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Doug Bostrom at 13:22 PM on 5 October 2010An underwater hockey stick
JMurphy JohnD's email quote appears to have been sourced here. It's worth reading the whole thing, a familiar refrain as we've yet again been treated to a rhetorically expedient selection. There's some discussion here further indicating things were not as simple as they've been portrayed. Not on-topic; maybe there's a better place here, such as "Models are unreliable." -
muoncounter at 13:08 PM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
"greenhouse gases in the atmosphere may reasonably be anticipated both to endanger public health and to endanger public welfare." The public health crowd has something to say here: It is now widely accepted that climate change is occurring as a result of the accumulation of greenhouse gases in the atmosphere arising from the combustion of fossil fuels. Climate change may affect health through a range of pathways, for example as a result of increased frequency and intensity of heat waves, reduction in cold related deaths, increased floods and droughts, changes in the distribution of vector-borne diseases and effects on the risk of disasters and malnutrition. The overall balance of effects on health is likely to be negative and populations in low income countries are likely to be particularly vulnerable to the adverse effects. The experience of the 2003 heat wave in Europe shows that high-income countries may also be adversely affected. Sounds unhealthy. A bit like a pollutant, no? -
Doug Bostrom at 13:01 PM on 5 October 2010Climate Change: Past, Present, and Future
Full text of Alley 2000 as mentioned by GC is here (pdf). -
gallopingcamel at 12:48 PM on 5 October 2010Climate Change: Past, Present, and Future
Albatross, (#72), Thanks, the Leaf sounds quite similar to the EV1 and the price is in the right ball park. John Cook, Picking up on what you said at the top of this thread: "Of course, it's also important to realise that this is the global average. Warming at high latitudes may be 3 times as much." This appears to be an accurate statement. The evidence from ice cores shows temperature swings of greater than 20 degrees Kelvin as the planet undergoes cycles of glaciation. It follows that it should be easier to measure warming or cooling by studying temperatures at high latitude. Back in 2000, Richard Alley published a paper on temperatures in Central Greenland at a latitude of 73N: http://www.ncdc.noaa.gov/paleo/pubs/alley2000/alley2000.html This paper shows a number of interesting things, at least for central Greenland. 1. The temperature swings ARE much greater than shown in reconstructions for low latitudes. 2. Current temperatures are higher than during the LIA. 3. Current temperatures are lower than during the MWP and various earlier warm periods. 4. The temperature has been higher than today for 8,500 years out of the last 10,000. 5. Ice accumulation increases during warm periods so declining ice volume is not necessarily evidence of warming. -
TOP at 12:08 PM on 5 October 2010An underwater hockey stick
Thanks scandenp #62. That's what I was looking for. -
Doug Bostrom at 11:59 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
But there is a danger in giving bureacratic agencies legislation which classifies something as a 'pollutant' which is also necassary for society to function. Like, say, oil in tankers and pipelines. Goodness knows, the petroleum industry willingly did such good a job with self-regulation, the as-usual-vaguely-characterized-government-bureaucracies have been simply dangerous in their overweening regard for keeping oil inside of the various things oil is supposed to be inside of. I tend to agree with Lonborg that money would be better spent on alternative energies and mitigation effects... Sounds like a believer. To get a broader perspective on economics of mitigation, etc. see Real Climate Economics (not related to "RealClimate") -
archiesteel at 11:58 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
@Ned: no problem, we provided two different links, thereby adding weigh to our shared position. -
archiesteel at 11:57 AM on 5 October 2010We're heading into an ice age
@TL: "Ah, me thinks the idea of Milankovitch cycles borders on blaming astrology for the ice ages." Cute. Completely wrong, but cute. "There is a much better explanation and it is lighting up the skies over both hemispheres ever more with each year." TSI has been going down, and we are past the Holocene Climatic Optimum. If it was up to natural cycles, we should be cooling, not warming up. -
Ned at 11:56 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
Argh, beaten by one minute. Congrats, archiesteel. -
Ned at 11:55 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
thingadonta ... you may think you agree with Lomborg, but Lomborg has apparently reconsidered, and he no longer agrees with you. -
archiesteel at 11:54 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
@thingadonta: You seem to be behind on the news: Bjorn Lomborg now admits that Global Warming to be one of the world's greatest threats. In the case of Anthropogenic Global Warming (which it seems you believe now), the bad outweighs the good. -
Doug Bostrom at 11:51 AM on 5 October 2010We're heading into an ice age
Oh, don't get me going on the widespread cold in the northern hemisphere... Agreed, it's apparent there would be little point in that, so please don't start. Clearly you're not a fellow to be swayed by collated data permitting of useful conclusions, meanwhile the strong preference here is to stick w/exactly that sort of information. -
Ned at 11:49 AM on 5 October 2010We're heading into an ice age
Tom Loeber writes: Ah, me thinks the idea of Milankovitch cycles borders on blaming astrology for the ice ages Please don't be a troll. The association between Milankovich geometry and glacial/interglacial cycles is very, very well established. The mechanisms by which this works are not completely understood, but we do know a lot about it. The very short version is that a reduction in seasonal insolation during high-latitude Northern Hemisphere summers allows snowpack to persist through the summer, leading to the inception of ice sheets. When summer insolation around 65 North begins increasing again, this process reverses itself. If you don't understand how this works, check out Bill Ruddiman's textbook (Earth's Climate) or David Archer's eminently readable book (The Long Thaw). -
thingadonta at 11:48 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
The nature of "pollution" and what it means is where alot of greens go wrong in science. The question is not whether something does 'bad' to the environment, the question from a human nd ecological perspective is whether the bad outweighs the good. Using the argument that everything that is 'bad' for the envrionment is no good would mean no houses (cuts down habitat), no roads, no mines, no anything. The question is one of balance, and that mean looking at things from a broader perpsective. This is general government policy in Australia, weighing up the environmental, social and economic costs and benefits of various policy decisions. With regard to 'pollution', the issues are the same. A pollutant can also be 'good', it depends on the degree of the relative effects. Eg DDT saves lives, and causes cancer at the same time. Mines damage an area and create jobs. Radiactivity creates energy and causes cancer. etc etc. This is also the general argument of the Skeptical Environmentalist by Lomborg. C02 obviously is necessay for life, but too much might not be good. But there is a danger in giving bureacratic agencies legislation which classifies something as a 'pollutant' which is also necassary for society to function. Have a look at the first definition, it is completely circular and doesn't define what a pollutant actually is: "The term “air pollutant” means any air pollution agent..." .......ie 'a pollutant is a pollutant'. the 2nd definition, doesnt weigh up the costs and benefits: "....anticipated to endanger public health or welfare". So do cars. This is not the issue, it is "whether the danger to public health or welfare" outweighs the benefits. Again, it is only half a definition. The third: "in some harmless form", which again fails to mention the cost/benefit issue. It only refers to whether somethng is harmless or not. By this defintion cars would have to stay in garages, otherwise they would be harmless. It is not about whther or not something is harmless, but whether the 'harm' outweighs the benefits, in other words, is a certain amount of harm acceptable, or can the hamr be reduced to an acceptable level? The argument over c02 as a pollutant depends on whether the IPCC worst-case scenarios turns out to be correct, and whether there is any practical way of mitigating greenhouse gas warming by other methods (eg large scale c02 extraction from the atmosphere and suitable capture). I tend to agree with Lonborg that money would be better spent on alternative energies and mitigation effects, than various other policies such as Kyoto nad issues relating to eg 'pollutants'. etc -
kdkd at 11:46 AM on 5 October 2010New temperature reconstruction vindicates ...
KL #133 Just to clarify: if you come up with something that has good validity with sound logic and empirical support then I'm happy to accept your argument. However the two main arguments that you repeat constantly are both fatally flawed with poor logic, lack of empirical support and confirmation bias. Yet another example of confirmation bias is that you take my statements on the empirical validity of your work and make the assumption that there's some non-empirical reason that I find your argument lacking. Anyway, as others have said, I'm not sure where this stuff is on-topic where it hasn't already been done to death. -
Charlie A at 11:40 AM on 5 October 2010Billions of Blow Dryers: Some Missing Heat Returns to Haunt Us
Updated OHC posted at NODC: http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/ A blink comparator of the old vs new heat content values: http://i54.tinypic.com/24178ur.jpgfrom Bob Tisdale's blog: http://bobtisdale.blogspot.com/
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Daniel Bailey at 11:38 AM on 5 October 2010What constitutes 'safe' global warming?
Re: ocrow (31)"I keep seeing articles that refer to particular atmospheric CO2 levels corresponding to particular global temperature changes. Is there a graph that shows the relationship between the two?"
Depending upon what you're interested in: Near-Term (Recent History) Mid-Term (The Age of Civilization; i.e., Old-As-Dirt) no CO2 levels on this one, but gives a neat perspective. The Last 5 De-glaciation Events superimposed on each other for comparison. Kinda Old (400,000 BP) Paleo (Really Old - 800,000 BP) Leave it to the public servants at the EPA to give us something useful. Note that while other forcings exist (some positive, some negative), the resulting temperatures comes from the summary balance of all of them, and forcings can and do change over time (albeit slowly). Until humans messed with the biggest control knob of temperatures. The Yooper -
Ned at 11:38 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
The Inconvenient Skeptic writes: The warming at the end of the last glacial is a serious problem for computer models that depend on CO2 levels. If the feedback of the global climate is so sensitive to CO2 levels then the any change in CO2 would cause unbounded feedback and thermal runaway. Since the Earth is stable (within a temperature range, +/- 7C over the past 1 million years) there has never been a thermal runaway. The reason is that the Earth is a stable system. The idea that positive feedback implies an "unbounded" increase in temperature (or "thermal runaway") is both common and completely mistaken. See the article on Does positive feedback necessarily mean runaway warming? for an explanation. Positive feedback will not lead to a "runaway" increase if the feedback factor f is less than 1. And, in fact, modest (f < 1) positive feedbacks are a necessary feature of the climate regime as seen in the glacial/interglacial cycles. So ... I'm sorry, but your ideas expressed in the quote I've excerpted above are pretty much completely wrong. I hope you'll continue reading this site. John Cook and the rest of the community here have developed an exceptionally high-value resource for exploring many of the common questions and misconceptions that persist around climate change issues.Moderator Response: And put comments about that topic on that page, not this one. -
Riduna at 11:32 AM on 5 October 2010What constitutes 'safe' global warming?
http://www.onlineopinion.com.au/view.asp?article=9370 might be of interest. The debate is no longer about whether temperature increase above pre-industrial temperatures can be limited to 2C. by 2100. Given our desire to burn increasing quantities of fossil fuels, we can be certain that temperatures will rise more than 2C by 2100 and that is unavoidable. The effects will of course include accelerated melting of the polar ice sheets and, as noted by others above, a sea level rise of at least 1m by 2050 and over 2m. by 2100. The effects on river delta’s sustaining much of the global population is also well known. It is already evident that global warming is responsible for accelerated retreat of glaciers. Normally, glaciers store and release fresh water which flows into rivers and underground aquifers that are drawn on for agriculture and human consumption. This source of fresh water is imperiled by retreating glaciers and by burgeoning population growth. We will not have to wait until 2100 to observe the combined effects of rising sea level and retreating glaciers on the ability of humans to feed themselves. We are starting to see those affects now. They will certainly become increasingly obvious over the next 20-30 years and catastrophic long before 2100. And we still cheerfully increase the level of CO2-e greenhouse gas we pump into the atmosphere, despite repeated warnings by scientists of the consequences. Why? -
Tom Loeber at 11:29 AM on 5 October 2010We're heading into an ice age
Ah, me thinks the idea of Milankovitch cycles borders on blaming astrology for the ice ages. There is a much better explanation and it is lighting up the skies over both hemispheres ever more with each year. -
adelady at 11:28 AM on 5 October 2010What constitutes 'safe' global warming?
I did notice the second quote, I just thought the idea was poorly expressed. When the facts change, I don't "change my mind" - I just go where the evidence leads. I get sick, the doc says here's what we have to do, I do it. I get better, I get up and get on with life. If the "facts" change in relation to climate science, I'll evaluate them. 25-30 years of declining temperature, coral reefs rebuilding, Arctic ice several metres thick, I won't just evaluate, I'll relax and enjoy. -
archiesteel at 11:26 AM on 5 October 2010We're heading into an ice age
@Tom: I'm not sure you understand what "anecdotal" means. In any case, there is no indication we are about to enter a very cold period. There were more heat records broken than cold records last year. The warming trend is strong, and shows no sign of reversing. Glacial periods are most likely the results of Milankovitch cycles, not of delicate "tipping points" that would be reached by increasing heat. You don't seem to be making much sense, I'm afraid. -
Ned at 11:22 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
The Blue Moderator wrote: As was mentioned earlier, the "Latest Posts" list at left is a convenient way of discovering where the crowd has gone. The "Latest Posts" list will tell you what the latest posts are, but the "Recent Comments" link at the top will tell you where the crowd has gone. -
Tom Loeber at 11:17 AM on 5 October 2010We're heading into an ice age
I think it was Professor Hansen stating that mantra that weather doesn't indicate climate about the record cold in the US NE and Europe not too long ago while actually there was record cold on all six continents at the time. Anecdotal evidence only pertains so far, you know. You can be killed by an anecdotal occurrence. If it is anecdotal that the whole planet is being pushed to collapse into the more stable set of conditions as evident by its holding way over 90% of the planet's existence at least in the last million or two years, well, heck, quick snap to major ice age conditions will be but an anecdotal odd and absolutely not average happening. Get it right. What I'm suggesting is that the record global warming is leading to a propensity to snap into extreme widespread cold. I'm not denying that there was record heat but I think the idea of a tipping point should be considered. What does the planet tip to? Just look at the record. Interglacials come and go. They are the transient phenomenon. The planet apparently gets tipped into its most stable set of conditions, ice age conditions, and they come on anecdotally and rapidly, beating the average trends quickly. I know it is a difficult concept. The ways to avoid global warming make sense to avoid quick snap to extreme global cooling except for the idea of using Hydrogen gas as a fuel. That would most likely lead to more of those noctilucents as suggested on the Wikipedia on the phenomenon. Hey, earth's climate system is not a linear process. It is dynamic with repeated seriously differing cycles. The change to something serious, what ever we might be tipping to, will be anecdotal. It will not be an average outcome. It will be new and looks like it is going to catch most quite off guard. Good luck all! -
Joe Blog at 10:52 AM on 5 October 2010An underwater hockey stick
CBDunkerson at 10:36 yet you are drawing a conclusion, that water at ~400 m warmed more than surface waters, which assumes they are. Well unless there has been a reduction in entropy, the warming has not come from the atmosphere in the region, we have their temperature anomalies. And you are looking at less than a degree, whilst the water temperature has increased more than a degree... at 400m. It has nothing to do with the atmosphere in the region, it is showing the relative strengths of warm and cold currents, which correlate well to hemispherical temperature anomalies. -
scaddenp at 10:51 AM on 5 October 2010We're heading into an ice age
Tom, picking local cold spell doesnt mean anything. Look at the global average temperatures. As to the storm that hit here - well it was bad but it was just a storm, unfortunately at bad timing after a very mild winter and otherwise early spring. Effect on NZ annual average temps - not much. Global warming does not preclude cold spells. There is more energy in the weather systems, more humidity, and if temperatures go below zero, you will get heavier snow. -
chris1204 at 10:49 AM on 5 October 2010What constitutes 'safe' global warming?
adelady, believe it or not, I also care - otherwise I wouldn't be hanging around this site. I'm not a contrarian who just wants to argue for the sake of it. You didn't notice my second quote from Keynes which is much more important than the first: 'When the facts change, I change my mind. What do you do, sir?' Doug, you ask of RSVP, 'Does being a refugee sound good?' I come from a family of refugees created not by climate but by the poisonous geopolitics of the 1930s. I've never been a refugee myself but the notion is embedded in my DNA. Currently, our refugee problems worldwide are not the result of climate change but the outcome of nasty governments and equally nasty revolutionary movements. I'd hate to see climate changed added to their burdens but so far that hasn't been happening. That of course doesn't mean it will never happen but as the Latin tag goes, 'Homo homini lupus' - literally 'man is wolf to man.' -
scaddenp at 10:40 AM on 5 October 2010Uncertain Times at the Royal Society?
JohnD - also please explain how to change winds independently of temperature. -
archiesteel at 10:40 AM on 5 October 2010We're heading into an ice age
@Tom: And yet 2010 is on par to be the second hottest year in the Southern Hemisphere. As for a cold winter in the NH last year, you certainly didn't come to Canada. It was very mild overall. The problem is that you seem to believe anecdotal evidence trumps measured averages. It doesn't, and therefore your theory that we are in a cooling trend does not stand scrutiny. -
CBDunkerson at 10:36 AM on 5 October 2010An underwater hockey stick
Joe Blog #64: "You are confusing energy with temperature..." No... I'm not. As to the rest, the most glaring flaw in your analysis is that you are comparing water temps at ~400 m depth in part of the North Atlantic to air temperatures for the entire northern hemisphere. The samples are not equivalent... yet you are drawing a conclusion, that water at ~400 m warmed more than surface waters, which assumes they are. -
Tom Loeber at 10:25 AM on 5 October 2010We're heading into an ice age
Here's a report of the cold in New Zealand killing "tens of thousands of lambs" though no record is mentioned as being broken it states its the worse since 1972: Tens of thousands of New Zealand lambs killed by cold. 9/22
Strong winds, heavy snow and record cold across Tasmania. 9/17
South pole has record cold. 7/31
Much of New Zealand experiencing record cold. 6/2
Queensland, Australia towns get record cold. 5/22
Cold snap hits Argentina, Paragua, Uruguay & Bolivia. 7/18
Record low temperature in Brazil. 7/15
At least this one is a record for 82 year old Juana Benitez: Cold snap hits several South America countries. 7/10
Well, how about coldest SE Australia in some 60 years?: Unusual widespread cold in Australia. 6/30
Here's the story about S. Africa penguins though it doesn't mention any records being broken. Maybe it is a record that over half of the penguin chicks died from the cold this time. One island hardly qualifies as wide spread though: Cold rain kills %50+ endangered S. Africa penguin chicks. 6/15
There was some widespread crop damage from cold in S. Africa but it doesn't mention any records being broken: Severe cold & frost damages S. Africa crops. 7/15
Oh, don't get me going on the widespread cold in the northern hemisphere over the last couple of years. Notices of those far out weigh those for the southern hemisphere. Two years ago, my mom died due to complications in what I understand was Washington state's first ever state of emergency due to record cold and snow. I truly expect the cold and snow to be worse this year across the northern hemisphere and there are some long range predictions suggesting that too. -
scaddenp at 10:22 AM on 5 October 2010Uncertain Times at the Royal Society?
Johnd- but ability to evaporate decrease as water content rises. That is my point. Spencer's paper published now so the discussion will continue in the proper way - by scientists checking, validating and publishing. If it has really has merit, then it will be basis of more work; if not, it will be refuted and science will move on. No guesses where my money goes - if sensitivity was that low, we wouldn't have ice ages. -
Joe Blog at 10:21 AM on 5 October 2010An underwater hockey stick
archiesteel at 10:16 AM Ive stated basically the same thing myself earlier... however(it would be a boring world if we all agreed), if you hold this graph as validation of the other reconstructions, you can hardly ignore the fact that the timing and magnitude of the anomalies are the wrong way around. It does correlate very well with the last 1000 years. Coincidences can happen, but... -
Joe Blog at 10:17 AM on 5 October 2010An underwater hockey stick
Im not arguing that co2 is NOT a greenhouse gas... i mean, i dont doubt the radiative properties of it one bit, or have any issue with the greenhouse effect... but the climate is actually a little bit more involved than just one variable. -
scaddenp at 10:16 AM on 5 October 2010CO2 was higher in the past
SRJ - for sun levels in deep time, you dont have measured proxy but rather the calculation based on sun being a main sequence star. See for instance: faint young sun paradox -
archiesteel at 10:16 AM on 5 October 2010An underwater hockey stick
@Joe Blog (68): Unless I'm mistaken, the top graph is for temperatures in the deep waters of the St. Lawrence Gulf. It does not represent all of the NH, so drawing conclusions based on eyeballing graphs that do not represent the same geographical area isn't going to tell you much about how well they correlate. -
Joe Blog at 10:07 AM on 5 October 2010An underwater hockey stick
scaddenp "While circumpolar current certainly makes pole cold, I cant see why that cools ocean - doesnt affect the solar energy uptake." Obviously, raised albedo on Antarctica would effect the earths albedo. But with reduced oceanic energy transport, this energy is going to transported via the atmosphere, a lot less efficiently, with vastly greater losses, driven by the differential in temperatures across latitudes. Cold water, holds more oxcygen, which enables it to support greater bio mass, Thus the greater burial, through lime stone etc(dead fish) Im not arguing that co2 is a GHG, or anything of the nature, i am just saying how i interpret these graphs relationship to each other, in relation to the warming event at the start to mid last century. -
Albatross at 10:04 AM on 5 October 2010Uncertain Times at the Royal Society?
Johnd @104, "The Spencer paper IIRC was discussed only prior to publication, with everyone quiet about since, unless I've missed any such discussion." They are probably busy validating his findings or trying to replicate them. I strongly suspect a comment (or perhaps even a refutation of his paper) is in the works. But be patient, good science takes time. -
Albatross at 10:00 AM on 5 October 2010Uncertain Times at the Royal Society?
Johnd @102, I'm rushed here, but I think it suffices to say that the following, "once it has absorbed the energy via the evaporation process it begins rising to be replaced by cooler drier air that continues the evaporation process", is not correct. You do not say where this "cooler/drier air originates from. I'm not sure maybe you are taking about the entrainment of drier air from the free atmosphere into the planetary boundary layer as the boundary layer grows during the day. Look up "moisture flux divergence" which consists of two terms the "horizontal moisture divergence" and the "moisture advection" term". Moisture is most certainly advected by the horizontal wind field. Also, it is the "pooling" or convergence of moisture which oftentimes leads to the formation of thunderstorms (assuming an unstable profile and presence of a trigger mechanism which can lift the near-surface air "parcels" to the level of free convection). Anyhow, many factors govern transpiration and evaporation. And in order for evapotranspiration to continue does not require the moisture added to the air to be replaced by "cooler and drier air". See for example the Penman-Monteith (P-M) equation for governing variables. There are more sophisticated models, but the P-M is a good start. The contribution of ET to near-surface water vapor mixing ratio to the boundary layer is well documented and under ideal conditions can be significant. -
johnd at 09:59 AM on 5 October 2010Uncertain Times at the Royal Society?
scaddenp at 09:44 AM,wrong, in my scenario the air would continually be absorbing moisture whilst it was present, even at night as we often see with saturated ground being dried on a windy night. The Spencer paper IIRC was discussed only prior to publication, with everyone quiet about since, unless I've missed any such discussion. -
CBDunkerson at 09:55 AM on 5 October 2010Carbon Dioxide - Everyone's Favorite Pollutant
TIS #41 is correct about the labeling. The two samples are correctly described in the comments under the picture (i.e. Blue = Taylor, Green = Law), but incorrectly in the legend on the chart itself (i.e. Blue = Law, Green = Taylor). -
scaddenp at 09:52 AM on 5 October 2010An underwater hockey stick
Joe, I dont doubt that continental placement is important but I dont think you could model a warm jurassic in any configuration without high CO2. As to why CO2 has dropped right through Tertiary - interesting question, but I would look at the rise of carbonate-rock forming species (esp forams) over that period for my money. While circumpolar current certainly makes pole cold, I cant see why that cools ocean - doesnt affect the solar energy uptake. -
SRJ at 09:45 AM on 5 October 2010CO2 was higher in the past
Quoting from the beginning of this post: "When CO2 levels were higher in the past, solar levels were also lower" Can anyone point to a source for the this? And a nice graph showing solar levels in the past? -
scaddenp at 09:44 AM on 5 October 2010Uncertain Times at the Royal Society?
JohnD, and your scenario, all ground air would be dry despite blowing over 100 kms of ocean which is not the case. I am trying to explain why on a basin-wide basis, the observed variation in evaporation with wind speed is lower than you seem to believe. Spencer use of "time-varying internal forcings" is somewhat novel and really is an exploration of the internal feedback mechanisms. This paper has been discussed before and I frankly doubt you can conclude anything concrete about feedbacks over longer term from the short term approach. -
Joe Blog at 09:44 AM on 5 October 2010An underwater hockey stick
I should add, by bottom water we are only talking 400m down... not 4km, its not really bottom water, that would be pretty homogeneous, the author of the paper believe that the warm current feeding into the gulf increased by close to 100%. So it was making up close to 50% of the bottom water flow into the gulf. -
adelady at 09:40 AM on 5 October 2010What constitutes 'safe' global warming?
MattJ. I'm afraid I tend to agree with you. The big issue is acting in a way to ensure that any rise over 2C is as brief as possible. If we get it 'right' the temperature spike might look a bit like that 1998 spike. It won't be a single year of course, but minimising the number of decades is worth a shot. It'd be nice to think that the climb up to and down from whatever maximum temperature is finally reached could be less than the lifetime of people within one generation. And yes Barry, I'm from the festival city. -
Joe Blog at 09:31 AM on 5 October 2010An underwater hockey stick
scaddenp at 09:03 Im open to suggestion as to the why of the increase of warm bottom water(conventional wisdom, big freezes up north dropping more water than normal pulling more up, and feeding off the change, etc)... but if you rescale those graphs, it is very clear that the bottom water temps are leading atmospheric anomalies at the beginning of last century...its even visible without rescaling. Continental placement, dictates ocean currents, Ocean currents affect heat transport, which affect ocean temp... which affect its ability for carbon burial... the reason our co2 levels fell to where they are is when the continents came to be where they are 45mybp, with Antarctica over the pole, it prevented heat transport to the pole, and the Antarctic circumpolar current came into being, which caused a slow but steady decrease in ocean temp, and absorption/burial o co2, over the next 30 million years it fell, till 15mybp it was at the levels it is at now, which started the northern hemisphere glaciations, and this process continued till 2.5mybp, it fell to the levels that enabled full blown glacial cycles to start... the continents set the stage. -
johnd at 09:28 AM on 5 October 2010An underwater hockey stick
JMurphy at 08:03 AM, just because an message is directed to a single person doesn't preclude it from being copied to others as part of a group discussion. Why don't you ask him if that aspect is the most important to you rather then the subject? It was sent early 2007 by the way, just so you can put it into the timeline relating to the UNSW revelation. -
johnd at 09:17 AM on 5 October 2010Uncertain Times at the Royal Society?
scaddenp at 11:02 AM, with regards to wind, your scenario assumes that the water vapour continues to be carried along by the wind at the surface. Consider instead the behavior of the wind in 3 dimensions where once it has absorbed the energy via the evaporation process it begins rising to be replaced by cooler drier air that continues the evaporation process. In your scenario, there would not be any such things as storms. With regards to clouds as a forcing, Roy Spencer in his latest paper proposes exactly that. He asserts that clouds act as a radiative forcing generated internal to the climate system, the problem having been the difficulty in identifying and separating such internally generated forcing from what he considers as a mixture of forcings and feedback. You ask the question, "How can clouds be a forcing?" I think to understand where Spencer is coming from, one has to be able to put aside any preconceived ideas that could cause one to ask that question, something Spencer thinks most people find difficult so deeply entrenched the conventional view is, as are most conventions. -
scaddenp at 09:03 AM on 5 October 2010An underwater hockey stick
Joe Blog. Its not called thermoHALINE for nothing - it is also driven in part by salinity difference. And deepwater formation transports heat into the depths. Best web reference I know is TCH And surely the BIGGIST difference between jurassic and now is not the distribution of heat but the huge difference in CO2 content of atmosphere, able to make up for weaker sun.
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