Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  1363  1364  1365  1366  1367  1368  1369  1370  1371  1372  1373  1374  1375  1376  1377  1378  Next

Comments 68501 to 68550:

  1. Galactic cosmic rays: Backing the wrong horse
    Eric, you're making suggestions that GCRs drive deglaciation and the Younger Dryas, yet these are not supported by evidence or your references. What is your support for GCRs being necessary for deglaciation in our current geographic configuration? Why, when this configuration has lasted throughout the Quaternary, are glaciations and deglaciations timed with orbital forcing? An again, why does any noticed correlation necessitate a causal connection? Your assertion about GCRs and the Younger Dryas is unsupported by the Hughen et al 2004 article from which you take your graph:
    "Peaks in 14C are also reconstructed at 40 and 29 cal. ka B.P. and previously reported at 12 cal. ka B.P. (13), coincident with Heinrich events H4, H3, and H0 (Younger Dryas), respectively (35). These events may also have been associated with unusually large perturbations in ocean ventilation and sea-ice cover explaining “anomalously” elevated 14C at those times (23, 36)."
    The main hypothesis is that the radiocarbon plateaux are driven by oceanic circulation changes (Hughen et al 2000 is ref 13 in the above quote). There is also doubt about the Cariaco radiocarbon spike - Muscheler et al 2008 suggest that upper ocean changes in the Cariaco basin itself influence the record.
  2. Galactic cosmic rays: Backing the wrong horse
    48, Eric, For the record, I was saying the same thing that you are, that in those cases CO2 was an amplifier tied to temperature itself, and not a control knob. It's fairly well accepted that the trigger for the event was a change in orbital configuration that changed not TSI but simply the duration and strength of Northern Hemisphere summers, which in turn triggered the retreat of the ice sheets, reflecting back less sunlight (and in that way causing a lower TSI). The main issue in the glacial termination debate is the main mechanism for the abrupt surge in methane and carbon dioxide that let the whole thing get from "there" to "here." I should point out, too, that in this sense I'm simply using the term "control knob" in a different sense that Dr. Alley. It's still a "knob" in that it affects temperatures, but it wasn't a knob before 1751 because no intelligent civilization had until then been able to change CO2 in the atmosphere. From that perspective, no, it wasn't a control then, but it is now.
  3. Galactic cosmic rays: Backing the wrong horse
    Eric (skeptic), a few thoughts that I cannot follow up properly at the moment: 1) Shaviv's temperature reconstruction is almost certainly wrong, both because it has been shown to not compensate for the effects of changing ocean pH, and because it is incompatible with the record of Earth's cryosphere. The oxygen 18 record from Royer et al, 2004, essentially reproduced below, although from a different paper is Shaviv's record as corrected for pH. Further, if Shaviv where correct, the absence of glaciation around 200 and 450 million years ago is astonishing, given the temperatures relative to current global temperatures. 2) Further, given a GCR connection to climate change, it seems unlikely that the early Earth would ever exit a snowball state. Essentially, the early Earth had 70% of the current TSI. That also meant a weaker magnetic field, and hence more GCM reaching the Earth. The logical conclusion with both a weaker sun and higher cloud albedo due to GCM's is that a snow ball state would have been a permanent feature of the Earth's climate until at least the last 200 million years. 3) Finally, I am uncertain that you can simply assume Be10 cannot be a dependent variable for climate. Specifically, Be10 is formed by spalliation from Oxygen or Nitrogen. It is then washed from the atmosphere in solution. When a particular sediment dries, the Be10 is left behind in proportion to its concentration in the water. Intuitively, there are then two controlls on Be10 concentration. The rate of formation, which determines concentration in the atmosphere; and the rate of rainfall. Larger quantities of rainfall, by washing the Be10 out of the atmosphere more frequently, and with a larger volume of water would result in a lower concentration of Be10 in the water, and hence in the resulting sediment. Alternatively, dry times such as the last glacial, would result in higher Be10 concentrations. This is just a suggestion by me, and may be entirely wrong. It would, however, neatly explain the correlation shown by Mercurio, and explain why Be10 concentrations do not always vary with fluctuations in the Earth's magnetic field (as indeed, is shown by Mercurio during the last glacial), and also why Be10 and C14 concentrations do not always correlate.
  4. Galactic cosmic rays: Backing the wrong horse
    Muoncounter, the end of the abstract says "However, we note the detectability of any potential links is strongly constrained by cloud variability." A control knob need not be overwhelming and instant and this GCR link would be offset by oceanic cycles and other weather. You asked "Are you suggesting here that a change in GCR flux is necessary to initiate deglaciation? If so, why - and on what evidence?" A large decrease in GCR flux appears necessary for deglaciation in the current geographic configuration, but a spike can throw it off e.g. in the Younger Dryas (13ky bp) I admit this is not a particularly strong event, but I don't think it is pure coincidence that the 14C spiked then Y.D. took place.
    (from http://alliance.la.asu.edu/temporary/students/Phil/Hughen.pdf) Skywatcher, the GCR spike shown in #29 took place in full glaciation so I would not expect a GAT response. My purpose in resurrecting this thread was to respond to the claim in Spharican's latest post "It took an increase of 105 ppm, or a factor of 1.6, to get us from an "ice age" into the world in which we currently not only live, but thrive" As I said there, it took more than CO2, it required a control knob, with the 1.6x CO2 functioning as an amplifier. The control knob could be TSI, and not GCR as there is considerable overlap in their effects.
  5. (Fahrenheit) 451 ppm
    skept.fr @20, no national representative at Durban may deny the 2 degree C, 450 ppmv target, yet they have all just signed of on a deal that almost guarantees that we will exceed that target.
  6. (Fahrenheit) 451 ppm
    skept.fr#32: Withlock deals with fire's role as an ecological process; re-defining fire-regime triangles has nothing to do with this discussion. Customizing the settings on climatewizard.org is straightforward. One of the options in a drop-down menu under 'Measurement' near the top is seasonal, monthly or annual. "For 'winners' and 'losers', replace these undue notions by there will be 'regions with more/less precipitation and greening'." 'Winners' and 'losers' were your choice of words; their replacement with gentler sounding euphemisms is mere semantics. "many countries depend on regional and global trade rather than sel-sufficiency." That's the point - the global interdependency of the world food supply is exactly why there can be no winners. "it is not unthinkable to imagine that there are adaptative capacities" Imagine the cost when those 'capacities' need to be developed and brought online at short notice because we sat around, pacified by those who claim 'its not bad,' and did nothing. Seems like we've had this conversation before.
  7. (Fahrenheit) 451 ppm
    #30 scaddenp : I globally agree with you. AFIAK, UE negotiators accept the principle of 'common but differential responsibility' in AGW diplomacy. That's why the Kyoto Protocol or the 20-20-20 European climate plan are not bound to commitment by other parties, from Annex I or non-Annex I. And that's why the first, second and third world will not have the same reduction targets in an (hypothetical) 2015 agreement.
  8. (Fahrenheit) 451 ppm
    @28 muoncounter : "Other than the word 'fire' in the title, is there any relevance in the Withlock reference to this discussion?" Quite surprising, did you read the paper? In #21, you speak of climate change and fire correlation. Withlock et al 2010 have developments on weather/climate conditions of fire in climatic archives, but also on all factors influencing fire, including vegetation change. If you consider that as OT, then your #21 wat OT too. For 'winners' and 'losers', replace these undue notions by there will be 'regions with more/less precipitation and greening'. That was my initial point in #15, the idea that vegetation will regress globally does not seem to be supported by vegetation models coupled to AOGCMs. Don't understand what you mean by 'tweaking climate wizard settings a tad' and how you get summer (or any particular season) precipitation on this site. (For extreme events, I guess the recent SREX is the most updated reference of the expert view. There is just the SPM for the moment, where I read : "There is medium confidence that droughts will intensify in the 21 st century in some seasons and areas, due to reduced precipitation and/or increased evapotranspiration. This applies to regions including southern Europe and the Mediterranean region, central Europe, central North America, Central America and Mexico, northeast Brazil, and southern Africa. Elsewhere there is overall low confidence because of inconsistent projections of drought changes (dependent both on model and dryness index). Definitional issues, lack of observational data, and the inability of models to include all the factors that influence droughts preclude stronger confidence than medium in drought projections."). If feeding the world is "at risk" (for change in precipitation), I suppose the global primary productivity conditions in 2050 and 2100 is the most wanted information. Because even today there are deserts, droughts, etc. so agriculture adapts to changing conditions and moves if necessary, many countries depend on regional and global trade rather than sel-sufficiency. At least, it is not unthinkable to imagine that there are adaptative capacities in two or three generations (agriculture was different from now in 1970 or 1930). Conversely, feeding the world without directly or indirectly fossil-assisted technologies that sustained current productivity (mechanical engines, fertilizers, construction of irrigation and stockge systems, R&D biotechnology, etc.) is a challenge, and I'm quite surprised that nobody considers that there are some "risks" here too...
  9. (Fahrenheit) 451 ppm
    Sphaerica, this is the skeptic sight so I imagine one would be skeptical of post 26, but I have spent 40 years on it, and have a masters from UCI, so please consider it. May contact me at p*******y@gmail.com. I hope this is not breaking spam rules, if so please forgive me.
    Moderator Response: [Sph] E-mail address edited for privacy.
  10. (Fahrenheit) 451 ppm
    "But the same is true for US government choices " Yes, there is broad agreement that there is pain in the future but we dont know how much. Even when we are confident that future pain will be worse than taking action now, however, there is an extreme reluctance to do so. The west has no concept of the idea that since we caused a problem, then it behoves us to take responsibility for it, even if it causes us pain. In short, we want the rights but not the responsibility. For all the lip service to equity, there is no intention of giving it, unless a way is found to do so without reducing standards of living and growth in the west. Now I am all for maintaining my standard of living if a way can possibly be found to do so. I am not however prepared to compromise the future of my children and grandchildren to maintain that. Those pushing anti-science are. We need precautionary measures first and then see if we can find a way to prosper within those constraints. Instead negotiators are settling for wild hopes, and a refusal to accept constraints unless there is a way to do so without causing any rich person some pain.
  11. (Fahrenheit) 451 ppm
    skept.fr#27: Other than the word 'fire' in the title, is there any relevance in the Withlock reference to this discussion? "their will probably be winners and losers in precipitation trends." I love that kind of thinking. Tweaking sphaerica's climate wizard settings a tad, look at the change in precipitation in summer for a few of the other ensemble percentiles. The growing season across a wide range of southern Europe, the middle east and west/central Asia, South America, western North America, southern Africa and much of Australia is at risk. In that scenario, there are no 'winners and losers.' Displaced populations and pressure on world food supplies will show no favorites; it's naive in the extreme to think that 'it will be greener where I live' makes one a 'winner.'
  12. (Fahrenheit) 451 ppm
    Well presented Sphaerica with much to consider. I personally am most intrigued by the paleoclimate studies focusing on the mid-Pliocene around 3 mya to see what sort of climate we may be in for. In determining the overall impact on humanity three key issues are of course paramount: 1) The effect on the food grains. How will wheat, corn, etc. do in a warmer world? Might they survive but their prime growing regions be shifted? What about genetic modifications to these crops to make them more successful in a warmer world? 2) How will the world respond to and accommodate climate refugees? Mass migrations are possible, and this could lead to conflict if not managed well. 3) The biggest unknown is the response of the oceans. Rising oceans may play some role, though I think accommodations can be made to mitigate the worst, but more importantly is the overall health of the oceans in terms of the biological and ecological parameters. The ocean has this far buffered us from the greatest impacts from the large scale dumping of CO2 into the atmosphere. This buffering has taken place on two levels: the retention of excess heat and the direct uptake of CO2. So the big question is-- how will the the ecosystems of the oceans respond to being warmer and more acidic? The answer to this question is important, perhaps even key to the overall health of the rest of the planet.
  13. Galactic cosmic rays: Backing the wrong horse
    David Lewis' point at #29 above is worth referring to. If GCRs were any kind of a control knob, you'd expect a response around 38,000 years ago. Alley showed there wasn't and so GCRs don't control the climate.
  14. Galactic cosmic rays: Backing the wrong horse
    Seeing as nobody has demonstrated a mechanism to connect GCRs and Earth's climate, despite lots of effort, then Eric, your first sentence does not make sense. A good example is here - very few of the requirements for a GCR hypothesis appear to be working. Frankly, we can safely put that one in the hold alongside fairies changing climate IMHO. Also on your first sentence in #44 - if there's an increase in piracy alongside global warming, do you "have to agree that there is some causation that we don't understand"? Bit of a non sequiter. Your final sentence is correct, however!
  15. (Fahrenheit) 451 ppm
    #21 muoncounter : about fire in this particular sense (non metaphorical), see also this very interesting paper from Withlock et al 2010 . #22 scaddenp : I totally agree that the ‘equity issue’ (ie historical responsability of Annex I UNFCCC countries) is a basis for a future international agreement. But for that I read about BRICS’s position in COP or in their national climate plans, it won’t be sufficient : emerging countries are not just searching symbolic rewards, but primarily material developments for their people, the same material developments Western countries has already achieved. I hope non fossil energy will be able so sustain such a quest and I think it’s now a major point of reflexion. But the same is true for US government choices : pipeline from Canadian tar sands, deep offshore GoM, shale gas and oil won’t be given up because of the future (and still uncertain) cost of droughts in 2050s or 2100s, as the present (and certain) cost of their too rapid abandonment would be huge for a heavily fossil-dependent society like the US. Find substitutes (even 10% more costly for a carbon tax compensation) of the same amount, and you’ll find the solution. #23 Sphaerica : as your map for 2080s clearly shows, their will probably be winners and losers in precipitation trends. Same is likely true for vegetation growth capacity (precipitation skills of models are still poor, but it is the best we have). That’s why I consider the Fire Age analogy as a good metaphor for regional changes (including probably France ‘sud de la Loire’), but not global changes. Anyway and beside the metaphor itself, concerning human choices in the 2010s, I think these two-generations-from-now predictions can not be considered as ‘killer arguments’ in the climate debate. For an example : Spain is a already a semi-arid country who, like others here in Europe, has known a strong warming in the past 30 years (approx 0,5K/dec since the mid-1970s for Spain, if I remember correctly). But in the same time, Spain is a leading exporter of fruits and vegetables and its most productive regions are in the warm South of the country (intensive hydroponics cultures adapt to climate variations, which change mainly the season of growth : in a warmer climate you get the first strawberries in march rather than april, february rather than march, etc.). I think there is a kind of ‘basic instinct’ for such short term adaptations to change and it is very difficult to fight that psychological bias, even with the scariest projections. And for my part, I refuse to endorse particular projections without mentioning their relative level of confidence or the existence of opposite view in the literature (I mean the ‘serious’ view in the 'serious' literature). That’s why IPCC reports are my ultimate reference because it’s their job to check all publications on a subject and to give an informed assessment on what we know. But mainly, my basic point is that such long term predictions are no more at stake in climate negotiations. I’m pretty sure nearly all negotiators have these kind of risks in mind, even before Durban COP17. But they have other risks in mind too for their socio-economic pathways, and that’s why they probably refuse a too fast or too constraining treaty (particularly if they benefits of very cheap energy as producers of coal, gas or oil, of course). But of course, our discussions have their own interest, as we can compare and evaluate our views on climatic change.
  16. (Fahrenheit) 451 ppm
    Wonderful clarity and completeness. Can I have permission to add this to my book as an appendix. It would be a wonderful convenience, rather than just the URL reference. My book proposes a solution based on use of the energy of latent heat in the atmosphere to resolve, energy, water, and land problems--- thus all commodities at once. Thanks, Atanacio Luna
  17. Galactic cosmic rays: Backing the wrong horse
    Eric#44: "you have to agree that there is some causation that we don't understand" Isn't the entire GCR argument based on 'some causation we don't understand'? "lower GCR's and corresponding higher TSI allow warming to take place, otherwise, for the most part, we would be stuck in a glaciated state" Are you suggesting here that a change in GCR flux is necessary to initiate deglaciation? If so, why - and on what evidence? Why isn't it simply sufficient for a change in TSI to start the warming process? "GCR appears moot in our current interglacial because it does not seem to happen in reverse" An odd sort of control knob, only working one way. That is not how I recall the Svensmark model - more solar, fewer GCRs, fewer clouds. Less solar, more GCRs, more clouds. That has to work both ways. A recent paper, Laken and Calogovic 2011, is relevant: We find no evidence that widespread variations in cloud cover at any tropospheric level are significantly associated with changes in the TSI, GCR or UV flux, and further conclude that TSI or UV changes occurring during reductions in the GCR flux are not masking a solar - cloud response. How is that a control knob?
  18. Galactic cosmic rays: Backing the wrong horse
    muoncounter, if you agree that it is "pure correlation without a mechanism", then you have to agree that there is some causation that we don't understand or simply the coincidental and complementary TSI changes. My sense is that the lower GCR's and corresponding higher TSI allow warming to take place, otherwise, for the most part, we would be stuck in a glaciated state in our current geological configuration. GCR appears moot in our current interglacial because it does not seem to happen in reverse (higher GCR's and lower TSI predictably causing cooling). Obviously the GCR/TSI knob, such as it is, is completely moot in light of our increasing GHGs. Our only worry right now is warming from GHGs.
  19. (Fahrenheit) 451 ppm
    I think newscrusader's point was that I was actually being generous by hoping that we'll simply hold emissions constant and thus forestall 451 until 2042. Obviously continued economic growth in India and Asia could even offset global efforts to reduce emissions in other ways, and hence lead to a higher annual emissions and reaching 451 more quickly. Honestly, things are already bad enough. I felt like I was pretty even handed in presenting the possibilities, without even being realistic about things such as increases in annual emissions. But for myself, I just didn't want to think about getting to 451 before 2042.
  20. Baked Curry: The BEST Way to Hide the Incline
    Judy Curry made a revealing comment at the AGU 2011 conference on Wednesday morning, in the ED32A session at 10:20. In her presentation she erected a straw man that previously, climate scientists have communicated only one-way with the public and policymakers, not listening to responses, not being open to ideas from those audiences, and not engaging in conversation. Then she described her approach as differing from everyone else's--as engaging in real, looping, conversations. There was time for only one question from the audience, and nobody used that to challenge her with the many blogs that have robust commenting with responses, and with the multitude of public lectures that include extensive discussion with the audiences. Her image of how teachers teach is bizarrely, stereotypically wrong. An accessible example is David Archer's free videos of his lectures in which he always takes questions and engages in discussions with his students. The one question the audience did ask was more revealing. Steve Easterbrook posed: If your students were discussing amongst themselves, but the information they were presenting to each other was wrong, wouldn't that reinforce their wrong ideas? Curry responded tellingly, that she views her job as being only to facilitate discussion among students, not to correct or direct them! I find that astonishing for a teacher of a scientific discipline. I don't know why she continues to be employed as a teacher. Apparently she runs her classes the same way she runs her blog.
  21. (Fahrenheit) 451 ppm
    @newcrusader Never heard about exponential functions (e.g. compounded interest)? If you add to a solution, the concentration grows exponentially. Actually any kind of growth is exponential => Growth is an Exponential Function
  22. (Fahrenheit) 451 ppm
    20, skept.fr, You are missing the point of the "Fire Age" analogy. The planet may well green overall, given enough time. But critical, agriculturally productive and heavily populated areas of the planet are in serious danger of suffering the opposite. Consider this prediction of precipitation changes (ensemble average for the Medium A18 emissions scenario) from Climate Wizard: I think the odds are stacked very heavily against Texas, Southern California, Mexico, Spain, Italy, the Balkans, Israel, Egypt, South America and others. Large parts of the northern USA, Canada, far northern Europe, Asia and others may well see a greener world. But some very basic parameters look to combine to make those particular changes fairly likely. Everyone is going to experience the upheaval of change, however, and that is the main point. The world is going to change, probably more quickly than people expect, and that is going to be both expensive and painful (in a real, personal sense for too many people). It doesn't really take much beyond common sense to look at things at a high level and to say that it is not worth the risk. Not when inexpensive, coordinated, moderate action now is capable of keeping the situation under control with far less expense than is seemingly inevitable given a continuing course of almost inaction. From the perspective of actual, living people and today's civilization, the term "Fire Age" may well seem appropriate.
  23. Plimer vs Plimer: a one man contradiction
    @John Cook: Re the first sentence of the final paragraph of your article, how would one "...pore through Professor Enting's thorough document..."?
    Moderator Response: [JH] I'm wiping the egg off my face. For my entire lifetime, I thought the phrase was "pour through." I guess I've never seen it in print before now.
  24. (Fahrenheit) 451 ppm
    Well I would agree wholeheartedly that "emerging" countries want to escape poverty and need to be more energy intensive to do so. On the other hand, they are the most vulnerable to rapid warming on the whole. The killer in this, is that Western world created the problem but is extremely unwilling to commit to change or to pay for consequences. While the western world won't make meaningful change, the rest of the world wonders why they should be making the sacrifices instead. Worse still, the countries with the highest historical contributions to elevated CO2 are also least affected. It swings on the question of equity. At present, dealing with a generational level problem, the world is committing to go to hell in a handbasket rather than face up to the equity issue. A frankly, I think the major sticking point for a democracy like US, is the denial of science by Republicans. This constrains what any negotiator can sign for and while the US wont make concessions, you can bet your life that China and India wont.
  25. (Fahrenheit) 451 ppm
    skept.fr#20: "excessive metaphor of 'Fire Age' against misleading horizon of 'Green Paradise' is mostly a low-effect rhetoric game" It would be nice if that was only a metaphor. Marlon et al 2009 find paleo correlation between rapid climate change during recent de-glaciation and fire activity in the US: Intervals of rapid climate change at 13.9, 13.2, and 11.7 ka are marked by large increases in fire activity. The timing of changes in fire is not coincident with changes in human population density or the timing of the extinction of the megafauna. Although these factors could have contributed to fire-regime changes at individual sites or at specific times, the charcoal data indicate an important role for climate, and particularly rapid climate change, in determining broad-scale levels of fire activity. Marshall et al 2008 make a case for increased fire frequency as temperature/precipitation events become more erratic: As climate change continues, we can expect increased precipitation variability (ie more frequent wet-and-then-dry periods). In addition, fuels are already being dried by earlier snowpack disappearance, earlier commencement of transpiration, and higher temperatures. Such changes in fire frequency or intensity are almost certain to influence ecosystem structure and function. If you've lived through a fire season, you'll agree this is no rhetorical exercise.
  26. (Fahrenheit) 451 ppm
    Sphaerica : the papers I linked did not deal with long term equilibrium sensitivity ("a few thousand years"), but with near term CO2 doubling or 2100 projection in a A family scenario. I've personally no prior assumption about greening or non-greening world, because there so many factors to be considered in plant growth (CO2, T, water, nitrogen, etc.). That's why I rely on vegetation-GCM models as best estimates of our current understanding. More broadly, I understand you're scare to death but as Durban COP17 ends, my own reflexion was that 'scary scenario strategy' is quite unable to accelerate political decisions, and will probably be as unable in the near future. First because the more scary are your projections, the more uncertain they (usually) are, so you expose yourself to the suspicion of unbalanced view. Second because India, Brazil, Indonesia and dozen of emerging countries do not basically object the reality of climate change (and the eventuality of huge and fast regional changes). No, they want to escape poverty, so as Western societies did thanks to fossil energy and the 120 ppm added to atmosphere since the 19th century (these 120 ppm are not just radiative forcing, they're also the historical witness of Western access to welfare). Give solutions to do so without relying massively on oil, coal and gas, and scary scenarios will be perfectly useless because climate targets will be fully compatible with development commitment. I think it is the Gordian knot in the new era of climate debate, as denial of basic science looses its (already low) influence except on the right wing of Republicans. And conversely, I think excessive metaphor of 'Fire Age' against misleading horizon of 'Green Paradise' is mostly a low-effect rhetoric game. No national representant at Durban denies the 2K / 450ppm target as a necessity from a climatic point of view, and it means all national representants grossly agree with adverse effects of a too fast and huge warming you describe here. That is no more the central point IMO.
  27. (Fahrenheit) 451 ppm
    Surely this should be forwarded for publication in a proper journal. It just might concentrate the minds of those that think we can relax now that we have a global agreement on CO2 reduction and can't hear the deafening clatter of the can being kicked down the road, yet again.
  28. (Fahrenheit) 451 ppm
    lovelock did this simple modelling awhile back and has written a number of books in plain english on what this warming means.
  29. (Fahrenheit) 451 ppm
    Aye, Sphaerica, and while I'm sure that skept.fr understands the following comment, others may not: if the planet stays just as green as it is now but viable areas for agriculture shift hither and fro, massive economic and social disruption will still occur. The bottom line doesn't describe the reality on the ground. In some ways, humanity is in a very good position to tackle the problem (technology). In other ways, we're in the worst possible position (political and economic complexity and fragility).
  30. Galactic cosmic rays: Backing the wrong horse
    40, Eric, I'll have to read the Mercurio paper, but it does not seem to ever have been published in a peer-reviewed journal (or even one that pretends to be, like GRL). As such, it's hard to figure out what flaws it might hold. No one seems to have paid much attention to it. I'll take a peek, at his paper, but everything I've ever seen shows little correlation between GCR and climate. It's possible that there is a vague connection there, but without a proven physical mechanism or clear correlation in the evidence, it's hard to put much weight on it at all. Sorry, I can't concede it as a "control knob" without a lot more evidence to support it.
  31. (Fahrenheit) 451 ppm
    15, skept.fr, I don't disagree that in the long run the planet may well be much greener. When a few thousand years have passed and new layers of topsoil are generated in the far north, and plants have shuffled around enough to find the ecosystems in which they do best, then the increase in overall atmopsheric moisture and plant-habitable regions at northern latitudes may well make the planet qualify as "greener." From a human perspective, however, places that are green now are going to brown. I'm scared to death of the expansion of the deserts, the loss of the Amazon, and most importantly serious agricultural difficulties in the US Southwest/Midwest and just as importantly Mediterranean Europe. I'll stick with the "Fire Age" analogy simply because it's too easy for people to fall into a too simplistic "CO2 is plant food, it must be good, yay, the planet will get greener" mentality.
  32. Greenland has only lost a tiny fraction of its ice mass
    John: The same paper I linked to earlier, on page 7 has another diagram that shows some modeled sea level curves since the last deglaciation. Glacial rebound from the last deglaciation is still occurring slowly - from a sudden deglaciation, you can think of the response as roughly exponential. My recollection from study and field work in northern Canada (in a past life) is that after the Laurentide Ice Sheet disappeared, the land west of Hudson Bay was flooded to something in the order of 150m above current sea level. As the land slowly rebounded, local sea level dropped. The abstract of the following paper talks about some of the dates involved: Dyke and Prest (1987) and says that the deglaciation took from roughly 18k to 8k years BP (lots of local variations). So using a period of 10,000 years for rebound (too short, because it's still recovering) and 100m of rebound (just to get a ballpark figure), we get average rates of rebound of 1m in 100 years. This definitely seems fast, and would be clearly noticeable. Rebound does take longer than ice melt, though. ...but in the context of Greenland and current sea level, the depressed area around Greenland is quite small compared to total ocean area, and we're talking about much less ice than the last glacial maximum. A Google search gets me areas of 22 million km2 for Greenland, and 361 million km2 for the worlds oceans, so Greenland is about 6% of the total ocean area. So this reduces the global effect on sea level associated with Greenland rising. Then you have to account for the fact that most of Greenland is not currently covered by ocean, so the uplift doesn't affect other areas because water isn't being displaced. Then add in the area around Greenland that sinks, and effects get smaller again... My largely unsubstantiated gut feeling is that the effect is small. My hopefully-somewhat-educated guesses as to the answers to your specific questions are: 1) short term (next 100 years) sea level rise cause by water displaced by sea bed rising is likely negligible. 2) people that study sea level and glacial mass balances have probably figured this out in much greater detail than I can, and if it is significant they have probably accounted for it. This whole question of crustal movement and apparent local sea level changes is one that has been extensively considered in the tidal gauge interpretations. In addition to glacial isostatic rebound, local tide gauges are affected by regional uplift or subsidence associated with plate tectonics and other geological factors. This sort of things was taught at the undergraduate level in the 1970s (at least, to me... and I don't think I got any special treatment), so it can't possibly come as a surprise to people working in the area...
  33. Galactic cosmic rays: Backing the wrong horse
    Eric (Sceptic). {- snip -}Galactic Cosmic Rays?? Maybe alien death rays. Really any more conjectures for the warming? This is as good as the neutron star in the center of the Sun theory!!! Maybe the back hole at the center of the Galaxy is causing all these. Then again all the hot air coming from {- snip -}. I am sick of the crazy (-snip-) theories.
    Moderator Response: [mc] Easy there, Tsk; watch the ad homs. Keep it civil.
  34. Antarctica is gaining ice
    Very useful feedback. Thanks
  35. Part Two: How do we measure Antarctic ice changes?
    Very useful feedback, thanks
  36. (Fahrenheit) 451 ppm
    Sphaerica : your metaphor of 'Fire Age' with mention of Amazonian drought and deserts' extension suggests that a warmer world will not favour vegetation on a global scale. But if vegetation models coupled to AOGCMs do simulate a regression of tropical rainforests, they also obtain an overall increase in net vegetal biomass with increasing CO2 and T, at least in some recent works like for example Notaro et el 2007 , O'ishi et Abe-Ouchi 2010 , Jiang et al 2011 . Or they detail many regional differences in vegetation response as in Levis et 2010 . For Amazonian drought, I mention this special issue of the New Phytologist. Its "whole or part turn into savanna" is at least an uncertain pathway, see Ramming et al on the risk of Amazonian forest dieback.
  37. Antarctica is gaining ice
    peacetracker#110: "based upon sea ice extent and subjective guesses" Can anyone seriously contemplate circumstances in which areal extent is decreasing, but volume is increasing? That's patently ridiculous. See the Arctic ice threads.
  38. 2011: World’s 10th warmest year, warmest year with La Niña event, lowest Arctic sea ice volume
    Changes to the Arctic are chronicled annually in the Arctic Report Card issued by the US National Oceanic and Atmospheric Administration (NOAA) The 2011 report, prepared by an international team of scientists from 14 different countries, was reseased by NOAA on Dec 1. Among the 2011 report highlights are: • Atmosphere: In 2011, the average annual near-surface air temperatures over much of the Arctic Ocean were approximately 2.5° F (1.5° C) greater than the 1981-2010 baseline period. • Sea ice: Minimum Arctic sea ice area in September 2011 was the second lowest recorded by satellite since 1979. • Ocean: Arctic Ocean temperature and salinity may be stabilizing after a period of warming and freshening. Acidification of sea water (“ocean acidification”) as a result of carbon dioxide absorption has also been documented in the Beaufort and Chukchi seas. • Land: Arctic tundra vegetation continues to increase and is associated with higher air temperatures over most of the Arctic land mass To access this informative document, click here.
  39. Galactic cosmic rays: Backing the wrong horse
    Eric#38: "even though there are likely some weather effects." That still is mere conjecture. #40: "But there is still the medium range evidence of a GCR control knob (Mercurio link above)" Mercurio is a summary article written for the 'Encyclopedia of Human Ecology,' whatever that is. His 'evidence' consists largely of rehashed Svensmark with some Willie Soon graphs thrown in. A hodge-podge of other concepts shows up as well: In my hypothesis for the control of climatic cycles by geomagnetically modulated GCR levels, greater inclination of the earth with relation to external gravitational attraction results in stronger geomagnetism and therefore lower GCR levels which, in turn, result in less condensation and low cloud cover and generally warmer conditions. External gravitational attraction results in stronger geomagnetism? Did I miss when that relationship was established? But at least he's up-front about his 'hypothesis': I do not know whether the values of geomagnetic intensity on my curves indicating glacial-interglacial chronology are what would be necessary to modulate GCRs to develop the climates predicted for them. In other words, it's pure correlation without a mechanism. But let's call it evidence anyway. Much of the remainder is good old climastrology: The next ~80 year cycle maximum is likely to be around the year 2013 and this is one of the reasons it has been getting warmer over the last several decades since the last minimum around 1975 And here's a prediction (circa 2002): Dust Bowl type droughts on the North American western Great Plains and Southwest as occurred on and off for several years following the last solar minimum around 1997 should not occur in the years following the next solar minimum around 2007. Dust Bowl type droughts could be expected around and after the minimum of the following antiparallel solar cycle around 2020 or a little over 22 years from 1997. So 2011 droughts should not have happened until 2020. That merits an "Oops."
  40. Greenland has only lost a tiny fraction of its ice mass
    Thanks for the info, Bob. So it seems that as the Greenland bedrock rises due to loss of ice sitting on it (currently 6mm/year), the surrounding sea bed also rises; but in a more complex way than I first envisaged. So to come back to the questions I first raised; 1) ...is there enough additional seawater being displaced by a net rising of the sea bed to influence observed sea level rise? 2) ... is this effect being factored in to long term sea level projections? I guess there's also the issue that both altimeter and gravity readings of the Greenland ice cap will need to take into account the rising land, which will tend to make it appear like there's less ice being lost than is actually the case. My word, this is complicated! I guess the people working on this area will need to keep their wits about them. I sure take my hat off to them.
  41. (Fahrenheit) 451 ppm
    Bill : An abrupt increase in the atmospheric CH4 concentration from the region of 350 to 400 ppb to the region of 700 to 800 ppb seems to slightly precede the steep temperature rise on the exit from a deep ice age (glacial period). I used to read that, contrary to this assertion from Byalko 2010, there was a lag too between temperature rise and CH4 rise, for example Delmotte et al 2004 or discussion in Konijnendij et al 2011 . Does Byalko refer to other paleoclimatic works for justifying that CH4 rise precede the temperature change or is synchronous with it ? I do not read Russian but there are probably some publications on this subject referred in his article.
  42. Antarctica is gaining ice
    @peacetracker #110: A recent example of direct measurement of central Arctic sea ice volume is described in detail in “Changes in Arctic Sea Ice: Young and thin instead of old and bulky.” To access this informative article, click here.
  43. Antarctica is gaining ice
    Peacetracker, if you want to find out the validity of someone's argument, ask them for evidence of their claims. Ask this WUWT joker for evidence of guesswork at PIOMAS. Essentially, the commenter is saying that PIOMAS scientists are faking each month's data point to make sure that volume is dropping like a rock. If you don't understand how sea ice volume is measured, then ask yourself what is the more likely claim: A) the dozens of scientists at several scientific organizations are knowingly committing fraud to make it look like sea ice volume is dropping. They come to work every day knowing that they're doing the exact opposite of what they're trained to do, the exact opposite of what they went through 6-10 years of college to do. B) sea ice volume is dropping, consistent with a warming ocean and atmosphere. Volume drop is also corroborated by evidence from people who live and work around the Arctic circle.
  44. Antarctica is gaining ice
    @ peacetracker
    "Currently, there are no objectively quantitative ice volume measurements with anthing remotely close to the necessary temporal and spatial coverages. Consequently, Morano and anyone else can only make objective observations about sea ice extent."
    That is simply untrue. It is widely known that multiple physical measurements of ice thickness are taken at regular intervals. These range from ice thickness measuring buoys to US Navy submarines to aerial ice thickness measuring instrumentation packages to ships measuring the thicknesses on their recon cruises to orbiting satellites (IceSat & CryoSat2). Anyone who would maintain otherwise is simply talking about things about which they know nothing...or simply lying with the intent to mislead. http://neven1.typepad.com/blog/2011/08/polarstern-reaches-north-pole.html http://neven1.typepad.com/blog/2011/09/more-on-ice-thickness-from-awi.html http://imb.crrel.usace.army.mil/ http://amap.no/swipa/ http://www.osi-saf.org/index.php PIOMAS is a useful tool to incorporate all of these metrics into a validated model using known ocean/atmospheric/ice dynamics to compare past observations to current ones: and
    Moderator Response: [JH] Perhaps this comment should be transformed into a rebuttal article?
  45. Galactic cosmic rays: Backing the wrong horse
    Thanks Sphaerica, those links address Shaviv fairly effectively. After those posts there was this paper directly addressing the spiral arm transit: http://www-zeuthen.desy.de/~pohlmadq/publications/apjl_705_2_101.pdf and effectively rebutting Shaviv. But there is still the medium range evidence of a GCR control knob (Mercurio link above). But the GCR knob is ganged with the solar TSI knob, as solar activity increases, TSI increases and GCR decreases. Both the TSI increases and the coincidental GCR decreases will warm the climate. The GCR will also depend on galactic flux variations which is independent of the solar effects. Suffice to say, solar-modulated GCR is a control knob, solar itself is another, and GHGs are another.
  46. Antarctica is gaining ice
    Look at the gravity probes measurements over Antarctica. They clearly and unequivocally show a loss of mass at an accelerated rate. No models no fitting, just good old empirical unadulterated data. And if somebody thinks that the rocks have been vaporizing, then think again. Mass loss -> Ice mass loss -> Ice volume loss. No need for models to tell us that.
  47. (Fahrenheit) 451 ppm
    @ Lloyd Flack @ 8
    "Is there any evidence of large methane releases at the end of glacials? And if so what is their source?"
    I would refer you to Davy et al 2010:
    "Comparison of the history of oxygen isotope variation (Figure 2) with the amplitude variations observed on the “Parasound” sub‐bottom profiler data enables matching of climate cycles over at least the last 0.6 My. We interpret the high‐amplitude reflection horizons to correspond to peak glacial stages and subsequent glacial‐interglacial transitions prior to the resumption of higher carbonate sedimentation in interglacial periods."
  48. Antarctica is gaining ice
    I have come across this comment on a thread at WUWT. "Although the Alarmist arguments sometimes include claims about ice volume, such claims are based upon sea ice extent and subjective guesses about what they beleive a model parameterization adjustment should be to produce a desired result. Currently, there are no objectively quantitative ice volume measurements with anthing remotely close to the necessary temporal and spatial coverages. Consequently, Morano and anyone else can only make objective observations about sea ice extent." Is there any validity to this guys argument? Thanks
  49. (Fahrenheit) 451 ppm
    Bill, the fact that the cross correlations are so broad means that, as a function of lead and lag in a control system, the effects of CO2 cannot be treated as a simple lag. Whether that qualifies as "inaccurate" or not may fairly be considered a matter of opinion, but it certainly supports Sphaerica's contention that it's "simplistic" and "indiscriminate." Running a simple cross-correlation with existing modern CO2 and temperature records and then sweeping it across +/- 20 years or so (using the annual record) produces a similar result - CO2 is leading temperature, but the cross-correlation is high (greater than what could be expected from random noise) across the entire period.
  50. (Fahrenheit) 451 ppm
    BillEverett@10: the Antarctic methane correlates nicely with D-O events. It's been hypothesized that D-O events might have modified the thermohaline circulation, which would have led to Antarctic warming. There's some indication that Caribbean waters warmed too. So it could well be benthic methane. It sounds like Byalko is suggesting that oxidation of methane is what causes the CO2 to increase later - explaining the time lag between temp and CO2 (in other words, I read what he says as saying that the methane causes the temp rise, and produces CO2 when it oxidizes, raising the temp still more). That's an interesting idea that I've not seen before. Am I interpreting him correctly?

Prev  1363  1364  1365  1366  1367  1368  1369  1370  1371  1372  1373  1374  1375  1376  1377  1378  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us