However, methane has a short half life of only 7 years; if all human causes emissions of methane were to stop today, then half of what we'd already added to the atmosphere would be gone in 7 years, 3/4 of it gone in 14 years, and so on.
Carbon dioxide, on the other hand, doesn't really break down into a simpler molecule. The carbon dioxide released today may well still be here centuries from now. Even if absorbed by a tree, that tree will die some day and release it back into the carbon cycle. The only way carbon ever leaves the cycle is if it somehow gets buried and trapped, such as in ocean floor deposits or the peat in a swamp - the same process that created those fossil fuels. This takes a really long time.
Methane actually does contribute significantly to global warming; however, we can always stop emitting methane in the future, and then it will be gone rather quickly as if it had never happened. That's certainly not the case with carbon dioxide.
The other major greenhouse gas is water. It is true that methane, ozone, and a couple other gases are greenhouse gases, but CO2 and water are the worst. That said, there's considerable methane locked up in permafrost, which, if it's released, would be a serious problem.
Water is self limiting. It keeps evaporating from the oceans, and when there's too much of it, it rains. CO2 is different. There isn't a process that can reduce the amount that we've added to the atmosphere. Plants do absorb some, as do oceans. The fact that CO2 has increased as much as it has is a pretty good indication that it's a problem that will be around for a while.
Water is not a waste product from our economy. CO2 is. That's why the focus is on CO2. And the problem there is that our economy is absolutely dependent on energy, and at the moment, the only reasonable source for most of that energy is burning fossil fuel. It will be good to transfer away from it, but that will be a long slow process.
Because, after water vapor, it is the most significant greenhouse gas. The amount of CO2 is significant--there is about 10% as much of it as there is water vapor (even more if you look at mass fraction). Its role in the greenhouse effect is larger than 10% though, simulations show its effect to be between 14% and 25% of the total effect. It is also relatively long-lived gas in the atmosphere, so as we dump more into the atmosphere the total amount keeps going up. In contrast, the amount of water vapor in the atmosphere is controlled by temperature, through the Clausius-Clapeyron relation, so if you were to dump more water vapor into the atmosphere it would quickly precipitate out; similarly if you made the atmosphere instantly drier, it would quickly evaporate from the oceans.
You can tell that the answers from Cyclops, Maxx and Jim Z are politically motivated. People have been worried about the effects of increasing CO2 in the atmosphere for more than 60 years, and even 19th century scientists knew it was a greenhouse gas.
The highly misleading plot of Cyclops deserves comment. The title of the plot is a lie--the impact from adding CO2 to the atmosphere does not shrink to zero. Add more CO2 to the atmosphere and you increase the potential warming. While they will tell you that its effect is "logarithmic", it is always increasing.
Also, the axis is scaled "per metric tonne" to make the effect look tiny, but that needs to be scaled up by a factor of 40 BILLION or so, because that's about how much CO2 is dumped into the atmosphere by humans every year.
http://pubs.giss.nasa.gov/docs/2010/2010...
I would also like Cyclops to produce the ENTIRE sentence that the purported Michael Mann comment came from (the part before the ellipsis). It's quite clear that if the quote is real, it is taken out of context. If he can't come up with the entire quote, I will assume that it's because it's either (1) fictional or (2) the rest of the sentence would show that Cyclops has been misleading.
Let's see whether he's honest enough to produce a reference with a complete sentence.
Because unlike the most significant greenhouse gas, water vapor, it does not rain out of the air; it builds up as we overload the natural carbon recycling systems in the environment. CO2 is the second most abundant greenhouse gas in the air, and the only one that is constantly increasing with the increase in lock step with amount of coal, oil, and natural gas being burnt. All other greenhouse gasses are present in such small amounts that their contribution to the overall greenhouse effect is much smaller than CO2.
We don't have to do anything to stop it; we just have to stop making it happen. If all human technology that uses coal, oil, or natural gas as a fuel suddenly vanished from the world, the world would instantly start recovering naturally. The world is (at present) naturally removing about 1/3 of the extra CO2 that we are adding, and if we stopped adding more the levels would likely recover to natural levels in (probably) a few centuries.
It may not be the only one but it is a major component of the atmosphere compared to the other greenhouse gases
Because it is hydrocarbons that we are pulling out of the ground in fossil reserves and burning them with oxygen in our atmosphere results in CO2 that had not been in our atmosphere for millions of years. It's where it's from that is the problem.
Because they would not be able to impose their ideaology, if they focused their concerns on water vapour which is the main greenhouse gas, how can you impose rules, regulations and taxes on water.
Because it is so prevalent and so long-lasting in the Atmosphere. CO2 has been a major factor in climate change during all the planets existence other than very early when Methane cause the climate to be much warmer. Water vapor is very short-lived in the atmosphere. It can cause rapid warming, but will fall quickly in response to a cooling forcing.
CO2 remains in the atmosphere for centuries. It has the ability to cause warming, especially with the water vapor and the Methane feedbacks. Most importantly right now, it is more than 80% of human ghg emissions. The increases in water vapor and methane in the atmosphere, are feedbacks from the CO2 increase.
Increases in CO2 always cause the global climate to warm. In past, natural, periods of warming, the increase was caused by astronomical factors, and that initial warming caused the oceans to throw-off more CO2 which in turn caused more warming. CO2 has been the greenhouse gas that drives the global temperature for millions of years.
Worth reading or at least skimming if you are interested.
http://www.aip.org/history/climate/index...
because they would lose government support and funding if they told the truth about cows farting produces methane gas Show me the money People may demonize the oil company but demonize burgers and steaks be darned
Dr. Michael Mann at a Senate Testimony in 2005 when asked why we were not more interested in water vapor,
he responded “...because it cannot be regulated.”
Because they want to tax CO2 and you literally cannot live without creating CO2, after all we exhale it. The man-made Global Warming SCAM is all about money and power. They only want two classes of people, the elite ruling class and the rest of us as slaves.
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It is the only one they can blame on man and use to attack industry and free markets. That is why certain political groups are focused on it and they fund the science that they can use to push their political agenda.
it's one of the easiest to manage
Because Co2 is one of the MAIN Ones that Humans are pumping Into the Atmosphere... -AND the One we can do the MOST- About . :)
Because it is by far the most important and longest-lived.
Science has nothing to do with fake geologist JimZ's paranoid misunderstandings of politics and massive ignorance of history.
http://en.wikipedia.org/wiki/Carbon_diox...
probably because we pump tons of it into the air every day, day after day
Because it it the worse one.
Fear and juan
