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archiesteel at 10:20 AM on 9 October 2010Melting ice isn't warming the Arctic
Where did you see that polar amplification was a "fingerprint of greenhouse warming"? The article doesn't seem to make that case. -
Karamanski at 10:07 AM on 9 October 2010Melting ice isn't warming the Arctic
I'm confused, why is polar amplification considered a fingerprit of greenhouse warming, if the amplified warming is the result of sea ice loss. Almost every radiative forcing that causes global warming would be acompanied by polar amplification, because sea ice would melt regardless of whether the warming was caused by greenhouse gases or another positive radiative forcing. So why is amplified warming in high latitudes considered a fingerprint of greenhouse warming? Could please explain this? -
kdkd at 09:56 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
KL #71 "Looks like BP #49 has gob-smacked the Sea level debate again." Not realy. His analysis is pretty naive. here's a nice blog post on how to process sea level rise data. -
Karamanski at 09:51 AM on 9 October 20102009-2010 winter saw record cold spells
Could the deep solar minimum that we had for the past few years have been the cause of the extreme negative phase of the Arctic Oscillation? Because I read paper(I don't recall the name) suggesting that low solar activity lowers the Arctic Oscillation index. Or could it have been Arctic warming that triggered the extreme negative phase of the Arctic Oscillation? A paper that I came across, Francis et al(2009)suggests that reduced sea ice extent weakens the equator to pole temperature gradient and lowers the Arctic Oscillation and North Atlantic Oscillation indexes, allowing arctic air to spill into mid latitudes. If so, will the Arctic Oscillation index trend more negative in coming decades, and could this outstrip the influence that stratospheric cooling from increases in greenhouse gases have on the Arctic Oscillation index(which tends to raise the Arctic Oscillaion index)? Do you have any answers? -
kdkd at 09:48 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
TTTM #80 Well you've certainly not managed to explain the issue (if it exists) with any coherence. It seems that you're suggesting there's some issue with the laws of physics as they're presently understood, but that could just be your poor quality explanation of "the issue". In any case, it's off topic for this thread, I suggest that if you want to follow it up, then take it to how do we know co2 is causing warming. -
Doug Bostrom at 09:46 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
Might help to clarify "the rate observed," TTTM. -
Spencer Weart at 09:38 AM on 9 October 2010The first global warming skeptic
Well done. The basic mechanism was never better explained in a sentence than by Tyndall, who said CO2 acts like a dam that raises the water level behind it. At whatever level the radiation escapes into space--pretty high up, it turns out, for the affected infrared--the temperature has to rise until the energy can escape. (By the way, that's Planck, not Plank). -
Doug Bostrom at 09:28 AM on 9 October 2010Skeptical Science housekeeping: Comments Gluttony
Further to Roger's suggestion, kind of like a rejection notice with an implicit invitation to revise and resubmit. -
TimTheToolMan at 09:25 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
You're way off the mark with that comment kdkd. The suggestion is that science simply hasn't worked out whether CO2 has the capability to warm the oceans at the rate expected because the actual mechanism is anything but a simplistic one. Most people dont even know there is an issue. -
Roger A. Wehage at 09:19 AM on 9 October 2010Skeptical Science housekeeping: Comments Gluttony
Each commenter has provided an E-mail address. It would be helpful if software could be developed that would send each deleted comment back to its originator for post analysis. Unless a commenter saves the text in another application before submitting, there is no way to recover a deleted post. Maybe some folks can remember the contents of their posts, but I certainly can't. Must be my age. -
kdkd at 09:19 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
TTTM #77 I think the moderator answered your question (with faulty premises) there. You're implying that heat retained by CO2 should go to a different location than heat caused by water vapour, or by the sun alone, which is clearly an insane position. The different components of the greenhouse effect have been quantified, but once they're heat, that's it, it's all ultimately going to end up in the same place. No need for flashy scientific papers to demonstrate that, it's just basic physics. -
Doug Bostrom at 08:54 AM on 9 October 2010It's the sun
Worth noting, the solarimeter used to measure radiation as shown in John's graph is located at the bottom of the atmosphere, an important detail. -
johnd at 08:40 AM on 9 October 2010It's the sun
pbjamm at 05:44 AM, this may have some relevance. The chart below came from a link another poster provided in another thread and relates to changing rice yields under warming conditions. The article is available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC454199/ Does anyone want to comment on the significant upward trend as indicated in the bottom graphs which track radiation measured at the different trial sites and put it into perspective.
Moderator Response: Just to be clear, let's not talk about rice yields on this thread. -
Albatross at 08:11 AM on 9 October 2010Global warming is accelerating the global water cycle
Johnd@35, I was referring to evapotranspiration, ET. That is, the actual latent heat flux from the terrestrial surface. ET is also what the NWP models and GCMs simulate with varying degrees of sophistication. -
Joe Blog at 08:08 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
Berényi Péter at 01:00 AM on 9 October, 2010 #69 TimTheToolMan at 21:11 PM on 8 October, 2010 Thats my bad, i was talking about surface interactions with solar and back radiation, as to why the oceans dont accumulate energy faster(as in a really sunny day), so by deep ocean i was talking 100s o meters, not thousands. -
TimTheToolMan at 08:03 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
I am saying the is no quantified science to verify the downward LW radiation due to increased CO2 has the capability to heat the oceans at the rate observed. Instead the assumption appears to be warming is observed and therefore must be attributable to CO2 If you disagree with this then find a paper that quantifies the effect described in the RC article.Moderator Response: Well, if you're disagreeing with the basics of "GHG" warming, you'll need to shift to another thread. Suggestions:
Empirical evidence that humans are causing global warming
and in particular
How do we know CO2 is causing warming?
Spencer Weart's chapter "The Carbon Dioxide Greenhouse Effect" is an excellent source for becoming familiar with the theoretical case for C02's role in Earth's energy budget. -
johnd at 08:01 AM on 9 October 2010Global warming is accelerating the global water cycle
Albatross at 04:08 AM, firstly my comment of pan evaporation exceeding P being self evident is based on the understanding that the conditions that cause moisture to evaporate in the natural environment do not cease once all available moisture has been consumed. I too view E as determined by pan evaporation as being a measure of the evaporation potential, and there I see it's value as being able to understand and quantify the components that drive evaporation, as well as track any trends, thus allowing any modeling formulated to be validated against standardised physical measurements. Fully understanding and quantifying those driving forces is important if the reasons for declining pan evaporation rates are to be found, and only then will it be able to be determined how those changes are manifesting themselves in other ways. So I do see that the trends in pan evaporation as being relevant, as well as important. Obviously the raw data produced by pan evaporation should not be used in any climate modeling because the moisture that it indicates as having been evaporated is not necessarily in the atmosphere. BOM use other terminology to define actual evaporation and that is why I wanted to know whether the E you referred to earlier was the same E as defined by others. The BOM definitions follow:- Evapotranspiration (ET)...is a collective term for the transfer of water, as water vapour, to the atmosphere from both vegetated and un-vegetated land surfaces. It is affected by climate, availability of water and vegetation. Areal actual ET ...is the ET that actually takes place, under the condition of existing water supply, from an area so large that the effects of any upwind boundary transitions are negligible and local variations are integrated to an areal average. For example, this represents the evapotranspiration which would occur over a large area of land under existing (mean) rainfall conditions. Areal potential ET ...is the ET that would take place, under the condition of unlimited water supply, from an area so large that the effects of any upwind boundary transitions are negligible and local variations are integrated to an areal average. For example, this represents the evapotranspiration which would occur over a very large wetland or large irrigated area, with a never-ending water inflow. A "large" area is defined as an area greater than one square kilometre. Point potential ET ...is the ET that would take place, under the condition of unlimited water supply, from an area so small that the local ET effects do not alter local air mass properties. It is assumed that latent and sensible heat transfers within the height of measurement are through convection only. For example, this represents the evapotranspiration which would occur from small irrigated fields with a never-ending water inflow, surrounded by unirrigated land. Point potential ET may be taken as a rough preliminary estimate of evaporation from small water bodies such as farm dams and shallow water storages. -
rhpflieger at 07:53 AM on 9 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
A simple experiment to see the effect of CO2 in high concentrations is to put dry ice in a box and take a quick breath of the result. CO2 dissolved in water creates an acid, which in the oceans is already is having a detrimental effect on animals which use calcium in their shells or exoskeleton. Larger concentrations will create serious problems in the fish population. I believe this meets the definition of a pollutant. It is fairly simple to calculate the amount of CO2 created by burning fossil fuels, and how this correlates to the mass of the recent increase of CO2 in the air. It is clear that the burning of fossil fuels creates sufficient CO2 so that the oceans must be absorbing a good portion. This is large enough to account for the measured increase in the acidification of the oceans. -
Doug Bostrom at 07:34 AM on 9 October 2010The value of coherence in science
Eric, I still don't quite understand how we've got MEC from what you describe. The role of convection and circulation of air and moisture at the tropopause as a radiative feedback has been explored for decades and it does not seem there's a conclusion in agreement with your hypothesis, or that is to say, the role of convection at the tropopause does not appear to affect surface sensitivity in a way that precludes (for example) substantial and swift ice sheet negative mass balance (trying to avoid the freighted term "collapse") at the surface. You did inspire me to go digging, where I found a myriad of interesting stuff on convective overshoot and the like. This paper by Hartmann seems to have had considerable knock-on effects: An important constraint on tropical cloud climate feedback Here's a useful general roundup: Radiation balance of the tropical tropopause layer -
pbjamm at 07:16 AM on 9 October 2010It's the sun
I heard about this news from a skeptic I know on IRC. Skeptic is being generous since he believes AGW to be a cult/conspiracy and has more than once referred to me as a "useful idiot" for not agreeing. Demonstrably false will not matter. Expect to see reference to this on all the usual sites. -
scaddenp at 06:46 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
TTTM - now I am really at a loss. You are saying that increased downward LW would not cause more heating and cite the RC article as evidence? What do you see as the "issue to explain"?? BP - ocean mixing operates on 800-1000 year cycle. You claim geothermal heating exceeds mass heat transport. Can you substantiate that? (I'll try to find time to feed that into my thermal modelling next week). -
Eric (skeptic) at 06:28 AM on 9 October 2010The value of coherence in science
Doug, there are some model experiments where variables are modified independently of others (although dependent variables will change too). A bunch of abstracts are here: http://www.cesm.ucar.edu/publications/PhD%20and%20Masters%20Theses.htm such as #3088067 where the increase in concentrated convection yields a drier upper troposphere and thus cooling or less warming. Drying is noted part of the time in 9948702 and the MJO activity is trending up in real world measurements. On the other hand, 3071048 shows stronger convection reducing aerosols which would be generally warming. It's not a simple issue, but although the concentrated convection can push more moisture to a higher altitude, the general effect of higher altitude convection is drying due to the subsidence starting from a higher altitude, see http://www.drroyspencer.com/Spencer-Braswell-97-BAMS.pdf It also makes sense looking at an IR satellite of a hurricane. The cloud tops in the hurricane are very cold (so globally warming if there are more of them), but the subsidence zone around the hurricane is generally much larger and it is globally warming if there is more of it. The caveat is the hurricane is over warm ocean which sends out lots of IR to space in subsidence areas, the same might not be true in extreme storms over land. -
Kooiti Masuda at 05:52 AM on 9 October 2010Global warming is accelerating the global water cycle
CBDunkerson (#27): Excuse me for not answering all of your questions. Water vapor content of air contacting sea surface follows Clapeyron-Clausius relationship. It is not guaranteed that total water vapor content in the atmosphere is proportional to it (i.e. average relative humidity is constant), but it seems to be valid in good approximation. It is something like an exponential function of temperature. On the other hand, evaporation is limited by energy available at the surface. I am confident that enhanced greenhouse effect yields more evaporation. Partly because increase of downward longwave radiation at the surface results in larger amount of energy potentially available for evaporation. Partly because higher temperature shifts the partition of the energy between latent heat flux of evaporation (LE) and sensible heat flux (H) more favourable to evaporation (i.e. lower Bowen ratio H/LE). But the increase by these two process combined is more like a linear function of temperature than exponential, so it is slower than the increase of water vapor content. So far I have been discussing global mean quantities. The variable shown in Syed's figure is the amount of flow of water from land to ocean. It is possible that the logic about global mean quantities applies here as well, but it is also possible that partition between land and ocean is more important than global mean. -
It's the sun
pbjamm - Nope, it appears (as commented upon here by CBD and here by muoncounter, that "the possible range of variation here is more than an order of magnitude less than GHG forcings." Oh, I guess someone could make the argument - but they would be demonstrably wrong at the start. Orders of magnitude, folks, orders of magnitude. They make a difference... -
pbjamm at 05:44 AM on 9 October 2010It's the sun
Prepare for a new argument front: Study: energy increased instead of decreased during lull in (solar) cycle The study finds that during the most recent lull in the sun's weather cycle, the amount of energy that reached Earth increased, instead of decreasing as predicted. The planet may have experienced a slight warming effect as well, researchers said. -
muoncounter at 05:18 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
#75 was a case of hitting submit before typing. Please delete. From Peltier 2009, Closure of the budget of global sea level rise over the GRACE era: the importance and magnitudes of the required corrections for global glacial isostatic adjustment The net rate of sea level rise is therefore predicted to be: 2.54 mm/year +/- 0.52 mm/year or 2.32 mm/year +/- 0.31 mm/year Clearly both of these estimates are consistent with the net rate of global sea level rise of 2.5 mm/year that has been measured by the altimetric satellites over the GRACE era. -
BBP at 04:27 AM on 9 October 2010The value of coherence in science
Eric, it partially depends on what the definition of 'catastrophic' is. For arguments sake, let’s accept the basic idea of your MEC (thanks Doug) premise – so that more storms and heat waves mean less sea level rise; that still doesn’t mean that both won’t be catastrophic. For example, let’s assume we can expect weather extremes like those seen this year every X years and Y meters of sea level rise by 2100 – even if changing X to 2X means Y goes to Y/2 doesn’t mean that both X and Y won’t be catastrophic. Were the floods in Pakistan and the heat wave in Russia catastrophic? I think the people effected would say ‘yes’, and the people of Bangladesh would probably say that even ½ a meter of sea level rise would be catastrophic. -
archiesteel at 04:22 AM on 9 October 2010A detailed look at climate sensitivity
@Karamanski: "Even though warming may continuing the rate of global temperature increase is steady and is not accelerating." CBDunkerson's graph seems to suggest otherwise. Instead of restating your original argument, you should respond to that counter-argument. "For example, thermal inertia might be much larger and slower than expected." It seems we would have observed this already. Do you have any scientific article that suggest this may be happening? -
Doug Bostrom at 04:22 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
By the way, BP, thanks for damping somewhat a reverberating misconception concerning how heat reaches the abyss. Understanding heat transport in the ocean is impossible without at least a glancing look at thermohaline circulation. Regarding geothermal flux, it helps to keep the numbers in context: Another neglected energy source is the geothermal heat flux through the sea floor. This trickle of heat, which is due to the slow cooling of the solid earth, is estimated to have a typical value of 50 mW m−2 (1 mW = 10−3 Watts) on abyssal plains and up to 200 mW m−2 on mid-ocean ridges [Sclater et al., 1980; Kadko and Baross, 1995; Stein et al., 1995; Murton et al., 1999]. Even these peak values are small compared to typical values of air-sea heat fluxes, which are of order 100 W m−2. Impact of Geothermal Heating on the Global Ocean Circulation (full text, pdf)
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archiesteel at 04:13 AM on 9 October 2010The value of coherence in science
@Eric: let's assume, for the sake of argument, that you are right, and such MECs exists (I'll be eagerly awaiting your detailed explanation of this as well). What you don't seem to understand is that having multiple possible outcomes is not being incoherent, as these are future probabilities, not statements on past events. Saying "there is no warming," then claiming "the warming is natural" is being incoherent, because it describes things that have allegedly already happened, but which are contradictory. -
Albatross at 04:08 AM on 9 October 2010Global warming is accelerating the global water cycle
Johnd @22, "Note that it is E as measured by pan evaporation that is charted. I think that pan evaporation should exceed rainfall is something that should be self evident." Actually, it is not self evident that pan evaporation should exceed P. Pan evaporation is not the same as ET, in fact it is is more of a measure of the potential evaporation or atmospheric demand-- a theoretical measure which is very rarely achieved. So, again, it is best to use actual ET. Making the rather dangerous concession that pan evaporation can be used as a proxy for ET, we see (as you note), that in semi-arid areas (which large swaths of Australia are), P-E << 0. In contrast, in more moist climates, such as over extreme southeastern Australia, P-E ~ 0 or P-E > 0. See this paper for a more thorough discussion. Some researcher use the difference (or ratio) to identify semi-arid areas, for example. Or to distinguish between drought (P-E < 0) and pluvials (P-E > 0). See here for an example. -
archiesteel at 04:06 AM on 9 October 2010It's the sun
@Ken: ""In fact, there is a continuous range of TSI values, any one of which can be balanced by a corresponding OLR value, leading to some particular stable temperature." Question: And can you guess what that particular temperature of interest is? " There is no such fixed temperature, it's a relative value. This theoretical equilibrium temperature would be determined by the sum of all forcings. Again, you're looking for an absolute reference point that doesn't exist. -
The value of coherence in science
Eric - There are whole ranges of negatives associated with global warming, particularly at the rates we're seeing. Assuming that there are MEC's (mutually exclusive catastrophes, excellent acronym) is a False Dichotomy; an oversimplification of the consequences. -
It's the sun
@Ken - I completely agree with archiesteel, he's stated it perfectly. You are taking graphs showing deltas (changes) from a baseline, and claiming that absolute values you derive from them (which are not present in just those graphs) are inaccurate. This is quite simply an incorrect use of the data on your part, completely without basis. Your insistence on continuing to do this over 50-60 posts on this thread indicates to me that you need to step back, and reconsider your approach. -
Doug Bostrom at 03:50 AM on 9 October 2010The value of coherence in science
Eric, I don't follow your reasoning on MEC (mutually exclusive catastrophes, :=) ). Would you please sketch that out a little more fully? -
Albatross at 03:37 AM on 9 October 2010Global warming is accelerating the global water cycle
Johnd and LukeW, Luke: "Pan evaporation rates have been reported to be decreasing not increasing, a reduction in windiness being a key driver" It is important to note that it has been demonstrated that pan evaporation can not be used to infer ET from the terrestrial land surface, especially vegetated surfaces. Brutsaert and Parlange (1998) showed that "although these studies are valuable, pan evaporation has not been used correctly as an indicator of climate change." Golubev et al. (2001, GRL) used parallel observations of actual evaporation and pan evaporation at five Russian experimental sites to callibrate the pan evaporation data. From their abstract "....we recalibrate trends in pan evaporation to make them more representative of actual evaporation changes. After applying this transformation, pan evaporation time series over southern Russia and most of the United States reveal an increasing trend in actual evaporation during the past forty years. " IMO, the take home message here is that pan evaporation data, while useful for some applications, should be used with caution when inferring trends in actual ET. Also, it is likely, that when handled properly, the pan data suggest that actual ET has actually been increasing. I cannot access the GRL paper by Roderick et al. (2007), so I am not sure if they considered or allowed for Golubev et al's or Brutsaert and Parlange's findings. -
Doug Bostrom at 03:37 AM on 9 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
...before going after CO2, why not first target the processes that are creating unwanted amounts of CO2 such as combustion of petrolium and coal? How exactly do we "target" these processes without identifying why we'd be doing so? Ignoring the very reason why we'd make changes in processes obviously leaves the question of rationale hanging in the air. Coal-fired generation plants liberate C02 as part of their operation, emissions which have been found detrimental to the continued desirable functionality of the atmosphere. Failing acknowledging the C02 itself, there's no reason to add expense and reduce efficiency of coal-fired generation plants. Short of a rationale, nobody is going to tamper with the economics of coal-fired generation plants. Once a rationale has been established and acknowledged, the operators of coal-fired plants are not going to act unless compelled by regulation. The comment is rhetorical... Yes, I think we're clear on the rhetoric part, considering that's all that's on offer. -
archiesteel at 03:30 AM on 9 October 2010It's the sun
@Ken, why are you looking for absolute values in graphs that show relative changes? -
Doug Bostrom at 03:26 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
Ok BP, I think I get it. In a nutshell, your hypothesis implies that because of cultural matters tide gauges are located mostly in places where isostatic adjustment is such that, taken together, the population of tide gauges produces a false impression of rising sea level. Is that about right? -
Albatross at 03:08 AM on 9 October 2010Global warming is accelerating the global water cycle
Dr. Masuda, Thank you fro dropping by, very much appreciated. -
Albatross at 03:06 AM on 9 October 2010Global warming is accelerating the global water cycle
Dr. Mandia, Thanks for that link @29. I forgot about Zhang et al. (2007), good paper. The observations (1925-1999)used in their paper show an increasing trend in zonally-averaged P (over land surfaces) in most latitude bands. The exception being 0-30 N, where data show a drying trend. Re Spencer. From what I know Scott, at least for thunderstorms, precipitation efficiency decreases as vertical wind shear increases. I am not aware of any papers which show a link between precipitation efficiency and temperature. That said, it is my understanding that a decrease in environmental lapse rates (i.e., leads to weaker updrafts and more entrainment)and/or a drier/warmer sub-cloud layer (more evaporation of precipitation) will reduce precipitation efficiency. Personally, I think that Spencer is being overly pessimistic. The land-surface component of the GCMs has received much attention in recent years. What they need to do is get the horizontal grid spacing down (to less than 20 km) so that they can use superior convective parameterization schemes and also better resolve convective systems (as well as eddies and currents in the oceans). Hopefully Moore's law continues to hold, b/c doing so is mostly a question of brute computing power. -
michael sweet at 02:35 AM on 9 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
RSVP, You keep changing your argument. see ricarrdo for the answer you want now. If I put 15 grams of fertilizer, a basic ingredient to the life cycle of plants, on my garden, that is food for the plants. If 15,000 tons of fertilizer washes into the ocean that is pollution. There are many pollutants that are natural products like CO2. Scientists propose going after CO2 by regulating processes that release CO2 like burning coal and oil. How else could you regulate CO2? Natural CO2 like animals release is not what would be regulated. You are the only one who suggested regulating natural products. The difficulty is you are not clear in your argument and you keep changing your emphasis. This is becasue what you say is not logical. Since you have trouble being understood when you are retorical I suggest you try to stay on the point. -
ProfMandia at 02:32 AM on 9 October 2010Global warming is accelerating the global water cycle
I did a blog post on climate change's impact on water resources that some may find useful: O Water, Water, Wherefore Art Thou Water? -
dana1981 at 02:28 AM on 9 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
RSVP, this is really quite simple. CO2 is the source of the problem (along with other greenhouse gases). Thus CO2 is what needs to be targeted. Coal and petroleum aren't the only sources of CO2. Some other major sources are cement production, agriculture, landfills, etc. Your conclusion that labeling CO2 as a pollutant is "lip service...in light of the current hysteria" is completely absurd and wholly unsupported by everything you've said. Your argument still consists of "I don't like it, therefore it's wrong." -
tobyjoyce at 02:26 AM on 9 October 2010Skeptical Science housekeeping: Comments Gluttony
Congratualations, John, it is hard to keep up with the stream of information coming from this site, but it is a superb resource! Hope it's not OT to say that. :( -
Berényi Péter at 02:19 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
#59 doug_bostrom at 03:12 AM on 8 October, 2010 the nut of your objection seems to come down to a hypothesis that, overall, continents are sinking below the waves, but you don't offer any details to support this remarkable claim. No, I was talking about neither rising nor sinking of continents (relative to the terrestrial center of gravity), just the temporal derivative of this motion, that is, its acceleration. But come to think of it, continents must be sinking, after all. Or let's be more accurate. Vertical motion averaged over the entire surface of solid Earth should be zero, provided volume of the planet does not change. However, tide gauges are not scattered just randomly over the surface, they are located along coastlines, per definitionem. Now, at the end of the last glaciation when the huge Laurentide and Fennoscandian ice sheets melted away, there was an almost step-like 120 bar pressure increase over marine basins, including continental shelfs. In other words at locations far from the previous ice sheets a pressure difference was built up between the interiors and margins of continents, therefore some isostatic rebound should have happened worldwide, with an opposite sign of course compared to sites close to previous ice sheets, but of smaller magnitude. Due to high viscosity of mantle stuff, it is likely not finished yet. Rate of vertical motion above land is not easy to measure, but average rate of sinking along coastilnes can easily be as large as 0.4 mm/yr (with a considerable dispersion). Just for a taste of the complexity of the issue see: Global and Planetary Change Volume 57, Issues 3-4, June 2007, Pages 396-406 doi:10.1016/j.gloplacha.2007.02.002 Geocentric sea-level trend estimates from GPS analyses at relevant tide gauges world-wide G. Wöppelmann, B. Martin Miguez, M.-N. Bouin and Z. Altamimi -
RSVP at 01:54 AM on 9 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
michael sweet #128 Why are you straying from the question and attempting to obfuscate things I say. The comment is rhetorical and only finds its context in the idea that CO2 (a basic ingredient to the life cycle on Earth) be considered a pollutant. It is not a suggestion, just a question that I will repeat one more time...that is, before going after CO2, why not first target the processes that are creating unwanted amounts of CO2 such as combustion of petrolium and coal? The difficulty with the question is that it reveals the underlying weakness in this movement. Put another way, labeling CO2 as a pollutant is basically a form of lip service or appeasement in light of the current hysteria. -
Ken Lambert at 01:42 AM on 9 October 2010Climate Cherry Pickers: Falling sea levels in 2010
kdkd #50 Looks like BP #49 has gob-smacked the Sea level debate again. Just 1.9mm/year - that's below my 2.1mm year from Jason, and near to the ice melt alone number of 2mm/year. Could this Sea level rise be 'flattening' kdkd? -
johnd at 01:42 AM on 9 October 2010Global warming is accelerating the global water cycle
Kooiti Masuda at 22:14 PM, Kooiti, thank you for your response,I hope that you become a regular visitor here. Though seemingly off-topic, understanding how such systems work or change over time is relevant to understanding the global water cycle. Not only for understanding how the cycle manifests itself under current climate conditions, but how it may manifest itself under changed conditions. I tend to agree with the oceanographers in that the IOD and ENSO are distinct entities as looking at them from the Australian regional view, being in the middle, the nett result delivered upon us will at times be due to them working in unison, feeding off one another, whilst at other times they are offsetting each other, with all sorts of combinations in between. This seems particularly evident when examining how drought develops over Australia, that perhaps giving some of the relevance to the water cycle. It is also relevant when considering whether or not everything that occurs in the region that is attributed to ENSO, may at times be attributable to the IOD thus perhaps downgrading the influence that ENSO is thought to have. -
Dikran Marsupial at 01:38 AM on 9 October 2010Positive feedback means runaway warming
Karamanski@20: The exchange of CO2 between the ocean and atmosphere isn't governed only by temperature, it is also governed by the difference in partial pressure of CO2 between the atmosphere and the surface oceans. Loosely speaking CO2 leaving the oceans has to push against the partial pressure of CO2 in the air, so as more CO2 is added to the atmosphere the comes a point where the increased partial pressure balances the effect of increased ocean temperature, and you get a new equilibrium. If the climate did not have equilibrium states formed by the balancing of positive and negative feedbacks, it is unlikely we would be here to see it! HTH
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