Emissions of Key Greenhouse Gas Stabilize 244
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."
Arctic (Score:5, Insightful)
Not good news (Score:1, Insightful)
Re:Sources of methane (Score:2, Insightful)
Just in case bozos out there actually believe it: The IPCC estimates that 60% of methane produced comes from our agriculture, industry, and waste. Humans are the biggest single source of methane. In North America and Europe, the largest single source of methane comes from landfills. The largest source of natural methane comes from wetlands.
Re:Arctic (Score:5, Insightful)
The ice that is there may come and go (freeze and thaw) with the seasons, but it is indisputable that there is a hell of a lot more going than there is coming back.
Satellite imagery from the 70's to now is shocking and disappointing, even bordering on the scary (beyond scary, I think).
20yrs is not a geological timeframe (Score:1, Insightful)
just why oh why are sane reasonable people wasting their time with this shit.
In most spheres of physics we put forward ideas and then test to see if those ideas are proveable and repeatable. We build from small ideas to larger models and then see if our models are consistent and accurate. We then take glee in trying to prove the model wrong or inaacurate. Only if the model matches observation and we find no conflicts do we begin to trust it.
To let you know how accurate the large model for climatologists is look at the weather prediction in your news paper.
The problem is they're trying to run before they'ved walked. They have no big model that is provably accurate so they have to guess. They are not sure as to just what influences our weather let alone to what extent. Ask them how much influence the sun or the earths core temp or the annual freezing of the southern oceans contribute to our weather and all they can do is shrug their shoulders and talk in non specifics.
So how as an intelligent person are you meant to interpet their findings and conclusions? I think that the findings are most likely accurate when they talk about discrete facts e.g. the level of CO2 in ice cores is less the further down the same core you go. But when they draw conclusions they are just blowing smoke the more assumptions the more smoke e.g. higher CO2 means higher temperature, therefore the level of CO2 measured in ice cores proves the temperatures years ago were less therefore we have global warming therefore etc etc
Re:H2O is #1, CO2 is #2, CH4 is #3. Mod parent up (Score:2, Insightful)
You seem to know a lot. So maybe you could then find me a single proper paper appearing in a real peer reviewed scientific journal in the last decade that says CO2 isn't to blame for global warming.
If you're going to spout off about how increasing CO2 emissions isn't a problem when the rest of the world thinks it is you could at least provide a link to your nonsense you're trying to pass as fact.
Re:20yrs is not a geological timeframe (Score:3, Insightful)
Weather forecasts are pretty accurate. And these global warming predictions are even less specific to area. All you should have to do to be scared is realize that: 1) higher CO2=higher temperatures (the greenhouse effect) and 2) it takes several years for changes on the surface to propagate into the upper atmosphere.
So, we pump CO2 into the atmosphere, and even if it was possible to stop emissions tomorrow, it would still take ten years for those changes to take effect.
I guess what I'm saying is: how would you like to find out (through experience) that global warming existed when your house was flooded by melting polar ice caps, and know that you still had ten more years of worsening conditions?
Re:20yrs is not a geological timeframe (Score:4, Insightful)
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 [realclimate.org] 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 [grida.no]. The simple reality, however, is that the models have worked pretty well, and have, in fact, made significant predictions that have since been observed [grist.org].
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 [wileywater.com]. The result is that, using ice cores, we can plot temperature and carbon dioxide independently [wikipedia.org].
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 [wikipedia.org] 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
Re:Not good news (Score:3, Insightful)
Unless, of course, the problem wasn't serious enough to warrent attention in the first place, as many environmental skeptics have been saying all along.
Re:Water Vapor? (Score:3, Insightful)
I meant that when you are considering the sun it's effects on the oceans and the irrigation areas constant.
"AGAIN you couldn't be more wrong. evaporation has nothing to with with depth, and everything to do with SURFACE AREA, of which the ocean clearly dwarfs our irrigation."
It has to with the temprature. Shallow waters heat up faster and evaporate faster. Furthermore a lot of irrigation is done by spraying water from sprinklers which also evaporates at a much higher rate then the ocean.
About the surface area. Yes the ocean has more surface area but that's not the point. If there was no irrigation then the water vapor would be less. Agriculture adds a tremendous amount of water vapor into the air that would not be there otherwise. As I said virtually every square inch of land that can be cultivated is being cultivated. Sure it's less then the oceans which cover 75% of the planet but it's a significant chunk of the remaining 25%.
But hey don't let common sense get in the way. Just ignore the fact that agriculture puts water vapor into the air.