what is global warming?

Question

and how does it effect the earth and enviroment>?

Answer 1

Global warming is the rise in average temperatures across the world, it's a long term trend that occurs over many, many years.

Throughout Earth's history there has been global warming and global cooling and this occurs in cycles. Here it gets complicated because there are cycles within cycles within cycles within cycles. The longest term cycle has seen the world in a cooling phase for the last 50 million years, the most recent cycle started 18,000 years ago and brought an end to the most recent ice age.

These natural phases are the results of comlex changes in the way that climate systems function. Changes can be triggered by the way the world moves, for example, sometimes it's tilted towards the sun and sometimes away from the sun, this is known as axial tilt, there are other 'wobbles' known as precission and eccentricity. If you'd like to know more about these then search for 'Milankovich Cycles'.

All these natural cycles occur over periods of many thousands of years. The concern now is that the world is warming up much faster than can be put down to any natural or solar cycle. It should be warming by 0.0005 C a year but it's actually rising by 0.00156 C a year - 31 times as fast as it should be doing.

A lot of global warming sceptics put this rise down to things such as sun spot activity (solar variation) or point to 'global warming' on Mars. Sun spots occur on an 11 year cycle and have only a very tiny effect on the worlds temperature, the difference between highest and lowest heat energy from the sun is less than one thousandth (1366 W/m²/yr ±1.3 W/m²/yr). The concept of global warming on Mars is a deliberate distortion of the truth and stems from a NASA report entitled 'Mars is Melting', it was published in National Geographic and has since been misrepresented in some other publications and websites. The NASA article states that the south polar ice cap is melting, the north polar ice cap is freezing and this is occuring because it's springtime on Mars and is a normal seasonal variation.

As for how it effects earth and the environment...

EFFECTS ON WEATHER
An increase in the amount of precipitation, mainly because the hotter atmosphere will evaporate more water from the seas and oceans which subsequently falls as rain, snow etc http://www.grida.no/climate/ipcc_tar/wg1/008.htm

Hurricanes and storms will become more frequent, widespread and severe, in the last 30 years the proportion of category 4 and 5 hurricanes has almost doubled ftp://texmex.mit.edu/pub/emanuel/PAPERS/NATURE03906.pdf Once exclusively confined to the northern hemisphere there have recently been hurricanes in the southern hemisphere, most notably in Brazil. The leading edge over which hurricanes can strike has increased by 1600km (1000 miles) http://en.wikipedia.org/wiki/Effects_of_global_warming

During the same time span there has been a sharp rise in the number of extreme weather phenomenon. The changing weather has resulted in more storms, droughts, floods and heavier rainfall; these in turn cause erosion, famine, disease etc http://yosemite.epa.gov/OAR/globalwarming.nsf/webprintview/ActionsIndustryInsurance.html .


DESERTIFICATION
Shifting weather patterns mean some areas receive less rainfall; the ground becomes barren and unable to sustain crops. In many parts of the world the layer of topsoil is both very thin and very poor. The dry, dusty soil is readily blown away and the area becomes desert. African and Asian countries are particularly hard hit http://en.wikipedia.org/wiki/Desertification


AGRICULTURAL IMPACT
For the reasons mentioned above there will be a major impact on agriculture. Rising sea levels (see below) will also impact resulting in the loss of large areas of agricultural land, the consequences of which will be population migration, famine and / or the need to import food from elsewhere. Again, it will be the African and Asian countries that are hardest hit with crop production falling by up to a third http://www.guardian.co.uk/climatechange/story/0,12374,1517935,00.html

Global warming can be a doubled edged sword. It has already resulted in the melting of a million square kilometres of Siberian permafrost, an area four times the size of the UK and covering the world’s largest peat bog http://www.guardian.co.uk/climatechange/story/0,12374,1546824,00.html The melting has created land suitable for crops but at the same time has causing billions of tons of methane gas to be released from the peat, which in turn contributes to further global warming. A further consequence is the loss of over 1,000 lakes but the creation of many new ones http://www.guardian.co.uk/international/story/0,,1503170,00.html


RISING SEA LEVELS
Sea levels are rising faster now than at any time since the melting of the glaciers that marked the end of the last ice age. As the glaciers melted sea levels rose by some 120 metres (400 feet) but for the last few thousand years sea levels have been almost constant rising only 10 centimetres (4 inches) per thousand years http://www.grida.no/climate/ipcc_tar/wg1/425.htm

Since the onset of global warming the seas have risen much faster. A hundred years ago they were rising by 1mm a year, today they are rising by 3mm a year and indications are that they will rise much quicker in the future http://www.grida.no/climate/ipcc_tar/wg1/426.htm Sea levels are rising 30 times faster now than they were before industrialisation and the onset of global warming.

In some places the rate of rise is much more dramatic. The Sundarman Delta has seen levels rising by more than 30mm a year http://news.bbc.co.uk/1/hi/world/south_asia/3102948.stm millions have already been forced to leave their homes http://news.bbc.co.uk/1/hi/sci/tech/5344002.stm and the Carteret Islands in the Pacific Ocean are currently being evacuated due to rising sea levels http://web.mac.com/pipstarr/iWeb/starr.tv/Climate/1389EF06-0A02-4BC3-A039-AD98E7B4E4DF.html making this the first complete land mass to be lost to rising sea levels.

It’s estimated that meltwater running off the Greenland ice sheet will in itself cause a rise of between 20 and 50mm a year http://www.geo.arizona.edu/dgesl/research/other/climate_change_and_sea_level/climate_change_and_sea_level.htm In time this will swamp cities including London, New York and Miami. Low lying areas such as Bangladesh, much of the European and American coasts and island groups including the Seychelles and Maldives would be submerged http://news.nationalgeographic.com/news/2004/04/0408_040408_greenlandicemelt.html

The two main causes of sea level rises are the expansion of the world’s seas and oceans as they warm up and the melting of the ice caps.

The temperature of the seas and oceans are rising faster then ever http://www.sciencemag.org/cgi/content/full/295/5558/1275?ijkey=nFvdOLNYlMNZU&keytype=ref&siteid=sci and like anything that heats up, they’re expanding. At the same time ice sheets are melting and releasing water into the oceans.


MELTING OF ICE CAPS
The Arctic ice cap is floating; the mass of water it contains is already displacing an equal amount of seawater so even if it were to melt entirely there would be no change in sea levels.

However, Antarctica is a continent, a land mass, it isn’t floating and any melting here adds to the sea level as does melting of ice sheets and glaciers in places such as Greenland.

The edges of the Antarctic Ice Sheet are breaking off and collapsing into the sea. One of the biggest breaks occurred in 2002 when the Larsen B Ice Shelf broke off. This huge mass of ice covered 3250 square kilometres and weighed half a trillion tons http://news.bbc.co.uk/1/hi/sci/tech/1880566.stm


POPULATION MIGRATION
For the reasons mentioned in this section, large numbers of people are going to find it increasingly difficult to remain in their present locations and in many cases it will be impossible. In Bangladesh some 13 million people will be forced to move if the sea level rises by just one metre http://www.worldviewofglobalwarming.org/pages/rising-seas.html and in the US tens of millions will be affected particularly along the north east coast, Florida, Louisiana and California http://www.geo.arizona.edu/dgesl/research/other/climate_change_and_sea_level/sea_level_rise/sea_level_rise.htm Globally it is expected that hundreds of millions of people will need to relocate or emigrate http://sun1.rrzn.uni-hannover.de/nhedinst/NATURE_416_389-395_2002.pdf


MARINE ENVIRONMENT
The world’s oceans absorb carbon dioxide, a little less than half the amount we have produced – about 150 billion tons in the last 200 years http://www.sciencemag.org/cgi/content/abstract/305/5682/367 Carbon dioxide dissolves in water to form carbonic acid and this is affecting the alkalinity of the oceans. Normally they have a pH of 8.3 but this has been reduced to 8.2 and is falling, it’s thought that by the end of the century the pH could drop to 7.7 http://web.archive.org/web/20050223042051/http://www.risingtide.nl/greenpepper/envracism/refugees.html

Many forms of marine life are highly sensitive to the level of alkalinity. The formation of corals is being affected and plankton, which forms the basis of the marine food chain, is also very sensitive.

The increasing levels of carbon dioxide make it harder for many species of fish and shellfish to breathe and reproduce. Changes in the ecology and chemistry of the seas and oceans reduce their ability to absorb CO2, which consequently increases the rate of global warming http://news.bbc.co.uk/1/hi/sci/tech/4633681.stm


ECOSYSTEMS
Global warming affects animals and plants as well as humans.

Parts of Antarctica are now covered in grass http://www.timesonline.co.uk/tol/news/uk/article405824.ece and there is a massive migration of animals towards the polar regions, these migrations extend an average of 6.1km further from the equator each decade http://www.animana.org/tab2/22refugespeciesfeelingtheheat.shtml Butterflies have extended their territory by some 200km further north in Europe and North America http://sun1.rrzn.uni-hannover.de/nhedinst/NATURE_416_389-395_2002.pdf

In the Arctic the habitat of polar bears and emperor penguins is being threatened. The waters of the Hudson Bay for example, are now ice free for three weeks more each year than they were 30 years ago. Polar bears are now starving because they need to venture onto the frozen ice to hunt food. In another 10 or 20 years there may no longer be polar bears in this region and within a hundred years they could be extinct http://www.lrb.co.uk/v27/n01/byer01_.html

The ecosystems are interlinked, if one species is affected it will undoubtedly affect others which in turn will affect others. The enforced migration of one animal for example, may result in the starvation of another which in turn could have other knock on effects and so ad infinitum.

The most extensive report into global warming and climate change predicts that up to 40% of animal species could become extinct due to global warming http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/30_10_06_exec_sum.pdf


MOUNTAIN ENVIRONMENTS
Glaciers are recognised as one of the best indicators of climate change and in many parts of the world are melting faster than has been known before http://www.nichols.edu/departments/glacier/ In the last 100 years 50% of the world’s glaciers outside the polar regions have melted http://earthscape.org/t1/low01/low01bc/low01bc.html The effects of glacial melt include flooding, landslides, avalanches and loss of habitat. In some mountainous regions melt water provides a year round water supply and without the glaciers there will be near drought conditions http://www.nichols.edu/departments/glacier/

Glacial retreat is happening at an incredible rate in many parts of the world. In Greenland the Kangerdlugssuaq Glacier is retreating by 40 metres a day and will soon disappear altogether http://www.agu.org/meetings/fm05/fm05-sessions/fm05_C41A.html Several other glaciers are retreating by 30 to 40 metres a day.


ECONOMY
The economic effect is staggering. Increased adverse weather in itself could cost 1% of the worldwide GDP and a temperature rise of 2 or 3°C would reduce global economic output by 3% http://news.bbc.co.uk/1/hi/business/6096594.stm In percentage terms these aren’t very big numbers but in terms of dollars the cost runs into trillions.

Insurance premiums are rising in line with the increased number of claims. The Association of British Insurers notes a 100% rise in weather related claims in recent years and states that climate change is already seriously impacting on the insurance industry http://www.abi.org.uk/Display/File/364/SP_Climate_Change5.pdf


OTHER EFFECTS
There are many other effects including disruption to transportation, loss of sea ports, forest fires, methane release from hydrates, the shutting down of the Gulf Stream, impact on development, the need for greater flood defences, spread of disease and drought. These and other concerns are addressed in the Wikipedia article ‘Effects of Global Warming’ http://en.wikipedia.org/wiki/Effects_of_global_warming .

Answer 2

Some say it's a radical temperature increase of the earth's surface in a short period of time.
If you look up any global temperature chart on the net, you'll find the earth's temperature has only increased by about 6/10 of one degree (C) - that's 1.1 degree (F), in the last 125 years. So yes, the globe is warming up, but it's not overheating like some would have you to believe. http://data.giss.nasa.gov:80/gistemp/2005/2005cal_fig1.gif

A recent article in the New York Times has even asked Al Gore to stop all the hype:
http://www.nytimes.com/2007/03/13/science/13gore.html?_r=1&oref=slogin That same article talks about Al Gore's claim that the oceans could rise 20 feet is exaggerated by 18.08 FEET! The latest UN study on the subject says the seas could rise a MAXIMUM of 23 inches. Al was only 18.08 FEET off. That, my freind IS hype...

The latest research shows that the methane from cows and pigs is a major factor in the increase of "heat trapping gas". It's actually 23 times more potent as a heat trapping gas than is carbon dioxide. http://www.greenpeace.org/international/campaigns/climate-change/science/other_gases According to the newest UN report on Global Warming, "Livestock are responsible for 18 per cent of the greenhouse gases that cause global warming, more than cars, planes and all other forms of transport put together." http://news.independent.co.uk:80/environment/article2062484.ece

So if Al Gore and all the alarmists are serious about doing something about climate change, they MUST become vegetarians and shut down cow and pig farms. I mean seriously, if they truly believe that global warming is as disastrous as they are preaching then they need to stop eating meat, period! I doubt that will happen. If not, then they are the hypocrites that some of us already suspect they are.

Also Al Gore preaches to you to conserve, but he does not practice it himself. He uses 20 times more energy in his Nashville mansion than the national average. http://www.tennesseepolicy.org/main/article.php?article_id=367
One thing he has not learned is that you MUST practice what you preach... at some point you will get caught as he has.

Answer 3

It is an upward change in the temperature of earth's atmosphere.

There are many possible contributing factors, from orbital cycles and sunspot activity to changes in our environment. However, there are a few key facts pretty much beyond dispute of anyone not in the coal and oil industry. These are that carbon dioxide is a greenhouse gas, and that the atmospheric concentration of carbon dioxide has steadily risen ever since we began making precise measurements of it. We also know the source of the carbon--it closely parallels the amount we have pumped and/or mined from the earth over the last six decades.

Answer 4

the rising temperature in the earths atmosphere witch will cause the polar ice caps to melt and flood the earth
this is very bad for the environment
it is caused by eccesive polution and things mostly cause by people

Answer 5

it is a natural occurrence caused by temperature fluctuations on the sun. do not listen to the scientist how are making their living from trying to scare people about it by saying it is man made and we have to stop it. remember if they admit that it is a natural occurrence them they no longer have jobs or the money that they get from the government for research.