how long is global warming supposed to take to set in?

Answer 1

It's already been around for some time.

Answer 2

Well, it has begun. It began several millions of years ago--and then it becomes "global cooling", and then it returns to "global warming" etc. Remember the "ice age?" The earth has been warming and cooling since its creation about 4.5 billion years ago. This has led to massive changes, which is why we can find fish fossils in the Gobi desert, or oil in the Kuwaiti sands.
The current "fuss" about global warming is because since man has been measuring the earth's temperature (since the 1700's) we've seen a spike. It began in about 1820, which is precisely when the "industrial revolution" began. The theory is that man's use of fossil fuels (notably coal and oil) which took off in ernest in the 1800's and has accelerated at a great rate in the last 40 years, is causing an "unnatural" global warming, not related to normal Earth cycles. This time, man is "smart enough" to control the phenomenum--or so it is theorized.
The results of this recent "global warming" really began with the retreat of the glaciers across North America, Europe, and Asia about 10,000 years ago. We'll need to cool the planet about 12 degrees to get back to that "natural" state where the planet has glaciers all over it. Conversely, if we increase the temperature about 9 degrees, we'll melt 90% of the ice, and the ocean levels will raise several feet. The Earth needs to be in a comfortable zone within just a few degrees! The recent paper presented to the world suggests that mankind's use of fossil fuels has raised the temperature of the atmosphere a little more than a half a degree Celcius. If so, and if we continue, it will continue to get warmer and warmer, and in another hundred years or so, might increase the atmosphere's temperature by a whole degree.

Answer 3

It has been going on since the last Ice Age. It will likley continue much as it has since before man figured out fosil fules.

It's not global warming we need to worry about it's the rapid switch to cold that puntuates the warming. When it gets cold the carrying capacity of the Earth will shrink and there will not be enough food for everyone. This switch from hot to cold is likley to be a mater of a few years once it starts.

Here is a clip from a good paper on climate history -
A particularly widespread cool event associated with relatively wet conditions seems to have occurred in many parts of the world around 2600 years ago (van Geel et al. 1996). A general pattern in climate during the Holocene has been detected from high-resolution cores in the north Atlantic. It seems that at least in the North Atlantic region, and possibly globally, there was a warm-cold cycle with a periodicity of around 1500 years (Bond et al. 1997). In the north Atlantic region, and probably adjacent oceanic areas of Europe, the change from peak to trough of each period was about 2 deg.C , a very substantial change in mean annual temperature (though only a small fraction of the change between glacial and interglacial conditions). The cold phases seem to have been relatively abrupt, and each lasted several centuries before an apparently rapid switch back to warmer conditions. on this approximate periodicity are dated at 11,100 10,300 9,400 8,100 5,900 4,200 2,800 and 1400 years ago; they include the 8,600 y.a. and 2,600 y.a. events which seem to have been the most extreme in terms of showing up in terrestrial records around the world.

Answer 4

That's one of the few things that scientists are still unsure of. The best estimates are 20-50 years before things get really bad.

But it will take longer than that to reduce the disatser we face. We need to start now.

"The science of global warming is clear. We know enough to act now. We must act now."

James Rogers, CEO of Charlotte-based Duke Energy.

"The overwhelming majority of atmospheric scientists around the world and our own National Academy of Sciences are in essential agreement on the facts of global warming and the significant contribution of human activity to that trend."

Russell E. Train, former environmental official under Presidents Nixon and Ford

"Global warming is already starting, and there's going to be more of it. I think there is still time to deal with global warming, but we need to act soon. Humans now control global climate, for better or worse."

James Hansen, Ph.D. climate scientist, NASA

"By mid-century, millions more poor children around the world are likely to face displacement, malnourishment, disease and even starvation unless all countries take action now to slow global warming."

Michael Oppenheimer, professor of geosciences and international affairs at Princeton University

"We simply must do everything we can in our power to slow down global warming before it is too late. The science is clear. The global warming debate is over."

Arnold Schwarzenegger, Republican, Governor, California

"Our nation has both an obligation and self-interest in facing head-on the serious environmental, economic and national security threat posed by global warming."

John McCain, Republican, Senator, Arizona

"These technologies will help us become better stewards of the environment - and they will help us to confront the serious challenge of global climate change."

President George Bush, Republican

Answer 5

It started back in the 1830's, but the normal year-to-year variations hid it for 150 years or so.

By the 1980's it was accelerating. By 2007, it was too obvious for most sensible people to ignore. By 2107, the melting ice from Greenland and Antarctica had raised the sea level 2 meters, forcing the abandonment of many coastal cities. Crop failures due to the increased climate caused the death of millions of people.

It was not until the year 2193 that global warming was reversed by the actions of ...

Answer 6

It has already begun, and it will continue unchecked without drastic (and admittedly, almost impossible) changes for at least the next 100 years. Huge chunks of ice are melting off Greenland and Antarctica, and this is unprecedented.

Answer 7

Well it's already setting in.
But it is predicted that the ice caps will have melted in 40 years. Is that what "set in" means to you?

Answer 8

i has set in for a while now ,you personally may not have suffered yet but plenty of other people know all about it

in recent times thousands of people have died because of exessive heat,usually old people.in India ,Mexico and France,
deforestation causing desertification,the desert conditions causing very cold nights and scorching hot days

in china, thousands of what used to be farmers are running for their lives from the dust storms that have burried their towns and turned their lands into dessert,the globe where they were got to hot for them .
and instead of producing food they are now needing it from some where else,and they will drastically effect the world food prices when they start buying water in the form of grains ,at any cost destabalising governments, in some countries ,could be the result
(are you seeing more Chinese around interested in agricultural lands ,we do here in Mexico)

,the Sahara is growing by 7 kilometers a year
and all of the desserts we know are a results of mans actions ,and they are increasing ,not getting less ,in the dinosaurs days ,there were no desserts.

collectively this planet is drying up because of bad farming practices like,over grazing and fertilizers,

as far as the food production is concerned, Global warming or some of its effects are serious,rising seas result in landloss

each degree rise in temperature means 10%crop loss

more landloss because of desertification every year,we have less areble land to produce food ,for an extra 70 million people ,

and there is less and less water (because of deforestation),to irrigate this production ,
and there are less and less farmers to do it..
who are overpumping deep carbon aquifiers
who are plowing more and more unstable lands because they have lost so many million hectares to desertification ,
because of bad farming practises ,such as using fertilizers and heavy machinary or over grazing

RISING SEAS
The northpole is melting ,and we will know it without ice in our life times.
this does not affect the sea level because it is ice that is already in the water.but the melting ice from Green land and the south pole ,are another matter.

Global warming is in theory reversable,but it will mean global co operation between all countries ,and taking into account human nature and the world politics ,it is unlikely that this will happen,

At least not untill we are all in the middle of planetary disastres and it becomes a battle for the survival of humanity every where.

SOLUTIONS
if you want to help the planet ,plant a tree every week ,if everyone on the planet did we we would be able to reverse the destructive processes

reduce carbon emisions,and they are already working on that by alternative forms of energy and regulations on carbon producing materials,aerosol cans,burning rubbish,industrial chimneys,powerplants etc.

the capture of carbon and the production of water and assist the aquiferous manta.

the world bank pays large subsidies for reforrestation to capture carbon and the best tree for this is the Pawlonia

Waterharvesting projects ,such as millions of small dams.to redirect over ground waterflows from the rains into the ground to supply subteranian water supplies.

the protection of existing forrests.

stop building more highways,urban planning to include vegetation stop building cities encourage people to return to the land to conduct their business from there which now has become possible thanks to the internet.

education to motivate people to auto sufficiency by building more home food gardens.

education on environmental awareness
education on family planning to curb over´populaion

Agricultural education and improvements to follow the principals or sustainability and soil management.

more environmental or land ,design to prevent bush fires,such as--fire breaks

,more dams.regulations and control for public behaviour

alternative effeciant public transport to discourage the use of the internal conbustion engine

recicling wastes,limit water use

i am a Permaculture Consultant for the department of Ecology for the regional government in Guerrero Mexico
http://spaces.msn.com/byderule

Source(s) Lester E Brown is the director and founder of the global institute of Environment in the United states .he has compiled a report based on all the satalite information available from NASA,and all the information that has
come from Universities and American embassies WORLD WIDE ,
his little book--a planet under stress , Plan B has been trans lated into 50 languages and won the best book award in 2003.