What causes global warming?

Question

I need a specific answer because i am doing a science project.

Answer 1

The sun radiates heat down onto Earth; some gets reflected by clouds and by Earth's surface (albedo). But some of the heat that's reflected by Earth's surface get trapped by greenhouse gases in the atmosphere (carbon dioxide, methane, CFCs, nitrous oxides) and get re-rediated back down to Earth in the form of infrared energy, which causes an increase in global temp. Also, the sun tilts every 23,000 years or something (Milankovitch cycles) which causes slight changes in global temp.

Answer 2

What causes global warming is the re-radiation of infrared energy to the earth's surface by various gases in the atmosphere, notably carbon dioxide, methane and water vapor. In the current tizzy, global warming is attributed by many to the use of carbon based fuels, although the real problem with carbon fuels is that the source is fossil (that is, from ancient reservoirs.) A carbon based fuel that was recently created (wood, straw, other plant material that has grown in the last few years) would not be contributing to an increase in atmospheric carbon dioxide since it was created from atmospheric carbon dioxide; thus it is recycling the carbon dioxide instead of increasing it.

Before getting the idea that all global warming is bad, be advised that if there were no carbon dioxide in the atmosphere, we likely would be enduring an ice age now. The reason there is a dispute over the subject is that drastically limiting the use of carbon based fuels would significantly upset the economies of developed countries and, generally, people have to be convinced that there is a serious danger before they are willing to give up their comfort and convenience.

Answer 3

All the hot air in Congress

If we are having global warming - why is the midwest freezing
and 500,000 people without power?

since less than half of scientists agree on GW - hmmmmmm
guess you PROVE your theory better when you pick and choose your data sources

so - really - what about POPULATION as a cause

1800 - world pop. 900 million
1900 - 1.6 Billion
2000 - 6 Billion
2005 - 6.5 BILLION - could the cause be people
and not SUV's

check out the Mt St Helen's eruption a few years back -
more 'pollution' went into the atmosphere in that one event -
than the last 100 years of man's existence

and what about the Kyoto Protocol
IF (if!) we spend Three TRILLION dollars
we MAY (may?) be able to slow G.W. by 7 tenths of ONE degree

are you kidding - $3,000,000,000,000 - on a maybe???

7/10 of 1

my math stinks - BUT - you gotta be kidding

sorry - this data (well maybe the population thing) won;t score you an A

all the best

Answer 4

That guy is a terd. :)

Global warming is caused by a lack of o-zone. The earth has an o-zone layer that is eroding because of excess carbon monoxide levels in the atmosphere (due to many things but most attribute the excess levels to vehicle emissions as well as any emissions from combustion of fuels).

Some years back there was an effort to reduce the erosion where people were asked to stop using aerosol spray cans such as deoderant, Lysol, etc. The federal government passed an emissions act that vehicle manufacturers had to meet with all vehicles being built.

The less o-zone we have the more UV rays are allowed to pass through. These UV rays heat up the earth. As bodies of water heat up polar caps melt. The more ice that melts the less UV is reflected back into space and more is absorbed by the earth.

It's a viscious cycle that needs to be slowed or we will start to see less land mass when oceans begin to rise. Beaches will disappear and coast lines will change. Rivers will expand and continents will begin to change as ground is eroded.

Earth will not look much like the earth you know today - unless we take action and a global strategy to reduce emissions is developed and followed.

Answer 5

Wow -- after seeing the answer form
Jeremiah Zacarias , just skip my answer and go to that one!

Increased global warming has occurred with the increase of the heat in our atmosphere caused by the increase of the green-house effect due to the increase of Carbon Dioxide in our atmosphere.

The sources of this increased Carbon Dioxide comes from the destruction ofour forests (mainly our rain forests) , the destruction of the algae along our ocean coastlines, but primarily from burning fossel fuels.

Atmospheric warming is quite evident today with the drastically melting ice caps and the ice on Greenland and the Antarctic Continent.

But the increased coastlines-- as much as 40 feet -- and the increase of hurricane severity is only the tip of the iceberg so to speak.

The ocean has ONE current. (All the ocean currents are actually one continuous "river of water." The "pump" that makes this current move is located north of Iceland in the Arctic Ocean where denser less saltier water drops thousands of feet in the very salty and less dense waters of that part of the ocean. Unfortunately as the Arctic becomes less salty due to the ice cap melt and from the melt off from Siberia, this "pump" may stop. Some predict as soon as 50 to 70 years from now if nothing stops the melt off. If this occurs the mediating effect of the ocean currents will no longer be operative thus allowing the north latitudes to get much colder and the central ones to get hotter. This will bring on an ice age allowing ice sheets to come down to as far as the gulf States. This can happen in VERY short order -- probably less than 10 years.

The resultant movement of vast populations southward and the resulting wars and starvation will end civilization as we knew it.

And according to some this can happen WELL before the turn of the next century.

See:

Expectance for the future
This is assumed to have been a consequence of the ocean current stopping due to warmer surface water and melting water of low salinity. ...
www.atmosphere.mpg.de/enid/2gn.html

Abrupt Climate Change: Should We Be Worried? : Woods Hole Oceanographic ...
Ocean Topics. Climate & Oceans. Abrupt Climate Change. Global Warming. Ocean ... a swift reorganization of the ocean currents circulating around the earth. ...www.whoi.edu/page.do?pid=12455&tid=282&cid=9986

Ocean Motion : Research and Applications : Curt Ebbesmeyer
Learn about the ocean in motion and how ocean surface currents play a role in ... Floating debris has become a permanent feature of the world's oceans. ...oceanmotion.org/html/research/ebbesmeyer.htm

A Chilling Possibility
By disturbing a massive ocean current, melting Arctic sea ice might trigger ... the vast heat that these ocean currents deliver--comparable to the power ...science.nasa.gov/headlines/y2004/05mar_arctic.htm


OR like "tom4bucks" you can ignore the whole thing and pretend it is not happening. (I bet he's a Bush republican and fundamentalist christian -- just the type of person who decides to abdicate their ability to think and reason)

Answer 6

if you have a little bit of time, go get al gore's movie. it is perfect for what you are working on.

Answer 7

There are 3 major causes of global warming
* greenhouse gases in the atmosphere
* feedbacks
* solar variation

explanation:
1. greenhouse effect

The greenhouse effect was discovered by Joseph Fourier in 1824 and was first investigated quantitatively by Svante Arrhenius in 1896. It is the process by which absorption and emission of infrared radiation by atmospheric gases warm a planet's atmosphere and surface.

Existence of the greenhouse effect as such is not disputed. Naturally occurring greenhouse gases have a mean warming effect of about 33 °C (59 °F), without which Earth would be uninhabitable.[17][18] The debate centers on how the strength of the greenhouse effect is changed when human activity increases the atmospheric concentrations of some greenhouse gases.

On Earth, the major greenhouse gases are water vapor, which causes about 36–70% of the greenhouse effect (not including clouds); carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone, which causes 3–7%.Some other naturally occurring gases contribute very small fractions of the greenhouse effect; one of these, nitrous oxide (N2O), is increasing in concentration owing to human activity such as agriculture. The atmospheric concentrations of CO2 and CH4 have increased by 31% and 149% respectively above pre-industrial levels since 1750. These levels are considerably higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from ice cores. From less direct geological evidence it is believed that CO2 values this high were last attained 20 million years ago. Fossil fuel burning has produced about three-quarters of the increase in CO2 from human activity over the past 20 years. Most of the rest is due to land-use change, in particular deforestation.

The present atmospheric concentration of CO2 is about 383 parts per million (ppm) by volume.Future CO2 levels are expected to rise due to ongoing burning of fossil fuels and land-use change. The rate of rise will depend on uncertain economic, sociological, technological, and natural developments, but may be ultimately limited by the availability of fossil fuels. The IPCC Special Report on Emissions Scenarios gives a wide range of future CO2 scenarios, ranging from 541 to 970 ppm by the year 2100.Fossil fuel reserves are sufficient to reach this level and continue emissions past 2100, if coal, tar sands or methane clathrates are extensively used.

2. feedbacks

The effects of forcing agents on the climate are complicated by various feedback processes.

One of the most pronounced feedback effects relates to the evaporation of water. In the case of warming by the addition of long-lived greenhouse gases such as CO2, the initial warming will cause more water to be evaporated into the atmosphere. Since water vapor itself acts as a greenhouse gas, this causes still more warming; the warming causes more water vapor to be evaporated, and so forth until a new dynamic equilibrium concentration of water vapor is reached with a much larger greenhouse effect than that due to CO2 alone. Although this feedback process involves an increase in the absolute moisture content of the air, the relative humidity stays nearly constant or even decreases slightly because the air is warmer.This feedback effect can only be reversed slowly as CO2 has a long average atmospheric lifetime.

Feedback effects due to clouds are an area of ongoing research. Seen from below, clouds emit infrared radiation back to the surface, and so exert a warming effect; seen from above, clouds reflect sunlight and emit infrared radiation to space, and so exert a cooling effect. Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud. These details are difficult to represent in climate models, in part because clouds are much smaller than the spacing between points on the computational grids of climate models. Nevertheless, cloud feedback is second only to water vapor feedback and is positive in all the models that were used in the IPCC Fourth Assessment Report.

Another important feedback process is ice-albedo feedback.When global temperatures increase, ice near the poles melts at an increasing rate. As the ice melts, land or open water takes its place. Both land and open water are on average less reflective than ice, and thus absorb more solar radiation. This causes more warming, which in turn causes more melting, and this cycle continues.

Positive feedback due to release of CO2 and CH4 from thawing permafrost, such as the frozen peat bogs in Siberia, is an additional mechanism contributing to warming. A massive release of CH4 from methane clathrates could cause rapid warming, according to the clathrate gun hypothesis.

The ocean's ability to sequester carbon is expected to decline as it warms, because the resulting low nutrient levels of the mesopelagic zone limits the growth of diatoms in favor of smaller phytoplankton that are poorer biological pumps of carbon.

3. Solar variation

A few papers suggest that the Sun's contribution may have been underestimated. Two researchers at Duke University, Bruce West and Nicola Scafetta, have estimated that the Sun may have contributed about 45–50% of the increase in the average global surface temperature over the period 1900–2000, and about 25–35% between 1980 and 2000.[30] A paper by Peter Stott and other researchers suggests that climate models overestimate the relative effect of greenhouse gases compared to solar forcing; they also suggest that the cooling effects of volcanic dust and sulfate aerosols have been underestimated. They nevertheless conclude that even with an enhanced climate sensitivity to solar forcing, most of the warming since the mid-20th century is likely attributable to the increases in greenhouse gases.

A different hypothesis is that variations in solar output, possibly amplified by cloud seeding via galactic cosmic rays, may have contributed to recent warming.It suggests magnetic activity of the sun is a crucial factor which deflects cosmic rays that may influence the generation of cloud condensation nuclei and thereby affect the climate.

One predicted effect of an increase in solar activity would be a warming of the stratosphere; however, the observed effect since at least 1960 has been a cooling of the lower stratosphere, which is one of the predicted results of greenhouse gas warming.Reduction of stratospheric ozone also has a cooling influence, although substantial ozone depletion did not occur until the late 1970s. Solar variation combined with changes in volcanic activity probably did have a warming effect from pre-industrial times to 1950, but a cooling effect since.In 2006, Peter Foukal and other researchers from the United States, Germany, and Switzerland found no net increase of solar brightness over the last thousand years. Solar cycles led to a small increase of 0.07% in brightness over the last 30 years. This effect is far too small to contribute significantly to global warming. A paper by Mike Lockwood and Claus Fröhlich found no relation between global warming and solar radiation since 1985, whether through variations in solar output or variations in cosmic rays.Henrik Svensmark and Eigil Friis-Christensen, the main proponents of cloud seeding by galactic cosmic rays, disputed the findings of Lockwood and Fröhlich.

Answer 8

excessive carbon emission...............pollution

Answer 9

obesity