressed in terms of “radiative forcing”, with positive forcing causing a warming of the surface and negative forcing a cooling of it. The overall effect of human activities since 1750 is very likely (> 90% certainty) to be one of warming, with an estimated increase of energy, or radiative forcing, of 1.6 Watt per square meter over the whole planet. The relative contribution of various factors can be seen in figure 2. The main warming drivers are the various greenhouse gases and it is likely that the warming that they cause has been increasing during the industrial era at a higher rate than at any time over the last 10 000 years. The main cooling drivers are aerosols and the changes in cloud cover that they cause.

Sea level rise

Sea level rise

With increasing average global temperature, the water in the oceans expands in volume, and additional water enters them which had previously been locked up on land in glaciers, for example, the Greenland and the Antarctic ice sheets. An increase of 1.5 to 4.5 °C is estimated to lead to an increase of 15 to 95 cm (IPCC 2001).

The sea level has risen more than 120 metres since the peak of the last ice age about 18,000 years ago. The bulk of that occurred before 6000 years ago. From 3000 years ago to the start of the 19th century, sea level was almost constant, rising at 0.1 to 0.2 mm/yr; since 1900, the level has risen at an average of 1.7 mm/yr; since 1993, satellite altimetry from TOPEX/Poseidon indicates a rate of about 3 mm/yr.

In a paper published 18th May 2007, the climatologist, James Hansen presented new evidence. George Monbiot, a British journalist, summarises his findings as follows:

"The IPCC predicts that sea levels could rise by as much as 59 cm this century. Hansen’s paper argues that the slow melting of ice sheets the panel expects doesn’t fit the data. The geological record suggests that ice at the poles does not melt in a gradual and linear fashion, but flips suddenly from one state to another. When temperatures increased to 2-3 degrees above today’s level 3.5 million years ago, sea levels rose not by 59 centimetres but by 25 metres. The ice responded immediately to changes in temperature.