why is global warming happening?

Question

why is it happening?

Answer 1

Global Warming has occurred over the past 120 years, and has been especially rapid in the last 20 years. We know this from surface temperature observations.

- Carbon Dioxide as well as other greenhouse gases cause a warming in the atmosphere.

- Carbon Dioxide has increased dramatically in the last 120 years, and is at its highest level taking into consideration ice core samples, which include a 400,000 year period.

- Humans are overwhelmingly responsible for the dramatic increase in Carbon Dioxide and other greenhouse gases. They’re emitted from our consumption of common fuel sources for energy, like fossil fuels.

Answer 2

At this point, most scientists agree it is because
human beings are allowing too much CO2 to
escape into the atmosphere.

CO2 prevents some heat from radiating out
into space, upsetting a long standing balance
between radiating heat and keeping it around.

The net effect is that the temperature slowly
climbs.

CO2 emissions come primarily from burning
fossile fuels, so people usually state that the
remedy will at least include cutting back on
burning them - but since most of the world's
energy comes from burning fossile fuels,
this will have economic impact.

We can also increase the amount of vegetation
(plants consume CO2 and release Oxygen),
perhaps trying to make up for all of the forrests
we're cutting down in South America etc.

Note that carbon emissions tend to have a
cascading effect: As the planet warms, places
that have been buried under ice and snow
thaw and the ground emits whatever
CO2 was trapped underneath it - for instance,
the peat bogs in Siberia are beginning to
emit CO2 as they are exposed. Even if
humans stopped emitting CO2, its possible
that the planet is suficiently warmer that we
cannot stop the cascade effect.

Most economic solutions to this problem
are stated in terms of decades. Most
scientists who have worked on this for
any period of time feel that the damage
has pretty much already been done and
that short of huge overhaults within months,
the effects will speed up regardless of
what we do.

Note that humans may only be accelerating
the process of global warming - that is,
some amount of CO2 release is natural
and it could perhaps be sufficient to cause
the atmosphere to warm.

However, the effects will be equally deadly
whether we caused it or whether this
is just something the planet does
every once in awhile. Clearly, humanity
should be investigating what it can do
to slow it down, even if we didn't cause it.

Dead is dead. Who was right is irrelevent.

Answer 3

The specific answer to your question is: because the presence of H2O and CO2 (and to a lesser extent CH4 and SO2) in our atmosphere causes the greenhouse effect – solar radiation comes in and heats the Earth’s surface - Earth radiates it’s heat back into space – on its way back into space some of this heat radiation gets absorbed by these gases and stays trapped on Earth, keeping us wrapped up in a warm blanket. It’s a good thing, too because without these gasses, Earth would be much too cold for any of us to have evolved here.

The issue that most people seem to be chiming in about is whether global warming is natural or anthropogenic. The answer is: it is BOTH.
Variations in the magnitude of global warming are due to natural climate variations; however, lately we have observed that the latest warming trend is being accelerated by human activity.

These are not scare tactics, these are scientific observations and measurements. Before putting too much stock into some graph on the internet, I suggest finding out if it has been published in modern peer-reviewed scientific literature.

Answer 4

global warming is actually a natural process, but we have sped it up. Normally, rays of radiation from the sun hit the earth and help to warm us. Normally, those same rays then bounce off the earth's surface and return to space. However, an excess of "greenhouse gases", such as carbon dioxide (an excess of which is due greatly to the cutting down of rainforests), allow the rays to strike the earth but then they block the rays from returning to space. As a result, the rays hit the earth a second time, warming the earth more than it normally would.

Answer 5

Global warming is happening because it's a natural cycle. Eventually, we will slip back to global cooling.

Man-made global warming is happening because pseudo-scientists, politicians, and other fearmongers have found an opportunity to profit from peoples' ignorance.

Answer 6

It is a naturally occuring cycle as can be seen clearly on this graph. Notice that most of the recent upswing was far before humans had a chance to influence it.

http://www.iitap.iastate.edu/gccourse/chem/carbon/images/paleotrends.gif

This graph shows how temperature and CO2 have changed over thousands of years. Note that it started rising far before industry had a chance to influence. It is also interesting to note the correlation of CO2 concentration. The correlation isn't necessarily an indication of causation. Since CO2 is not nearly as significant a green houes gas as water vapor, it seems likely that the temperature is affecting the CO2 concentration, not necessarily vice versa. It is also important to point out the hockey stick at the end of the graph. It shows that it really isn't very important when looking at the overall trend. Those who talk about the hockey stick are ignorant or just trying to scare in my opinion.

Answer 7

Plus Ça (Climate) Change
The Earth was warming before global warming was cool.

BY PETE DU PONT
Wednesday, February 21, 2007 12:01 a.m. EST (Wall Street Journal Online)

When Eric the Red led the Norwegian Vikings to Greenland in the late 900s, it was an ice-free farm country--grass for sheep and cattle, open water for fishing, a livable climate--so good a colony that by 1100 there were 3,000 people living there. Then came the Ice Age. By 1400, average temperatures had declined by 2.7 degrees Fahrenheit, the glaciers had crushed southward across the farmlands and harbors, and the Vikings did not survive.

Such global temperature fluctuations are not surprising, for looking back in history we see a regular pattern of warming and cooling. From 200 B.C. to A.D. 600 saw the Roman Warming period; from 600 to 900, the cold period of the Dark Ages; from 900 to 1300 was the Medieval warming period; and 1300 to 1850, the Little Ice Age.

During the 20th century the earth did indeed warm--by 1 degree Fahrenheit. But a look at the data shows that within the century temperatures varied with time: from 1900 to 1910 the world cooled; from 1910 to 1940 it warmed; from 1940 to the late 1970s it cooled again, and since then it has been warming. Today our climate is 1/20th of a degree Fahrenheit warmer than it was in 2001.




Many things are contributing to such global temperature changes. Solar radiation is one. Sunspot activity has reached a thousand-year high, according to European astronomy institutions. Solar radiation is reducing Mars's southern icecap, which has been shrinking for three summers despite the absence of SUVS and coal-fired electrical plants anywhere on the Red Planet. Back on Earth, a NASA study reports that solar radiation has increased in each of the past two decades, and environmental scholar Bjorn Lomborg, citing a 1997 atmosphere-ocean general circulation model, observes that "the increase in direct solar irradiation over the past 30 years is responsible for about 40 percent of the observed global warming."
Statistics suggest that while there has indeed been a slight warming in the past century, much of it was neither human-induced nor geographically uniform. Half of the past century's warming occurred before 1940, when the human population and its industrial base were far smaller than now. And while global temperatures are now slightly up, in some areas they are dramatically down. According to "Climate Change and Its Impacts," a study published last spring by the National Center for Policy Analysis, the ice mass in Greenland has grown, and "average summer temperatures at the summit of the Greenland ice sheet have decreased 4 degrees Fahrenheit per decade since the late 1980s." British environmental analyst Lord Christopher Monckton says that from 1993 through 2003 the Greenland ice sheet "grew an average extra thickness of 2 inches a year," and that in the past 30 years the mass of the Antarctic ice sheet has grown as well.




Earlier this month the U.N.'s Intergovernmental Panel on Climate Change released a summary of its fourth five-year report. Although the full report won't be out until May, the summary has reinvigorated the global warming discussion.
While global warming alarmism has become a daily American press feature, the IPCC, in its new report, is backtracking on its warming predictions. While Al Gore's "An Inconvenient Truth" warns of up to 20 feet of sea-level increase, the IPCC has halved its estimate of the rise in sea level by the end of this century, to 17 inches from 36. It has reduced its estimate of the impact of global greenhouse-gas emissions on global climate by more than one-third, because, it says, pollutant particles reflect sunlight back into space and this has a cooling effect.

The IPCC confirms its 2001 conclusion that global warming will have little effect on the number of typhoons or hurricanes the world will experience, but it does not note that there has been a steady decrease in the number of global hurricane days since 1970--from 600 to 400 days, according to Georgia Tech atmospheric scientist Peter Webster.

The IPCC does not explain why from 1940 to 1975, while carbon dioxide emissions were rising, global temperatures were falling, nor does it admit that its 2001 "hockey stick" graph showing a dramatic temperature increase beginning in 1970s had omitted the Little Ice Age and Medieval Warming temperature changes, apparently in order to make the new global warming increases appear more dramatic.




Sometimes the consequences of bad science can be serious. In a 2000 issue of Nature Medicine magazine, four international scientists observed that "in less than two decades, spraying of houses with DDT reduced Sri Lanka's malaria burden from 2.8 million cases and 7,000 deaths [in 1948] to 17 cases and no deaths" in 1963. Then came Rachel Carson's book "Silent Spring," invigorating environmentalism and leading to outright bans of DDT in some countries. When Sri Lanka ended the use of DDT in 1968, instead of 17 malaria cases it had 480,000.
Yet the Sierra Club in 1971 demanded "a ban, not just a curb," on the use of DDT "even in the tropical countries where DDT has kept malaria under control." International environmental controls were more important than the lives of human beings. For more than three decades this view prevailed, until the restrictions were finally lifted last September.

As we have seen since the beginning of time, and from the Vikings' experience in Greenland, our world experiences cyclical climate changes. America needs to understand clearly what is happening and why before we sign onto U.N. environmental agreements, shut down our industries and power plants, and limit our economic growth.

Mr. du Pont, a former governor of Delaware, is chairman of the Dallas-based National Center for Policy Analysis. His column appears once a month.

Answer 8

Because of overpumping and no refilling of underground water.
Then the sun rays overheat the rocks instead to developp the trees which recycle the co2.
So you know now what we have to do....

Answer 9

Do you mean why has the average temperature gone up 0.5 degrees in the last one hundred years? Probably because of solar cycles, and it has nothing to do with human activity.

Answer 10

All the data I have Sean is wrong and your main gases that is supposed to be causing it are not there.