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Steve Brown at 21:21 PM on 6 July 2011The Last Interglacial Part Two - Why was it so warm?
The global average temperature during the Last Interglacial was likely no higher than 1C. The figure of 5C of warming only applied to high northern latitudes due to the relatively high insolation. This is discussed in part 1 of the series. There is evidence for around 2m of sea-level rise contributed by the melting of the West Antarctic Ice Shelf. It's unlikely that the WAIS would have melted only because of higher insolation at 65N. I totally agree with you that orbital forcing and insolation has been the main driver behind the recent glacial/interglacial cycles, but it's not sound science to exclude all of the feedbacks and processes that would have amplified and distributed the warming around the globe. Reduced albedo, heat uptake by the sea and ocean currents played their part. The orbital forcing behind the last glacial termination peaked with the Holocene Climatic Optimum. For the past few thousand years our orbital configuration has been moving into a cooling phase, yet global temperatures are on the increase. -
hfranzen at 21:09 PM on 6 July 2011OA not OK part 2: Thermodynamic duo
Equation 1 is not sufficient. The correct approach depends upon the model system. Taking a solution of dissolved carbon dioxide, bicarbonate, carbonate, calcium ion and water (containing as always hydrogen ion and hydroxide ion) to be in equilibrium with solid calcium carbonate and gaseous carbon dioxide we can ask what happens when the partial pressure of caron dioxide increases? First the equiulibrium between gaseous and dissolved molecular carbon dioxide is determined by the Henry's Law constant and the concentration of dissolved cabon dioxide increases independent of what happens to the other chemical species. Secondly the product of the carbonate ion and calcium ion concentrations is a constant (the solubility product) and since in this model calcium ion is fixed the concentration of carbonate remains fixed. That leaves the bicarbonate ion concentration to be considered. This concentration will increase and, by electrical neutrality, the hydrogen ion concentration will increase as well (unless it is determined by other reactions not involving carbon dioxide species). The hydroxide concentration will decrease according to the ion dissociation constant for water. When all of these constraints are considered the net result of increasing the carbon dioxide pressure (say according to the Keeling curve): 1. dissolved mo;ecular carbon dioxide concentration increases, 2. dissolved bicarbonate ion concentration increases, 3. pH decreases, 4. carbonate ion concentration remains fixed, 5. calcium carbonate precipitates. This discussion can be modified for the case of "buffering". i.e. nearly fixed hydrogen ion concentration in which case the molecular carbon dioxide concentration increases (Henry's Law), carbonate is fixed by the calcium carbonate solubility product, bicarbonate is fixed by electroneutrality and calcium carbonate precipitates. -
les at 21:08 PM on 6 July 2011Climate's changed before
174 - DougCotton And if anyone says there is no physics basis for planetary orbit driven cycles, and cycles within cycles... just show them this -
Eric (skeptic) at 21:07 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
#269, Albatross, thanks for that post. A couple of questions though, why are the Great Plains and/or Argentina considered continental tropical areas? Or is that not what you meant? The subtropical parts of the U.S. have the most thunderstorms (Orlando Florida), but not the most severe. Typically the missing ingredient there is cooler and/or drier air aloft. Also my question to Tom in 259 applies, where is global-local connection? You pointed out that more moisture in the low levels is a big contributor to instability. But the increase in moisture is a worldwide average, not necessarily some local area prone to thunderstorms. For example there is currently an anomalous increase in moisture in the U.S. desert SW (a weather pattern). Some storms and dust storms have resulted. But that doesn't mean there is more or less moisture anywhere else in the U.S. The patterns dictate the moisture levels, not the GAT. -
DougCotton at 20:59 PM on 6 July 2011Climate's changed before
There is now statistically significant Fourier transform analysis which detects 60 year cycles in temperature data. There are also obvious other cycles, notably one of about 934 years. These cycles also correlate with planetary orbits as I have explained at earth-climate.com and so we now have proof that gravity from the sun and planets affects Earth's climate. Predictions are for slight cooling till 2028, then warming to 2059 then long-term (934 year) cycle is at maximum and so a long term decline to Little Ice Age conditions about 450 years after that. There is a detailed explanation and reasons on my site. I am happy to answer questions to my email address thereon. -
BBD at 20:58 PM on 6 July 2011A Detailed Look at Renewable Baseload Energy
adelady #163We've already seen how far and how fast the price of solar PV and of wind can come down. Without pushing them further, we'll never know just how cheap they can be.
This is baffling. Please see the article by Helm I quote at #159. For example:Take wind. Britain has one of the most expensive support packages in the developed world. Customers have to buy a proportion of energy from renewable sources, paying the usual price and a premium that the Government guarantees. And that has been doubled for offshore wind. The costs are far greater than conventional technologies, and make even nuclear look cheap. If, as a result, overall emissions were cut on a significant scale, it would at least meet the carbon objective. But because the wind does not blow all the time, there has to be back-up — carbon-emitting coal and gas.
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The Inconvenient Skeptic at 20:40 PM on 6 July 2011The Last Interglacial Part Two - Why was it so warm?
Steve, I am aware of the situation with CO2. You are trying to get off topic. The topic is about the high temperatures of the Eemian and the high 65N insolation. Since you bring up CO2. I will clarify to other readers the situation and why the Eemian is so bad for the theory of global warming. The Eemian was 5C warmer than the Earth currently is with a max CO2 level of 285 ppm and it was really 270-280 for most of the time. But it had a temperature that the theory of global warming associates with almost 2 full doublings of CO2. So lets say the CO2 level for that temperature is 1150 ppm. The Holocene had basically identical pre-industrial CO2 levels, but a temperature that was 5C lower than the Eemian. So the purpose of the above article is to try to explain how the Earth was much, much warmer with CO2 levels that are lower than they are today. The reasonable and simple explanation is that 14% higher solar insolation is the cause. The problem is that the theory of global warming has discounted 65N insolation as being capable of causing the glacial/interglacial cycle. I am glad that you recognize the importance of this Steve. Many would not fully comprehend the significance of the very warm Eemian. I am pretty sure that this website very often uses the CRU temperature as an indication of warming. Even one of the articles that you linked to uses the CRU as 'evidence.' There are other methods, but throwing up a CRU temperature plot is very common and hence would be a standard measure of the Earth's temperature. You still have not discussed the issues I brought up in #4 about the high degree of correlation between insolation and temperature between the Holocene and Eemian. Which I point out might indicate that insolation plays a larger role than you are willing to allowing. -
BBD at 20:40 PM on 6 July 2011A Detailed Look at Renewable Baseload Energy
Mark Harrigan Apologies - not the only bad link I posted yesterday. This is the problem with rattling out comments, late at night, when dog tired. Sometimes I consider giving up on HTML tags and going back to the old ways... It may not have been pretty, but it worked. Anyway, here's the link to the critique(s) of the J&D paper. -
Mark Harrigan at 20:16 PM on 6 July 2011A Detailed Look at Renewable Baseload Energy
@JMurphy #164 - thanks for the link - good to see this is continuing to improve. But I think we must acknowledge there is still a long way to go. It's now got to be able to do 24hrs for 365 days a year - a goal so far not yet achieved anywhere - and 20MW is tiny compared to what we need. And it (ultimately) needs to do so without high subsidy. I think what this demonstrates is validation of my point 3- that CST is the most promising reliable renewable alternative and we should be continuing to invest in it but we should not pretend that is yet able to provide the full solution. It will take many years to scale up to a decent generation size and to provide a 24/7 solution. I'd love to see an example of CST in use as part of a "test" network of wind and possible gas turbine along the lines Diesendorf's plan suggests. I'm told on another post that Hawaii might be an ideal place to do this as it has abundant geothermal, solar and wind capacity. I wonder are there forums where these ideas can be communicated to those in the actual industry and if they read blogs like this? After all just talking amongst "ourselves" is fun but how do we get the message to those that can actually implement these things? -
JMurphy at 19:38 PM on 6 July 2011How would a Solar Grand Minimum affect global warming?
Looks like the UK could be in for some more regular cold Winter spells : UK faces more harsh winters in solar activity dip Among the so-called skeptics, this will obviously result in two responses - 1) New Ice-Age coming; 2) This 'proves' that it's all down to the sun, so AGW doesn't exist. -
ranyl at 19:12 PM on 6 July 2011Over the tipping point
Considering it is the total amount of CO2 that is put in to the atmosphere that counts for global warming outcome and taking the precaution of wanting a 95% chance of keeping to ~2C (that is at most 350ppm by 2100) then isn't zero emissions just the starting point and aren't all the CO2 used to employ any new energy system CO2 that will have to be re-removed from the atmosphere again? To be safe from latest predictions means 350ppm asap and that means a massive carbon sequestration effort or many years of human activity resulting in carbon sequestration or negative carbon emissions. Peak 400ppm, that means 20% reductions in emissions to 2017 and carbon sequestration is necessary to get to 350ppm by 2100 and that is being optimistic about the carbon cycle! This is never going to happen of course as it means the west would have simplify its lifestyle, so what does unsafe CC mean and will it matter how many renewables there are? -
DLB at 18:50 PM on 6 July 2011Great Barrier Reef Part 1: Current Conditions and Human Impacts
Osborne and Sweatman collected lots of cherries from the tree between 1986 and 2009 indicating little change on the reef over the last 24 years. Prior to 1986 there were less cherries left on the ground to pick. Therefore I would be cautious about making any judgement on what the reef health was before 1986. And besides doesn't fruit always taste better in the good old days :) -
Steve Brown at 18:50 PM on 6 July 2011The Last Interglacial Part Two - Why was it so warm?
#4 - Your hypothesis will only work if you can provide a case that falsifies our knowledge of the radiative cross-section of CO2, Methane etc, as well as fundamental physical properties such as the specific heat of water and Planck's Law. If Earth's temperature is dependent on the seasons, why are winters warming faster than summers? Also, the standard measure of the Earth's temperature is not just the atmosphere, but the total heat content anomaly of the oceans and atmosphere. How we know global warming is still happening - Part 1 How we know global warming is still happening - Part 2 The human fingerprint in the seasons -
les at 18:46 PM on 6 July 2011OA not OK part 2: Thermodynamic duo
3 - Rob Painting of course food is going to come into the argument sooner or later. It's what all 'real' scientists know; chemistry is just cooking. "thermodynamics" == oven temperature "equation" == recipe etc. -
skywatcher at 18:43 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
Albatross, can I just thank you for the superb post on thunderstorms at #269! Having just watched a 'Spanish Plume' breakdown in the UK and a day when a convective cap was not broken despite high dew points and lots of CAPE, I've learned a lot in the last 10 minutes. -
les at 18:15 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
267 - Norman"Precipitation patterns for Mid-Atlanctic region. Look at the graphs. They show cycles. "
You have spent quote a lot of time, as 270 Dikran points out, setting very particular requirements for what is science and then make the strong statement "They show cycles" based just on the eye-ball-o-matic?!?! May I suggest this post by Tamino for how to scientifically analyse an AMO data set for cycles. That's doing science; compiling 10 or 20 links isn't.Moderator Response: [Dikran Marsupial] Link fixed -
Mark Harrigan at 18:01 PM on 6 July 2011Over the tipping point
@Jerry #4 Perhaps then you need to lobby the relevant pollies in Hawaii who want a highly visible electoral platform to get in touch with Mark Diesendorf and see if they will adopt such a program? I've no idea what the generation cost base is in Hawaii but I can see that it would, on the face of it, be a natural place as you say for geo-thermal, solar and wind. It would also seem to be highly vulnerable to a break in oil supply? Is the power utility there private or government? Who knows - Hawaii could be a great showcase for a renewables experiment? :) -
JMurphy at 17:53 PM on 6 July 2011A Detailed Look at Renewable Baseload Energy
Mark Harrigan, your plan is not bad at all. With regard to concentrated solar, though, things are moving on : Gemasolar solar power plant reaches 24 hours of uninterrupted production -
adelady at 17:42 PM on 6 July 2011A Detailed Look at Renewable Baseload Energy
Mark "I can't see ANY way forward except putting a whole lot of effort into ANYTHING that looks promising. We should rule nothing out if it can contribute. ... Okay - now tear me to pieces!" Nuh, no pieces. My view is much the same about trying absolutely everything. We've already seen how far and how fast the price of solar PV and of wind can come down. Without pushing them further, we'll never know just how cheap they can be. And the same thing goes for other technologies. We might think they're expensive now, but we haven't tried hard enough for long enough to see which of them will (and which of them won't) follow the same cost trajectory. As for coal being around for a long time ...? That's another reason for pushing renewable technologies as hard and fast as possible as soon as possible. If the climate goes truly and horribly pear-shaped without much warning*, there'll be an outcry demanding either clean coal or no coal - which will lead to ghastly impacts when some areas lose most or all of their power supply. If people demand that coal be left in the ground (think asbestos, there's still plenty of that around, it's just too dangerous to use) everyone will be much better off if we already have a range of fairly cheap alternatives on the go. *not much warning? from the pov of view of those who weren't paying attention. Think WWII. -
adelady at 17:25 PM on 6 July 2011Over the tipping point
Paul D I agree that zero emissions will always be impossible. However I don't think that zero net emissions is out of reach. It's perfectly sensible for people to complain, at the moment, that carbon offsets with tree planting schemes and the like are little more than greenwashing. However, if emissions were only the truly unavoidable ones - say liquid fuels for (some) air travel and other specialty applications, it would be pretty easy to work out the size of the block of olivine (or similar rock) you need to buy for crushing to ensure near instant absorption by weathering of the equivalent amount of airborne CO2. So a little bit of appropriate geoengineering - speeding up absorption of CO2 to exactly match the accelerated release of CO2 - would be manageable. Viola! Zero net emissions. -
Jerry at 17:00 PM on 6 July 2011Over the tipping point
Mark, I live in a place that would be perfect for such a test--Hawaii county. We have a relatively small population (185,000) with ample geothermal, solar and wind resources. Yet the vast majority of our electricity is produced from oil. It drives me crazy that this island is not self-sufficient in electrical production. The power utility thinks they are being radical by trying to produce 30% from non oil sources by 2020. Jerry -
Dikran Marsupial at 16:58 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
Norman The reason that I introduced the double pendulum into the discussion was to correct your deeply misguided view of what is science and what is not. The lack of certainty or the ability to make accurate predictions does not mean something is not good science, and the double pendulum demonstrates that. Like the weather it is chaotic and hence unpredictable, even though we can write down equations that provide a perfect characterisation of its behaviour. You had been brought to the point where you could not reasonably discuss the double pendulum any further without contradicting yourself. The fact that you tried to deflect the discussion away from the double pendulum suggests to me that you know that, are not really interested in counter arguments to your position and are just trolling. This confirms my earlier prediction that further progress in discussing the science with you was unlikely. -
Paul D at 16:47 PM on 6 July 2011Over the tipping point
Zero emissions will always be impossible. Wind turbines are not zero carbon systems, they are very low carbon systems, as are most renewables and sustainable systems. Production, maintenance and decommissioning of the systems will have a small carbon footprint. We can ultimately only do our best and reduce greenhouse gas emissions to the lowest possible. -
owl905 at 16:32 PM on 6 July 2011History Matters: Carbon Emissions in Context
Quite the opposite of being a 'moral' piece, the assignment of responsibility is a core issue of this pollution problem. President Bush derailed the American response with his false escape argument about America's unfair share. The Chinese grabbed the angle, and used it at the Bangkok Conference in 2004 to claim the old western imperialist nations were responsible for 90% of all the pollution to date. Proper share is a stumbling block that derails the mitigation approach. The result isn't someone else throwing a bucket of water in the tub - it's everyone throwing a bucket of water in the tub. -
Albatross at 15:52 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
Tom, Norman, EricS,and others. Gee, this thread going to get as long as the "Its not the sun" at this rate ;) I think that Dr. Masters is of the opinion that the preponderance of severe events in 2010 is consistent with the increasing trend, and a system that is increasing in sensible and especially latent energy (i.e., moisture). This post is going to focus on thunderstorms and severe thunderstorms in particular, and how they might change in a warmer and more moist planet. I have written about this at length elsewhere at SkS, so I encourage people to read the posts made here, and here. In short, the research to date suggests that severe thunderstorms will increase in intensity as the planet warms and low-level moisture increases. Some seem to think that there is a "jump" or disconnect between the observations that low-level moisture has increased (and will continue to do so) and the occurrence of severe thunderstorms. I'll show that the physics and theory support that link. First, that lightning map that Tom showed us at #258. Tom, I have to agree with Norman on this one. Lightning frequency or occurrence is not typically a good proxy for thunderstorm severity. The strongest storms are typically observed over mid-latitude land areas, not over the tropics. Thunderstorms, are of course, most frequently observed over those areas. The reason for that are simple. For a thunderstorm to form one requires the realization of three criteria (all of them, not just one or two): low-level moisture (by that we typically mean in the near surface or boundary-layer, although some storms are what we call 'elevated'), instability and a trigger to lift the air to its level of free convection (examples of triggers include surface heating, fronts, outflow boundaries, drylines etc.). These criteria are, not surprisingly, most often met over the continental tropical areas. In fact, research has shown that the the most intense thunderstorms on the planet are likely found over Argentina and the southern Great Plains of the USA. I can attest to this as someone I work with told me about how a Lear jet flying into one of the storms stalled on account of the incredibly strong updraft-- we are talking updraft speeds of 50 m/s. Now for severe weather one either requires really strong buoyancy (difference in temperature between the storm's updraft and the surrounding ambient air) and/or vertical wind shear. The wind shear has a two-fold affect on updraft-- it can organize the upraft and separate the updraft and downdraft, also it can induce non-hydrostatic pressure perturbations in the storm which can cause the updraft to accelerate. Thermodynamically, one can increase the amount of buoyancy by increasing the low-level moisture and/or by increasing the lapse rate of the environmental air. The biggest bang for you buck though in this regard is to increase the low level moisture. Now this can all be explained using theory. The moist-static energy (MSE) in the low levels is given by: MSE = gz +CpT +qL (1), where g is the gravitational constant, z the height, Cp the heat capacity of air, T the air temperature, q the specific humidity or water vapour mixing ratio, and L is the Latent heat of vapourization. Because L is such a huge term, the moisture really dominates the MSE of the air. Now a metric that is used to quantify the amount of buoyant energy in the atmosphere is the convective available potential energy (CAPE). CAPE is simply the vertical integration of the positive temperature difference between a parcel rising along the moist adiabat and the corresponding ambient air temperature between cloud base and the equilibrium level. It can be shown that the maximum updraft in a storm is given by: Wmax = (2*CAPE)^0.5 (2), Now this is a theoretical value and it ignores the decrease in the updraft strength because of entrainment of cooler/drier air into the updraft and the reduction in of updraft strength by water loading of the precipitation and other factors. Empirical observations have found that observed Wmax values are closer to 0.6-0.7 of the theoretical value. The important part. Crook (1996) showed that by manipulating equation (1)increasing the low moisture by 1 g/kg increases the CAPE by 2.5 the amount as a 1 C warming of the low-level air would. So changes in near surface specific humidity of 10% or so of typical background values can have a huge impact on the buoyancy available to a storm, and in turn the maximum updraft strength-- as found by the papers I cited in one of my posts above. Increasing low-level moisture also has another important factor, it increases the liquid water content of the updraft. For hail to develop one, in basic terms, requires strong updrafts, long residence time in the updraft (typically a longer-lived updraft), and relatively high liquid water content. As the aforementioned discussion has shown increasing the low-level moisture increases the buoyancy (i.e., updraft strength), and the liquid water content of the updraft. For a hail embryo to grow into a large stone it needs to reside in a strong (moist) updraft for a long period of time, so an organized updraft helps, and that is oftentimes (but not always as shown below) where the vertical wind shear comes into the picture. So the short of it is that increasing the low-level moisture is likely to increase the chances for more intense/severe thunderstorms, and perhaps larger hail too. Work by Botzen et al. (2010) predicts that: "Extrapolations of the historical relations between hailstorm damage and weather indicators under climate change scenarios project a considerable increase in future hailstorm damage." But what about the vertical wind shear that is supposed to decrease (note that they are not predicting it will go away) over the mid latitudes as the planet warms? Well, as the research has shown, the impacts of less wind shear are offset by the increase in CAPE. Additionally, strong vertical wind shear is not a requirement for extremely large hail. Consider this recent example from Kansas, where they had > 5 cm diameter hail on 2 July 2011. The sounding below shows that the low levels were very moist (dewpoints > 20 C), the CAPE was also near 3400 J/kg, see here. The only problem was the stable air between 900 and 800 mb (aka a capping lid)-- that had to be overcome to tap into the huge convective available energy. Note the relatively weak winds in the lowest 6 km (0-6 km AGL wind shear is often used to quantify the bulk wind shear), suggesting relatively weak vertical wind shear. To cut a long story short the capping lid was broken and this was the result:
[Source]
Hail with a diameter of near 7 cm. The huge CAPE on this day was clearly critical in permitting giant hail to be produced in an environment with relatively-low wind shear, and this case is by no means an outlier.
And a closing, but important, note on wind shear. Research has shown (see for example the work by Markett and Allen (2003)) that the precipitation efficiency of thunderstorms increases as vertical wind shear decreases. So in the future we could see a higher incidence of torrential downpours from storms having higher precipitation efficiencies arising from any decrease in wind shear. Hardly a plus.
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Mark Harrigan at 15:31 PM on 6 July 2011A Detailed Look at Renewable Baseload Energy
Oops - that's dialogue of the deaf!! under my definition of "The Problem". DOH!! -
Mark Harrigan at 15:28 PM on 6 July 2011A Detailed Look at Renewable Baseload Energy
@tom #145 and all the above Tom with due respect I do not think comments about courtesy or otherwise are helpful. I did not say anything discourteous (or if I did I apologise) My post at 142,was challenging some of your logic about mine deaths (which I think you acknowledge) and also taking issue with your characterisation of my comments about Nuclear being CO2 free in operation by which I thought was clear meant when it is in operation providing power (which is an indisputable fact) But let me pick up on some of your further points (especially at #150) which I think are very pertinent and see if I can take them further? @BDD this is I think relevant for your points too as I agree the post at #159 cannot be ignored (I can't get your link at #154 to work on the critique). This appears to be the problem that Britain is grappling with (and I suspect Australia is about to have to contend with) and I think is a real example of everyone pushing a particular barrow. I don't have the answers but maybe I can add some thoughts? We can all argue till the cows come home about the exact Nuclear CO2 life cycle emissions and safety. I think (please correct me if you disagree) that we can all agree that what matters is the comparison? If we compare nuclear with coal it wins hands down on both safety and emissions - no matter how you calculate them. So in my opinion nuclear displacing coal is a "win" If we compare nuclear with renewables the situation is somewhat more vexed. (for the purposes of this post I'll focus only on those renewables such as Solar PV, Concentrated Solar Thermal (CST) and Wind all of which have almost no geographic limitations in application) On Safety I don't want to argue the toss about someone else's data showing nuclear to be more or less safe than renewables or more or less CO2 emissions - it probably comes down to whose figures you accept and, let's face it, both the nuclear industry and the renewables industry have axes to grind and this will bias their data and views accordingly. My own personal opinion is that it would be hard to argue conclusively that renewables are inherently less safe than nuclear. I stand by my comments on risk and hazard above for nuclear at #135 and #142. The risk is tiny but the hazard is huge So score a win for renewables on safety but not a slam dunk? On Emissions So what's the situation with CO2 emissions of nuclear versus renewables? Tom makes I think the relevant points in the last paragraph of his post #145 When they are producing power it's probably a scoreless draw? On the life cycle issue they should be about equal on plant fabrication and nuclear ought to lose a peg or two on the fuel cycle issue. So score a (minor) victory to renewables on that one? But with renewables the issue comes down to what today is still an incontrovertible fact. A renewables plant by itself simply cannot meet reliable 24/7 baseload demand. The only available solution to this involves backing up renewables with CO2 producing alternatives. A problem nuclear does NOT have score a decisive victory for nuclear on that issue The Problem If you broadly accept my characterisation above then this describes pretty well for me at least what I meant in my earlier posts about the world being full of lesser evil choices. So how to pick the lesser evil? This is where I think the real problem lies that we need to solve and until we do there will continue to be a debate between nuclear and renewables advocates that too often descends into a dialogue of the death. The article that spawned this thread makes a case for getting round this real renewables problem by (my characterisation) a widely geographically dispersed generation "utility" linked together in a smart grid supported by rapid response gas/biofuel turbines to handle the "unreliability" issues of any given renewables plant. In principle this sounds feasible but the reality is we don't know as it has not been tested. The other way around this problem would be for renewables to improve their reliability. The only serious contender for this is surely CST. But it isn't viable today. But now here is the problem and where I think the wishful thinking on the part of renewables advocates lets them down. It is simply not feasible to move to 100% renewables today without considerable technical, commercial and social risk. And I don't want to ignore the real problem of nuclear hazard So how do we get from here to there? (there being the wonderful CO2 free emissions environment of future power emissions) and within our limited budgets? A Part Answer? There's no magic answer but I think we must do several things. First because I think there is no certain answer we should not bet on a single approach. So nuclear by itself is NOT the answer (and in any event won't fly politically) but neither are renewables. Whilst I don't accept BDD's limitation of 30% as being forever the fact is right now renewable are a whole lot less than that and if we don't want the lights to go out won't be higher anytime soon. I suggest the following (though not in any order of importance) 1) Invest in a realistic test of Mr Diesendorf's plan - the idea has merit - to what degree can we make it work? That implies some work on the grid which is wise 2) Replace aging goal with latest technology Gas (it's more expensive but it works, has substantially lower emissions than today and can be part of 1 ) 3) Pour more investment into CST reliability. 4) Because none of the above can happen quickly, don't take nuclear off the table anywhere but require any new nuclear proposals to be subjected to rigorous overview and assessment. 5) because of all the above Coal is going to be around, whether we like it or not, for a LONG time globally (just look at china) we need to continue to develop sequestration or other clean coal alternatives Summary Most of all I wish we'd stop arguing about alternatives as if it's one or the other. I can't see ANY way forward except putting a whole lot of effort into ANYTHING that looks promising. We should rule nothing out if it can contribute. We can use Carbon pricing (tax) to price higher emissions out of the market over time and we can use incentives (direct investment, accelerated depreciation, tax discounts) to try and get alternatives off the ground. (Direct investment for early stage, accelerated depreciation for capital requirements on large scale implementations of lower CO2 plans and tax discounts for more mature low CO2 operations). Okay - now tear me to pieces! :) -
Bern at 15:26 PM on 6 July 2011Over the tipping point
I delved into the comments over at The Drum... and now my head hurts! Comments about how arctic ice doesn't affect solar heating during the arctic winter; equating "models have uncertainty" with "models are completely wrong"; and the best one of all, quoting WUWT as an authoritative source of scientific information! That one also linked a graphic showing total global sea ice area, claiming it doesn't show any decrease. I tried to post a comment that the graphic in fact clearly shows a decline of at least 2 million km2 over just the last 30 years, which is an area as large as NSW, Victoria, and Sth Australia put together, but that hasn't made it through the ABC moderators yet. -
dana1981 at 15:25 PM on 6 July 2011Glickstein and WUWT's Confusion about Reasoned Skepticism
Don't worry Chris, all that warming is still just due to magical natural cycles. -
Stevo at 15:18 PM on 6 July 2011History Matters: Carbon Emissions in Context
daisym @7 Isn't mitigating the effect of sea level rise, ice cap melt, extreme weather events, agricultural losses and population displacement a good enough swag of benefits fow you? -
scaddenp at 15:15 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
Norman, when you are talking about "cycles", then there needs to be a clear distinction between unforced cycles, which have no external driver, and forced changes. ENSO and thus any downstream influences is example of unforced cycle. The interesting question is whether there is any evidence for unforced cycles with periods longer than 30 years. These are postulated - notably Tsonis and Swanson. However, other supposed "cycles" are more likely forced by variations in TSI and aerosols. On top of that, is the question as to whether warming increases the severity of weather effects within the normal cycles. La Nina's now are warmer than El Nino's of decades past - what does that do to weather? So merely saying that there has been periods of drought,storms, etc in the past is uninteresting. The postulate is that when there are extremes, then these are on average worse/more frequent etc. The most robust prediction would be about severe precipitation events and the Min et al paper, and the papers on flood events in IPCC would both appear to bear that out. I reiterate though that it is consistent with predictions, not "proof". Now 2010 events might indeed be linked to natural cycles but the severity of them is may be increased. -
Chris G at 14:42 PM on 6 July 2011Glickstein and WUWT's Confusion about Reasoned Skepticism
Umm, from Watts' paper: "... no matter what CRN class is used, the estimated mean temperature trend for the period 1979-2008 is about 0.32ºC/decade." Did I read that right? That rate is slightly higher than the GISS US surface rate, ~0.30ºC/decade, over the same period. He is co-author of a paper that contradicts one of his main themes, that warming is not really happening? I know this is only US surface station data, and not accounting for lag, or getting too particular about logs, but if he says we are getting 0.32/decade out of ~335 to 380 ppm, would that not put Watts himself in the category of 'warmist'? -
Norman at 14:20 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
scaddenp @ 245 "I would say that you are making the hypothesis that there is unforced cycles in the weather pattern and these alone are enough to explain weather. An alternative hypothesis which doesnt require unexplained cycles is to use existing physics and postulate that these are result of global warming." Good point, my objection is that when I go searching for articles on past climate (and I have only hit the tip of the iceberg) I see cycles and no strong evidence (except temperature graphs) that climate (long term weather patterns in a specific region) is shifting to a new more severe pattern because of forcing caused by warming. Here is another example. Most the time I post these I am accused of cherry-picking. It would be a valid point if it was just one article. But when you find numerous articles with much the same evidence, I do not know how the cherry-picking charge remains valid. Precipitation patterns for Mid-Atlanctic region. Look at the graphs. They show cycles. I can get more. Maybe I should just compile 10 or 20 links on one post that show cycles and when going back further in time, the extremes are no longer that disturbing as for some reason this extreme pattern was able to form in a non globally warmed world. At this time I plan on researching Dikran Marsupial's concept that the proof of Global Warming being a driver in extreme weather is the frequency of the extreme events. I have been focused on intensity of events. Next study is to see if the long term historical record indicates extreme patterns are taking place more often than they did in a cooler world.Response:[DB] "when I go searching for articles on past climate (and I have only hit the tip of the iceberg) I see cycles" and "Look at the graphs. They show cycles."
This becomes tiresome. Seeing "cycles" without proposed physical causatives mechanisms to explain them is little different than numerology/superstition or tilting at windmills. Your preconceptions are blinding you, despite the able help of some of the august contributors to this thread. Eg., you can't see the forest due to all the trees in your way.
Please refer back to the OP for this Dr. Masters quote:
"A warmer planet has more energy to power stronger storms, hotter heat waves, more intense droughts, heavier flooding rains, and record glacier melt that will drive accelerating sea level rise. I expect that by 20 - 30 years from now, extreme weather years like we witnessed in 2010 will become the new normal."
and this cited by Dr. Masters:
"those who deny a human-caused impact on weather need to pose a viable mechanism of how the Earth can hold in more energy and the weather not be changed. Think about it."
Emphasis added (to both quotes); that last bit is good advice. As for this last bit from your comment:
"I can get more."
Please don't. You don't want to accept the premise of the OP, that we may be witnessing the human-caused impacts on weather now, and that extreme conditions of the present may be the new norm in 20-30 years; we get that.
But unless you can prove that these extremes currently being experienced are NOT due to human-influence and that you have physics-based hypothesis' supplemented by solid statistical analysis to back up your contentions, then you are just being contrarian and most here will no longer waste any of their valuable time trying to help you gain understanding.
-
Norman at 14:03 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
Dikran Marsupial @ 257 I am wondering what you are getting at by bringing up chaotic systems. Looking at the little animations of the pendulum by DB and Riccardo. Maybe you are pointing out that if you increased the energy of this system (made the pendulum swing faster), the frequency of the various cycles would increase (based upon your point that the return rate is a way to measure extreme events: "Extreme events already have a good statistical definition, namely the return period, for instance an event might have a return period of 100 years, in laymans terms, a "once in a hundred year event". This definition has the advantage of automatically taking into account the skewness of the distribution.") My question, if that is the case, is the 0.8C temp increase and 4% moisture increase of the atmosphere enough of difference to be noticeable? That is the conclusion of Jeff Masters of which this thread is about. He belives the extremes of 2010 and 2011 (not anyone event but the aggregate of all the events) are enough to determine the pendulum is moving faster. -
Mark Harrigan at 13:45 PM on 6 July 2011Over the tipping point
I wish Beyond Zero Emissions were realistic - but it isn't, as this critique shows. beyond zero critique Wishful thinking won't solve our problems. We need to confront the realities of renewables not (yet) being ready to provide the full answer and focus on what needs to be done to get them there while we put in place bridging solutions. It would be good to see Mark Diesendorf's plans Baseload renewable plan put to the test somewhere with a "utility" that uses a mix of wind (with intelligent predictive anemometering) and solar thermal supported by gas/biofuel turbines (or similar) to manage the variability Or perhaps there are other variations on this theme? A plan to make a relatively modest investment as a sort of "demonstrator" seems smarter to me than trying to push a whole of industry transformation plan that lacks credibility and won't get support because of entrenched interests and easily attacked heroic assumptions. We need to put up proposals that acknowledge we don't know all the answers and need to find out rather than grand schemes that purport to "fix" the problem. -
Norman at 13:44 PM on 6 July 20112010 - 2011: Earth's most extreme weather since 1816?
Tom Curtis @ 258 I do not think you are correct on this one about severe thunderstorms. I have been checking around for the type of thunderstorms that dominate the ITCZ. I am not sure your lightning proxy is totally valid for detemining the severity of a thunderstorm when dealing with the different kinds (like comparing apples to oranges). No doubt an air-mass thunderstorm with more lightning strokes is more severe than an air-mass thunderstorm with fewer strokes. But it would not be as severe as a super-cell thunderstorm. From article on the ITCZ: "The ITCZ is formed by vertical motion largely appearing as convective activity of thunderstorms driven by solar heating, which effectively draw air in; these are the trade winds.[2]" Article source of above quote. A quote from another article: "Supercells are the most powerful thunderstorms. By their definition, supercells are always severe. Supercells are responsible for a disproportionate amount of damage and casualties." Article source for supercell quote. The air mass storms can be intense for short periods of time but not nearly as long as a supercell. Another quote from above article link: "The air mass thunderstorm is a common and usually non-severe phenomenon that forms away from frontal systems or other synoptic-scale disturbances. They form where moist and unstable conditions exist in the atmosphere. Air mass thunderstorms are usually produced in areas of very little vertical shear. As a result, the threat for severe is small. When they do reach severe limits, the thunderstorms may produce brief high winds or hail which develop because of high instability. These storms are know as pulse severe storms. Although several storm cells can develop, each individual cell lasts about 30-60 minutes and has three stages." Another article on Thunderstroms similar to the others. Article on thunderstorms. And yet another article. Air Mass Thunderstorms are usually weak. From what I was able to find out about thunderstorms, I cannot agree with your concluding statement. "Consequently, every element of "severe" thunderstorms, with the possible exception of tornadoes, is expected to increase globally with a warming climate, though not in all regions. That is, we can expect more damaging winds, more large hail, more flash floods, and more lightning strikes. And tornado frequency is also predicted to increase, though I can't lay out the logic of it the way I can for thunderstorms in general." The following information just about goes opposite of your concluding statement. Most severe storms in US occur in spring and early summer. -
sentient at 13:12 PM on 6 July 2011The Last Interglacial - An Analogue for the Future?
Philippe Chantreau I tend to find that speculating on things which have happened is decidedly more comfortable than speculating on things which have not happened yet, as in model speculations. Especially when one is frequently engaged to dig into the opposition's modeling in toxic torts and insurance litigation related to same. Fascinating work, by the way. On Dansgaard-Oeschger oscillations. There were 24 Dansgaard-Oeschger oscillations between this interglacial, the Holocene, the interglacial in which all of human civilization has occurred, and the last one, the Eemian, and yes, we were indeed there as our stone-age selves. D-O oscillations average 1,500 years, and have the same characteristic sawtooth temperature shape that the major ice-age/interglacials do, a sudden, dramatic, reliable, and seemingly unavoidable rise of between 8-10C on average, taking from only a few years to mere decades, then a shaky period of warmth (less than interglacial warmth), followed by a steep descent back into ice age conditions. Each D-O oscillation is slightly colder than the previous one through about seven oscillations; then there is an especially long, cold interval, followed by an especially large, abrupt warming up to 16C (a Bond cycle). During the latter parts of the especially cold intervals, armadas of icebergs are rafted across the North Atlantic (Heinrich events), their passage recorded reliably by the deep ocean sediment cores which capture the telltale signature of these events in dropstones and detritus melted out of them. D-O events may indeed be caused by changes in oceanic circulation. Indeed many workers agree with this paradigm, however it would seem as many suggest other mechanisms, however I tend to agree with Sole, Turiel and Llebot (quoted in my first post) when they conclude "However, a cause for this regular arrangement of cycles, together with a justification on the abruptness of the warming phase, is still absent in the scientific literature.” Then again, Michael Shultz, writing in PALEOCEANOGRAPHY, (VOL. 17, NO. 2, 10.1029/2000PA000571, 2002) states in the abstract "During this interval the spacing of the Dansgaard-Oeschger onsets varied by ±20% around the fundamental 1470-year period and multiples thereof. The pacing seems unaffected by variations in the strength of North Atlantic Deep Water formation, suggesting that the thermohaline circulation was not the primary controlling factor of the pacing period." Which would tend to suggest that not only may we really not know what causes them, but as also quoted in the initial post, T1 exhibits the same characteristic, and we still do not know exactly why the terminations occur. Yet again, we continue to discover that even on things which have happened, the science is not that particularly well settled. Evidence was early presented for the presence of D-O signal within the Holocene, which is best preserved. Bond et al (SCIENCE, VOL. 278, 14 NOVEMBER 1997) (the Bond the cycles were named after)state in their abstract: "Pacings of the Holocene events and of abrupt climate shifts during the last glaciation are statistically the same; together, they make up a series of climate shifts with a cyclicity close to 14706500 years. The Holocene events, therefore, appear to be the most recent manifestation of a pervasive millennial-scale climate cycle operating independently of the glacial-interglacial climate state. Amplification of the cycle during the last glaciation may have been linked to the North Atlantic’s thermohaline circulation." I think you are partially correct in that there is at least a probability that "Whatever else is "naturally happening" according to Sentient is bound to be profoundly affected." so long as we critically examine the term "bound to be". This, by definition, is speculation. Speculation about events which have not happened yet. We have mathematically guessed that it should happen, but that does not mean that it is bound to happen. Though it very well might. The evidence I presented in my first post suggests that at least in the B and C cycles of Sole Turiel and Llebot, "profoundly" does indeed figure in to the precautionary principle calculus. -
Dave123 at 12:21 PM on 6 July 2011OA not OK part 2: Thermodynamic duo
Doug, Are you going to use Rustum Roy's work as examples in this for the biological side of things? Anyhow good with the peanuts, but it may not carry the speed or extent to which individual atoms and molecules can move from one side to the other, while the numbers remain constant on each side at equilibrium. -
Doug Mackie at 11:56 AM on 6 July 2011OA not OK part 2: Thermodynamic duo
@4JosHag: 1) No simple K for this reaction as calcification is biological and multistep. 2) Yes, calcite and aragonite are different. We cover both of these later. Right now we are just getting a few basics straight. -
The Inconvenient Skeptic at 11:43 AM on 6 July 2011The Last Interglacial Part Two - Why was it so warm?
Steve and Chris, Since the answers are related I will address you both. Chris misses the point that the Earth's overall temperature is in phase with the seasons and not in phase with the TSI. That makes the Earth's temperature dependent on the seasons and not the TSI. If the Earth's temperature was in phase with the TSI the warmest temperature would ALWAYS take place within a month of the perihelion. That is not the case. The standard measure of the Earth's temperature is the atmosphere. Chris takes issue the the Southern Ocean and comments on heat capacity, but that high heat capacity simply prevents as much change in temperature. Therefore the Earth is coolest when the SH is in summer even though the Earth as a whole gets the most energy. The data on the Earth being warmest is from the CRU. Hardly a skeptical bastion. That leads back to Steve. If you look at the temperature spike of the Eemian it ramps up to the peak temperature ~128,000 years ago and then dropped as insolation peaked. The main vegetation peak could not have happened that quickly. The forests of the Eemian dwarf those of today. They could not have filled the void that quickly. Far more likely from the reconstructed temperature data is that the vegetation filled in and caused the temperature drop that happened ~126,000 years ago. The question is does the positive (albedo) or the negative (evapotranspiration) dominate. Here is your conundrum. You require a far more complex theory to explain what is simply explained by insolation. 14% extra summer energy is significant in the NH. If insolation is the correct answer, that causes significant problems for your current theory of global warming. Hence you must find an alternate solution and must discard the simple and most probable conclusion. You disregard the current climate data (NH summer causes warmer Earth by 4C) in favor of the far more complex and unprovable solution. The solution is readily available. The Holocene experienced ~10C temperature change with a 50 W/m2 change in 65N insolation. The Eemian experienced a 71 W/m2 change which is ~14C change in temperature. That would also be how much the temperature warmed up in the early Eemian according to the EPICA data. Northern Hemisphere Climate Sensitivity -
adelady at 09:56 AM on 6 July 2011A Detailed Look at Renewable Baseload Energy
BBD "Realistic projections must reconcile with a sharp increase in overall electricity demand over coming decades as the wholesale electrification of personal, commercial and public transport really gets underway. " I don't see this increase in overall electricity demand as inevitable. In fact, I'd see investment in negawatts expanding in parallel. A home or business building can be its own source of power using the grid as a battery. As long as the structure is progressively improved with more insulation and other retrofits, recharging electric vehicles should not draw more power than is provided - esp if the vehicles' batteries export power when required. A city with several thousand (or tens of thousands) vehicles should have access to a fair amount of power in those batteries. When we're talking about supplying power to established cities and communities, we must always remember that there's a huge benefit in investing in negawatts by upgrading structures for not much outlay. Combining this with import/export of power through a grid connected to other areas which don't suffer simultaneous loss of wind/solar input relieves a lot of the stress on the local system. -
Bob Lacatena at 09:40 AM on 6 July 2011Antarctica is too cold to lose ice
5, Steve, I'm not sure what your point is, but it's important to read everything, and not just stop when you find something you like. That's not what I'd call "skeptical." I have a lot more research to do, but after just a few minutes work... First, remember the report was released in 2007, meaning it was based on data compiled before then. In particular, however, the section you linked to includes these words:Further accelerations in ice flow of the kind recently observed in some Greenland outlet glaciers and West Antarctic ice streams could increase the ice sheet contributions substantially, but quantitative projections cannot be made with confidence (see Section 10.6.4.2).
Just a year later, a study found that ice lose in Antarctica was in fact accelerating: Antarctic is losing ice ‘nearly twice as fast as ten years ago’ In addition, I don't know what GRACE data was available at the time. The satellite was only launched in 2002, and some years would be needed to identify a trend -- a very serious and bad trend, it turned out. From NASA's GRACE pages:Gravity data collected from space using NASA's Grace satellite show that Antarctica has been losing more than a hundred cubic kilometers (24 cubic miles) of ice each year since 2002. The latest data reveal that Antarctica is losing ice at an accelerating rate, too.
At the same time, the numbers in the IPCC AR4 report do not seem to have used GRACE data at all (although they could have). They were instead based on models that apparently predicted mass gain in the Antarctic (if we are interpreting that table correctly). But it was based on model runs, and so limited by assumptions made in constructing the models. It would appear that the models then did not take into account what has since been discovered, and explained fairly clearly in the above post. Appendix 10.A: Methods for Sea Level Projections for the 21st Century -
BBD at 08:52 AM on 6 July 2011A Detailed Look at Renewable Baseload Energy
My views on renewables are shaped by the UK experience. As I said at the outset, the UK chief scientific advisor to DECC provides a rigorous assessment of what this will entail. In 2009, Dieter Helm wrote an article in the Times in which he said:Instead of a coherent, integrated policy, we have piecemeal support for particular technologies. Politicians want to be seen to be “doing something” for the various interested parties — especially for renewables and clean coal. So each gets its own set of supports. Take wind. Britain has one of the most expensive support packages in the developed world. Customers have to buy a proportion of energy from renewable sources, paying the usual price and a premium that the Government guarantees. And that has been doubled for offshore wind. The costs are far greater than conventional technologies, and make even nuclear look cheap. If, as a result, overall emissions were cut on a significant scale, it would at least meet the carbon objective. But because the wind does not blow all the time, there has to be back-up — carbon-emitting coal and gas. Next, take clean coal. It too has its own government support. Carbon sequestration (CCS) — storing carbon in the ground — will be subsidised by a new levy on customers — linked to the price of carbon in the European Emissions Trading Scheme. What the customer gets is not, however, just clean coal technology — they will support several large new coal stations, most of which will not have to store carbon emissions until 2025. We need coal now because otherwise we will be too dependent on gas — and to back up the intermittent wind. Now take nuclear. Unlike with wind power, customers are not obliged to buy it, and there is no special subsidy or levy. Nuclear is left to the market, but wind and clean coal are not. The result is a mess, driven by the dangerous combination of the Government choosing the winners and lobbyists trying to capture subsidies. For all the good intentions, the result will be high cost and low impact. Instead of starting with the cheapest ways of reducing carbon emissions, Britain has started with the most expensive. So far success has been limited: We not only pay among the highest bills for wind, but in Europe only Cyprus and Malta generate a lower proportion of their electricity from it. Old nuclear is closing, but new nuclear is unlikely to appear much before 2020, and coal will not come to the rescue any time soon. The result is more gas, and, but for the recession, real risks to the security of supply.
Helm, like MacKay is serious, and should be taken seriously. I recommend reading the rest - it's short. -
Steve Case at 08:49 AM on 6 July 2011Antarctica is too cold to lose ice
Chapter 10 Figure 10.7 in the IPCC's AR4 shows negative numbers across the board for the contribution of the Antarctic Ice sheet to Sea level rise which would indicate that Antarctica is gaining ice. http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-6-5.html All the other numbers in table 10.7 are positive. -
JosHagelaars at 08:49 AM on 6 July 2011OA not OK part 2: Thermodynamic duo
@Doug Mackie, I appreciate the topic very much, but I hope you go more in depth later on. What is the value of the dissociation constant (pK) of this calcification reaction ? Is there a difference in pK for the two main forms of calcium carbonate, aragonite and calcite ? -
BBD at 08:04 AM on 6 July 2011A Detailed Look at Renewable Baseload Energy
JMurphy Perhaps we are losing our way. There is no doubt that nuclear and renewables are all low-emissions generation technologies. Lifecycle emissions profiles are relevant, but not decisive. We can argue all night about the details but what would be the point? I can only remind everyone that the EU is conspicuously committed to emissions reductions and to renewables, and is unlikely to use bad data that misrepresents the relative lifecycle emissions of nuclear, wind and solar plant. Which is why I provided the link to EU documentation. The essential question (as we are reminded by the moderator) is whether or nor renewables can actually deliver reliable large-scale baseload capacity sufficient to meet the needs of an industrialised economy. Realistic projections must reconcile with a sharp increase in overall electricity demand over coming decades as the wholesale electrification of personal, commercial and public transport really gets underway. The shift from gas (and to a lesser extent oil) to electricity for domestic heating is a major factor in the UK. No doubt it will be elsewhere. Here and elsewhere, an energy-hungry surge in urban AC is projected to manage increasingly extreme urban temperatures. And so on. Nothing I have seen on this thread demonstrates a plausible case for high-renewables scenarios as things stand, never mind over decades of increased demand. I wish it were otherwise, but we have to play with the cards on the table. -
Rob Painting at 07:55 AM on 6 July 2011Great Barrier Reef Part 1: Current Conditions and Human Impacts
John Bruno - I wonder how those researchers would react in the following situation: Say for instance Sweatman was feeling poorly; stomach cramps, nausea, headaches and a high fever. Off he trundles to the doctor (Bob Carter), who hasn't treated him before and isn't aware of his normal physical condition. Dr Bob Carter diagnoses and prescribes various medications. A week later he hasn't improved at all, so back he goes to the doctor. Dr Bob examines him again and, based on Sweatman's condition in the first visit, finds his condition hasn't deteriorated any further, whereupon he declares "You're in fine fettle Mr Sweatman!" I think that little analogy reflects the absurdity of the claims. And I hope none of your poorly informed colleagues make it into practicing medicine! -
BBD at 06:55 AM on 6 July 2011A Detailed Look at Renewable Baseload Energy
Moderator #153 I am now even more painfully embarrassed. Link. For the record here: The original head-face gaffe was both careless and unintentional. I fully accept your criticism wrt a poor choice of simile in a sensitive discussion. I apologise unreservedly to TC for the apparent slur. -
Tom Curtis at 06:44 AM on 6 July 2011A Detailed Look at Renewable Baseload Energy
JMurphy @155, Barry Brook cites a study by Bilek et al which shows whole of fuel cycle emissions for nuclear power as 60 gCO2e/kWh for light water reactors (10-130), and 65 (10-120) for heavy water reactors. The study quotes other studies using comparable methods to show 21 gCO2e/kWh (13 – 40) for wind, and 106 (53 – 217) for photovoltaics. Having now gone through the methodology, I can confirm that Bilek and all do cover all major inputs and make reasonable assumptions and methodological choices, so the 60 gCO2e/kWh looks like a reasonable figure from which to make comparisons. Brook makes the reasonable point "...for fast spectrum reactors like the IFR, it would be substantially lower, since we skip the mining, milling and storage steps", but does not comment on how much lower. Brook does not give a figure for how much lower, but from the report it appears missing those steps would save from 10 to 25% of emissions, giving us emissions of 60 gCO2e/kWh for old reactors, and 45 gCO2e/kWh for generation III and IIIplus reactors. These figures should be reduced for countries with primarily low emission power generation (as, of course, should the equivalent figures for renewable power). -
Patrick 027 at 06:32 AM on 6 July 2011The Planetary Greenhouse Engine Revisited
Re Michele - as the results of my simulation show, You're simulation was designed based on your assumptions; it doesn't show those assumptions to be correct. I think that if you continue to argue about the total radiative balance we could leak the true causes leading to actual temperature profiles (GH effect). I and others already did. You refused to accept it. Of course the radiation/evaporation also takes place on the way but it seems to be very tiny as its contribute to the lapse rate seems to be negligible: if it had a real weight the lapse rate of troposphere, e.g., would be always hyper-adiabatic, whereas we well know it is, at large scale, adiabatic or at least hypo-adiabatic. No. We've been over that. The lapse rate is in radiative disequilibrium; the troposphere has to have net radiant cooling. See Real Climate thread - June 2011 Unforced Variations. Aside that, it is undeniable that the atmosphere, by means of the temperature gradients, behaves as a scavenger which sweeps and collects The temperature profile shapes the radiant flux profile. There's no 'scavenging', 'sweeping', 'collecting', except in limited analogy; - the radiation just goes where it goes; it's emitted at higher rates at higher temperatures, at lower rates at lower temperatures; optical properties determine the rate of emission per unit volume or for a given temperature; they also determine the rate of absorption per unit volume for a given incident flux. Radiation from all levels can reach space in so far as the intervening layers are transparent - but they can't be transparent if they can also emit, hence, greater fractions of what are emitted from higher layers can reach space. If you can't be bothered to distinguish reality from fantasy, I can't help you. I'm done.
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