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Camburn at 13:53 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
muoncounter: I dn't have access to the full paper, Kirkbride and Dugmore. Note tho, that the glaciers did not peak at the same approx time. With that in mind, remember how small Iceland is. I will also point out that the proxy data from the Sargosa Sea presented in my link does not match the reanalysis from the Mann paper ref fig 1. -
muoncounter at 13:53 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Camburn#28: "a paper that has been cited 70 times about temperatures during the MWP" Good one. From 1999, the primary evidence presented for MWP temperatures dates from 1966: Graph is modified from Keigwin, L. D., 1966, The Little Ice Age and Medieval Warming Period in the Sargasso Sea: Science, v. 274, p. 1504 - 1508. Nothing much has changed in dating technology since the '60s. Or at least what little I remember of the '60s.Moderator Response: [muoncounter] Correction: Keigwin's Sargasso Sea paper was published in 1996. The referenced source (Bluemle, Global warming: a geological perspective, which appears in NDGS Newsletter, vol. 26 no. 2) misprints the date of Keigwin as 1966 in their Figure 4 caption. -
RW1 at 13:44 PM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
scaddenp (RE: 18), "Um, I think "back radiation" is radiation emitted from the atmosphere that strikes the surface. I cant see how "last originated from surface emitted" can make any kind of sense. It's a key distinction because the amount that last originated from the surface is what is actually determining the net surface energy flux, which is what ultimately is determining the surface temperature. A lot of the downward emitted LW is 'forward radiation' that last originated from the Sun, yet to reach the surface. Also, the kinetic energy (latent heat and thermals) moved from the surface into the atmosphere is in addition to the radiative flux at the surface, so any amount from it radiated back to the surface also did not last originate from surface emitted of 396 W/M^2, which is the just net energy flux at the surface (in the steady-state at least). -
muoncounter at 13:41 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Camburn#27: "during the MWP the precip was extensively higher than present. That would cause the advancement of glaceriers even if the temperature was warmer." High precipitation plus warm temperatures = glacial advance? Not what Kirkbride and Dugmore 2008 found in Iceland: medieval glacier advances between the 9th and 13th centuries are firmly identified for the first time in Iceland. This challenges the view of a prolonged Medieval Warm Period and supports fragmentary historical data that indicate significant medieval episodes of cooler and wetter conditions in Iceland. -- emphasis added Koch 2008 is also a good short summary on this question: an advance of Llewellyn Glacier, which drains the northeast sector of the Juneau Icefield, at the time of the Medieval Warm Period, cannot be reconciled with temperatures similar to those of today. This evidence suggests that temperatures were significantly lower than at present during the Medieval Warm Period, calling into question the existence of prolonged warmth at that time. We conclude that the Medieval Warm Period is at best an ill-defined term that encompasses a number of possibly unrelated climate anomalies. -- emphasis added -
Camburn at 13:41 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
DB: Koch etal talks about the increased precipitation in the Western Conus. Here is a paper that has been cited 70 times about temperatures during the MWP: Global Warming: A Geological Perspective -
Camburn at 13:16 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
DB: The reason for the advancement of the glaciers is not certain. There are proxies from NA that show during the MWP the precip was extensively higher than present. That would cause the advancement of glaceriers even if the temperature was warmer.Response:[DB] Citations please. Unsupported claims carry little weight.
Precipitation increases do not necessarily translate into glacier advances. The mass balance between increased depositions in the accumulation zone have to outweigh losses in the ablation zone for glaciers to advance. Warming typically increases the size of the ablation zone and decreases that of the accumulation zone resulting in glaciers pulling back from their terminal moraines.
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Rob Honeycutt at 12:58 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Eric... You might check out the first diagram in the article here. It seems that, for one, almost the entire central Eurasia region was actually cooler. I believe this is the point. There are clearly areas around the planet that show a MWP but the warming is heterogeneous in both time and place, and many areas of the planet were actually cooler during the MWP. This is completely different than today where we have extremely accurate measurements of the homogeneous warming. Call it a braided hockey stick with a very straight blade.Response:[DB] Interested parties may see also Koch and Clague 2011 wherein they show that that several glaciers in western North America and elsewhere in the world advanced during Medieval time and that some of these glaciers achieved extents similar to those at the peak of the Little Ice Age, a very cold period many hundreds of years later.
More discussion on this here.
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Alec Cowan at 12:48 PM on 12 July 2011A Detailed Look at Renewable Baseload Energy
@267 Tom, I only have read what I supposed a faithful quotation in #264. In the sentence "We can figure a capacity of .2KW per SM of land (an efficiency of 20% of the 1000 watts that strikes the surface in each SM of land)." the phrase between parenthesis is factually wrong unless that land is a small spot that changes location by the minute -though I don't understand why third person singular if 20% and 80% are striking the same SM so 20% is not the subject- In the best case, it is a sloppy way to say it. I have at least the excuse of hardly speaking English -in spite of me using my real name here what seems to suppose some kind of linguistic obligation-. The term capacity is not really a problem, though it suggest a technological limit. I don't need to be "sold" solar energy. But I wasn't born yesterday. Free energy like solar or petroleum has the cost of knowing where to find it -solar is easy about that- and later the cost of making it available where and when you need it. I think that many people is needing lessons of economy, not ecology or physics, so they can land safely at last. If the topic was feasibility of solar energy, of course it is. What surface is needed? Just within the same order of magnitude of paved roads and urban sprawl in the United States. -
heystoopid at 12:30 PM on 12 July 2011SkS Weekly Digest #6
To whom it may concern, there appears to be a mixed up link in News bites thus:- "Millions of African Climate Refugees Desperate for Food, Water" currently links to Science Daily story ;'Fire to Become Increasingly Important Driver of Atmospheric Change in Warming World' I believe the correct link to be:- http://www.ens-newswire.com/ens/jul2011/2011-07-06-01.html -
Eric the Red at 12:26 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Do you have any references showing otherwise? -
Eric the Red at 12:24 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Especially the global temps from Lohle. -
Eric the Red at 12:22 PM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Yes, Notive how all the proxies show the MWP as being warmer than today?Response:[DB] Factually incorrect. See Martín-Chivelet et al.
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scaddenp at 11:51 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Um, I think "back radiation" is radiation emitted from the atmosphere that strikes the surface. I cant see how "last originated from surface emitted" can make any kind of sense. -
scaddenp at 11:40 AM on 12 July 2011The 2nd law of thermodynamics and the greenhouse effect
Rosco - this is basic version. This argument has been done to death at in here. I note some confusion on Trenberth. I suggest you might like to get your head around some basics at Science of Doom (and the many other articles there). In short, the physics is more subtle than you think it is. -
RW1 at 11:30 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Rosco (RE: 16), "I know they provide 333 W/sq metre "back radiation" but where do these joules come from to heat the atmosphere to the level where it radiates more than the incoming solar radiation?" If you read the tables in the paper, it's not really 'back radiation' but downward LW radiation received at the surface. Why he refers to this as 'back radiation' I don't know. The fundamental problem is downward LW at the surface has three potential sources: Some of it last originated from surface emitted LW, some of it last originated from the Sun absorbed by the atmosphere yet to reach the surface, and some of it last originated from the kinetic energy moved from the surface into the atmosphere while also radiates in the LW infrared. The term 'back radiation' generally implies downward emitted LW that last originated from surface emitted. The diagram makes it look like of the 396 W/m^2 emitted at the surface, 333 W/m^2 are coming back from the atmosphere, which is why it's confusing. -
Bern at 11:27 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
The question that comes to my mind after reading this excellent article, and the discussion above, is this: How does this affect model predictions for the next century? If Dr Trenberth is correct, that there is a decadal-scale sequestration of heat in the deep ocean, then this would, I presume, result in larger, decadal-scale oscillations in global temperature superimposed on the upward trend. It would appear that we're in a 'cool' period at the moment, which leads to the obvious conclusion that some time in the next few years to a decade or, we might see a very dramatic upward swing in global surface temperatures, as that deep ocean heat storage temporarily slows or even reverses. On the other hand, if Dr Hansen is correct, then as aerosols are scrubbed from more developing world power stations, we might see a similar upward surge in temperatures as the aerosol effects reduce. Either way, the next decade or two could see substantial surface temperature rises, but how would it affect temperatures later in the century? Would either of these options significantly change global climate model predictions of the long-term trend over that timescale? And if so, in which direction? -
RW1 at 11:12 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
As everyone knows, I have many questions for Kevin regarding the Energy Flows diagram.Moderator Response: (DB) Your best bet is to post them here. -
Tom Curtis at 11:11 AM on 12 July 2011A Detailed Look at Renewable Baseload Energy
Alec Cowan @265, nobody in this "discussion" or being discussed (ie, LAGI) assumes that "sun radiation direction is determined by gravity so every square metre of the planet gets plenty of it". LAGI discuss the potential of solar generation for sites located in southern Spain, North Africa, South West United States and Central Australia. These are all areas with high insolation and low cloud cover and, as shown by a comparison of Andasol data with their estimate, the estimate is reasonable, indeed conservative for most areas discussed. They do include a very few and small locations for which your criticism may be valid - South Africa, New Zealand, Seattle (what where they thinking), and Armenia. However, some of these can be fixed by simple relocation (South Africa to Namibia for example) and in others (New Zealand, Seattle) there are ample alternative sources of renewable energy (geothermal). That, however, does not detract from their point, which is not a proposal, but a demonstration of the capability of solar power. -
Camburn at 11:10 AM on 12 July 2011Ocean acidification: Coming soon
Doug: Excellent job. -
Rob Painting at 10:44 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Dean - have a read of page 44 in Hansen's paper, and the references cited therein. The top of the atmosphere satellite measurements are not without issues themselves.. -
Alec Cowan at 10:43 AM on 12 July 2011A Detailed Look at Renewable Baseload Energy
#263 erratum Dang! Volume of all oceans are three orders of magnitude higher. That volume of natural gas matches just the volume of the Caspian Sea and Black Sea together, or just more than a sixth of the Mediterranean's. -
Rosco at 10:36 AM on 12 July 2011The 2nd law of thermodynamics and the greenhouse effect
This is simply wrong. You are trying to compare a heat generating source - a human body - with a heat recipient. Our body loses heat by conduction of heat to the atmosphere and then by convection of warmed air. Clothes and blankets simply keep the warm air close to our body. We radiate heat at the same rate whether we are naked or clothed. We cannot heat up our immediate environment more than our core body temperature. Radiation is such a poor method of heat transfer that we can keep warm. Remember wind chill if you don't think convection is the major factor in heat transfer in an atmosphere. Your explanation also completely fails to deal with the requirements of thermodynamics which state that heat cannot flow from a hot object to a colder object unless there is work performed. Your answer totally fails to explain the work performed and therefore completely fails to refute the claim you set out to refute.Moderator Response: (DB) The law says NET heat cannot flow from cold to hot, so your comment is self-refuted. -
Ken Lambert at 10:32 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Very much appreciate Dr Trenberth coming on to SKS. Well done John Cook. At first glance, the article is a comprehensive summary of the existing state of uncertainty regarding the energy imbalance and the location of the missing heat. Will Dr Trenberth be answering any questions on SKS?Moderator Response: (DB) Dr Trenberth could not guarantee that time would permit him to do so; feel free to place any questions here in case he is able to do so. -
muoncounter at 10:30 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Dean#7: "As far as I'm concerned, emissions of sulphate aerosols has been increasing globally in the 2000:s due to the Chinese rapid rise," Even that's not so clear. See Has Sulfate Pollution from Asia Masked a Decade of Warming? for a short discussion. Between 2003 and 2007, global sulfur emissions have gone up by 26 percent. In the same period, Chinese sulfur dioxide emissions have doubled. ... sulfur dioxide emissions rates in China ... began to decline in 2006 after China began installing large numbers of flue-gas desulfurization (FGD) devices in coal power plants. -
Alec Cowan at 10:23 AM on 12 July 2011A Detailed Look at Renewable Baseload Energy
Well, based on the evidence shown, I don't know who is more deadly wrong, they who assume that sun radiation direction is determined by gravity so every square metre of the planet gets plenty of it -they must live inside some sort of Dyson sphere- or they who assume that the year has 2000 hours. Efficiency of 10, 15 or 20%, who cares? One has a wrong assumption in one term, the other one has two inconsistent values in a product. In my neck of the woods, with an overall efficiency of 15%, and taking into account local heliophany, I'd have 0.36 KW-h per day and horizontal square metre in June and 1.01 in December, that is 270 Kw-h a year. With a square metre of solar panels placed at an angle of 45° and the same efficiency of 15% I would get 380 Kw-h a year with peaks in the last days of Winter (heliophany is not constant through the year). And I'm at a 35.5° latitude what qualifies as mid-latitude, and I get 1,150mm of rain a year, with an heliophany of 71%, so this is no dessert at all but one of the most fertile plains in the world. I'd got 270 Kw-h from an horizontal square meter and 380 from a well oriented one with an efficiency of 15%. So, anyone can see which one was wronger: 400 KW-h with 20% efficiency or 60 KW-h with 15%. I don't have an efficiency of 15%. I hope I'll do in the future. The rest of it is out of discussion: I know what I'm talking about and I'm not interested in other opinions about what happens in the roof of my home. If someone disagrees, consider it a private matter. -
michael sweet at 09:57 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Here we see real skepticism at work in science. Hansen has proposed that aerosols reflect more heat into space. Trenberth proposes that the missing heat has been absorbed into the deep ocean. Hansen is skeptical of Trenberth's results and Trenberth is skeptical of Hansen. Both of them will marshall their data to determine which is more correct (it may be a combination of both effects). In the end the data will determine who is correct. This is an example of real climate scientists debating the data. Both Trenberth and Hansen agree that strong action is needed to counter the problems caused by BAU. -
Dean at 09:46 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Rob #8: Thanks again for the info. Just one issue that I still think it is not clear: Reflecting aerosols will obviously mean less heat going into the oceans. But the reflected sunlight should also reduce the TOA balance, which is measured. So at least in the simplest model, aerosols cannot explain the "missing heat" while both the ocean heat content and the TOA energy imbalance will decrease. -
Dave123 at 09:35 AM on 12 July 2011Climate Solutions by dana1981
Sorry editing problems using droid. Will come back to this later. -
Dave123 at 09:34 AM on 12 July 2011Climate Solutions by dana1981
PaulDI've been on the road for a few days, and thinking and your .... challenging PaulD- I've been on the road for a few days, and thinking and your .... challenging... post. I live in the midwest of the US. I have allergies, like many people. Leaving windows open is less than optimal, requiring ineffective medication that can leave me drowsy. Closing the windows requires the use of AC otherwise indoor temperatures will rapidly exceed anything bearable...and I have to sleep to both maintain my health, and to keep my job that pays for my health insurance. I thought the point of Dana's challenge is what we are doing relative to where we could be, not necessarily some absolute standard, otherwise we spring the trap laid by deniers who point to Al Gore not living in a hut in the woods foraging for food. But I find it hard to beleive that anyone other than a denier posting here doesn't know enough about our industrial ecosystem to get how fragile and dependent on cheap resources it is, or what we stand to lose if it breaks. I don't really want to go into my personal medical history here, but I really do mean it that I can count something like 5 times I would be dead without modern medical technology.... and NOT because of my lifestyle either. I'll give one example- mitral valve repair surgery... open heart. All of the diagnostics- trans thoracic echo cardiograms, tranesophageal echos, CT scans, angiograms require modern (last 15 years) computer technology. This means chip fab technology. Chip technology requires advance polymers for masking, the safe use of higly purified and highly toxic materials including phosphine and arsine. It requires a pre-existing computer infrastructure to create and test the circuit design (bootstrapping), create the mask design and huge, computer controlled machines to burn the mask into the chip. Etching the chip requires highly pure hydrofluoric acid and highly pure water (no, not distilled water...water that has megohm resistance needs to be purifided by reverse osmosis technology, which requires its own specialized polymer membrane technology. The surgery itself is safe at a 97% level because of advances in technique and anaesthesiology monitoring that reduce the operating time and thus the ris -
scaddenp at 09:29 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
A better link for Kaufmann courtesy of WUWT. From quick look, it uses Kaufmann's 2006 statistical model to relate forcings to temperature but with update forcing data including the new aerosol data which is up. Hansen also states "Global warming has been limited, as aerosol cooling partially offsets GHG warming" and argues that aerosols are understated in the models. Kaufmann cannot rule out natural variability but I think the Argo network will eventually make this clearer. -
Rob Painting at 09:16 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Dean, if one accepts Hansen is correct and that there is no 'missing heat' in the ocean because the models are wrong, then yes there is no imbalance. He could be right - but seems a bit light on evidence at the moment. On the other hand the warming found by Von Schuckmann & Le Traon is a bit more than that found in other recent analysis, so it does 'close the gap a little'. As for sulfates, although they do tend to wash out of the atmosphere within weeks to months, they can have a profound effect on cloud formation - the finer particles seeding smaller, but more numerous cloud 'droplets' - for want of a better word. Being smaller they are less likely to condense into rain, and they also make clouds more effective mirrors. So more sunlight is reflected back out to space. This effect is greater is the dry seasons, when sulfates are less prone to being 'washed out'. If Hansen is correct, this affects the energy budget because less energy is being received at the Earth's surface (there's far less incoming energy to account for). The climate models use an estimate of the aerosol cooling effect in their simulations, but if the ocean mixing rate is wrong in models (i.e. too efficient), the model match with 20th century observations is simply fortuitous. Seems a stretch. One would expect the budget doesn't balance for a number of reasons, the large uncertainty in measurements being a significant one, but also a greater aerosol cooling, deep ocean mixing and increased radiation to space (Katsman & Oldenburgh (2011) -
BBD at 09:11 AM on 12 July 2011A Detailed Look at Renewable Baseload Energy
All This is what we are discussing:average raw energy density x plant conversion efficiency = average output
Here's what LAGI does: - reasonably assumes 200W/m2 raw energy density - multiplies 200W/m2 by the estimate of 2000 hours p/a of direct sunlight: 200W/m2 x 2000 = 400kWh per m2 - and on this assumption estimates: - 500,000 km2 = 23TW Plant conversion efficiency is not calculated. Much of the ambiguity arises from LAGI's use of 'capacity' (emphasis added):We can figure a capacity of .2KW per SM of land (an efficiency of 20% of the 1000 watts that strikes the surface in each SM of land). So now we know the capacity of each square meter and what our goal is. We have our capacity in KW so in order to figure out how much area we’ll need, we have to multiply it by the number of hours that we can expect each of those square meters of photovoltaic panel to be outputting the .2KW capacity (kilowatts x hours = kW•h).
What capacity? What are we talking about here? MacKay includes a value for conversion efficiency. Say it's 15% (it doesn't matter; this is an example only). Remember:average raw energy density x plant conversion efficiency = average output
200 x .15 = 30W/m2 So: 30W/m2 x 2000 = 60kWh per m2 vs LAGI:average raw energy density = average output
200W/m2 x 2000 = 400kWh per m2 This is not esoteric. Can someone please come to the rescue. I'm tired. -
Dean at 08:29 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Thanks Rob, looking forward to your post. However, Hansen states in the beginning of chapter 11: "our calculated energy imbalance is consistent with observations (Fig. 19b), implying that there is no missing energy in recent years" This is different to your "closes the gap a little". As far as I'm concerned, emissions of sulphate aerosols has been increasing globally in the 2000:s due to the Chinese rapid rise, despite the western long term decline since the 1970:s. A reference. But even if this affects the surface temperature negatively, it is not obvious to me how/if this affects the energy balance accounting. If sunlight is reflected upwards again things cancel out, or? -
Rob Painting at 07:58 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Dean, Fig 19 relates to Von Schuckmann & Le Traon 2011 who find that the upper ocean from 2005-2010 has warmed significantly. I'm writing up a post on it at the moment. It doesn't resolve the 'missing heat', but rather closes the gap a little - down to a .59W/m2 imbalance. Hansen suggests that the shielding effect of aerosols may be greater than anticipated, and that the climate models match 20th century observations in that they underestimate the strong cooling effects of aerosols, but overestimate the ocean response because they mix heat too quickly down into the ocean, compared to chemical tracer observations. -
Paul D at 07:46 AM on 12 July 2011Climate Solutions by Rob Painting
TrueOfVoice said: "Should I stock up on really warm clothing?" The object of heating is to keep the human body at a temperature at which it can happily survive. So the question is, what is the most efficient way of doing that? I don't have central heating (I live in the UK) and these days tend to turn the thermostat down in the winter and wear more layers of clothing. The biggest problem tends to be others expectations, most buildings are heated in the UK with the assumption that people wear one layer of thin clothing, jumping out of their heated car into a heated building. Which means if you go out of your home and walk to a shop with about 6 layers of clothing on, you break out in a sweat when in the shop for to long. So the inefficiency of others and the legislation that says the working place must be a minimum temperature, means those that want to cut back are hindered. -
Alec Cowan at 07:39 AM on 12 July 2011A Detailed Look at Renewable Baseload Energy
To add to the dance of figures loosely related with the post: 9? 7.7? 4.1 W/m2? Wow! Brazil get some 0.8W/m2 in bio-ethanol in their best model crops. USA gets some 0.3W/m2 in bio-ethanol from corn. And land is no cheap because ... it produces a lot of sugar cane or corn! That land is better used for sun harvesting! On the other hand, USA managed to got many hundreds of TW during Hiroshima's blast, and using less than a cubic metre. And those 23TW so discussed and compromising the area of whole countries can easily be got from burning 40 milliard tons of coal per year, if you only want heat, an amount of heat that could melt 2,200 km3 of ice itself if you ignore the effect of more than 140 GTons of CO2 added to the atmosphere by burning it, which stands for that greenhouse gas rising some 17 ppm by year. But don't get dismayed by this as you can cut emission to a half or less by using petroleum and natural gas, all provided you only needed heat and you needed it in the same place the fuel is. But, obviously, bio-fuel and nuclear are very expensive while sun, wind, petroleum, natural gas and coal are 100% free -nothing sarcastic there, not at all-. And that may have been the problem from the very beginning. Well, we may or may not need in a period of thirty years some hundreds of thousands of square kilometers to harvest sun or at least 800 km3 of coal or oil, or 650,000 km3 of natural gas (more than half the volume of all oceans together), what I'm sure is here and there, and a 100% free too, as said, not in a sarcastic fashion but because it's true. Well, number crunching is over. It was very entertaining. What on Earth are you talking here about? and, how does that relate to the topic in the post? [Few adjectives were used in this, and none of them was harmed while making this comment] -
scaddenp at 07:39 AM on 12 July 2011Climate Solutions by Rob Painting
Should also ask you what part of NZ you are moving to? Auckland has mangroves and thinks 5 deg C is freezing. From Invercargill, there is nothing between you and Antarctica and 28 deg C would seem like the end of the world. -
Albatross at 07:30 AM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Sphaerica @20, Good points. And let us not forget this:
Comparison of temperature reconstructions, re-centered to match CRUTEM NH land record (based on each reconstruction's period of overlap).
[Source]
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Rob Painting at 07:28 AM on 12 July 2011The Medieval Warm(ish) Period In Pictures
Eric Red - "The MWP has been acknowledged as the last period of globally warm temperatures (not just NH as claimed above). The global temperature anomalies are similar to today" So you comment without actually reading the post? How can global temperature anomalies be similar to modern-day when North American glaciers were growing in the MWP?, and when the central and eastern tropical Pacific was much cooler than the 1961-1990 reference period? -
Doug Mackie at 07:22 AM on 12 July 2011Ocean acidification: Coming soon
Camburn: Since we have not heard otherwise, we trust you have found the explanations thus far to be sufficiently robust to satisfy your expectations. -
Bob Lacatena at 07:16 AM on 12 July 2011The Medieval Warm(ish) Period In Pictures
18, Eric the Red, First, did you actually look at the papers you linked to? The last, Kellerhals et al, shows current temps substantially higher than the MWP.
The first, Cook, shows the MWP to be a fractionally present bump not much greater than other temps in the period, and also much lower than current temps.
So what exactly are you trying to prove?
And even if you found 3 proxy studies that show what you want, you're missing both points. The first is that that is mere cherry picking. A careful analysis of the data shows that warming that is supposedly the MWP is not contemporaneous... one study shows a peak in 1100, another 1300, another 950. It's also not nearly uniform around the globe. While one study shows a warm period here, another location at that same time shows cooling.
There is no doubt that there was a MCA, but there is no evidence that it was global, substantial evidence that it was not, and substantial evidence (as you have so kindly provided yourself) that temperatures even regionally did not match those of modern times.
Beyond this, you missed the other main points, which are first that whether there was a MWP or not, it does not change the radiative physics which clearly show we are causing greenhouse gas warming now, and if there was a MWP, and it was as warm as temperatures are now, then climate sensitivity is high and your constant admonishment that you are sure that climate sensitivity is likely to be below 2C goes out the window.
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Dean at 07:09 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Hansen claims to have resolved the issue with the "missing heat"(e.g. fig 19) in a draft paper. Does any expert here have a simple summary of the difference between Hansen's and Trenberth's approaches? -
Albatross at 06:47 AM on 12 July 20112010 - 2011: Earth's most extreme weather since 1816?
EricRed @327, You, like Norman, seem intent on missing the point entirely-- I even bolded the text @326 and reproduced the figure from Trapp et al. (2007). You somehow missed this from my post @ 326: "You are conflating the more subtle changes by month or by seasons with the quite drastic changes observe during the course of the spring and summer (March-August). This is similar to stating that most locations experience marked temperature changes between winter and summer each year, so a few degrees of AGW is nothing to be concerned about. The studies I am referring (see Trapp et al. 2007 kindly provided by Tom Curtis here) to look at the changes between the mean MAM (March, April, May) conditions for 1962-1989 and how mean MAM conditions might look in the future, 2072–2099." They are comparing apples with apples, you are not. You and Norman are in fact hopelessly confused on this. Also, it is obvious that you have either not read Trapp et al. (2007, 2009), or you did read it but are incapable of following the science (and there is no shame in that, we can't all be experts at everything or even most things). I'll give you the same advice that I gave Norman: "I urge you to read Trapp et al. (2007) and Trapp et al. (2009)in their entirety." Otherwise it is very clear that you are pontificating and talking through your hat, and I have no intention of wasting any more of my time arguing in circles with you either. You both keep repeating the same incorrect notions, sadly that doesn't make them any more correct or real. PS: In retrospect asking you to read the paper when you are not an expert in the field and have preconceived ideas may not help. then again, Tom Curtis is not an expert in this field, yet he managed to correctly interpret the science in the papers. PPS: The point of me quoting Schaefer and Edwards was to demonstrate that Norman had not accurately reflected their findings. -
Albatross at 06:31 AM on 12 July 20112010 - 2011: Earth's most extreme weather since 1816?
Norman at 16:03 PM on 9 July, 2011 You say "I am reading the articles you link to (mostly abstracts). They are predictions based upon their models about what will take place. They seem to assume the lapse rate will stay the same and the warmer wetter air will have more energy to generate more intense storms. I do not understand the logic they used to arrive at that conclusion. That is part of what I am questioning." Actually, Tom Curtis provided you links to two of the seminal papers, not just abstracts. This glib dismissal of the science based on your incorrect and incomplete understanding of the science left me speechless. They did not "assume the lapse rate will stay the same", your claim in this regard is demonstrably false (see below), yet it seems to be your reason for dismissing their findings as you then go on to argue the strawman that you created. This is nonsense Norman. In fact, your whole premise for creating your argument about lapse rates just shows how out of your depth you are and how little you understand the science-- in fact, so confuse dis your reasoning that I had a hard time figuring out what you were trying to say. You also seem to be confusing meridional gradients with vertical temperature gradients (i.e., lapse rates), are far too focused on the role of differential temperature advection in creating steep lapse rates (forgetting the role of the Mexican plateau and strong diabatic heating in generating steep lapse rates over the southern Great Plains, for example) and under the misconception that Arctic air is somehow stored in the upper-levels of the troposphere. Yet, you seem to feel compelled to argue the experts in this field and dismiss their findings equipped only with your preconceived and misguided notions and Google. From Trapp et al. (2007): "The two quantitative measures of CAPE and S06 were computed at each model grid point, for each day during the RF and A2 periods, using the RegCM3 output at 00 UTC." To calculate CAPE they used the vertical profiles of temperature (the RegCM3 model has 18 levels in the vertical), which would by default include information about the vertical lapse rates. The profiles were not constant, nor were the lapse rates. From Marsh et al. (2009): "The atmospheric portion of the CCSM3, the Community Atmospheric Model 3 (CAM3), is a spectral model with 85- wavenumber triangular truncation (approximately 1.4° at the equator) in the horizontal with 26 terrain-following hybrid levels in the vertical. The numerical scheme used in the CAM3 is an Eulerian spectral transform with semi-Langrangian tracer transport and semi-implicit leapfrog time stepping (Collins et al., 2006). CAM3's vertical resolution contains 4 levels below 850 hPa and 13 levels above 200 hPa (topmost being 2.2 hPa)." Again, the temperature profiles were not constant/specified. Again, any changes in the lapse rates would be reflected in the CAPE values. Please do not respond to me Norman, I and others have wasted hours of our lives drafting these posts and trying to explain the science to you, all to no avail it seems. I'm done here. PS: I have no idea what compels people to think that climate science and complex issue such as severe storms are an open house to speculation and 'debunking'; that equipped with Google and their misguided and shallow understanding that the science and physics can be dimissed or overthrown. It is infuriating to say the least. I am pretty well educated, yet have no intent or drive to argue with an engineer or oncologist that they have gotten something wrong because I happen to think differently, or because a result is not intuitive to me (nor should it be, I am not an expert in that field) and have access to Google. So it blows my mind to see self-professed 'skeptics' on the internet passionately arguing the physics and science on all aspects on climate science (oceanography, radiative transfer, physics, modelling etc.). Worse yet, when presented with the physics and facts, they then contort all kinds of excuses to dismiss them rather than using it as an opportunity to learn. -
scaddenp at 06:31 AM on 12 July 2011Climate Solutions by Rob Painting
Trueofvoice - central heating and double glazing are rare. Insulation levels are low (estimated that 600,000 home are uninsulated period in a country of 4m). Talking to visitors, we do indeed live differently, wearing warmer clothes. However, except in Central Otago and mid North Island, it doesnt get that cold. Winter frosts except in upper quarter yes, but seldom below zero. Normally people heat one or two rooms (wood burners often, but heat pumps are making a big impact). -
Kevin C at 06:27 AM on 12 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Muoncounter #3: If there is an increase in the net energy budget, then either more energy is coming in or less is going out. If it's not the sun, then doesn't that leave either albedo (changing the absorption of incoming radiation) or greenhouse effect (changing the outgoing radiation)? What else is there? The change in figure 4a is not small: The difference in net energy flux from 2000 to 2009 in figure 4a is nearly 1W/m^2, and half of that in the last 2 years. That's equivalent to adding ~80ppm of CO2! Can weather cause fluctuations that big, or is it change in natural or anthropogenic forcing? -
Eric the Red at 06:05 AM on 12 July 20112010 - 2011: Earth's most extreme weather since 1816?
Albatross, Your last two paragraphs above seem to be saying the same thing, rather than being contrasting. In fact, if you eliminate April from the first paragraph and wind from the second, they are the same. If May becomes similar to July, then severe storms should diminish in May and June, with July and August diminishing further. -
LorenCobb at 05:49 AM on 12 July 2011SkS Weekly Digest #6
EDITORS ATTENTION NEEDED! The link in your "News Bites" section that says "Climate Change May Pose Biggest Security Threat" does not go to the correct URL. Instead of linking to the intended article, it links to a Skeptical Science blog-editing page which needs an administrative password.Response:[dana1981] Thanks to you and Byron Smith for the correction. Link fixed.
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Albatross at 04:33 AM on 12 July 20112010 - 2011: Earth's most extreme weather since 1816?
#314 Norman at 14:59 PM on 9 July, 2011 You ask "The question to you would be why do severe storms diminish in July and August even though that air is the warmest and contains the most amount of water vapor (fuel for storms)?" Norman, you may not realize it but your question is quite ridiculous in the context of what the research shows and int he context of what I said-- your question makes no sense in relation to what I said. You are conflating the more subtle changes by month or by seasons with the quite drastic changes observe during the course of the spring and summer (March-August). This is similar to stating that most locations experience marked temperature changes between winter and summer each year, so a few degrees of AGW is nothing to be concerned about. The studies I am referring (see Trapp et al. 2007 kindly provided by Tom Curtis here) to look at the changes between the mean MAM (March, April, May) conditions for 1962-1989 and how mean MAM conditions might look in the future, 2072–2099.
I urge you to read Trapp et al. (2007) and Trapp et al. (2009) in their entirety. They are not talking about the "new May" becoming similar to the present July, for example. One has to compare apples with apples. This is a very important point, and one that you repeatedly keep on missing. I do not know whether this is intentional on your part, or simply because you are so far out of your depth on this complex issue.
Marsh et al. (2009) made similar findings for Europe concerning the potential for an increase in severe thunderstorm episodes over Europe. They found that:
"Preliminary comparisons of the CCSM3's 21st century simulation under the IPCC's A2 emissions scenario to the 20th century simulation indicated a slight increase in mean CAPE in the cool season and a slight decrease in the warm season and little change in mean wind shear. However, there was a small increase in favorable severe environments for most locations resulting from an increase in the joint occurrence of high CAPE and high deep layer shear."
They add that:
"At best, one can say that the CCSM3 predicts the number of favorable severe environments will increase in a future characterized by anthropogenic warming."
You say "In the United States the most severe storms occur April, May, June and diminish in July and August (tornadoes, hail, rain, lightning)"
Funny how we can look at the same graphs and arrive at different conclusions. According to the database compiled by Schaefer and Edwards, they say "May and June are the peak months for the occurrence of tornadoes and large hail. In contrast, July and June are the top months for wind storms." April and July are the next highest for all tornadoes, respectively.
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BBD at 04:06 AM on 12 July 2011A Detailed Look at Renewable Baseload Energy
CBDunkerson #264Thus, a 20% efficient panel would indeed generate an average of about 200 W/m^2 (more nearer the equator / less nearer the poles)... when the Sun was shining.
Well, it's average performance that counts. So what concerns us is this: 20% x 250 = 50W/m2 Slighly less idealised: 15% x 200 = 30W/m2 MacKay gives a real-world estimate for CSP of 15W/m2. I think he's right, as efficiency will no doubt rise over time. However, current real-world plant power density is even lower than assumed above. There are a number of reasons for this. Here are some real-world numbers:Europe’s first commercial solar tower, PS (Planta Solar) 10, completed by Abengoa Solar in Sanlúcar la Mayor in 2007, is rated at 11 MWp. With annual generation of 24.3 GWh (87.5 TJ, 2.77 MW), its capacity factor is 25%. Its heliostats occupy 74,880 m2 (624 x 120 m2), and the entire site claims about 65ha; the facility’s power density is thus about 37 W/m2 factoring in the area taken up by the heliostats alone, and a bit more than 4 W/m2 if the entire area is considered. PS20 (completed in 2009) is nearly twice the size (20 MWp; 48.6 GWh or 175 TJ/year at average power of 5.55 MW and capacity factor of nearly 28%). Its mirrors occupy 150,600 m2 and hence the project’s heliostat power density is, at 36.85 W/m2, identical to that of PS10 but, with its entire site covering about 90 ha, its overall power density is higher at about 6 W/m2. Bright Source Energy’s proposed Ivanpah CSP in San Bernardino, CA should have an eventual rating of 1.3 GWp and it is expected to generate 1.08 TWh (3.88 PJ) a year and deliver on the average 123.3 MW with a capacity factor of just 9.5%. Heliostat area should be 229.6 ha and the entire site claim is 1645 ha. This implies power densities of 53.75 W/m2 for the heliostats and 7.5 W/m2 for the entire site. Again, no stunning improvements of these rates are expected any time soon and hence it is safe to conclude that optimally located CSP plants will operate with power densities of 35-55 W/m2 of their large heliostat fields and with rates no higher than 10 W/m2 of their entire site area.
So, again but with 10W/m*2: 10,000km2 = 100GW 100,000km2 = 1TW 2,300,000km2 = 23TW Smil's examination of the impact of packing factor on installation footprint finds the following energy densities for SPV plant: Olmedilla 85 GWh/year = 9.7 MW 9.7 MW/108 ha = 9 W/m2 Moura 88 GWh/year = 10 MW 10 MW/130 ha = 7.7 W/m2 Waldpolenz 40 GWh/year = 4.56 MW 4.56 MW/110 ha = 4.1 W/m2
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