Methane (CH?) is more effective than carbon dioxide (CO?), mostly because there is a lot less of it in the atmosphere. CH? is at about 1.8 to 1.9 ppm, I vaguely recall. CO? is at about 400 ppm. You can imagine this as a kind of "smoke" of sorts. So if you could "see" into the CH?, you would see a slight darkening of the sky. But if you could "see" in the CO?, you would see a very dark (not totally dark, though) sky. If you add some CH? darkening, it's more noticeable than is the same amount of added CO? to its darkening.
But CH? is much shorter-lived in the atmosphere. So it is scrubbed out (mostly in the equatorial regions where hydroxyls are more readily generated from solar insolation) and breaks down into CO?, eventually. CO? is much more concern on the longer term because it sticks around for a very long time and so its effects accumulate, year by year, into very large effects in the end.
On the other hand, it turns out there is a LOT of CH? sitting around. And as the earth warms, (1) fermentation of thawing organic carbon, (2) trapped methane gas in ice pockets, and (3) warming of methane clathrates (also called 'hydrates' and which is a different kind of trapping mechanism for methane in ice than #1 just mentioned) each pose a serious "pulse" risk. You may have heard the term "clathrate bomb" or "compost bomb" or "methane bomb" in the news. That's what this is referring to.
Problem is, although human activity has more than doubled the levels of methane in the atmosphere in a century's time, the long term effects are low enough that it is less of a concern than CO?. Besides, CH? turns into CO? in the end. Also, no one can really predict much about the CH? risks, just yet. And human inputs, while high, aren't (a) yet high enough to be a principle issue, and (b) we can more easily do something about this as well (stop fracking, for example.) However, recent reports this year describe fairly high levels of escaping CH? int the Siberian arctic under-water shelves. So... there is worry. But unfortunately, good data from many years ago aren't yet available, so it's hard to know if this has been going on for a while or if this is a recent, sudden change indicating more of a concern.
The same way as carbon dioxide. It allows short wavelengths from the Sun through and blocks shorter wavelengths from Earth from escaping into space, even though it has a higher global warming potential. People are adding much greater quantities of carbon dioxide to the atmosphere, but as Earth warms, the permafrost will warm and fermentation in the permafrost will release large quantities of methane.
Kano
Your graph does not show the comparative potency of greenhouse gases. It shows the amount of energy the amount of each gas which is in the atmosphere is absorbing now.
That is because there is very little methane in the atmosphere. If water vapor were 1.5ppm, it would not absorb much more bandwidth.
And the most potent greenhouse gases are potent because they are currently absorbing almost no infrared at current atmospheric concentrations. Don't forget, the effect of a greenhouse gas on temperature is logarithmic.
The primary human produced greenhouse gases are CO2
Methane, CFC12, and HCFC22 These are the primary gases related to global warming. Methane accumulates in the atmosphere/Troposphere.and is @ 23 times stronger than CO2. They prevent some of the solar energy Earth receives and this makes the planet grow warmer, leading to global warming.
These gases have accumulated since the first industrial revolution in the late 1700s and saw a marked increase beginning with the second industrial revolution, At this time coal became the primary fuel for both industry and residential users. With the advent of the automobile, both CO2 and Nitrous Oxide gases accumulated exponentially.
Methane is produced naturally, but the human contribution comes primarily from our sewage and organic garbage. Ignore the morons that claim it is cow farts They play a minuscule role in global warming. One way you as an individual can reduce methane is to not waste food. Cook what you will eat and don't let food go to waste. When you come home from the market, dice and chop your vegetables and place them in freezer bags so they don't go bad. Same or leftovers If you don't think you will eat them the next day, freeze them
Sorry, forgot to mention water vapor which is not only natural, but is the largest greenhouse gas.
It does'nt. In 2008 I proved useing an experiment as a gift to all to use safely to 350 million people and 43,000 scientists that ex president Bush hired to find the cause and solution to Global warming that all non solids that rise into the upper atmosphere separate by nature into nothingness, so all gases, exhaust, co2, smoke, etc. actually separate into nothingness. Infact when you see on the news forest fires, watch the helicopters come down and drop their water on the fires/// but ask yourself WHERE'S THE SMOKE from the fires. normally nature separate's it into nothingness and is gone so the helicopter pilot can plainly see the fires to open their water poaches on the fires. Global warming ended last year in 2012 and all 4 seasons have returned to all parts of earth naturally. Mike
It is a greenhouse gas, like CO2, water vapor, NOx and CFC's
Check out this graph http://upload.wikimedia.org/wikipedia/co...
Now what is interesting is that it is not as powerful as CO2 in fact it is in fourth place as a potent greenhouse gas, so why do they say it is 23 (or 100) times as powerful, it is because, as you can see it has not reached the top of its own graph only about one third high, meaning it is not saturated and more methane will cause more warming.
This only conclusion is that methane is potent only because CO2 is saturated and can cause very little or no more warming, end of AGW argument.
Climate Realist. of course this graph show how little potency methane has, look at the very small radiation bandwidth it covers, most of Earth's long wave radiation is unaffected.
Methane gas is a greenhouse gas.. Which as you should know greenhouse gasses are what scientists believe are causing global warming.
same way CO2 and water do. It is transparent to higher energy light but adsorbs infrared. It is actually more efficient in absorbing the IR than either CO2 or water. Water is still THE most important greenhouse gas though, simply because it is by far the most important in mass or concentration. It achieves through numbers what individual molecules cannot.
It harms the ozone layer.
No scientific evidence as to that fact.
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