Arguments
Recent Comments
Prev 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 Next
Comments 43101 to 43150:
-
BWTrainer at 04:29 AM on 6 August 2013How much will sea levels rise in the 21st Century?
It's important to keep in mind this is the global average. Localities may see twice this.
-
franklefkin at 03:06 AM on 6 August 20132013 Arctic Sea Ice Extent Prediction
Why didn't you step in the ring? You're not going to make it worse by pulling a Goddard and claiming long-term recovery based on one year, are you?
It's not really fair for me to guess now when it looks like most of these guesses were made months ago.
As to the Goddard ref.... 1 year data point does not a trend make.
-
Rob Honeycutt at 02:52 AM on 6 August 20132013 Arctic Sea Ice Extent Prediction
I remember saying earlier this year that I thought this year would actually break last year's minimum. I'm probably going to be wrong on that point, but there are still about 6 weeks of rapid melt left.
And I noticed just today there is a shift in direction in the NSDIC chart... toward more rapid melt.
I should probably be on that list with Paul and Michael at 3m sq km.
-
DSL at 02:17 AM on 6 August 20132013 Arctic Sea Ice Extent Prediction
Nope. You're sniping from the audience. Why didn't you step in the ring? You're not going to make it worse by pulling a Goddard and claiming long-term recovery based on one year, are you?
Want to predict GISS L-OTI anomaly for July?
-
Djon at 02:13 AM on 6 August 2013How much will sea levels rise in the 21st Century?
@KR You didn't quite answer Michael's question. The current wording "Even if we were to stop emitting greenhouse gases tomorrow, the oceans would continue to rise, driven by the heat already stored." doesn't seem to be saying that future sea level rise is inevitable as a result of future heating that will continue until the atmosphere warms up enough for the outgoing TOA energy flow to balance the incoming energy flow. It seems to be saying that the heat that is already stored in the oceans would cause additional future sea level rise even if atmospheric temperatures were to immediately become stable.
-
franklefkin at 01:44 AM on 6 August 20132013 Arctic Sea Ice Extent Prediction
Let's summarise:
Kevin - 5,000,000
dwr - 4,250,000
Roger D - 4,200,000
scaddenp - 4,100,000
KR - 4,040,000
DSL - 3,900,000
Michael sweet & Paul W - 3,000,000
L Hamilton - 2,300,000
Eternal Consumption - 1,110,00
Did I miss anyone? Quite a range. Anyone care to change their quess?
-
Bob Loblaw at 00:56 AM on 6 August 2013Levitus et al. Find Global Warming Continues to Heat the Oceans
dvaytw:
Apart from MA Rodger's comment, perhaps it helps to know how heat content and temperature are related. The graphs above are actually changes in heat content, relative to a baseline. This has to be the case, as the oceans did not have negative heat content in the 1960s.
Now, to get the change in heat content, you simply take the change in temperature, multiply it by the heat capacity (in J/kg/degree or J/m3/degree, whichever you prefer), and then multiply that by the number of kg (or m3, whichever you used for heat capacity), and magically you have now converted temperature changes (in degrees) to heat content changes (in Joules). To a first approximation, you could consider heat capactiy of water to be a constant for all the ocean, and then the temperature-->heat content conversion and averaging becomes one of weighting the layer temperatures by the volume or mass in each layer. It's alittle more complex when you start to take the slight variations in heat capacity due to temperature, denisty, etc., into account, but it doesn't change the big picture.
Granted, my PhD thesis (partly) involved developing a numerical model for heat transfer, so I may know a bit more about this than most, but does anyone here really think that a person that who thinks Ocean Heat Content is "very different from temperature" should be considered a reliable source? Maybe it's a surprisingly different thing to a Blog Scientist, but it's high school physics. It doesn't take much to conclude that Eschenbach is in way over his head.
-
dvaytw at 00:39 AM on 6 August 2013Levitus et al. Find Global Warming Continues to Heat the Oceans
Ohhh... that comment went over my head the first time. Thanks!
-
How much will sea levels rise in the 21st Century?
michael sweet - "In the pipeline", or as I prefer to call it, "unrealized warming", is the change in temperature required to cancel out the current top of atmosphere (TOA) energy imbalance. It is in effect the difference between the GHG changes and the lagged climate response, mostly due to the thermal mass (inertia) of the oceans.
If climate forcings stopped changing right now, there would still be warming until the oceans caught up with previous forcing changes. As it stands, however (under current economic outlooks), changes in forcings are remaining well ahead of the climate response.
-
saileshrao at 00:20 AM on 6 August 2013Toward Improved Discussions of Methane & Climate
Nafeez Ahmed's response in the Guardian is well worth reading.
-
MA Rodger at 23:37 PM on 5 August 2013Levitus et al. Find Global Warming Continues to Heat the Oceans
dvaytw @54.
Coinsidently, I think that's been covered up-thread @38. Still it is perhaps wothy of repeating being such a forehead-smackingly stupid piece of analysis (although you need not look far on Wattsupia to find similar stuff).
The fool was only "quite surprised" to find that a number as big as 205 could be converted into three numbers as small as 45+60+100. But only being "quite surprised" didn't stop him yet again making a fool of himself. He was after all a fool so he couldn't wait to tell the rest of the class. 'Look,' he said 'Look how the wiggles on the graph stay so close to the line at the bottom when I split the numbers up. How fantastic this arithmateratic is - numbers made small by cutting them up into seperate pieces!'
-
michael sweet at 21:06 PM on 5 August 2013How much will sea levels rise in the 21st Century?
Excellent post. Many of these numbers are lower than others I have heard.
I find the first paragraph in "whats in the pipeline" to be a little confusing. Is the future sea level rise caused by heat already absorbed or is it from the current energy imbalance caused by greenhouse gases already emitted?
Hopefully scientists will forecast sea level rise more successfully than they have forecast Arctic Sea Ice.
-
TonyW at 20:54 PM on 5 August 2013How much will sea levels rise in the 21st Century?
It would be interesting to see how "the most likely" estimates of sea level rise have changed over the years. Are these increasing as the science gets better? -
John Russell at 19:24 PM on 5 August 2013Toward Improved Discussions of Methane & Climate
Nafeez Ahmed has just responded to what he calls "Skeptical Science's unusually skewered analysis" in this new Guardian article.
It seems to me that when it comes to Arctic methane there's much uncertainty, and the wise course is to hope for the best but plan for the worst. Having strong opinions on this particular issue is backing oneself into a corner.
-
chriskoz at 18:58 PM on 5 August 2013How much will sea levels rise in the 21st Century?
I want to nitpick on your AR5 date: you mention 2014.
But the part of AR5 relevant to this article (WG I: The Physical Science Basis) should be ready in September 2013, so just one month from now. So readers will not wait for the official document for as long as you imply.
The other parts of AR5 (WG II, WG III & synthesis) to be released successively until Oct 2014, will be mostly irrelevant to this article or not changing anything.
-
dvaytw at 18:49 PM on 5 August 2013Levitus et al. Find Global Warming Continues to Heat the Oceans
Guys thanks again for all input. I was wondering how you'd respond to this point from the Eschenbach article:
"The good news is that we’re measuring ocean heat content (OHC), so it’s very different from temperature. We can simply subtract the changes in the 700 metre level OHC from the 2000 metre level OHC changes, and what is left is the change in heat content for the layer from 700 metres down to 2000 metres. Can’t do that with temperature. Figure 3 shows the same OHC data as in Figure 2, except split out into distinct and separate layers, at the same scale. as Figure 2...
I was quite surprised by this result. Once I split the information up so that I could see the changes in each of the layers separately, much of the apparent change post-2001 disappeared. In Figure 2 there’s not a lot of change in 2001." -
chriskoz at 13:05 PM on 5 August 20132013 SkS Weekly News Roundup #31B
Recent marine life study by CSIRO (reported for example here and here) reveals the poleward migration pace by marine species (7.2km/y) outpacing that of the land species (6km/y) indicating the AGW impact on upper ocean waters be greater than that of surface air.
Another indication, that the latest denialists' bunkum point that "global warming has stopped for 15 years" is irrellevant to the issue at hand. It looks to me that AGW warming impact on ocean, including acidification will be greater than on land. And it is final time to start judging the changes in the ocean as primary indicators of the pace of AGW. And let's cease proclaiming the nonsense that "global warming stopped" over and over again. Unfortunately, the deniaslist who refuse to accept the fact the athmosphere holds less heat than the ocean will always have trouble understanding such simple indicator.
-
Richard Komorowski at 10:41 AM on 5 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
Thanks for the info, Baerbel. I'm already registered for both of them, so I expect we'll be meeting again on the forums.
Cheers
-
Riduna at 10:38 AM on 5 August 2013Toward Improved Discussions of Methane & Climate
Will – Thanks for the ref. to interview with Dr Shakhova Deweaver
@ 9. – on your point 3: When onshore permafrost melts from the surface down, underlying permafrost inhibits drainage with the result that shallow water covered surfaces are produced. Methane produced beneath the water-table in anoxic conditions vents directly to the atmosphere unoxidised.
However, CH4 produced in the presence of oxygen, particularly where sphagnum moss is present, are largely oxidized and enter the atmosphere as CO2. It can be concluded from this that during early stages of permafrost loss most methane produced as a result of permafrost loss will enter the atmosphere as CH4 but as loss continues at greater depth and surface drainage occurs CH4 will be increasingly oxidized to CO2. Lawrence et al (2005) estimate that permafrost covering ~9.5m km2 will have thawed to a depth of 3 meters by 2100.
On your point 4: Most of the Siberian continental shelf is covered by water ≤ 50 metres deep. Methane escaping from the seabed vents to the surface through a water column which is too shallow to bring about any oxidation before it reaches the sea surface and enters the atmosphere. For CH4 escaping from the seabed to oxidize a water column of at least 200 metres is required. Methane escaping from the seabed west of Svalbad from depths of 200-400 metres is very largely but not fully oxidized or absorbed by ocean water before reaching the surface but even from these depths some CH4 is present at the surface.
-
Leland Palmer at 07:58 AM on 5 August 2013Toward Improved Discussions of Methane & Climate
About the graph of the single large release in the original article-
Nice graph. It's somewhat reassuring, actually, visually.
But how does it correspond to reality?
What if that single large release of methane sets off additional releases, of various magnitudes, via increased greenhouse forcing and stimulation of both chronic and large scale individual releases?
What if that large release severely degrades the hydroxyl radical oxidation mechanism, and causes additional greenhouse forcing and a slower return to chronic methane release behavior?
What if those atmospheric chemistry effects leading to increased forcing, as postulated by Isaksen's modeling, set off additional methane releases?
Why should we limit ourselves to a single large release event scenario, when each large release could both amplify chronic releases and possibly stimulate additional large releases, via positive feedback?
What if increases in both CO2 and methane concentrations lead to higher temperatures, increasing water vapor concentrations, amplifying the combined effects of all the greenhouse gases on radiative forcing? This postive correlation between CO2 concentration and water vapor concentration is well accepted by most climate scientists.
The methane concentration graph that results could look like a jagged series of peaks, climbing up, and up, and up...
And not come down...for maybe a hundred thousand years, as apparently happened during other possible methane catastrophes, such as the End Permian.
Life could regain its former diversity...in several tens of millions of years.
Except that the sun is hotter now, than it was during the End Permian, by maybe two or thee percent- an effect that James Hansen says is equivalent in forcing to around a thousand ppm of CO2.
Apparently James Hansen has a new paper coming out, which I have not yet been able to gain access to on the web. The Guardian reports (July of this year):
The world is currently on course to exploit all its remaining fossil fuel resources, a prospect that would produce a "different, practically uninhabitable planet" by triggering a "low-end runaway greenhouse effect." This is the conclusion of a new scientific paper by Prof James Hansen, the former head of NASA's Goddard Institute for Space Studies and the world's best known climate scientist.
The paper due to be published later this month by Philosophical Transactions of the Royal Society A (Phil. Trans. R. Soc. A) focuses less on modeling than on empirical data about correlations between temperature, sea level and CO2 going back up to 66 million years.
Given that efforts to exploit available fossil fuels continue to accelerate, the paper's principal finding - that "conceivable levels of human-made climate forcing could yield the low-end runaway greenhouse effect" based on inducing "out-of-control amplifying feedbacks such as ice sheet disintegration and melting of methane hydrates" - is deeply worrying.
The paper projects that global average temperatures under such a scenario could eventually reach as high as between 16C and 25C over a number of centuries. Such temperatures "would eliminate grain production in almost all agricultural regions in the world", "diminish the stratospheric ozone layer", and "make much of the planet uninhabitable by humans."
Hansen seems to think destabilization of the hydrates via a mixture of chronic and multiple large releases over several centuries is a realistic possibility, with final effects far beyond what Chris Colose or David Archer and his collaborators think is possible. -
Andy Skuce at 05:15 AM on 5 August 2013Toward Improved Discussions of Methane & Climate
TonyW@26
Indeed there is gas seeping to the surface from deep sources on the ESAS. A paper by Cramer and Franke (2005) documented this very nicely, with sea-bed samples, gas analyses and deep seismic reflection data. I really do not know why this paper is not cited more widely, since it seems to me to be much more through and detailed than subsequent papers on the ESAS.
Yes, the methane migrates up gas chimneys through the permafrost, some of which are related to faults. However, this gas release is slow and steady, as evidenced by the fact that it is still ongoing in deeper-water parts of the shelf in the northern Laptev Sea, where there is no permafrost. It might well be the case that melting of the permafrost cap will eventually perforate it in places where it is currently continuous, but this will take time and even when it happens, what we will end up with is what we see in the N Laptev Sea and not a sudden outburst.
Here's a section from the Cramer and Franke paper, showing gas chimneys, deep structure and permafrost in the central Laptev Sea:
I have written about sub-cap methane in a series of SkS articles: Part1, Part2, Part3 and Part4. In the last one, I speculate on the origin of methane on the ESAS and give my (blogger's) assessment of the relative importance and timing of GHG emissions resulting from a thawing cryosphere. I think that the one we have to worry about most in this century is the thawing of onshore permafrost and the emissions of CO2 and CH4 that will come from biodegradation of thawed organic matter. There will be some additional releases of thermogenic methane coming from perforation of permafrost caps on land and in shallow seas, but the quantities and the timing of these releases is uncertain. Emissions from hydrates in the deep sea, under and within permafrost and (maybe) under ice sheets, may well prove substantial over longer timescales.
I would have had no problem with the Whiteman et al article if they had portrayed it as a what-if model of an unlikely worst-case-imaginable scenario. But they did not qualify it that way, instead they wrote (my emphasis, references removed):
As the amount of Arctic sea ice declines at an unprecedented rate the thawing of offshore permafrost releases methane. A 50-gigatonne (Gt) reservoir of methane, stored in the form of hydrates, exists on the East Siberian Arctic Shelf. It is likely to be emitted as the seabed warms, either steadily over 50 years or suddenly. Higher methane concentrations in the atmosphere will accelerate global warming and hasten local changes in the Arctic, speeding up sea-ice retreat, reducing the reflection of solar energy and accelerating the melting of the Greenland ice sheet. The ramifications will be felt far from the poles.
which I think is irresponsible.
-
Andy Skuce at 03:13 AM on 5 August 2013Toward Improved Discussions of Methane & Climate
People should take the post by Potomac Oracle with a grain of salt since it is scientifically incoherent. Note that the site that it was referenced from is full of anti-vaccine nonsense.
I was taken, though, with the image of formaldehyde crawling along the floor into "open widows".
-
wili at 03:07 AM on 5 August 2013Toward Improved Discussions of Methane & Climate
One more point/set ofquestions:
Hasn't this been a particularly long interglacial?Doesn't that mean that the relative warmth from this long period has had thousands of years now to penetrate deep into the permafrost?
Doesn't that likely make the permafrost more susceptible now to sudden shocks like seismic activity...than it has been in the past, both during the Holocene and during other, shorter interglacials?
Thanks ahead of time for any light anyone can throw on any of these areas. -
Rob Honeycutt at 02:57 AM on 5 August 2013An accurately informed public is necessary for climate policy
Terranova @63... The point of asking the question was to suggest that, at least on a certain level, Obama's statement of AGW being dangerous is inclusive of what is represented by the larger body of published research.
Whether AGW is dangerous was not an explicit aspect of Cook13, but you could easily state that it is implied by the body of research. Thus, Obama's tweet is not far from the mark, and therefore a justifiable inclusion.
Moderator Response:[JH] We've beaten this horse to death. Let's move on to another topic.
-
An accurately informed public is necessary for climate policy
I find this entire line of objections rather absurd. If someone is informed about the scientific consensus on climate change to the extent that they understand 97% of scientists studying it agree on AGW, then they are likely informed enough as to the outlook for future warming (given current economics and policy decisions) and the consensus on consequences thereof (IPCC WG II, "Impacts, Adaptation and Vulnerability") to consider those consequences dangerous.
I'll note that one of the major threads of denial is "It's not bad", and from the perspective of those denying AGW that's a frequent accompaniment. But understanding the consensus on the causes of global warming includes understanding the consequences, whether they were specfically addressed in the Cook et al 2013 paper or not. Because knowldge about causes leads to knowledge about effects. And from that standpoint the Obama tweet and other reportings on this issue are entirely reasonable. The objections raised on this thread and elsewhere require a schizophrenic separation between cause and effect, a selective blindnesss to consequences. That is entirely unreasonable, a piece of sophistic nonsense.
Just my personal point of view...
Moderator Response:[JH] Let's move on to another topic. This one has been exhausted.
-
Terranova at 01:53 AM on 5 August 2013An accurately informed public is necessary for climate policy
MA Rodger @58
Now you obfuscate and make suppositions based on your misconceptions about my mindset. Again, you are failing to recognize that I already supplied an answer - there doesn't have to be an adjective.
Let me make it clear for you. Based on my educational background (B.Sc., M.Sc. and second M.Sc. in progress), and the research I have conducted: I firmly believe that AGW does exist and is having an effect on the global climate. I cannot say it any more clearly than that.
Moderator Response:[JH] You have made your point. It has been responded to. Let's move on.
-
Terranova at 01:45 AM on 5 August 2013An accurately informed public is necessary for climate policy
Tom Curtis @59
Well said.
Honeycutt @63
It certainly could be dangerous. But, that is changing the subject from the point of view of the importance of accuracy. Do 97% of "climate scientists" think it is "dangerous"? There would have to be research done to determine that. The study was not about whether AGW was dangerous, or not. It was about endorsing the scientific consensus on AGW.
-
Potomac Oracle at 00:37 AM on 5 August 2013Toward Improved Discussions of Methane & Climate
Andrea Silverthorne writes: http://clck.ru/8mXDo
Natural gas is methane gas.
The T. Boone Pickens' of the world have created a terrible monster. The release of methane into our atmosphere has increased geometrically compared to CO2. Add to this that the method used to make methane in the earth...shale formations, requires 5 mil. gals of water mixed with a carcinogenic cocktail of chemicals for each well they drill. Only 10% of the water is recovered. The rest mixes with natural carbon to create even more CH4.
(This exessive use of water is why there's a growing dust bowl in the West and N.West, S. West and wherever they drill for oil and gas. Google Dust bowl.)
Then, if the CH4 is not completely oxidized to CO2 and remains at its first oxidant HCHO formaldehyde, the HCHO contributes to soft tissue evisceration in man and beast. Ergo, bees disappearing, mass fish and bird kills and over the past five to seven years endemic outbreaks in children of nose bleeds and asthma, and an increase in autism. HCHO hides in shallow water, caves, and dew. It is heavier than air and flows along the ground and into open widows and crawls along floors.
You have people out there who have millions and millions of reams of what they call facts and they spin this kind of web of half-truths and misinterpreted truths and lies, and it’s very difficult for a lay person to go through them. So I try to leave that kind of thing to the scientific community, who are really steeped in scientific literature.
But just having one of these kinds of arguments, unfortunately, people like me and you and those of us who feel like this is really a big problem that we are criminally negligent in not addressing, have kind of lost that public debate right now. And that’s really scary I think, to be honest.” That’s the word I would use, not just depressing but downright scary. There happens to be one side, on the scientific front, that’s just unassailable.
So let us apply our ethical standards to telling the whole scientific story about the formation of methane hydrates; its formation only with fresh water not sea water unless that water is saturated with methane and over a very short time forms Pingoes. We can carbon date Pingo material to prove that Pingoes never existed in the Beaufort Sea, the Arctic Tundra or elsewhere before 180 years ago. Oil and gas drilling use of fresh water needs through examination as the only source of methane hydrate, CO2 saturation and exess formaldehyde in our world.Moderator Response:[DB] Fixed font issues.
-
wili at 22:44 PM on 4 August 2013Toward Improved Discussions of Methane & Climate
Here are some points I got from Chris's well constructed article:
We don't know exactly how much methane there is in Siberian shelf.
We don't know how much of this methane may be stored within the permafrost layer (though we do know that this uppermost layer is the one most vulnerable to warming and melting).
We don't know whether the massive releases of methane that have been observed are continuations of long-term phenomenon or the beginnings of major feedbacks (this from the first two "Responses from Scientists" who admit that this point is already made by Shakhova).
...I am somehow not comforted by any of these unkowns. The inference seems to be that these are not known, so we can safely assume the most benign end of the spectrum. Is that a legitimate scientific approach to unknowns?
There have been times in the past when temperatures were likely warmer in these areas, but those were also times when sea level was rising rapidly, and methane stability depends on both temperature and pressure (and presumably salinity plays some role, which presumably would have been lowered during the same period with water flowing in from melting ice sheets.
I certainly hope that the conclusion is right: that we are not likely to see massive rapid increases in release of methane from the Arctic sea bed any time soon.
But many of the main points intended to support such a certainty do not seem particularly...certain.Thanks again for the important discussion (and no less a climatologist than Michael Mann has said that it is important to have discussions about the possibility of rapid increases in methane release from ocean bed hydrates).
-
TonyW at 19:35 PM on 4 August 2013Toward Improved Discussions of Methane & Climate
This article was linked on another site. The point was made that it doesn't cover free methane, only hydrates. The commenter had this to say:"The warning [of catastrophic release] is about free methane on the ESAS dissociated by geothermal flux and submersion of the shelf over the last 8,000 years and subsequent warming that has degraded the permafrost cap and the methane is now finding pathways to escape from the seabed to the atmosphere. No hydrate dissociation is required. 1 to 2% of the methane on the ESAS is enough to cause catostrophic warming and that is all free methane, not hydrates.Also, the Hydrate Stability Zone is now down to a depth of 1400 meters. The maximum depth of the ESAS is 100 meters, with an average depth of 50 meters.The latest research is showing not only is the degradation of the relic permafrost providing pathways, but seismic activity on the ESAS is creating fissures that are providing pathways for free methane to escape."Any response, Chris? -
Paul D at 18:54 PM on 4 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
I think the Richard Alley course also starts in September.
-
BaerbelW at 17:23 PM on 4 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
Richard - there is a course which might fit what you are looking for and it starts on August 12:
Climate Change - University of Melbourne
"This course develops an interdisciplinary understanding of the social, political, economic and scientific perspectives on climate change."
Instructors: Professor Jon Barnett, Professor John Freebairn, Professor David Jamieson, Dr. Maurizio Toscano and Rachel WebsterAnd, while on the subject of additional courses in this topic area, there is one more I already signed up for. It starts on Sept. 16:
Energy, the Environment and Our Future - Penn. State University
"Get Rich and Save the Earth…Or Else! Learn about the past, present, and possible futures of human energy use."
Instructor: Richard B. Alley -
Richard Komorowski at 15:31 PM on 4 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
Having studied and written about climate change for quite a while, I would call myself knowlegable, although certainly not an expert.
I too am nearing the end of this course (just the final to go). Have I learned anything fundamentally new to me? Probably not. On the other hand, I have learned a great deal about how everything fits and interacts together, so all in all I understand the science of climate change better now than I did ten weeks ago.
I would recommend this course for anyone who is looking for a good overview of the subject. It is an excellent foundation for anyone who wants to progress towards a deeper understanding of the many branches of climate science.
For myself, I would love to see a course geared towards the politics, economics and sociology of climate change.
-
Doug Hutcheson at 15:25 PM on 4 August 2013Toward Improved Discussions of Methane & Climate
Thanks for this article. I am now less alarmed by Arctic methane than I was.
The point, however, is moot: even if the was a likelihood of devastating, rapid injections of methane into the atmosphere, there is precious little we could do about it. The future under BAU CO₂ emissions is projected to be so bad that adding a methane menace does not materially affect the outcome for our civilisation, or for our species. Homo Stupidus stupidus.
-
One Planet Only Forever at 14:09 PM on 4 August 20132013 SkS Weekly News Roundup #31B
The focus of the Times Editorial on planet warming and climate change can be broadened. The concern is the sustainability of the economy. Fundamentally, any economic activity that relies on burning non-renewable resources is not sustainable. The accumulating impacts make it even less sustainable by diverting resources to deal with the climate change consequences.
So, if the concern really is to develop an economy that can sustainably grow the burning of fossil fuels has to end sooner rather than when the economy fails. The current economy is actually struggling because of all the activity within it that is simply not sustainable.
-
Rob Honeycutt at 11:37 AM on 4 August 2013An accurately informed public is necessary for climate policy
Terranova... If human activities are responsible for >50% of warming, is that dangerous?
-
JasonB at 11:17 AM on 4 August 20132013 SkS Weekly News Roundup #31B
Forrest,
I did a quick test for "Industrialised Countries" (red flag there — trying to pretend that everyone else will continue BAU will of course reduce the impact of the actions of a subset of countries), 100% reduction, and 3°C degrees sensitivity, and it said that by 2100 the consequence would be a reduction of 0.278°C compared to A1B (second red flag, since they're really advocating A1FI, and A1B doesn't really equate to "do nothing about climate change", which is precisely what they're trying to suggest).
The IPCC temperature change for 2090-2099 relative to 1980-1999 for each scenario shows a range of -1.0°C relative to A1B (for B1) up to +1.2°C (for A1FI). That's a difference of 2.2°C depending on emissions scenario, and even B1 with its 1.0°C drop relative to A1B isn't as agressive as their purported scenario from what I can see.
If it was actual science rather than simply propaganda I'd expect them to explain why they think their results are so small compared to what people might expect rather than just present it as "fact" with no more to say about it.
-
David Kirtley at 11:14 AM on 4 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
I took this course too and thought it was very good. I highly recommend it. My next Coursera class will be on Statistics.
-
Forrest at 10:08 AM on 4 August 20132013 SkS Weekly News Roundup #31B
Encouraging to see the NY Times editorial. However, the comments in the Times include a reference to a "Handy-Dandy Carbon Tax Temperature-Savings Calculator" created by the CATO Institute which claims to calculate the temperature impact in the year 2100 of reducing CO2 emissions by a user-selected amount for the next 50 years.
The comment says that eliminating all CO2 for the next 50 years will mean global temperature is 0.28 degrees C lower than it would have been otherwise. The commenter claims this is equivalent to moving 10 miles south. This makes no sense. Assuming 12,000 miles from the pole to the equator, then 0.28 degrees per 10 miles means an average temperature difference of 336 deg C between the pole and equatotor.
Would someone more knowledgable than I take a look at the calculator and comment on whatever other "issues" it may have?
-
Composer99 at 09:28 AM on 4 August 2013It's not bad
without appropriate context noting studies like this distorts our necessary perception and responses to climate change
You mean such as, say, omitting the peak season for influenza in the United States from consideration?
With studies such as this, or news articles such as this, it appears much of the seasonal mortality in winter is the result of not the weather, but of the seasonal variation in influenza circulation.
Or perhaps you mean, say, referring strictly to seasonal trends in mortality in a single country rather than from a global perspective?
-
Sceptical Wombat at 09:04 AM on 4 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
Also starting in September is a MOOC on Solar Energy being run by Delft University of Technology in the Netherlands on EdX. This looks like a fairly technical course.
-
Daniel Bailey at 09:01 AM on 4 August 2013It's not bad
Hmm. Available evidence shows that it is the human adaptation to weather extremes that is key in limiting mortality. Evidence for that assertion:
"Adaptation measures have prevented a significant increase in heat-related mortality and considerably enhanced a significant decrease in cold-related mortality. The analysis also suggests that in the absence of any adaptive processes, the human influence on climate would have been the main contributor to both increases in heat-related mortality and decreases in cold-related mortality."
and
"With regard to heat-related mortality, projected future increases in the frequency and intensity of heat waves may exert a stress beyond the adaptive limits of the population."
Causes for the recent changes in cold- and heat-related mortality in England and Wales
Nikolaos Christidis, Gavin C. Donaldson, Peter A. Stott; Climatic Change, October 2010That's called supporting an assertion with evidence.
-
John Hartz at 07:55 AM on 4 August 2013It's not bad
@Ray Coleman #352
You blithely assert,
Intermittent Heatwave 'costs' in terms of mortality are insignificant compared to the 'benefit' of a warmer continental US.
Please provide documentation to support your statement.
-
Roy Coleman at 07:06 AM on 4 August 2013It's not bad
"Increased deaths to heatwaves - 5.74% increase to heatwaves compared to 1.59% to cold snaps (Medina-Ramon 2007)"
SO? This has no context in terms of the general population mortality. The CDC figures on US death rates (2007-8) are quite clear, 900 more people per million die in cold weather, at temperatures below 12 degrees, that's in excess of 250000 people annually! Intermittent Heatwave 'costs' in terms of mortality are insignificant compared to the 'benefit' of a warmer continental US. You must excuse me but without appropriate context, noting studies like this distorts our necessary perception and responses to climate change.
-
Leland Palmer at 04:49 AM on 4 August 2013Toward Improved Discussions of Methane & Climate
By the way, even if most of the methane doesn't make it into the atmosphere, it could still do the biosphere major harm via ocean acidification, as it oxidizes into CO2 in the oceans.
I seem to recall seeing a modeling paper of this phenomenon in the Arctic ocean, which predicts that chronic methane release from the hydrates would overwhelm the oceans ability to absorb and oxidize the methane, and lead to more direct venting of methane to the atmosphere.
There are also suspicions that anoxic oceans could increase their production of NOx, I think.
As gws said, the atmospheric chemistry effects of methane release have to be considered- but so do the oceanic chemistry effects.
In his book "Under a Green Sky" Peter Ward talks about the truly catastrophic effects of massive methane release on the oceans, including anoxia and proliferation of strange bacteria. We're not there yet, and have a long way to go before things get that bad.
But, once it starts, could we stop the process?
-
gws at 04:26 AM on 4 August 2013Toward Improved Discussions of Methane & Climate
I would like to emphasize a point made by Leland, namely that further increasing atmospheric methane will have significant impacts on atmospheric chemistry. Increased atmospheric methane tends to decrease OH radical abundance and increase ozone abundance under current NOx availability, which increases atmospheric pollutant lifetimes and further stresses ecosystems (via ozone).
A review paper by Wuebbles and Hayhoe can be found here. The potential changes described in the more recent Isaksen paper cited by Leland are indeed "alarming", wherefore the atmospheric chemistry community does place a priority on how methane sources may change, including due to AGW factors.
Humans have so far approx. trippled the amount of methane in the troposphere (particularly via meat consumption, rice cultivation, and organic waste dumping; aka via boosting methanogenesis, but also via fossil fuel extraction and use), and more adverse atmospheric chemistry effects of that have so far not occurred due to a rather stable cleansing capacity of our atmosphere (supported by our simultaneous pollution of it with NOx). But as its response is non-linear, an out-of-control increasing methane source strength could be devastating, regardless of its speed.
Meaning, even if the chances of a rapid release are remote from today's point of view, if there is a large reservoir that could be released to the atmosphere, we should be very concerned about that possibility and take any and all preventive action to stop it from actually doing so, regardless of the speed of release.
-
John Mason at 02:52 AM on 4 August 2013Toward Improved Discussions of Methane & Climate
Michael, #21,
I agree to an extent - what we are doing here WRT atmospheric composition may be unprecedented in the entire Phanerozoic in terms of rate. On that basis, Chris, are we not comparing apples and oranges? It may be completely irrelevant that nothing like the things Wadhams is concerned about appear to have occurred over the past few glacial-interglacial cycles: nothing within them, apparently at the very l;east, occurred so quickly. One to consider!
-
michael sweet at 02:24 AM on 4 August 2013Toward Improved Discussions of Methane & Climate
Glenn,
Since the forcing today is much greater today than in the PETM (at least 10 times greater), why do you suppose the methane releases during the PETM are the maximum speed possible? Since the forcing is so much greater, it stands to reason that the methane release will also be much faster. Can you explain your argument?
-
acjames76 at 01:31 AM on 4 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
I started the course near the end, but it will be worthwhile starting it again. The instructors say:
We are planning a second offering of Climate Literacy, likely to start in late September. If you have friends, family, or colleagues you think would like to participate, they can currently click the "Add to Watchlist" button on Coursera. Soon there will be a button to actually register for the second offering.
-
Leland Palmer at 01:25 AM on 4 August 2013Toward Improved Discussions of Methane & Climate
Hi Glenn Tamblin at post # 18-
It's true that methane hydrate dissociation is an endothermic process and that there may be a rate limit to its release.
A lot of the total methane release from the hydrates depends on the total methane hydrate inventory, though - the total amount that exists on the earth.
Estimates, as you know, range from about 400 billion metric tons to about 77 trillion metric tons - roughly 440 to 85,000 cubic kilometers.
That's a big range, Glenn.
Archer and his collaborators estimate we have something like 4,000 cubic kilometers of methane hydrate, while Dickens and his collaborators talk about a consensus estimate of around 10,000 to 20,000 cubic kilometers. I've seen a paper on the End Triassic which talks about roughly 13,000 cubic kilometers released, rather slowly, which in my mind casts doubt on the lower estimates of total hydrate inventory.
So, first point, we don't know how much hydrate is down there, on the continental shelves. Multiply a low rate of dissociation by a large hydrate inventory, and one can arrive at a high total methane release. This alone argues that complacency is contraindicated.
Since we are coming out of a series of ice ages, with low ocean temperatures promoting hydrate stability, we could in fact have massive amounts of hydrate in the global hydrate inventory. And hydrate deposits which are uneconomically thin or scattered and useless to the fossil fuel corporations, not worth mapping, really- might release methane even more rapidly than the economically valuable deposits, because of their scattered and porous nature- especially if they are shallow deposits.
Some of the papers I've looked at on hydrate dissociation assume that the convoluted three dimensional hydrate deposits, full of chimneys large enough to show up quite well on sonar, will act like a one or two dimensional model spread uniformly over a two dimensional surface- a highly questionable assumption. Complicated real world processes like convection, convoluted geometry, and chimneys, could make such estimates seriously underestimate the rate of methane release from the hydrates.
I don't want to bet the future of the biosphere on models of hydrate dissociation which could easily be wrong due to the highly fractured nature of hydrate deposits, often full of chimneys from past release of methane.
My conviction is that if we surround the hydrate deposits with warmer water, the deposits will find a way to dissociate, via complicated mechanisms including convection and release of pressure build up of associated free methane gas reservoirs. Undersea landslides are a distinct possibility, especially after substantial methane release has weakened the deposits. So, the landslide phenomenon could be an accelerating process.
The methane gun hypothesis of mass extinctions requires a trigger mechanism, to set off the hydrates- generally a rapid rise in CO2 is postulated.
The fact that our modern triggering event is so much more rapid than past triggering events makes me more alarmed rather than less alarmed. The rate that Lee Kump observed for PETM hydrate dissociation might be characteristic of that event given a much slower triggering event, less severe positive feedback effects, and the methane hydrate geographical distribution at the time.
Regarding geographical distribution- the location of the East Siberian Arctic Shelf, located as it is under the most rapidly warming region on the planet, is particularly worrisome. Another worrisome thing is the current imbalance in ice distribution with most of the ice located in Antarctica. It seems possible that we could have a full blown methane catastrophe occurring in the north, while Antarctica remains relatively intact. This would slow water rise, which in the past has helped stabilize the hydrates due to a rise in hydrostatic pressure by increased water levels.
There are times in life when alarm is appropriate, and this is one of those times, I believe.
Prev 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 Next
