skierinvermont
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Everything posted by skierinvermont
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The rise of CH4 concentrations over the last 20-100 years has nothing to do with natural methane release. It is a product of anthropogenic emissions. Humans represent HALF of global CH4 emissions, natural and anthropogenic (by comparison we are just 1 or 2% of CO2 emissions). That's why CH4 has risen from 750ppb to 1800ppb in the last 120 years. Thus concluding that the current arctic bubbling is 'not normal' simply because global concentrations have skyrocketed makes no sense. Global concentrations have skyrocketed because of direct human emissions, not the arctic. Whether arctic methane release is contributing significantly to the global increase in CH4 concentrations is a valid question which I don't have an answer to. But the global increase is not proof in and of itself that arctic emissions are abnormal or significant.
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And despite all this alarmism, methane concentrations in the atmosphere remain way below where the IPCC predicted just 5 years ago. They've only recently begun to inch back upwards and nobody even knows if this is due to the arctic, or due to the massive amount of methane produced by human activity. Methane release is a serious concern, but the fact that plumes exist in the arctic doesn't add an incredible amount of knowledge to what we already knew. It remains to be seen exactly how stable these methane deposits will be in the long-run.
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Agreed. I'd like to know how much this is on a global scale.
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Notice the scale.. pretty much the whole earth is within +/- 3 or 4% of the mean, just like CO2 which also varies slightly from the mean locally. Yes there are slight variations locally, but Methane concentrations 4% greater than the global mean in the arctic are not going to make much difference in temperature at all.
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Methane is a well mixed atmospheric gas like CO2. Local concentrations only vary slightly from global concentrations.
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I don't think anybody knows for sure exactly.. the IPCC wasn't able to predict the pause. But unlike CO2 in which humans represent only a very small fraction of CO2 emissions (something like 1-2% I forget exactly), we represent a large fraction of methane emissions (nearly half). So either 1) our emissions were lower for a period 2) natural sinks sped up 3) the breakdown of methane in the atmosphere increased (which is controlled by a chemical reaction with hydroxyl radicals)
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Methane actually started rising from around 750ppb in 1800. It had stayed near 750ppb for most of the last 10,000 years. So the rise is definitely anthropogenic given the rise coincides with rapidly increasing human methane emissions (primarily related to livestock and energy production). The pause is probably due to some natural factor temporarily overriding human emissions. Here's a chart showing the rise.. current concentration is around 1810ppb:
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Before trying to answer your questions, I'd like to agree with other posters who've said that the newspaper article was a bit biased/frilly in using words like 'deadly' to describe the gas. But the possibility of rapid methane release is of great scientific concern. And it appears that arctic emissions are beginning to ramp up. What I am not entirely sure of is how significant these methane releases are on a global scale. I do know there is enough methane stored in the arctic to cause massive global warming (like enough to turn earth into venus if it were all released into the atmosphere) but what these studies of recent surface emissions never answer is how significant the current emissions are on a global scale. Vergent claiming a 100000X increase may or may not be true on a regional scale, but that may still be quite small globally. It appears that global CH4 concentration has again begun to rise in the atmosphere since 2006. See chart below. This may be a response to the increased arctic emissions, or to some other source of emissions, I do not know. Methane is 25X more potent as a GHG than CO2 (per unit of mass).
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Reconsider majoring in meteorology!
skierinvermont replied to stormguy80's topic in Weather Forecasting and Discussion
BTW the BLS summary Don posted somewhat concurs with this statement stating that those in this field will face "keen competition" which is defined as job seekers growing faster than the number of available positions. It is one of 3 categories, the others being "good or favorable opportunities" (job growth and applicant growth in rough balance) and "excellent opportunities" (job growth outstrips the number of qualified applicants). It also says that those with graduate degrees will have better prospects (obviously). The posters comments may be a slight exaggeration, as hard work will probably get you a job in the private sector at least, maybe even public. But the general surplus of met majors is a real phenomenon. -
Is baroclinic_instability TIp???