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Emissions of Key Greenhouse Gas Stabilize
brian0918 writes "Multiple news sites are reporting that levels of the second most important greenhouse gas, methane, have stabilized". From Scientific American: "During the two decades of measurements, methane underwent double-digit growth as a constituent of our atmosphere, rising from 1,520 parts per billion by volume (ppbv) in 1978 to 1,767 ppbv in 1998. But the most recent measurements have revealed that methane levels are barely rising anymore — and it is unclear why." From NewScientist: "Although this is good news, it does not mean that methane levels will not rise again, and that carbon dioxide remains the 800-pound gorilla of climate change."
What about Water Vapor (or vapour, depending on where you live)? I've heard that's a major contributor... though the talk you hear about it is... a heated discussion at the very least (flamefests usually).
Actually, no. Our knowledge is complete. Visit the Creationism Museum to learn more.
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The real 800lb gorilla for methane is the Arctic. If the predictions are right then this is the calm before the storm. If the Arctic melts, which it is, it'll release vast amounts of methane. It's likely to dwarf all other greenhouse sources. Everyone seems to be ignoring the Arctic but all the CO2 sources combined can't compare so a melting Arctic should be our primary concern. If it's the canary then the canary isn't just dead but it has been reduced to a skeleton.
The single largest source of methane as a greenhouse gas is (flatulence from)cattle raised in the third world for food. The next sources in order are cattle raised in the western world, and human flatulence IIRC.
Does the stabilization of methane levels mean they're now feeding beano to cattle?
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The thing is that it takes lots of years for the effect of gas ratio changes at sea level to propagate up into the upper atmosphere.
From the vague article, these appear to be sea-level measurements - so the density of methane in the upper atmosphere (where it actually matters) will continue to grow for maybe 10 years before it starts to level off.
We are seeing the effects of methane growth rates in the 1980's and 1990's...it'll get worse before it gets better.
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I see you are new to humor...
I keep telling myself I'm not the desperate type.
Ok, let me get this straight.
The methane gas was coming from an 800-pound gorilla?
So here we are, currently doing basically bugger all about global warming, but with plenty of computer simulations and estimates about how much warming will happen in how many years, and plenty of politics going on about who should pay for it, and what about second world countries, and AFAICS it's basically a game of how long can be put off doing something about this, because it's going to cost plenty of money and we don't seem to need to be doing it just right now...
Now, out of the blue, something *utterly* unexpected, inexplicable and major happens - the rate of methane emission levels out; and no one has a *CLUE* why.
Well, I can hear this ticking noise...
I sure hope we figure out interplanetry colonization soon.
You know - just in case.
But in fact, human behaviour does not seem to be changing water vapour concentrations in the atmosphere, while as many many scientists have observed, rising concentrations of CO2 (which seem to be linked to rising levels of development, and energy production and use) are proportional to temperature increases. Water is a much more complicated greenhouse gas because it goes into the atmosphere easily, but it also comes out easily. CO2, on the other hand does not leave the atmosphere easily, and it is having a measurable effect on our climate.
They're not a major source of methane in the atmosphere OR their crap puts off a ton of methane and we should use it as fuel?
Or their crap has no methane and yet can still be used for fuel (your dichotomy is false).
Anyway, http://www.ciesin.org/TG/AG/liverear.html claims that livestock causes 15 of all organic-sourced methane "emissions". Mostly due to fermentation in their stomachs, mostly from low quality feed.
If I have been able to see further than others, it is because I bought a pair of binoculars.
There is, of course, a vast difference between predicting weather - which is a local phenomena, with significant specificity - and predicting the climate trends - which is averaging general trends globally. Consider, for instance, that it is very hard to stand on a beach and predict the exact height and shape of the next wave and precisely where and when it will break. On the other hand predicting the approximate height and time of the next high tide is rather easier. GCMs are, indeed, currently rather poor at making predictions down to the level of day to day local weather. They have, however, been very accurate at predicting year on year global climate.
As noted above, contrary to your claim, the models have proved to be remarkably robust and accurate. They are also, contrary to popular perception in some circles, not just a big pattern matching machine that are "trained" on past data. They are models that are fed in physics. Yes, there are some tweakable parameters, as there should be in any model where there is some uncertainty. The greatest area of uncertainty in models currently is clouds, since they can be both a positive or negative feedback depending on the exact nature of their formation. Of course this problem is taken very seriously and there is a lot of study. The last IPCC report had considerable detail summarising that work. The simple reality, however, is that the models have worked pretty well, and have, in fact, made significant predictions that have since been observed.
Historical temperatures from ice-cores are determined by ratios of hydrogen or oxygen isotopes in the ice. The guts of the issue is that when combined in water the different isotopes, being different masses, fractionate out at slightly different temperatures, thus the exact isotope ratio is a function of many things, but a very signficant factor is the prevailing temperature at the time the water became vapout before precipitting out. Thus the ratio, while not an exact indication of specific temperatures (unless the many other factors are also accounted for), is a good indicator of general temperature trends over long time scales. For more detail see here. The result is that, using ice cores, we can plot temperature and carbon dioxide independently.
Furthermore, more recent temperature reconstructions (as in reconstructions of only the past 1000 years or so) rely not on ice cores but on a wide variety of sources including coral, tree rings, glaciers, and more. Usually many of these different methods are cross referenced with each other to create any single reconstruction. The results can be seen in this plot of 10 different reconstructions by different independent teams. The results, as you can see, while different, all show the same trend. If you're still uncertain, feel free to use the
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