what is global warming in general sense

8/14/2019 What is GLOBAL WARMING in General Sense

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Group

Members

NameName:

Roll no.Anuja Desai 3

Komal Gupta 5

Divya Kabra 7

Nitin Aashiwal 14

Nasrulla Adamji 15


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Kunal Chehria 20

Ankit Jain 28

Pratik Kapadia 35Vikas Vyas 38

Neel Mehta 39

IndexSr.

No.Particulars Remar

s


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What is GLOBAL WARMING in general

sense? Global warming in general sense means a change

in the atmosphere. As the word itself suggests that

it is due to large amount of heat produced on the

earth surface which causes change in temperature.

Now the question to be asked is that is this

because of human or due to nature?

GLOBALWARMING
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Definitions of Global Warming :

1) Global warming is the increase in the average

temperature of the Earth's near-surface air and

oceans in recent decades and its projectedcontinuation.

2) According to World Web Dictionary An increase

in the averagetemperature of the earth's

atmosphere (especially a sustainedincrease that

causesclimaticchanges).

3) According to MSN Encarta-Dictionary global

warming meansincrease in the world's

temperatures, believed to be caused in part by the

greenhouse effect.

4) According to Merriam-Webster an increase in the

earth's atmospheric and oceanic temperatureswidely predicted to occur due to an increase in the

greenhouse effect resulting especially from

pollution.

Introduction:Global Warming was thought to be a new hot topic in the

science world, and for the most part this is true. The

concentrated research on "Global Warming" began after

the very hot and dry summer of 1988 in parts of the world
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(U.S., Europe, Asia). However scientists and

paleoclimatologists have been studying past climates and

the climate changes for over 100 years.

Global Warming is not only a meteorologicalissue. Oceanographers are concerned with the increaseof the sea surface height and glaciers. Economists areconcerned with change in crops and commodities causedby the warming. Environmentalists are concerned howplant and animals habitats may be altered from thewarming. Global Warming is also very much political.Treaties are developed to attempt to control the warming,

and global efforts are beginning to develop.

Global Warming is one of the mostcontroversial scientific issues of the twenty-first century.This is a problem that has serious economic, sociological,geopolitical, political, and personal implications.

A warmer Earth may lead to changes in rainfall

patterns, a rise in sea level, and a wide range of impactson plants, wildlife, and humans. When scientists talk aboutthe issue of climate change, their concern is about globalwarming caused by human activities. A warmer Earth maylead to changes in rainfall patterns, a rise in sea level, anda wide range of impacts on plants, wildlife, and humans.When scientists talk about the issue of climate change,their concern is about global warming caused by human

activities.

Three of the four methods of measuringglobaltemperature show no signs of global warming Proxymeasurements

(Tree rings, sediments etc) for the past 1000 years.

Weather balloons (radio sondes) for the past 44

years.


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Satellites (MSU Units) for the past 21 years.

The fourth method, surface measurement at weatherstations, gives an averaged mean global rise of a mere0.6C over 140 years, but is intermittent and irregular.Individual records are highly variable, regional, and

sometimes, particularly in remote areas, show no change,or even a fall in temperature. It is concluded thattemperature measurements carried out away from humaninfluence show no evidence of global warming.

Globe gettinghotter


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CAUSES OF GLOBAL

WARMING:

The Earth's climate changes in response toexternal forcing, including variations in its orbitaround the Sun (orbital forcing), volcanic eruptions,and atmospheric greenhouse gas concentrations.The detailed causes of the recent warming remainan active field of research, but the scientificconsensus is that the increase in atmospheric

greenhouse gases due to human activity causedmost of the warming observed since the start ofthe industrial era. One hypothesis proposes thatwarming may be the result of variations in solaractivity. None of the effects of forcing areinstantaneous. The thermal inertia of the Earth'soceans and slow responses of other indirect effectsmean that the Earth's current climate is not inequilibrium with the forcing imposed. Climatecommitment studies indicate that even ifgreenhouse gases were stabilized at 2000 levels, afurther warming of about 0.5 C (0.9 F) would stilloccur.

A warmer Earth may lead to changes in rainfall

patterns, a rise in sea level, and a wide range ofimpacts on plants, wildlife, and humans. When

scientists talk about the issue of climate change,

their concern is about global warming caused by

human activities.

1)Greenhouse Effect:
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The greenhouse effect was discovered by JosephFourierin 1824 and was first investigated quantitatively bySvante Arrhenius in 1896. It is the process by whichabsorption and emission ofinfrared radiation byatmospheric gases warm a planet's lower and surface. The

greenhouse effect is the rise in temperature that the Earthexperiences because certain gases in the atmosphere trap energyfrom the sun. Without these gases, heat would escape back intospace and Earths average temperature would be about 60Fcolder. Because of how they warm our world, these gases arereferred to as greenhouse gases.

A schematic representation of the exchanges of energy

between outer space, the Earth's atmosphere, and theEarth surface. The ability of the atmosphere to capture

and recycle energy emitted by the Earth surface is the

defining characteristic of the greenhouse effect

The greenhouse effect is important. Without the

greenhouse effect, the Earth would not be warm enough for

humans to live. But if the greenhouse effect becomes stronger, it

could make the Earth warmer than usual. Even a little extra

warming may cause problems for humans, plants, and animals.
http://en.wikipedia.org/wiki/Joseph_Fourierhttp://en.wikipedia.org/wiki/Joseph_Fourierhttp://en.wikipedia.org/wiki/Svante_Arrheniushttp://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation)http://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Planethttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Joseph_Fourierhttp://en.wikipedia.org/wiki/Joseph_Fourierhttp://en.wikipedia.org/wiki/Svante_Arrheniushttp://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation)http://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Planethttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Earth's_atmosphere


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2) Climate and Weather:

Weather:Weather describes whatever is happening outdoors in a

given place at a given time. Weather is what happens from

minute to minute. The weather can change a lot within a very

short time. For example, it may rain for an hour and then

become sunny and clear. Weather is what we hear about on the

television news every night. Weather includes daily changes in

precipitation, barometric pressure, temperature, and wind

conditions in a given location.

Climate :

Climate describes the total of all weather occurring over a period

of years in a given place. This includes average weather

conditions, regular weather sequences (like winter, spring,

summer), and special weather events (like tornadoes and floods).

Climate tells us what it's usually like in the place where you live.

3)Carbon Dioxide Power Plants:

In 2002 about 40% of U.S. carbon dioxide emissions stem


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from the burning of fossil fuels for the purpose of electricity

generation. Coal accounts for 93 percent of the emissions from

the electric utility industry.

Coal emits around 1.7 times as much carbon per unit of

energy when burned as does natural gas and 1.25 times as much

as oil. Natural gas gives off 50% of the carbon dioxide, the

principal greenhouse gas, released by coal and 25% less carbon

dioxide than oil, for the same amount of energy produced. Coal

contains about 80 percent more carbon per unit of energy than

gas does, and oil contains about 40 percent more. For the typical

U.S. household, a metric ton of carbon equals about 10,000

miles of driving at 25 miles per gallon of gasoline or about oneyear of home heating using a natural gas-fired furnace or about

four months of electricity from coal-fired generation.

4)Cars:About 20% of U.S carbon dioxide emissions comes from

the burning of gasoline in internal-combustion engines of cars

and light trucks (minivans, sport utility vehicles, pick-up trucks,and jeeps). Vehicles with poor gas mileage contribute the mostto global warming. In other words for each gallon of gas avehicle consumes, 19.6 pounds of carbon dioxide are emittedinto the air. A new Honda Insight that gets 61 miles to the gallonwill only emit about 161 pounds of carbon dioxide over thesame distance of 500 city miles. Sports utility vehicles werebuilt for rough terrain, off road driving in mountains and deserts.When they are used for city driving, they are so much overkill tothe environment. If one has to have a large vehicle for theirfamily, station wagons are an intelligent choice for city driving,especially since their price is about half that of a sports utility.The United States is the largest consumer of oil, using 20.4million barrels per day. In his debate with former DefenseSecretary Dick Cheney, during the 2000 Presidential campaign,
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Senator Joseph. Lieberman said, "If we can get 3 miles more pergallon from our cars, we'll save 1 million barrels of oil a day.

If car manufacturers were to increase their fleets' averagegas mileage about 3 miles per gallon, this country could save amillion barrels of oil every day, while US drivers would save

$25 billion in fuel costs annually.

4)Airplanes:

The UN's Intergovernmental Panel on Climate Change

estimates that aviation causes 3.5 percent of global warming,

and that the figure could rise to 15 percent by 2050.

5)Buildings:

Buildings structure account for about 12% of carbon

dioxide emissions. This also gives an helping hand to global

warming .

6)Methane:While carbon dioxide is the principal greenhouse gas,

methane is second most important. According to the IPCC,

Methane is more than 20 times as effective as CO2 at trappingheat in the atmosphere. Levels of atmospheric methane haverisen 145% in the last 100 years. Methane is derived fromsources such as rice paddies, bovine flatulence, bacteria in bogsand fossil fuel production.

7)Nitrous oxide :

Another greenhouse gas is Nitrous oxide (N2O), acolourless, non-flammable gas with a sweetish odour, commonlyknown as "laughing gas", and sometimes used as an anaesthetic.Nitrous oxide is naturally produced by oceans and rainforests.Man-made sources of nitrous oxide include nylon and nitric acidproduction, the use of fertilisers in agriculture, cars withcatalytic converters and the burning of organic matter. Nitrous
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oxide is broken down in the atmosphere by chemical reactionsthat involve sunlight.

8)Deforestation :After carbon emissions caused by humans, deforestation is

the second principle cause of atmospheric carbon dioxide.

Deforestation is responsible for20-25% of all carbon emissionsentering the atmosphere, by the burning and cutting of about 34million acres of trees each year. We are losing millions of acresof rainforests each year. The destroying of tropical forests aloneis throwing hundreds of millions of tons of carbon dioxide intothe atmosphere each year. We are also losing temperate forests.The temperate forests of the world account for an absorption rate

of 2 billion tons of carbon annually. In the temperate forests ofSiberia alone, the earth is losing 10 million acres per year.

Effects of globalwarming:

1)What is Acid Rain and WhatCauses It?

"Acid rain" is a broad term used to describe several ways that

acids fall out of the atmosphere. A more precise term is acid

deposition, which has two parts: wet and dry.
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Were not suggesting that global warming is going to be allpuppies and rainbows.

Here are the top 5 alleged

positive effects of global

warming.

1. Less dead peopleAssuming there arent any wars over scarce resources,food production stays ok, sea levels dont drown people,

and basically nothing else bad happens, we can expectless people to die in the winter. Global warming wouldcause winter temperatures to rise. In addition to savingus money on our heating bills, this could literally savebillions in health care costs and mean less dead peopleduring the colder months. One study said that warmerwinters could save up to 40,000 lives a year in the USalone, mostly the young and elderly, with the reductionsmostly in things like pneumonia deaths and other coldweather diseases.

2. More foodThis ones related a bit to the longer summers. Thosehotter temperatures would also translate into a longergrowing season. Plus, plants love CO2! Its like food forthem. All that global warming causing CO2 would act likea fertilizer. With free airborne plant fertilizer and longer

growing seasons, food production will skyrocket. Ofcourse, this is assuming that global warming doesntcause massive droughts or floods that destroy the crops.As long as that doesnt happen were golden!

3. More summer fun!WOOOOOOOO!:Summer itself wont technically last longer, as the dates
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are based on sunlight instead of temperature. But if youdefine summer by warm temperatures, youre in luck. Itllstay hot for much longer, so stock up on bathing suitsnow.

4. Florida trailer parks will finallybe safe:For years scientists have been quick to claim that globalwarming will cause more severe storms and a rise inhurricanes and all that sort of severe weather. But abrand new study in the journal Geophysical ResearchLetters suggests that it might actually be the opposite.

The researchers suggest that warmer temperatures will

actually decrease the amount of hurricanes that hit theUS each year. So feel free to drive your RV down nearMiami and just hang out for a while. Youre safe fromeverything except alligators and high murder rates!

5. Booming businesses.in theArctic

The world economy needs a shot in the arm. I know thefeds just cut interest rates by .75, but thats nothingcompared to what a melted Arctic circle could do. Withoutall that pesky ice in the way, the Arctic ocean would becompletely open, creating a brand new trade route fromthe Atlantic to Asia. Its only traversable in the summernow, but global warming could open it year round, savingmoney for everyone. It might kill the polar bears, butbusiness would boom in the north, which it sorely needs.

Plus youd save fuel on shipping, so if you think about it amelted Arctic circle is almost green.

The 5 deadliest effect of global

warming:
http://www.usatoday.com/weather/climate/2006-05-29-alaska-globalwarming_x.htmhttp://www.reuters.com/article/environmentNews/idUSN2364087920080123?feedType=RSS&feedName=environmentNewshttp://www.reuters.com/article/environmentNews/idUSN2364087920080123?feedType=RSS&feedName=environmentNewshttp://www.reuters.com/article/environmentNews/idUSN2364087920080123?feedType=RSS&feedName=environmentNewshttp://www.abc.net.au/news/stories/2007/09/19/2037198.htm?section=businesshttp://www.abc.net.au/news/stories/2007/09/19/2037198.htm?section=businesshttp://www.usatoday.com/weather/climate/2006-05-29-alaska-globalwarming_x.htmhttp://www.reuters.com/article/environmentNews/idUSN2364087920080123?feedType=RSS&feedName=environmentNewshttp://www.reuters.com/article/environmentNews/idUSN2364087920080123?feedType=RSS&feedName=environmentNewshttp://www.reuters.com/article/environmentNews/idUSN2364087920080123?feedType=RSS&feedName=environmentNewshttp://www.abc.net.au/news/stories/2007/09/19/2037198.htm?section=businesshttp://www.abc.net.au/news/stories/2007/09/19/2037198.htm?section=business


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1)Spread of disease:

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

2)Warmer waters and more hurricanes

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

3) Increased probability and intensity ofdroughts and heat waves

Although some areas of Earth will become wet due to global warming,other areas will suffer serious droughts and heat waves. Africa willreceive the worst of it, with more severe droughts also expected in

Europe. Water is already a dangerously rare commodity in Africa, and


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according to the Intergovernmental Panel on Climate Change, globalwarming will exacerbate the conditions and could lead to conflicts andwar.

4) Economic consequences

Most of the effects of anthropogenic global warming wont be good.And these effects spell one thing for the countries of the world:economic consequences. Hurricanes cause do billions of dollars indamage, diseases cost money to treat and control and conflictsexacerbate all of these.

5) Polar ice caps melting

The ice caps melting is a four-pronged danger.

* First, it will raise sea levels. There are 5,773,000 cubic miles of waterin ice caps, glaciers, and permanent snow. According to the NationalSnow and Ice Data Center, if all glaciers melted today the seas wouldrise about 230 feet. Luckily, thats not going to happen all in one go! Butsea levels will rise.*Second, melting ice caps will throw the global ecosystem out of

balance. The ice caps are fresh water, and when they melt they will

desalinate the ocean, or in plain English - make it less salty. The


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desalinization of the gulf current will screw up ocean currents, whichregulate temperatures. The stream shutdown or irregularity would coolthe area around north-east America and Western Europe. Luckily, thatwill slow some of the other effects of global warming in that area!*Third, temperature rises and changing landscapes in the artic circlewill endanger several species of animals. Only the most adaptable will

survive.*Fourth, global warming could snowball with the ice caps gone. Icecaps are white, and reflect sunlight, much of which is relected back intospace, further cooling Earth. If the ice caps melt, the only reflector is theocean. Darker colors absorb sunlight, further warming the Earth.

Other effects of GlobalWarming:

1)Methane release from

melting permafrostpeat bogs:Western Siberia is the world's largestpeat bog, a one million squarekilometer region ofpermafrost peat bog that was formed 11,000 yearsago at the end of the last ice age. The melting of its permafrost is likelyto lead to the release, over decades, of large quantities ofmethane. Asmuch as 70,000 million tonnes of methane, an extremely effective

greenhouse gas, might be released over the next few decades, creating anadditional source of greenhouse gas emissions. Similar melting has beenobserved in eastern Siberia.

2)Effects on weather

Global warming is responsible in part for some trends in natural

disasters such as extreme weather.Increasing temperature is likely to
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lead to increasing precipitation but the effects on storms are less clear.

Extratropical storms partly depend on the temperature

gradient, which is predicted to weaken in the northern hemisphere as thepolar region warms more than the rest of the

Over the course of the 20th century, evaporation rates have reducedworldwide this is thought by many to be explained by global dimming.As the climate grows warmer and the causes of global dimming arereduced, evaporation will increase due to warmer oceans. Because theworld is a closed system this will cause heavierrainfall, with moreerosion. This erosion, in turn, can in vulnerable tropical areas (especially

in Africa) lead to desertification due to deforestation. On the other hand,in other areas, increased rainfall lead to growth of forests in dry desertareas.

Many scientists think that increased evaporation could result in moreextreme weatheras global warming progresses. The IPCC Third AnnualReport says: "...global average water vapor concentration and

precipitation are projected to increase during the 21st century. By thesecond half of the 21st century, it is likely that precipitation will haveincreased over northern mid- to high latitudes and Antarctica in winter.At low latitudes there are both regional increases and decreases overland areas. Larger year to year variations in precipitation are very likelyover most areas where an increase in mean precipitation is projected".

3)Glacier retreat and

disappearanceA map of the change in thickness of mountain glaciers since 1970.Thinning in orange and red, thickening in blue.
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Lewis Glacier, North Cascades, WA USA is one of five glaciers in thearea that melted away

In historic times, glaciers grew during a cool period from about 1550 to1850 known as the Little Ice Age. Subsequently, until about 1940,glaciers around the world retreated as the climate warmed. Glacierretreat declined and reversed in many cases from 1950 to 1980 as a

slight global cooling occurred. Since 1980, glacier retreat has becomeincreasingly rapid and ubiquitous, and has threatened the existence ofmany of the glaciers of the world. This process has increased markedlysince 1995.

Excluding the ice caps and ice sheets of the Arctic and Antarctic, thetotal surface area ofglaciers worldwide has decreased by 50% since theend of the 19th century.

The loss of glaciers not only directly causes landslides, flash floods and

glacial lake overflow, but also increases annual variation in water flowsin rivers.

Glacier runoff declines in the summer as glaciers decrease in size, thisdecline is already observable in several regions. Glaciers retain water onmountains in high precipitation years, since the snow coveraccumulating on glaciers protects the ice from melting. In warmer anddrier years, glaciers offset the lower precipitation amounts with a highermelt water input.

Of particular importance are the Hindu Kush and Himalayan glacialmelts that comprise the principal dry-season water source of many of themajor rivers of the South, East and Southeast Asian mainland. Increasedmelting would cause greater flow for several decades, after which "someareas of the most populated regions on Earth are likely to 'run out ofwater'" as source glaciers are depleted.

According to a UN climate report, the Himalayan glaciers that are thesources ofAsia's biggest rivers - Ganges, Indus, Brahmaputra, Yangtze,

Mekong, Salween and Yellow - could disappear by 2035 as temperatures
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rise. Approximately 2.4 billion people live in the drainage basin of theHimalayan rivers. India, China, Pakistan, Bangladesh,Nepal andMyanmarcould experience floods followed by droughts in comingdecades. In India alone, the Ganges provides water for drinking andfarming for more than 500 million people.

4)OceansThe role of the oceans in global warming is a complex one. The oceansserve as a sink for carbon dioxide, taking up much that would otherwiseremain in the atmosphere, but increased levels of CO2 have led to oceanacidification. Furthermore, as the temperature of the oceans increases,they become less able to absorb excess CO2. Global warming is

projected to have a number of effects on the oceans. Ongoing effects

include rising sea levels due to thermal expansion and melting ofglaciers and ice sheets, and warming of the ocean surface, leading toincreased temperature stratification. Other possible effects include large-scale changes in ocean circulation.

5)Sea level riseSea level has been rising 0.2 cm/year, based on measurements ofsealevel rise from 23 long tide gauge records in geologically stable

environments

With increasing average global temperature, the waterin the oceansexpands in volume, and additional water enters them which had

previously been locked up on land in glaciers, for example, theGreenland and the Antarctic ice sheets. An increase of 1.5 to 4.5 C isestimated 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 lastice age about 18,000 years ago. The bulk of that occurred before 6000years ago. From 3000 years ago to the start of the 19th century, sea levelwas almost constant, rising at 0.1 to 0.2 mm/yr; since 1900, the level hasrisen at an average of 1.7 mm/yr; since 1993, satellite altimetry fromTOPEX/Poseidon indicates a rate of about 3 mm/yr.
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6)Temperature riseFrom 1961 to 2003, the global ocean temperature has risen by 0.10C

from the surface to a depth of 700 m. There is variability both year-to-year and over longer time scales, with global ocean heat contentobservations showing high rates of warming for 1991 to 2003, but somecooling from 2003 to 2007. The temperature of the Antarctic SouthernOcean rose by 0.17 C (0.31 F) between the 1950s and the 1980s,nearly twice the rate for the world's oceans as a whole. As well as havingeffects on ecosystems (e.g. by melting sea ice, affecting algae that growon its underside), warming reduces the ocean's ability to absorb CO2.

7)AcidificationThe worlds oceans soak up much of the carbon dioxide produced byliving organisms, either as dissolved gas, or in the skeletons of tinymarine creatures that fall to the bottom to become chalk or limestone.Oceans currently absorb about one tonne of CO2 per person per year.

It is estimated that the oceans have absorbed around half of all CO2generated by human activities since 1800 (120,000,000,000 tonnes or120petagrams of carbon).

But in water, carbon dioxide becomes a weakcarbonic acid, and theincrease in the greenhouse gas since the industrial revolution has alreadylowered the averagepH (the laboratory measure of acidity) of seawater

by 0.1 units, to 8.2. Predicted emissions could lower it by a further 0.5by 2100, to a level not seen for millions of years.
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There are concerns that increasing acidification could have a particularlydetrimental effect on corals (16% of the world's coral reefs have diedfrom bleaching caused by warm water in 1998, which coincidentally wasthe warmest year ever recorded) and other marine organisms withcalcium carbonate shells.

8)Tundra regioneffected by global

warmingA name very suited to the environs of the arctic and subarctic,

tundra means 'treeless plain' in Finnish. The tundra is a biome (amajor segment of a particular region having distinctive vegetation,

animals and microorganisms adapted to a unique climate), home to

about 1700 kinds of plants, including shrubs, mosses, grasses, lichens

and 400 kinds of flowers.

About 50 billion tons of carbon are estimated to be held in a

frozen state in the tundra, and now the tundra is beginning to becomea source of carbon dioxide. In the 1970's University of California

biologist Walter Oechel studied carbon dioxide emissions in the

tundra, which until this time had been thought of as a carbon sink.

Doing further tests in the 1980's, Oechel discovered that this was no

longer the case, that warming temperatures had changed the tundra to

a net emitter of carbon dioxide. Says Oechel, "We found to our great

surprise that the tundra was already losing carbon dioxide to the

atmosphere. So that by the start of these experiments, which was in

1982, the tundra had already warmed and dried enough, that its

historic role as a carbon sink had reversed and changed. It was now

losing carbon dioxide to the atmosphere. That was totally

unexpected."

9)Forest fires
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Rising global temperature might cause forest fires to occur on largerscale, and more regularly. This releases more stored carbon into theatmosphere than the carbon cycle can naturally re-absorb, as well asreducing the overall forest area on the planet, creating a positivefeedback loop. Part of that feedback loop is more rapid growth ofreplacement forests and a northward migration of forests as northern

latitudes become more suitable climates for sustaining forests. There is aquestion of whether the burning of renewable fuels such as forestsshould be counted as contributing to global warming.

10)Other Consequences

As recent estimates of the rate of global warming have increased, sohave the financial estimates of the damage costs.

11) Effects on agricultureFor some time it was hoped that a positive effect of global warmingwould be increased agricultural yields, because of the role of carbondioxide inphotosynthesis, especially in preventingphotorespiration,which is responsible for significant destruction of several crops. InIceland, rising temperatures have made possible the widespread sowing

ofbarley, which was untenable twenty years ago. Some of the warmingis due to a local (possibly temporary) effect via ocean currents from theCaribbean, which has also affected fish stocks.

While local benefits may be felt in some regions (such as Siberia), recentevidence is that global yields will be negatively affected. "Risingatmospheric temperatures, longer droughts and side-effects of both, suchas higher levels of ground-level ozone gas, are likely to bring about asubstantial reduction in crop yields in the coming decades, large-scale

experiments have shown".
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Moreover, the region likely to be worst affected is Africa, both becauseits geography makes it particularly vulnerable, and because seventy percent of the population rely on rain-fed agriculture for their livelihoods.Tanzania's official report on climate change suggests that the areas thatusually get two rainfalls in the year will probably get

more, and those that get only one rainy season will get far less. The netresult is expected to be that 33% less maizethe country's staple cropwill be grown.

Climate change may be one of the causes of the Darfur conflict. Thecombination of decades of drought, desertification and overpopulationare among the causes of the conflict, because the ArabBaggaranomadssearching for water have to take their livestock further south, to land

mainly occupied by farming peoples."The scale of historical climate change, as recorded in Northern Darfur,is almost unprecedented: the reduction in rainfall has turned millions ofhectares of already marginal semi-desert grazing land into desert. Theimpact of climate change is considered to be directly related to theconflict in the region, as desertification has added significantly to thestress on the livelihoods of pastoralist societies, forcing them to movesouth to find pasture," the UNEP report states

12) TransportRoads, airport runways, railway lines and pipelines, (including oil

pipelines, sewers, water mains etc) may require increased maintenanceand renewal as they become subject to greater temperature variation.Regions already adversely affected include areas ofpermafrost, whichare subject to high levels ofsubsidence, resulting in buckling roads,sunken foundations, and severely cracked runways.

13) Flood defenseFor historical reasons to do with trade, many of the world's largest andmost prosperous cities are on the coast, and the cost of building bettercoastal defenses (due to the rising sea level) is likely to be considerable.Some countries will be more affected than others low-lying countriessuch as Bangladesh and theNetherlands would be worst hit by any sea

level rise, in terms offloods or the cost of preventing them.
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In developing countries, the poorest often live on flood plains, because itis the only available space, or fertile agricultural land. These settlementsoften lack infrastructure such as dykes and early warning systems.Poorer communities also tend to lack the insurance, savings or access tocredit needed to recover from disasters.

14) MigrationSome Pacific Ocean island nations, such as Tuvalu, are concerned aboutthe possibility of an eventual evacuation, as flood defense may becomeeconomically inviable for them. Tuvalu already has an ad hoc agreementwithNew Zealand to allow phased relocation.

In the 1990s a variety of estimates placed the number of environmentalrefugees at around 25 million. (Environmental refugees are not included

in the official definition ofrefugees, which only includes migrantsfleeing persecution.) The Intergovernmental Panel on Climate Change(IPCC), which advises the worlds governments under the auspices ofthe UN, estimated that 150 million environmental refugees will exist inthe year 2050, due mainly to the effects of coastal flooding, shorelineerosion and agricultural disruption (150 million means 1.5% of 2050s

predicted 10 billion world population).

15) Northwest Passage

Arctic ice thicknesses changes from 1950s to 2050s simulated in one ofGFDL's R30 atmosphere-ocean general circulation model experiments

Melting Arctic ice may open theNorthwest Passage in summer, whichwould cut 5,000 nautical miles (9,000 km) from shipping routes betweenEurope and Asia. This would be of particular relevance forsupertankerswhich are too big to fit through the Panama Canal and currently have togo around the tip of South America. According to the Canadian Ice

Service, the amount of ice in Canada's
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eastern Arctic Archipelago decreased by 15% between 1969 and 2004.

In September 2007, the Artic Ice Cap retreated far enough for theNorthwest Passage to become navigable to shipping for the first time inrecorded history.

While the reduction of summer ice in the Arctic may be a boon toshipping, this same phenomenon threatens the Arctic ecosystem, mostnotably polar bears which depend on ice floes. Subsistence hunters suchas the Inuit peoples will find their livelihoods and cultures increasinglythreatened as the ecosystem changes due to global warming.

16) DevelopmentThe combined effects of global warming may impact particularlyharshly on people and countries without the resources to mitigate thoseeffects. This may slow economic development andpoverty reduction,and make it harder to achieve the Millennium Development Goals.

In October 2004 the Working Group on Climate Change andDevelopment, a coalition of development and environmentNGOs,issued a report Up in Smoke on the effects of climate change ondevelopment. This report, and the July 2005 report Africa - Up in

Smoke? predicted increased hunger and disease due to decreased rainfalland severe weather events, particularly in Africa. These are likely tohave severe impacts on development for those affected.

17) EcosystemsUnchecked global warming could affect most terrestrial ecoregions.Increasing global temperature means that ecosystems will change; somespecies are being forced out of their habitats (possibly to extinction)

because of changing conditions, while others are flourishing. Secondaryeffects of global warming, such as lessened snow cover, rising sealevels, and weather changes, may influence not only human activities

but also the ecosystem. Studying the association between Earth climateand extinctions over the past 520 million years, scientists fromUniversity of Yorkwrite, "The global temperatures
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predicted for the coming centuries may trigger a new mass extinctionevent, where over 50 per cent of animal and plant species would bewiped out."

Many of the species at risk are Arctic and Antarctic fauna such aspolarbears and emperor penguins. Species that rely on cold weatherconditions such as gyrfalcons, and snowy owls that prey on lemmingsthat use the cold winter to their advantage may be hit hard. Marineinvertebrates enjoy peak growth at the temperatures they have adaptedto, regardless of how cold these may be, and cold-blooded animals foundat greaterlatitudes and altitudes generally grow faster to compensate forthe short growing season. Warmer-than-ideal conditions result in highermetabolism and consequent reductions in body size despite increasedforaging, which in turn elevates the risk ofpredation. Indeed, even aslight increase in temperature during development impairs growth

efficiency and survival rate in rainbow trout.

Rising temperatures are beginning to have a noticeable impact on birds,andbutterflies have shifted their ranges northward by 200 km in Europeand North America. Plants lag behind, and larger animals' migration isslowed down by cities and highways. In Britain, spring butterflies areappearing an average of 6 days earlier than two decades ago. In theArctic, the waters ofHudson Bay are ice-free for three weeks longerthan they were thirty years ago, affectingpolar bears, which prefer to

hunt on sea ice.

Many species of freshwater and saltwater plants and animals aredependent on glacier-fed waters to ensure a cold water habitat that theyhave adapted to. Some species of freshwater fish need cold water tosurvive and to reproduce, and this is especially true with Salmon andCutthroat trout. Reduced glacier runoff can lead to insufficient streamflow to allow these species to thrive. Ocean krill, a cornerstone species,

prefer cold water and are the primary food source for aquatic mammals

such as the Blue whale. Alterations to the ocean currents, due toincreased freshwater inputs from glacier melt, and the potentialalterations to thermohaline circulation of the worlds oceans, may impactexisting fisheries upon which humans depend as well.
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18) Forests

Pine forests in British Columbia have been devastated by apine beetleinfestation, which has expanded unhindered since 1998 at least in partdue to the lack of severe winters since that time; a few days of extreme

cold kill most mountain pine beetles and have kept outbreaks in the pastnaturally contained. The infestation, which will have killed 50% of thelodgepole pines by 2008 has passed to Alberta and will spread furtherEast and eventually into America given continued milder winters.Besides the immediate ecological and economic impact, the huge deadforests provide a fire risk as well.

Forests in some regions potentially face an increased risk offorest fires.The 10-year average of boreal forest burned in North America, after

several decades of around 10,000 km (2.5 million acres), has increasedsteadily since 1970 to more than 28,000 km (7 million acres) annually.This change may be due in part to changes in forest management

practices. In the western U. S., since 1986, longer, warmer summershave resulted in a fourfold increase of major wildfires and a sixfoldincrease in the area of forest burned, compared to the period from 1970to 1986. A similar increase in wildfire activity has been reported inCanada from 1920 to 1999.

Also note forest fires since 1997 in Indonesia. The fires are started toclear forest for agriculture. These occur from time to time and can set

fire to the large peat bogs in that region. The CO2 released by these peatbog fires has been estimated, in an average year, to release 15% of thequantity of CO2 produced by fossil fuel combustion.
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19) Mountains: Mountains coverapproximately 25 percent of earth's surface and provide a home to morethan one-tenth of global human population. Changes in global climate

pose a number of potential risks to mountain habitats. Researchersexpect that over time, climate change will affect mountain and lowlandecosystems, the frequency and intensity offorest fires, the diversity ofwildlife, and the distribution of water.

Studies suggest that a warmer climate in the United States would causelower-elevation habitats to expand into the higher alpine zone. Such ashift would encroach on the rare alpine meadows and other high-altitudehabitats. High-elevation plants and animals have limited space available

for new habitat as they move higher on the mountains in order to adaptto long-term changes in regional climate.

Changes in climate will also affect the depth of the mountainssnowpacks and glaciers. Any changes in their seasonal melting can have

powerful impacts on areas that rely on freshwaterrunofffrommountains. Rising temperature may cause snow to melt earlier and fasterin the spring and shift the timing and distribution of runoff. Thesechanges could affect the availability of freshwater for natural systems

and human uses.

20) EcologicalproductivityIncreasing average temperature and carbon dioxide may have the effectof improving ecosystems' productivity. Inphotorespiration, carbon

dioxide that oxygen can enter a plant's chloroplasts and take the place ofcarbon dioxide in the Calvin cycle. This causes the sugars being made tobe destroyed, suppressing growth. Higher carbon dioxide concentrationstend to reduce photorespiration. Satellite data shows that the

productivity of the northern hemisphere has increased since 1982(although attribution of this increase to a specific cause is difficult).

IPCC models predict that higher CO2 concentrations would only spurgrowth of flora up to a point, because in many regions the limiting
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factors are water or nutrients, not temperature or CO2; after that,greenhouse effects and warming would continue but there would be nocompensatory increase in growth.

Research done by the Swiss Canopy Crane Project suggests that slow-growing trees only are stimulated in growth for a short period underhigher CO2 levels, while faster growing plants like liana benefit in thelong term. In general, but especially in rain forests, this means that liana

become the prevalent species; and because they decompose much fasterthan trees their carbon content is more quickly returned to theatmosphere. Slow growing trees incorporate atmospheric carbon fordecades.

21) EnvironmentalSecondary evidence of global warming reduced snow cover, risingsea levels, weather changes provides examples of consequences ofglobal warming that may influence not only human activities but alsoecosystems. Increasing global temperature means that ecosystems maychange; some species may be forced out of their habitats (possibly toextinction) because of changing conditions, while others may flourish.Few of the terrestrial ecoregions on Earth could expect to be unaffected.

Increasing carbon dioxide may increase ecosystems' productivity to a

point. Ecosystems' unpredictable interactions with other aspects ofclimate change makes the possible environmental impact of this isunclear, though. An increase in the total amount ofbiomass producedmay not be necessarily positive:biodiversity can still decrease eventhough a relatively small number of species are flourishing.

22)Water scarcityPositive eustasy may contaminate groundwater, affecting drinking waterand agriculture in coastal zones. Increased evaporation will reduce theeffectiveness of reservoirs. Increased extreme weather means morewater falls on hardened ground unable to absorb it, leading to flashfloods instead of a replenishment of soil moisture or groundwater levels.In some areas, shrinking glaciers threaten the water supply. Thecontinued retreat of glaciers will have a number of
http://pages.unibas.ch/botschoen/scc/index.shtmlhttp://en.wikipedia.org/wiki/Lianahttp://en.wikipedia.org/wiki/Rain_foresthttp://en.wikipedia.org/wiki/Ecosystemhttp://en.wikipedia.org/wiki/Specieshttp://en.wikipedia.org/wiki/Terrestrial_ecoregionshttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Biomasshttp://en.wikipedia.org/wiki/Biodiversityhttp://en.wikipedia.org/wiki/Groundwaterhttp://pages.unibas.ch/botschoen/scc/index.shtmlhttp://en.wikipedia.org/wiki/Lianahttp://en.wikipedia.org/wiki/Rain_foresthttp://en.wikipedia.org/wiki/Ecosystemhttp://en.wikipedia.org/wiki/Specieshttp://en.wikipedia.org/wiki/Terrestrial_ecoregionshttp://en.wikipedia.org/wiki/Climate_changehttp://en.wikipedia.org/wiki/Biomasshttp://en.wikipedia.org/wiki/Biodiversityhttp://en.wikipedia.org/wiki/Groundwater


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different impacts. In areas that are heavily dependent on water runofffrom glaciers that melt during the warmer summer months, acontinuation of the current retreat will eventually deplete the glacial iceand substantially reduce or eliminate runoff. A reduction in runoff willaffect the ability to irrigate crops and will reduce summer stream flowsnecessary to keep dams and reservoirs replenished. This situation is

particularly acute for irrigation in South America, where numerousartificial lakes are filled almost exclusively by glacial melt. CentralAsian countries have also been historically dependent on the seasonalglacier melt water for irrigation and drinking supplies. In Norway, theAlps, and the Pacific Northwest of North America, glacier runoff isimportant for hydropower. Higher temperatures will also increase thedemand for water for the purposes of cooling and hydration.

In the Sahel, there has been on average a 25% decrease in annual rainfall

over the past 30 years.

23) Health

Direct effects oftemperature riseThe most direct effect of climate change would be the impacts of hottertemperatures themselves. Extreme high temperatures increase thenumber of people who die on a given day for many reasons: people withheart problems are vulnerable because one's cardiovascular system mustwork harder to keep the body cool during hot weather, heat exhaustion,and some respiratory problems increase. Global warming could meanmore cardiovascular diseases, doctors warn. Higher air temperature alsoincrease the concentration of ozone at ground level. In the lower

atmosphere, ozone is a harmful pollutant. It damages lung tissues andcauses problems for people with asthma and other lung diseases.

Rising temperatures have two opposing direct effects on mortality:higher temperatures in winter reduce deaths from cold; highertemperatures in summer increase heat-related deaths.

The distribution of these changes obviously differs. Palutikof et alcalculate that in England and Wales for a 1 C temperature rise the

reduced deaths from cold outweigh the increased deaths from heat,
http://en.wikipedia.org/wiki/Irrigationhttp://en.wikipedia.org/wiki/Sahelhttp://en.wikipedia.org/wiki/Cardiovascular_diseasehttp://en.wikipedia.org/wiki/Deathhttp://en.wikipedia.org/wiki/Irrigationhttp://en.wikipedia.org/wiki/Sahelhttp://en.wikipedia.org/wiki/Cardiovascular_diseasehttp://en.wikipedia.org/wiki/Death


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resulting in a reduction in annual average mortality of 7000. TheEuropean heat wave of 2003 killed 22,00035,000 people, based onnormal mortality rates. Peter A. Stott from the Hadley Centre forClimate Prediction and Research estimated with 90% confidence that

past human influence on climate was responsible for at least half the riskof the 2003 European summer heat-wave. In the United States, more

than 1000 people die from the cold each year, while twice that numberdie from the heat. The 2006 United States heat wave has killed 139

people in California as of 29 July 2006. Deaths of livestock have notbeen well-documented. Fresno, in the central California valley, had sixconsecutive days of 110 degree-plus Fahrenheit temperatures.

Other Impacts ofGlobal Warming

Global warming will have serious impacts on the environment andon society. Higher temperatures will cause a melting of ice in Greenlandand Antarctica. This will accelerate the rise ofsea level. The speed at

which global warming is expected to occur in the 21

st

century is fasterthan most plant and animal species will be able to cope with. Some willadapt but others will suffer and may become extinct.

Global warming will affect agriculture. New crops will be able tobe grown in areas that are currently too cold to support them. However,more pests and diseases may offset any benefits higher temperaturesmay have. Water resources will also be affected. Some reservoirs maydry up if temperature increases, especially if rainfall also decreases.

Rising sea levels may pollute fresh groundwater supplies with salt water.Global warming will also affect human health. There may be more

heat-related illnesses in hotter summers, and increased breathingproblems as higher temperatures increase air pollution in cities, reducingair quality. The malaria mosquito may also be able to spread to otherregions of the world where it is currently too cold to survive and breed.

More extreme weather, for example storms, floods and droughtswill have severe impacts on the environment and on society. The poorest
http://en.wikipedia.org/wiki/European_heat_wave_of_2003http://en.wikipedia.org/wiki/Hadley_Centre_for_Climate_Prediction_and_Researchhttp://en.wikipedia.org/wiki/Hadley_Centre_for_Climate_Prediction_and_Researchhttp://en.wikipedia.org/wiki/2006_United_States_heat_wavehttp://en.wikipedia.org/wiki/Fresno%2C_Californiahttp://en.wikipedia.org/wiki/Fahrenheithttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/Sea_Level.htmlhttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/21st_Century.htmlhttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/21st_Century.htmlhttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/21st_Century.htmlhttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/Extreme_Weather.htmlhttp://en.wikipedia.org/wiki/European_heat_wave_of_2003http://en.wikipedia.org/wiki/Hadley_Centre_for_Climate_Prediction_and_Researchhttp://en.wikipedia.org/wiki/Hadley_Centre_for_Climate_Prediction_and_Researchhttp://en.wikipedia.org/wiki/2006_United_States_heat_wavehttp://en.wikipedia.org/wiki/Fresno%2C_Californiahttp://en.wikipedia.org/wiki/Fahrenheithttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/Sea_Level.htmlhttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/21st_Century.htmlhttp://www.ace.mmu.ac.uk/eae/Global_Warming/Younger/Extreme_Weather.html


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people in society will unfortunately be those least able to cope with theimpacts of global warming.

How to prevent?

*Switch to energy-efficient lighting-Replace the familiar incandescent light bulbs with compact fluorescent

bulbs. For each CFL bulb replacement, you'll lower your energy bill andkeep nearly 700 pounds of carbon dioxide out of the air over the bulb'slifetime. CFL bulbs last much longer and use only a quarter of the

energy consumed by conventional bulbs. LED bulbs are also energy-saving, but have a narrower range of application. Advances in LED bulbtechnology, however, are leading to more applications for these bulbs inthe home. LEDs are more efficient than CFLs and do not have issuessurrounding disposal, as do the CFLs.


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*Improve the efficiency

of home

appliances -Home appliances vary greatly interms of energy-efficiency and operating costs. The more energy-

efficient an appliance is, the less it costs to run. You can lower your

utility bill and help protect the environment.

*Buy energy-efficient

appliances When shopping for a new appliance - especially a major appliance such

as a refrigerator, dishwasher, or air-conditioner - select the one with the

highest

energy efficiency rating. By opting for a refrigerator with the Energy

Star label -- indicating it uses at least 15 percent less energy than thefederal requirement -- you can reduce carbon dioxide pollution by nearly

a ton in total.

*Reduce energy

needed for heating

According to the U.S. Department of Energy, heating and cooling

systems in the U.S. emit over a half billion tons of carbon dioxide into

the atmosphere each year. Much of the energy used for heating our

homes is wasted, and yet the prevention is, in many cases, simple and

inexpensive.


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*Reduce energy

needed for cooling

Air conditioners alone use up to 1/6th of the electricity in the U.S. and,on hot summer days, consume 43% of the U.S. peak power load. You

can reduce much of the need for air conditioning, and enjoy a cost

savings benefit, by using 'passive' techniques to help cool your home.

Improve vehicle fuel-

efficiency- The second largest source ofgreenhouse gases is transportation. Motor vehicles are

responsible for about a third of all carbon dioxide

emissions in the U.S. and Canada.

*Recycle air

conditioner coolant - If yourcar has an air conditioner, make sure you recycle its

coolant whenever you have it serviced. You can save

thousands of pounds of carbon dioxide each year by

doing this.

*Drive less - You'll save energy by takingthe bus, riding a bike, or walking. Try consolidating trips

to the mall or longer routine drives. Encourage car-

pooling.


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*Reduce lawn size - Lawn size canbe reduced by adding shrubs, beds, ground covers and mulched areas.Try creating a lawn area small enough to be mowed using an efficientreel (push) mower. Lawn edging can be set low enough to mow over,reducing or eliminating the need for a weed-eater.

*Recycle wheneverpossible - aluminum cans, newspapers, magazines,cardboard, glass - anything recycled reduces the energy needed to createnew products.To find the recycling center nearest you, call: 1 800-CLEANUP.

*Eat locally produced

food- Today, the food choices available insupermarkets come from all over the world. All of this

'traffic' in food requires staggering amounts of fuel -

generally by refrigerated airplanes or transport trucks.

Food transportation is one of the fastest growing sources

of greenhouse gas emissions.

*Eat vegetarian meals -Vegetarian food requires much less energy to produce.

Enjoying vegetarian meals once or twice a week results in

significant CO2 savings.

*Choose clean energy

options - If you can choose your electricitysupplier, pick a company that generates at least half its

power from wind, solar energy and other renewable

sources.


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*Buy clean energy

certificatesand

carbon offsets - Help spur therenewable energy market and cut global warming

pollution with "wind certificates" or "green tags," which

represent clean power you can add to the nation's energy

grid in place of electricity from fossil fuels.

*Conserve energy inthe home and yardYard maintenance contributes significantly to greenhouse emissions. Perhour of operation, a power lawn mower emits 10-12 times as muchhydrocarbon as a typical auto. A weed eater emits 21 times more and aleaf blower 34 times more.


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Making energyconservation a part ofour daily awareness isessential to the goal

of reducing globalwarming.

Scientists fear global warming higherthan expected

New scientific modelling suggests the earth's average temperaturecould rise by 7.8C by 2300 if fossil fuel consumption remains

unchanged, with polar ice caps melting and seas rising by sevenmeters.

Brief News:


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New climate modelling by researchers at the Lawrence LivermoreNational Laboratory in California suggest the magnitude of globalwarming could be much higher than expected, with direconsequences for the economy.

The researchers' simulations show that, if humans use theentire planet's available fossil fuels by the year 2300, the polarice caps will be depleted, sea levels will rise by seven meters andmedian air temperatures will soar to 7.8C warmer than thepresent day. The Arctic and Antarctic would be hardest hit withtemperatures there rising more than in the tropics, by more than20C, forcing the land in the region to change from ice and tundrato boreal forests.

Separate research performed by scientists at the HarvardMedical School of Public Affairs point to significant impact ofclimate change on human health with dire costs for the economyand significant impact on the insurance industry.

Rates of vector-borne and infectious diseases such as lymeand malaria are expected to increase as ticks and mosquitoesresponsible for their transmission proliferate. These are expectedto affect African countries most but also other regions such asNorth America, the researchers pointed out. Rising incidence ofasthma is also expected as emissions of carbon dioxide rises. Thestudy was co-sponsored by Reinsurance firm Swiss Re and theUnited Nations Development Programme (UNEP).

As a reinsurance company, our goal is to evaluate and plan

for the long-term," said Jacques Dubois, Chairman of Swiss ReAmerica Holding Corporation. "This report provides a crucial lookat physical and economic aspects of climate change. It alsoassesses current risks and potential business opportunities thatcan help minimise future risks.

Chilling global forecast

Global warming could disrupt the world's sea currents,

sending Europe into a chill within 100 years anddevastating tropical ocean life, a CSIRO scientist says.

Richard Matear, a Hobart-based marine researcher, said

the oxygen content of deep ocean water between

Australia and Antarctica had fallen 3 per cent since 1968.

If new research confirmed the decline was happening

throughout the world's southern oceans, it would be a

strong sign global warming was interfering with sea


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currents.

According to NASA "the thawing of sea ice covering the

Arctic could disturb or even halt large currents in the

Atlantic Ocean.

"Without the vast heat these currents deliver -

comparable to the power generation of a million nuclearpower plants - Europe's average temperature would likely

drop 5 to 10 degrees."

While North America would not be as severely hit, the

space agency said "such a dip in temperature would be

similar to global average temperatures toward the end of

the last ice age roughly 20,000 years ago".

While NASA said many scientists were sceptical, it quoted

Dr Robert Gagosian, director of the private Woods Hole

Oceanographic Institution, Massachusetts, as saying such

a change in ocean currents could happen within 20 years.


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Conclusion:Global temperature measurements remote

from human habitation and activity show noevidence of a warming during the last century.

Such sites include proxy measurementssuch as tree rings, marine sediments and ice

cores, weather balloons and satellitemeasurements in the lower atmosphere, andmany surface sites where human influence is

minimal. The small average and highlyirregular individual warming displayed by

surface measurements is therefore caused bychanges in the thermal environment of

individual measurement stations over longperiods of time, and not by changes in the

background climate.


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Bibliography:

www.epa.gov

www.wikipedia.com

www.ecobridge.org

www.environmentalgraffiti.com

www.eartheasy.com

www.managementparadise.com
http://www.epa.gov/http://www.wikipedia.com/http://www.ecobridge.org/http://www.environmentalgraffiti.com/http://www.eartheasy.com/http://www.managementparadise.com/http://www.epa.gov/http://www.wikipedia.com/http://www.ecobridge.org/http://www.environmentalgraffiti.com/http://www.eartheasy.com/http://www.managementparadise.com/


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what is global warming in general sense

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