If you block the sun?

Question

pump CO2 in the air like depends on it... would the earth warm up or go in a deep freeze?

If you believe CO2 warms the climate then block the sun or even just block part of the sun.

If you believe the sun warms the climate then why listen to some politician, turned inventor, turned envirofreak, turned prophet?

Answer 1

If the sun didn't warm the earth, everything on earth would die.

Answer 2

The greenhouse effect is, as many people have stated here, responsible for retaining a small amount of the energy from the Sun. Without it, the Earth would be retaining slightly less heat (not "none" as some of our less educated claim), 20-30 degrees celsius. All this does is keep the Earth in a habitable range for humans along with most of the Earth's current species - and that's a LOT from our perspective.

CO2 is NOT a potent greenhouse gas unless you magically take every molecule of water off of the planet. Water vapor is responsible for about 90% of global warming. Man-made CO2 only accounts for about 10% of all CO2 in the atmosphere - so we're talking of a "potent" man-made effect of less than a percent of the 20 - 30 degrees of heating.

Answer 3

If you blocked out the sun, CO2 would not have a warming effect. Greenhouse gases simply trap heat in, but you need a heat source.

Nobody is saying CO2 causes global warming by itself. Just because the sun is the source of heat doesn't mean that CO2 isn't a big cause of global warming. Your logic is extremely flawed.

Answer 4

Wha...? When did anyone ever say CO2 provides the energy that warms the atmosphere? All anyone's ever said is that CO2 is a potent greenhouse gas and is responsible for the current climate =change=.

Greenhouse gases trap radiation from the sun. Without them none of the sun's energy would stay put to warm the planet and Earth would be a frozen wasteland. So the importance of GHG's is not their ability to radiate heat, it's their capacity to retain heat radiated by the sun.

Answer 5

Even trapped heat has to come from somewhere to start with ,if you block the sun completely and for long enough ,you would start an Ice age .

But you need a hell of a big parasol.

Answer 6

Have you ever burned anything using the suns rays and a magnifying glass? Consider CO2 as the magnifying glass of the earth.

Answer 7

CO2 is a very heavy gas and u cant make it stay up high in the atmosphere. It is heavy enough to smother a fire . If u put a lot in the air it would come down and smother u.

Answer 8

Here's some light reading for you....moron.

When sunlight reaches the surface of the Earth, some of it is absorbed and warms the Earth. Because the Earth's surface is much cooler than the sun, it radiates energy at much longer wavelengths than does the sun. The atmosphere absorbs these longer wavelengths more effectively than it does the shorter wavelengths from the sun. The absorption of this longwave radiant energy warms the atmosphere; the atmosphere also is warmed by transfer of sensible and latent heat from the surface. Greenhouse gases also emit longwave radiation both upward to space and downward to the surface. The downward part of this longwave radiation emitted by the atmosphere is the "greenhouse effect." The term is a misnomer, as this process is not the mechanism that warms greenhouses.

The major natural greenhouse gases are water vapor, which causes about 36-70% of the greenhouse effect on Earth (not including clouds); carbon dioxide, which causes 9-26%; methane, which causes 4-9%, and ozone, which causes 3-7%. It is not possible to state that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. (The higher ends of the ranges quoted are for the gas alone; the lower ends, for the gas counting overlaps.)[2][3] Other greenhouse gases include, but are not limited to, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, perfluorocarbons and chlorofluorocarbons (see IPCC list of greenhouse gases).

The major atmospheric constituents (nitrogen, N2 and oxygen, O2) are not greenhouse gases. This is because homonuclear diatomic molecules such as N2 and O2 neither absorb nor emit infrared radiation, as there is no net change in the dipole moment of these molecules when they vibrate. Molecular vibrations occur at energies that are of the same magnitude as the energy of the photons on infrared light.

It is worth noting that late 19th century scientists experimentally discovered that N2 and O2 did not absorb infrared radiation (called, at that time, "dark radiation") and that CO2 and many other gases did absorb such radiation. It was recognized in the early 20th century that the known major greenhouse gases in the atmosphere caused the earth's temperature to be higher than it would have been without the greenhouse gases.


[edit] Anthropogenic greenhouse gases

Global anthropogenic greenhouse gas emissions broken down into 8 different sectors for the year 2000.The concentrations of several greenhouse gases have increased over time.[4] Human activity increases the greenhouse effect primarily through release of carbon dioxide, but human influences on other greenhouse gases can also be important.[5] Some of the main sources of greenhouse gases due to human activity include:

burning of fossil fuels and deforestation leading to higher carbon dioxide concentrations;
livestock and paddy rice farming, land use and wetland changes, pipeline losses, and covered vented landfill emissions leading to higher methane atmospheric concentrations. Many of the newer style fully vented septic systems that enhance and target the fermentation process also are major sources of atmospheric methane;
use of chlorofluorocarbons (CFCs) in refrigeration systems, and use of CFCs and halons in fire suppression systems and manufacturing processes.
agricultural activities, including the use of fertilizers, that lead to higher nitrous oxide concentrations.
The seven sources of CO2 from fossil fuel combustion are (with percentage contributions for 2000-2004)[6]:

Solid fuels (e.g. coal): 35%
Liquid fuels (e.g. petrol): 36%
Gaseous fuels (e.g. natural gas): 20%
Flaring gas industrially and at wells: <1%
Cement production: 3%
Non-fuel hydrocarbons: <1%
The "international bunkers" of shipping and air transport not included in national inventories: 4%
Greenhouse gas emissions from industry, transportation (they are 1/3 of total US global warming pollution)[7] and agriculture are very likely the main cause of recently observed global warming.[8].[9]

Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gases (sulfur hexafluoride, HFCs, and PFCs) are the major greenhouse gases and the subject of the Kyoto Protocol, which entered into force in 2005.[10]

CFCs, although greenhouse gases, are regulated by the Montreal Protocol, which was motivated by CFCs' contribution to ozone depletion rather than by their contribution to global warming. Note that ozone depletion has only a minor role in greenhouse warming though the two processes often are confused in the popular media.

The United States emitted 16.3% more GHG in 2005 than it did in 1990.[11] Major sources of an individual's GHG include home heating and cooling, electricity consumption, and automobiles. Corresponding conservation measures are improving home building insulation, cellular shades, Compact fluorescent lamps, and choosing high miles per gallon vehicles.


[edit] The role of water vapor

Increasing water vapor at Boulder, Colorado.Water vapor is a naturally occurring greenhouse gas and accounts for the largest percentage of the greenhouse effect, between 36% and 90% [2]. Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at local scales (for example, near irrigated fields).

Current state-of-the-art climate models include fully interactive clouds[3]. They show that an increase in atmospheric temperature caused by the greenhouse effect due to anthropogenic gases will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity. The increased water vapor in turn leads to an increase in the greenhouse effect and thus a further increase in temperature; the increase in temperature leads to still further increase in atmospheric water vapor; and the feedback cycle continues until equilibrium is reached. Thus water vapor acts as a positive feedback to the forcing provided by human-released greenhouse gases such as CO2.[12]


[edit] Increase of greenhouse gases
Measurements from Antarctic ice cores show that just before industrial emissions began, atmospheric CO2 levels were about 280 parts per million by volume (ppm; the units µL/L are occasionally used and are identical to parts per million by volume). From the same ice cores it appears that CO2 concentrations stayed between 260 and 280 ppm during the preceding 10,000 years. Studies using evidence from stomata of fossilized leaves suggest greater variability, with CO2 levels above 300 ppm during the period 7,000-10,000 years ago,[13] though others have argued that these findings more likely reflect calibration/contamination problems rather than actual CO2 variability.[14][15]

Since the beginning of the Industrial Revolution, the concentrations of many of the greenhouse gases have increased. The concentration of CO2 has increased by about 100 ppm (i.e., from 280 ppm to 380 ppm). The first 50 ppm increase took place in about 200 years, from the start of the Industrial Revolution to around 1973; the next 50 ppm increase took place in about 33 years, from 1973 to 2006. [4]PDF (96.8 KiB). Many observations are available on line in a variety of Atmospheric Chemistry Observational Databases. The greenhouse gases with the largest radiative forcing are:

Relevant to radiative forcing Gas Current (1998) Amount by volume Increase over pre-industrial (1750) Percentage increase Radiative forcing (W/m2)
Carbon dioxide 365 ppm {383 ppm(2007.01)} 87 ppm {105 ppm(2007.01)} 31% {37.77%(2007.01)} 1.46 {~1.532 (2007.01)}
Methane 1,745 ppb 1,045 ppb 150% 0.48
Nitrous oxide 314 ppb 44 ppb 16% 0.15

Global carbon dioxide emissions 1751–2000.Relevant to both radiative forcing and ozone depletion; all of the following have no natural sources and hence zero amounts pre-industrial Gas Current (1998)
Amount by volume Radiative forcing
(W/m2)
CFC-11 268 ppt 0.07
CFC-12 533 ppt 0.17
CFC-113 84 ppt 0.03
Carbon tetrachloride 102 ppt 0.01
HCFC-22 69 ppt 0.03

(Source: IPCC radiative forcing report 1994 updated (to 1998) by IPCC TAR table 6.1 [5][6]).


[edit] Recent rates of change and emission
The sharp acceleration in CO2 emissions since 2000 of >3% y-1 (>2 ppm y-1) from 1.1% y-1 during the 90's is attributable to the lapse of formerly declining trends in carbon intensity of both developing and developed nations. Although over 3/4 of cumulative anthropogenic CO2 is still attributable to the developed world, China was responsible for most of global growth in emissions during this period. All this indicates a global failure to decarbonise energy supply and an underestimation of emissions growth on the part of the IPCC in their Special Report on Emissions Scenarios. Localised plummetting emmissions associated with the collapse of the Soviet Union have been followed by slow emissions growth in this region due to more efficient energy use, made necessary by the increasing proportion of it that is exported.[6] In comparison, methane has not increased appreciably, and N2O by 0.25% y-1[7].


[edit] Removal from the atmosphere and global warming potential

Major greenhouse gas trendsAside from water vapor near the surface, which has a residence time of days, most greenhouse gases take a very long time to leave the atmosphere. Although it is not easy to know with precision how long, there are estimates of the duration of stay, i.e., the time which is necessary so that the gas disappears from the atmosphere, for the principal greenhouse gases. For the first five years of this century, 48% of total anthropogenic CO2 emissions remained in the atmopshere, a figure that is increasing and diagnostic of weakening carbon sinks.[6] Greenhouse gases can be removed from the atmosphere by various processes:

as a consequence of a physical change (condensation and precipitation remove water vapor from the atmosphere).
as a consequence of chemical reactions within the atmosphere. This is the case for methane. It is oxidized by reaction with naturally occurring hydroxyl radical, OH· and degraded to CO2 and water vapor at the end of a chain of reactions (the contribution of the CO2 from the oxidation of methane is not included in the methane Global warming potential). This also includes solution and solid phase chemistry occurring in atmospheric aerosols.
as a consequence of a physical interchange at the interface between the atmosphere and the other compartments of the planet. An example is the mixing of atmospheric gases into the oceans at the boundary layer.
as a consequence of a chemical change at the interface between the atmosphere and the other compartments of the planet. This is the case for CO2, which is reduced by photosynthesis of plants, and which, after dissolving in the oceans, reacts to form carbonic acid and bicarbonate and carbonate ions (see ocean acidification).
as a consequence of a photochemical change. Halocarbons are dissociated by UV light releasing Cl· and F· as free radicals in the stratosphere with harmful effects on ozone (halocarbons are generally too stable to disappear by chemical reaction in the atmosphere).
as a consequence of dissociative ionization caused by high energy cosmic rays or lightning discharges, which break molecular bonds. For example, lightning forms N anions from N2 which then react with O2 to form NO2.
Two scales can be used to describe the effect of different gases in the atmosphere. The first, the atmospheric lifetime, describes how long it takes to restore the system to equilibrium following a small increase in the concentration of the gas in the atmosphere. Individual molecules may interchange with other reservoirs such as soil, the oceans, and biological systems, but the mean lifetime refers to the decaying away of the excess. It is sometimes erroneously claimed that the atmospheric lifetime of CO2 is only a few years because that is the average time for any CO2 molecule to stay in the atmosphere before being removed by mixing into the ocean, uptake by photosynthesis, or other processes. This ignores the balancing fluxes of CO2 into the atmosphere from the other reservoirs. It is the net concentration changes of the various greenhouse gases by all sources and sinks that determines atmospheric lifetime, not just the removal processes.

The second scale is global warming potential (GWP). The GWP depends on both the efficiency of the molecule as a greenhouse gas and its atmospheric lifetime. GWP is measured relative to the same mass of CO2 and evaluated for a specific timescale. Thus, if a molecule has a high GWP on a short time scale (say 20 years) but has only a short lifetime, it will have a large GWP on a 20 year scale but a small one on a 100 year scale. Conversely, if a molecule has a longer atmospheric lifetime than CO2 its GWP will increase with time.

Examples of the atmospheric lifetime and GWP for several greenhouse gases include:

CO2 has a variable atmospheric lifetime (approximately 200-450 years for small perturbations). Recent work indicates that recovery from a large input of atmospheric CO2 from burning fossil fuels will result in an effective lifetime of tens of thousands of years.[16][17] Carbon dioxide is defined to have a GWP of 1 over all time periods.
Methane has an atmospheric lifetime of 12 ± 3 years and a GWP of 62 over 20 years, 23 over 100 years and 7 over 500 years. The decrease in GWP associated with longer times is associated with the fact that the methane is degraded to water and CO2 by chemical reactions in the atmosphere.
Nitrous oxide has an atmospheric lifetime of 120 years and a GWP of 296 over 100 years.
CFC-12 has an atmospheric lifetime of 100 years and a GWP(100) of 10600.
HCFC-22 has an atmospheric lifetime of 12.1 years and a GWP(100) of 1700.
Tetrafluoromethane has an atmospheric lifetime of 50,000 years and a GWP(100) of 5700.
Sulfur hexafluoride has an atmospheric lifetime of 3,200 years and a GWP(100) of 22000.
Source : IPCC, table 6.7.


[edit] Related effects

MOPITT 2000 global carbon monoxideCarbon monoxide has an indirect radiative effect by elevating concentrations of methane and tropospheric ozone through scavenging of atmospheric constituents (e.g., the hydroxyl radical, OH) that would otherwise destroy them. Carbon monoxide is created when carbon-containing fuels are burned incompletely. Through natural processes in the atmosphere, it is eventually oxidized to carbon dioxide. Carbon monoxide has an atmospheric lifetime of only a few months[18] and as a consequence is spatially more variable than longer-lived gases.

Another potentially important indirect effect comes from methane, which in addition to its direct radiative impact also contributes to ozone formation. Shindell et al (2005)[19] argue that the contribution to climate change from methane is at least double previous estimates as a result of this effect.[20]


[edit] See also
Energy Portal
Atmospheric Chemistry Observational Databases for links to freely available data.
Avoiding Dangerous Climate Change
Biofuel
Carbon emissions by country
Carbon sink
Carbon neutral
Clean Air Act
Corporate Average Fuel Economy (CAFE)
Emission standard
Environmental accounting
Environmental agreements
European Climate Change Programme
GHG Vehicle Test Group
Greenhouse gas emissions from transportation
Greenhouse gas emissions in the USA
Global Atmosphere Watch
Hydrogen Economy
United Nations Intergovernmental Panel on Climate Change
Life cycle cost analysis
Massachusetts v. Environmental Protection Agency
North American Carbon Program
Ocean acidification
Radiative forcing
Regional Greenhouse Gas Initiative
Western Regional Climate Action Initiative
World energy resources and consumption

[edit] References
^ EPA's Clean Air Markets - Climate Change
^ Kiehl, J. T.; Kevin E. Trenberth (February 1997). "Earth’s Annual Global Mean Energy Budget" (PDF). Bulletin of the American Meteorological Society 78 (2): 197-208. Retrieved on 2006-05-01.
^ Water vapour: feedback or forcing?. RealClimate (6 Apr 2005). Retrieved on 2006-05-01.
^ Climate Change 2001: Working Group I: The Scientific Basis: C.1 Observed Changes in Globally Well-Mixed Greenhouse Gas Concentrations and Radiative Forcing. Retrieved on 2006-05-01.
^ Climate Change 2001: Working Group I: The Scientific Basis: figure 6-6. Retrieved on 2006-05-01.
^ a b c Raupach, M.R. et al. (2007) "Global and regional drivers of accelerating CO2 emissions." Proc. Nat. Acad. Sci. 104(24): 10288-93.
^ http://www.planetark.org/dailynewsstory.cfm?newsid=42594&newsdate=14-Jun-2007
^ EPA's Clean Air Markets - Climate Change
^ Climate Change 2007: The Physical Science Basis. Summary for PolicymakersPDF (1.25 MiB)
^ Lerner & K. Lee Lerner, Brenda Wilmoth (2006). Environmental issues : essential primary sources.". Thomson Gale. Retrieved on 2006-09-11.
^ Emissions inventory from the EPA, cited in Science News, vol. 171, p. 318
^ Robust Responses of the Hydrological Cycle to Global Warming
^ Friederike Wagner, Bent Aaby and Henk Visscher (2002). "Rapid atmospheric CO2 changes associated with the 8,200-years-B.P. cooling event". PNAS 99 (19): 12011-12014. DOI:10.1073/pnas.182420699.
^ Andreas Indermühle, Bernhard Stauffer, Thomas F. Stocker (1999). "Early Holocene Atmospheric CO2 Concentrations". Science 286 (5446): 1815. DOI:10.1126/science.286.5446.1815a. Early Holocene Atmospheric CO2 Concentrations. Science. Retrieved on May 26, 2005.
^ H.J. Smith, M Wahlen and D. Mastroianni (1997). "The CO2 concentration of air trapped in GISP2 ice from the Last Glacial Maximum-Holocene transition". Geophysical Research Letters 24 (1): 1-4.
^ Archer, David (2005). "Fate of fossil fuel CO2 in geologic time". Journal of Geophysical Research 110, C09S05. DOI:10.1029/2004JC002625.
^ Caldeira, Ken and Wickett, Michael E. (2005). "Ocean model predictions of chemistry changes from carbon dioxide emissions to the atmosphere and ocean". Journal of Geophysical Research 110, C09S04. DOI:10.1029/2004JC002671.
^ Impact of Emissions, Chemistry, and Climate on Atmospheric Carbon Monoxide: 100-year Predictions from a Global Chemistry-Climate ModelPDF (115 KiB)
^ Shindell, Drew T.; Faluvegi, Greg; Bell, Nadine; Schmidt, Gavin A. "An emissions-based view of climate forcing by methane and tropospheric ozone", Geophysical Research Letters, Vol. 32, No. 4 [1]
^ Methane's Impacts on Climate Change May Be Twice Previous Estimates