Effects of global warming on India

Lakshadweep, comprising tiny low-lying islands, are at risk of being inundated by sea level rises associated with global warming.

The effects of global warming on the Indian subcontinent vary from the submergence of low-lying islands and coastal lands to the melting of glaciers in the Indian Himalayas, threatening the volumetric flow rate of many of the most important rivers of India and South Asia. In India, such effects are projected to impact millions of lives. As a result of ongoing climate change, the climate of India has become increasingly volatile over the past several decades; this trend is expected to continue.

Greenhouse gases in India

Elevated carbon dioxide emissions contributed to the greenhouse effect, causing warmer weather that lasted long after the atmospheric shroud of dust and aerosols had cleared. Further climatic changes 20 million years ago, long after India had crashed into the Laurasian landmass, were severe enough to cause the extinction of many endemic Indian forms. The formation of the Himalayas resulted in blockage of frigid Central Asian air, preventing it from reaching India; this made its climate significantly warmer and more tropical in character than it would otherwise have been.

Effects of global warming on India and Bangladesh

Several effects of global warming, including steady sea level rise, increased cyclonic activity, and changes in ambient temperature and precipitation patterns, have affected or are projected to affect India. Ongoing sea level rises have submerged several low-lying islands in the Sundarbans, displacing thousands of people. Temperature rises on the Tibetan Plateau, which are causing Himalayan glaciers to retreat.

Environmental

Increased landslides and flooding are projected to have an impact upon states such as Assam. Ecological disasters, such as a 1998 coral bleaching event that killed off more than 70% of corals in the reef ecosystems off Lakshadweep and the Andamans, and was brought on by elevated ocean temperatures tied to global warming, are also projected to become increasingly common.

The first among the countries to be affected by severe climate change is Bangladesh. Its sea level, temperature and evaporation are increasing, and the changes in precipitation and cross boundary river flows are already beginning to cause drainage congestion. There is a reduction in fresh water availability, disturbance of morphologic processes and a higher intensity of flooding and other such disasters. In comparison to the United States, Bangladesh only contributes 0.1% of the world’s emissions yet it has 2.4% of the world’s population. In contrast the the United States makes up about 5 percent of the world's population, yet they produce approximately 25 percent of the pollution that causes global warming.

Economic

The Indira Gandhi Institute of Development Research has reported that, if the predictions relating to global warming made by the Intergovernmental Panel on Climate Change come to fruition, climate-related factors could cause India's GDP to decline by up to 9%; contributing to this would be shifting growing seasons for major crops such as rice, production of which could fall by 40%. Around seven million people are projected to be displaced due to, among other factors, submersion of parts of Mumbai and Chennai, if global temperatures were to rise by a mere 2 °C (3.6 °F).

Villagers in India's North Easter state of Meghalaya are also concerned that rising sea levels will submerge neighbouring low-lying Bangladesh, resulting in an influx of refugees into Meghalaya—which has few resources to handle such a situation.

If severe climate changes occur, Bangladesh will lose land along the coast line. This will be highly damaging to Bangalies especially because nearly two-thirds of Bangladeshis are employed in the agriculture sector, with rice as the single-most-important product. The economy has grown 5-6% over the past few years despite inefficient state-owned enterprises, delays in exploiting natural gas resources insufficient power supplies, and slow implementation of economic reforms. However, Bangladesh remains a poor, overpopulated, and inefficiently-governed nation. If no further steps are taken to improve the current conditions global warming will effect the economy severely worsening the present issues further.

Past climate change
Thick haze and smoke along the Ganges River in northern India.

However, such shifts are not new: for example, earlier in the current Holocene epoch (4,800–6,300 years ago), parts of what is now the Thar Desert were wet enough to support perennial lakes; researchers have proposed that this was due to much higher winter precipitation, which coincided with stronger monsoons. Similarly, Kashmir, which once had a warm subtropical climate, shifted to a substantially colder temperate climate 2.6–3.7 mya; it was then repeatedly subjected to extended cold spells starting 600,000 years ago.

Pollution

Thick haze and smoke, originating from burning biomass in northwestern India and air pollution from large industrial cities in northern India, often concentrate inside the Ganges Basin. Prevailing westerlies carry aerosols along the southern margins of the steep-faced Tibetan Plateau to eastern India and the Bay of Bengal. Dust and black carbon, which are blown towards higher altitudes by winds at the southern faces of the Himalayas, can absorb shortwave radiation and heat the air over the Tibetan Plateau. The net atmospheric heating due to aerosol absorption causes the air to warm and convect upwards, increasing the concentration of moisture in the mid-troposphere and providing positive feedback that stimulates further heating of aerosols.

Awareness

Tribal people in India's remote northeast plan to honour former U.S. Vice President Al Gore with an award for promoting awareness on climate change that they say will have a devastating impact on their homeland.

Meghalaya -- meaning 'Abode of the Clouds' in Hindi -- is home to the towns of Cherrapunji and Mawsynram, which are credited with being the wettest places in the world due to their high rainfall.

But scientists state that global climate change is causing these areas to experience an increasingly sparse and erratic rainfall pattern and a lengthened dry season, affecting the livelihoods of thousands of villagers who cultivate paddy and maize. Some areas are also facing water shortages.

El Niño and La Niña

El Niño is a weather event involving the eastward migration of a mass of warm water normally found in the western equatorial Pacific Ocean.

Periodically (usually every three to seven years), the easterly trade winds in the Pacific weaken and allow the pool of warm water to drift from Australia to the western coast of South America, often triggering heavy rains there.


This vast pool of warm water is thought to set off a chain reaction that can affect jet stream and weather patterns around the world, especially in the winter months in the northern hemisphere. El Niño is sometimes referred to as ENSO for El Niño–Southern Oscillation. The Southern Oscillation is a seesaw of air pressures on the eastern and western halves of the Pacific.

La Niña is essentially the opposite of El Niño. La Nina is a migrating pool of cooler-than-usual ocean water. The cool water can suppress rain-producing clouds, which leads to dry conditions.

Peruvian fishermen first noticed the effects of a new El Niño at Christmas ime, when storminess off the coast reduced the supply of fish. "El Niño" is Spanish for "the boy child," and is used to refer to the Baby Jesus. The name La Niña ("the girl child") was coined to deliberately represent the opposite of El Niño.

Because even the most dedicated scientists do not thoroughly understand El Niño and La Niña (we do not know, for instance, why the trade winds suddenly die down and allow the warm water pool to move eastward), we can only describe certain tendencies in the weather.

In the past, El Niño has often brought heavy rains to southern California and to a portion of the South from Atlanta to Cape Hatteras; it can bring relatively mild winter temperatures to the northern third of the country. However, these effects are not consistent in every El Niño event on record.

The stronger the La Niña, the more severe the droughts. Tha La Niña in 2009 is creating severe drought in much of the world, causing an agricultural crisis.


El Niño

The data from TOPEX/Poseidon, and in the future Jason-1, helps us study and understand the complex interactions between the oceans and the atmosphere which affect global weather and climate events. One well-known example of this interaction is an El Niño event.

El Niño was named by people who fish off the western coast of central America to refer to the warm current that invades their coastal waters around Christmastime. El Niño events disrupt fisheries and bring severe weather events worldwide.

In a normal year, the trade winds blow westward and push warm surface water near Australia and New Guinea. When warm water builds up in the western Pacific Ocean, nutrient-rich cold water comes up off the west coast of South America and fosters the growth of the fish population.


During an El Niño event, the trade winds weaken and warm, nutrient-poor water occupies the entire tropical Pacific Ocean. Heavy rains that are tied to the warm water move into the central Pacific Ocean and cause drought in Indonesia and Australia. This also alters the path of the atmospheric jet stream over North and South America.

The effects of El Niño disrupt normal winter conditions throughout the Pacific Ocean, and can persist into May or June. Reliable predictions of an El Niño occurrence will lead to better preparation for its widespread impact.

La Niña

Warm El Niños and cold La Niñas follow each other against the backdrop of the ocean seasons. During a La Niña, the trade winds are stronger and cold, nutrient-rich water occupies much of the tropical Pacific Ocean. Most of the precipication occurs in the western tropical Pacific Ocean, so rain is abundant over Indonesia.

Excess Rain in Monsoon

Most scientists agree that global warming presents the greatest threat to the environment.

There is little doubt that the Earth is heating up. In the last century the average temperature has climbed about 0.6 degrees Celsius (about 1 degree Fahrenheit) around the world.

From the melting of the ice cap on Mount Kilimanjaro, Africa's tallest peak, to the loss of coral reefs as oceans become warmer, the effects of global warming are often clear.

However, the biggest danger, many experts warn, is that global warming will cause sea levels to rise dramatically. Thermal expansion has already raised the oceans 4 to 8 inches (10 to 20 centimeters). But that's nothing compared to what would happen if, for example, Greenland's massive ice sheet were to melt.

"The consequences would be catastrophic," said Jonathan Overpeck, director of the Institute for the Study of Planet Earth at the University of Arizona in Tucson. "Even with a small sea level rise, we're going to destroy whole nations and their cultures that have existed for thousands of years."

Overpeck and his colleagues have used computer models to create a series of maps that show how susceptible coastal cities and island countries are to the sea rising at different levels. The maps show that a 1-meter (3-foot) rise would swamp cities all along the U.S. eastern seaboard. A 6-meter (20-foot) sea level rise would submerge a large part of Florida.

Uncertainties

Just as the evidence is irrefutable that temperatures have risen in the last century, it's also well established that carbon dioxide in the Earth's atmosphere has increased about 30 percent, enhancing the atmosphere's ability to trap heat.
The exact link, if any, between the increase in carbon dioxide emissions and the higher temperatures is still under debate.

Most scientists believe that humans, by burning fossil fuels such as coal and petroleum, are largely to blame for the increase in carbon dioxide. But some scientists also point to natural causes, such as volcanic activity.
"Many uncertainties surround global warming," said Ronald Stouffer at the U.S. National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey. "How much of it would still occur if humans were not modifying the climate in any way?"

The current rate of warning is unprecedented, however. It is apparently the fastest warming rate in millions of years, suggesting it probably is not a natural occurrence. And most scientists believe the rise in temperatures will in fact accelerate. The United Nations-sponsored Intergovernmental Panel on Climate Change reported in 2001 that the average temperature is likely to increase by between 1.4 and 5.8 degrees Celsius (2.5 and 10.4 degrees Fahrenheit) by the year 2100.

INDONESIA Tsunami After and Before photos collection

Very Tragetic images of Tsunami in Indonesia
































Earthquake characteristics

Epicentre of the earthquake, just north of Simeulue IslandThe earthquake was initially reported as moment magnitude 9.0. In February 2005 scientists revised the estimate of the magnitude to 9.3. Although the Pacific Tsunami Warning Center has accepted these new numbers, the United States Geological Survey has so far not changed its estimate of 9.1. The most recent studies in 2006 have obtained a magnitude of Mw 9.1 to 9.3. Dr. Hiroo Kanamori of the California Institute of Technology believes that Mw = 9.2 is a good representative value for the size of this great earthquake.

The hypocentre of the main earthquake was at 3°18′58″N 95°51′14″E / 3.316°N 95.854°E / 3.316; 95.854, approximately 160 km (100 mi), in the Indian Ocean just north of Simeulue island, off the western coast of northern Sumatra, at a depth of 30 km (19 mi) below mean sea level (initially reported as 10 km). The northern section of the Sunda megathrust, which at the time was assumed to be dormant ruptured, the rupture having a length of 1600 km. The size of the rupture caused plate shifting of up to 20 m, causing the earthquake (followed by the tsunami) to be felt simultaneously as far away as Bangladesh, India, Malaysia, Myanmar, Thailand, Singapore and the Maldives. Splay faults or secondary "pop up faults" caused long narrow parts of the sea floor to pop up in seconds elevating the height and increased the speed of waves to cause the complete destruction of the nearby Indonesian town of Lhoknga.

Indonesia lies between the Pacific Ring of Fire along the north-eastern islands adjacent to and including New Guinea and the Alpide belt along the south and west from Sumatra, Java, Bali, Flores, and Timor.

Great earthquakes such as the Sumatra-Andaman event, which are invariably associated with megathrust events in subduction zones, have seismic moments that can account for a significant fraction of the global earthquake moment across century-scale time periods. The Sumatra-Andaman earthquake was the largest earthquake since 1964, and the second largest since the Kamchatka earthquake of October 16, 1737.


Graphic of largest earthquakes 1906-2005Of all the seismic moment released by earthquakes in the 100 years from 1906 through 2005, roughly one-eighth was due to the Sumatra-Andaman event. This quake, together with the Good Friday Earthquake (Alaska, 1964) and the Great Chilean Earthquake (1960), account for almost half of the total moment. The much smaller but still catastrophic 1906 San Francisco earthquake is included in the diagram at right for perspective. Mw denotes the magnitude of an earthquake on the moment magnitude scale.

Since 1900 the only earthquakes recorded with a greater magnitude were the 1960 Great Chilean Earthquake (magnitude 9.5) and the 1964 Good Friday Earthquake in Prince William Sound (9.2). The only other recorded earthquake of magnitude 9.0 or greater was off Kamchatka, Russia, on November 4, 1952 (magnitude 9.0). Each of these megathrust earthquakes also spawned tsunamis in the Pacific Ocean, but the death toll from these was significantly lower. The worst of these caused only a few thousand deaths, primarily because of the lower population density along the coasts near affected areas and the much greater distances to more populated coasts.

Other very large megathrust earthquakes occurred in 1868 (Peru, Nazca Plate and South American Plate); 1827 (Colombia, Nazca Plate and South American Plate); 1812 (Venezuela, Caribbean Plate and South American Plate) and 1700 (Cascadia Earthquake, western U.S. and Canada, Juan de Fuca Plate and North American Plate). These are all believed to have been of greater than magnitude 9, but no accurate measurements were available at the time.


Energy released by the earthquake

The energy released on the Earth's surface only, MEwhich is the seismic potential for damage, by the 2004 Indian Ocean earthquake and tsunami was estimated at 1.1×1017 joules or 26.3 megatons of TNT. This energy is equivalent to over 1502 times that of the Hiroshima atomic bomb, but less than that of Tsar Bomba, the largest nuclear weapon ever detonated. However, this is but a tiny fraction of the total work done MW (and thus energy) by this quake, 4.0×1029 ergs (40 ZJ), the vast majority underground. This equates to 4.0×1022 J, over 363 thousand times more than its ME. This is a truly enormous figure, equivalent to 9,560 gigatons of TNT equivalent (550 million times that of Hiroshima), or about 370 years of energy use in the United States at 2005 levels of 1.08×1020 J.

The only recorded earthquakes with a larger MW were the 1960 Chilean and 1964 Alaskan quakes, with 2.5×1030 ergs (250 ZJ) and 7.5×1029 ergs (75 ZJ) respectively. Please see USGS:Measuring the size of earthquakes.

The earthquake generated seismic oscillation of the Earth's surface of up to 20–30 cm (8–12 in), equivalent to the effect of the tidal forces caused by the Sun and Moon. The shock waves of the earthquake were felt across the planet; as far away as the U.S. state of Oklahoma, where vertical movements of 3 mm (0.12 in) were recorded.

Because of its enormous energy release and shallow rupture depth, the earthquake generated remarkable seismic ground motions around the globe, particularly due to huge Rayleigh (surface) elastic waves that exceeded 1 cm in vertical amplitude everywhere on Earth. The record section plot below displays vertical displacements of the Earth's surface recorded by seismometers from the IRIS/USGS Global Seismographic Network plotted with respect to time (since the earthquake initiation) on the horizontal axis, and vertical displacements of the Earth on the vertical axis (note the 1 cm scale bar at the bottom for scale). The seismograms are arranged vertically by distance from the epicenter in degrees. The earliest, lower amplitude, signal is that of the compressional (P) wave, which takes about 22 minutes to reach the other side of the planet (the antipode; in this case near Ecuador). The largest amplitude signals are seismic surface waves that reach the antipode after about 100 minutes. The surface waves can be clearly seen to reinforce near the antipode (with the closest seismic stations in Ecuador), and to subsequently encircle the planet to return to the epicentral region after about 200 minutes. A major aftershock (magnitude 7.1) can be seen at the closest stations starting just after the 200 minute mark. This aftershock would be considered a major earthquake under ordinary circumstances, but is dwarfed by the mainshock.


Vertical-component ground motions recorded by the IRIS/USGS Global Seismographic NetworkThe shift of mass and the massive release of energy very slightly altered the Earth's rotation. The exact amount is not yet known, but theoretical models suggest the earthquake shortened the length of a day by 2.68 microseconds, due to a decrease in the oblateness of the Earth. It also caused the Earth to minutely "wobble" on its axis by up to 2.5 cm (1 in) in the direction of 145° east longitude, or perhaps by up to 5 or 6 cm (2.0 to 2.4 in). However, because of tidal effects of the Moon, the length of a day increases at an average of 15 µs per year, so any rotational change due to the earthquake will be lost quickly. Similarly, the natural Chandler wobble of the Earth, which in some cases can be up to 15 m (50 ft), will eventually offset the minor wobble produced by the earthquake.

More spectacularly, there was 10 m (33 ft) movement laterally and 4–5 m (13–16 ft) vertically along the fault line. Early speculation was that some of the smaller islands south-west of Sumatra, which is on the Burma Plate (the southern regions are on the Sunda Plate), might have moved south-west by up to 36 m (118 ft), but more accurate data released more than a month after the earthquake found the movement to be about 20 cm (7.9 in). Since movement was vertical as well as lateral, some coastal areas may have been moved to below sea level. The Andaman and Nicobar Islands appear to have shifted south-west by around 1.25 m (4.1 ft) and to have sunk by 1 m (3.28 ft).

In February 2005, the Royal Navy vessel HMS Scott surveyed the seabed around the earthquake zone, which varies in depth between 1,000 m and 5,000 m (3,300 ft and 16,500 ft). The survey, conducted using a high-resolution, multi-beam sonar system, revealed that the earthquake had made a huge impact on the topography of the seabed. 1,500-meter (5,000 ft) high thrust ridges created by previous geologic activity along the fault had collapsed, generating landslides several kilometers wide. One such landslide consisted of a single block of rock some 100 m high and 2 km long (300 ft by 1.25 mi). The momentum of the water displaced by tectonic uplift had also dragged massive slabs of rock, each weighing millions of tons, as far as 10 km (7 mi) across the seabed. An oceanic trench several kilometres wide was exposed in the earthquake zone.

The TOPEX/Poseidon and Jason satellites happened to pass over the tsunami as it was crossing the ocean. These satellites carry radars that measure precisely the height of the water surface; anomalies of the order of 50 cm (20 in) were measured. Measurements from these satellites may prove invaluable for the understanding of the earthquake and tsunami. Unlike data from tide gauges installed on shores, measurements obtained in the middle of the ocean can be used for computing the parameters of the source earthquake without having to compensate for the complex ways in which close proximity to the coast changes the size and shape of a wave.


Tsunami characteristics

Animation of the tsunami caused by the earthquake showing how the tsunami radiated from the entire length of the 1,600 km (994 mi) rupture.The sudden vertical rise of the seabed by several metres during the earthquake displaced massive volumes of water, resulting in a tsunami that struck the coasts of the Indian Ocean. A tsunami which causes damage far away from its source is sometimes called a teletsunami and is much more likely to be produced by vertical motion of the seabed than by horizontal motion.

The tsunami, like all others, behaved very differently in deep water than in shallow water. In deep ocean water, tsunami waves form only a small hump, barely noticeable and harmless, which generally travels at a very high speed of 500 to 1,000 km/h (310 to 620 mph); in shallow water near coastlines, a tsunami slows down to only tens of kilometres an hour but in doing so forms large destructive waves. Scientists investigating the damage in Aceh found evidence that the wave reached a height of 24 m when coming ashore along large stretches of the coastline, rising to 30 m (100 ft) in some areas when travelling inland.

Radar satellites recorded the heights of tsunami waves in deep water: at two hours after the earthquake, the maximum height was 60 cm (2 ft). These are the first such observations ever made. Unfortunately these observations could not be used to provide a warning, since the satellites were not built for that purpose and the data took hours to analyze.

According to Tad Murty, vice-president of the Tsunami Society, the total energy of the tsunami waves was equivalent to about five megatons of TNT (20 petajoules). This is more than twice the total explosive energy used during all of World War II (including the two atomic bombs), but still a couple of orders of magnitude less than the energy released in the earthquake itself. In many places the waves reached as far as 2 km (1.24 mi) inland.

Because the 1,600 km (994 mi) fault affected by the earthquake was in a nearly north-south orientation, the greatest strength of the tsunami waves was in an east-west direction. Bangladesh, which lies at the northern end of the Bay of Bengal, had very few casualties despite being a low-lying country relatively near the epicenter. It also benefited from the fact that the earthquake proceeded more slowly in the northern rupture zone, greatly reducing the energy of the water displacements in that region.

Coasts that have a landmass between them and the tsunami's location of origin are usually safe; however, tsunami waves can sometimes diffract around such landmasses. Thus, the Indian state of Kerala was hit by the tsunami despite being on the western coast of India, and the western coast of Sri Lanka also suffered substantial impacts. Also distance alone was no guarantee of safety; Somalia was hit harder than Bangladesh despite being much farther away.

Because of the distances involved, the tsunami took anywhere from fifteen minutes to seven hours (for Somalia) to reach the various coastlines. The northern regions of the Indonesian island of Sumatra were hit very quickly, while Sri Lanka and the east coast of India were hit roughly 90 minutes to two hours later. Thailand was also struck about two hours later despite being closer to the epicentre, because the tsunami travelled more slowly in the shallow Andaman Sea off its western coast.

The tsunami was noticed as far as Struisbaai in South Africa, some 8,500 km (5,300 mi) away, where a 1.5 m (5 ft) high tide surged on shore about 16 hours after the earthquake. It took a relatively long time to reach this spot at the southernmost point of Africa, probably because of the broad continental shelf off South Africa and because the tsunami would have followed the South African coast from east to west. The tsunami also reached Antarctica, where tidal gauges at Japan's Showa Base recorded oscillations of up to a metre, with disturbances lasting a couple of days.

Some of the tsunami's energy escaped into the Pacific Ocean, where it produced small but measurable tsunamis along the western coasts of North and South America, typically around 20 to 40 cm (7.9 to 15.7 in). At Manzanillo, Mexico, a 2.6 m (8.5 ft) crest-to-trough tsunami was measured. As well, the tsunami was large enough to be detected in Vancouver, British Columbia, Canada. This puzzled many scientists, as the tsunamis measured in some parts of South America were larger than those measured in some parts of the Indian Ocean. It has been theorized that the tsunamis were focused and directed at long ranges by the mid-ocean ridges which run along the margins of the continental plates.

Environment Pollution

Pollution became a popular issue after WW2, when the aftermath of atomic warfare and testing made evident the perils of radioactive fallout. Then a conventional catastrophic event The Great Smog of 1952 in London killed at least 8000 people. This massive event prompted some of the first major modern environmental legislation, The Clean Air Act of 1956.

Pollution began to draw major public attention in the United States between the mid-1950s and early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean Water Act and the National Environmental Policy Act.

Bad bouts of local pollution helped increase consciousness. PCB dumping in the Hudson River resulted in a ban by the EPA on consumption of its fish in 1974. Long-term dioxin contamination at Love Canal starting in 1947 became a national news story in 1978 and led to the Superfund legislation of 1980. Legal proceedings in the 1990s helped bring to light Chromium-6 releases in California--the champions of whose victims became famous. The pollution of industrial land gave rise to the name brownfield, a term now common in city planning. DDT was banned in most of the developed world after the publication of Rachel Carson's Silent Spring.

The development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds of thousands of years. Lake Karachay, named by the Worldwatch Institute as the "most polluted spot" on earth, served as a disposal site for the Soviet Union thoroughout the 1950s and 1960s. Second place may go to the to the area of Chelyabinsk U.S.S.R. (see reference below) as the "Most polluted place on the planet".

Nuclear weapons continued to be tested in the Cold War, sometimes near inhabited areas, especially in the earlier stages of their development. The toll on the worst-affected populations and the growth since then in understanding about the critical threat to human health posed by radioactivity has also been a prohibitive complication associated with nuclear power. Though extreme care is practiced in that industry, the potential for disaster suggested by incidents such as those at Three Mile Island and Chernobyl pose a lingering specter of public mistrust. One legacy of nuclear testing before most forms were banned has been significantly raised levels of background radiation.

International catastrophes such as the wreck of the Amoco Cadiz oil tanker off the coast of Brittany in 1978 and the Bhopal disaster in 1984 have demonstrated the universality of such events and the scale on which efforts to address them needed to engage. The borderless nature of atmosphere and oceans inevitably resulted in the implication of pollution on a planetary level with the issue of global warming. Most recently the term persistent organic pollutant (POP) has come to describe a group of chemicals such as PBDEs and PFCs among others. Though their effects remain somewhat less well understood owing to a lack of experimental data, they have been detected in various ecological habitats far removed from industrial activity such as the Arctic, demonstrating diffusion and bioaccumulation after only a relatively brief period of widespread use.

Growing evidence of local and global pollution and an increasingly informed public over time have given rise to environmentalism and the environmental movement, which generally seek to limit human impact on the environment.

Effects of Global Warming

Climate changes characterized as global warming are leading to large-scale irreversible effects at continental and global scales. The likelihood and magnitude of the effects are observed and predicted to be increasing and accelerating.

Many consequences of global warming once controversial or thought to be unlikely are now being observed. Arctic shrinkage and Arctic methane release, alongside 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 are accelerating, leading to expectations of runaway climate change.

The probability of warming having unforeseen consequences increases with the rate, magnitude, and duration of climate change. Additionally, the United States National Academy of Sciences has stated, "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."

The IPCC reports that the effects of global warming will be mixed across regions. For smaller values of warming (of up to 3°C, or about 5°F), changes are expected to produce net benefits in some regions and for some activities, and net costs for others. Greater warming may produce net costs (or to reduce the benefits from smaller warming) in all regions. Developing countries are vulnerable to reduced economic growth as a result of warming.

Most of the consequences of global warming would result from physical changes: sea level rise, higher local temperatures, and changes in rainfall patterns. Sea level is expected to rise 18 to 59 cm (7.1 to 23.2 inches) by the end of the 21st century, not including the unknown contribution from non-linear changes to large ice sheets.

It has also been proposed that the melting in the Arctic may bring fresh water to the North Atlantic to disrupt the Gulf Stream, which may cause a destabilisation or shutdown of the Thermohaline circulation.

Will know the Global Warming

Hi All,

This is the serious time to tackle the global warming, but it seems no authorities, governments are considering it and they want only money.

So, we the members in this earth, gather for tackle this climate changes, so only our beloved next generation can live happily in this world as how we had. Its our duty to give them this world as a peaceful and opted place to make their lifestyle.


Thanks!