Due to the Halting Problem, reliable automated detection of malware is theoretically impossible. This doesn't mean antivirus software is useless, but it is simply inevitable that it will miss stuff. Human security experts will always need to be involved, but humans are expensive, slow, and make more mistakes compared to machines - so it's inevitable that we'll miss stuff, too.
The best long-term route to increasing computer security for society seems to be limiting the capabilities of a program's execution environment to a less dangerous subset of the full range of possible capabilities via air gaps, sand boxing, fine-grained permissions, etc. However, between the continual efforts of three-letter agencies to poke holes in the sand boxes, and the universality of the critical PEBKAC vulnerability, I think the internet is doomed to remain a dangerous place until Judgment Day comes.:-(
If you don't think the software matters, you don't understand big-O notation.
No matter how advanced the software is, it cannot overcome hard theoretical limits on complexity. For example, it has been mathematically proven that no general-purpose sorting algorithm can ever have a time complexity better than O(N * log(N)) on a Turing Machine; even "real AI" cannot change that. This also means that any algorithm which includes such a sort - even just one - can never be faster than O(N * log(N)).
60 microseconds (his allotted time per generation) is a very short span of time: it's not even enough to stream the full source code of a really large program (such as the Linux kernel) through a single CPU core, let alone actually do anything with all that data.
And if you think major breakthroughs in the design of computer hardware are impossible, you're just not paying attention.
Moore's Law (which has officially ended already, by the way) has brought us exponential improvements in throughput, primarily (but not exclusively) through increasing parallelism in the past ten years. However, 60 microseconds is such a short period of time that latency becomes a problem, as well. Latency within the CPU and memory has not improved much at all in the past ten years, because it is limited by the speed of light.
Any estimate for this task is fine considering it'll take several generations of both Moore's Law and software engineering to get to the stage that the computation is even feasible.
Neither computer software nor computer hardware is magic. There are known theoretical limits to how fast either can get, barring a fundamental physics breakthrough or (possibly) the advent of a stronger computational model than the Turing Machine.
Quantum computers are likely to improve things on the software side - but only for certain algorithms; many would be no faster on a quantum computer than on a standard Turing Machine. On the hardware side, latency in quantum computers will still be limited by the speed of light.
10 minutes is an utterly absurd estimate for this task, to anyone who understands how modern computers actually work. Completing even one generation in that time span would be an amazing achievement. 10,000,000 is simply impossible, barring a major breakthrough in the design of computer hardware (regardless of how advanced the software used is).
Define 'much higher'? The areas I've been in where the sidewalk was right up against the road was always 25 mph or less.
The Los Angeles basin has places where the sidewalk is right next to a road with a limit of 45 mph or more.
As for 'right', well, the goal isn't to only hit pedestrians when they're following the rules, but to avoid hitting them as much as possible. Which means that you have to assume jaywalking, people pushing other people into the street, etc...
Yes. That's why I was surprised by your "25 mph" claim. I presume it's true (or close enough) wherever you live, but it certainly isn't where I am.
What utter nonsense. Lithium is not burning via some Li + Li --> Li_2 reaction in the absence of other elements.
That is true, but in the case of Lithium batteries the required oxidizer is an essential component of the battery itself. No outside chemical input is required for the battery to burn or explode; the military has investigated the use of lithium batteries as improvised grenades.
The problem with water ingress would not necessarily be that it serves as a concentrated oxidizer, but rather that it may short out the batteries, causing sufficient local heating to trigger a self-sustaining chain reaction within the batteries themselves.
In numerous studies it has been found that stopping is pretty much the universal solution
The shift toward electric drive trains (whether hybrid, or pure battery powered) may help with this: the combination of regenerative and mechanical breaking shortens the emergency stopping distance meaningfully, when sufficient traction is available. In particular, the recently unveiled Nikola One hybrid-electric tractor design claims to halve the distance.
Given a sidewalk where people can unexpectedly enter the road, the speed limit should be around 25 mph
Perhaps you mean "where people have the right to unexpectedly enter the road"? Because there are lots of places (in the USA, at least) with much higher speed limits than that, and no barrier - or even strip of grass/trees - between pedestrians and the road.
the new ShenWei (roughly translates to The Wrath of God in Mandarin)
Umm... what? Got an official source for that translation? Because that sounds like propagandistic nonsense to me.
1) China is an officially atheist state, and on that basis alone I doubt they would choose such a name.
(China did have an ancient tradition of monotheism, but it ceased to be the dominant religion a long, long time ago. Moreover, in ancient times it was closely associated with the position of the emperor, considered an enemy of the people under Communism. In modern times, it is associated with Christianity and Islam, both regarded as dangerous (albeit in somewhat different ways) foreign ideas by the government.)
2) A naive effort using Google translate suggests that the actual translation is something more like "Extend Prestige" which sound far more plausible, coming from a (nominally) Communist government. Translating the other way, starting from the English "The Wrath of God", doesn't yield anything remotely resembling ShenWei.
If you have an external medium to move (air), you want a low exhaust velocity (about the same as the aircraft speed).
You seem to have skipped the most important parts of my posts. Even a jet that burns more fuel per unit thrust, can still be more efficient at actually moving the airplane from origin to destination, because the higher top speed means that it doesn't need to sustain that thrust as long to complete the journey.
There is a little thrust from the jet exhaust, but that is low efficiency because its velocity is so much higher than the aircraft efficiency.
Subsonic turbofans typically have a bypass ratio somewhere between [5:1] and [10:1]. Taking into account the mass of the fuel being mixed into the core air stream, this means that you are ignoring between [21.2%] and [10.5%] of the mass flow.
Moreover, that portion of the mass flow is ejected at considerably higher speed, so you are actually ignoring an even greater percentage of the thrust - perhaps [30%] to [15%]? Maybe more at cruising speed, given that the rate of thrust lapse is higher for the fan output, than for the core. (My quick search didn't turn up any hard numbers on the speed of the core exhaust, specifically.)
That difference in thrust is of the same magnitude as the shaft power efficiency difference for your turboprop example, and must not be neglected if you want the comparison to be meaningful.
In turbines the maximum combustion temperature has to be within the operating range of the turbine blades.
Finally, that one random turboprop you picked as the point of comparison isn't very efficient compared to a lot of modern turbines. Hard numbers are not easy to find, but even the 1966 [Rolls-Royce/Snecma Olympus 593](https://en.wikipedia.org/wiki/Rolls-Royce/Snecma_Olympus_593) had a thermodynamic efficiency of [43%]. This beats any of the airplane engines in your shaft power comparison.
While the Concorde was an exotic, bleeding-edge design, materials science has advanced considerably since then, and modern high-end turbines have higher pressure ratios and peak temperatures. If you want to see good examples of this, you need to go look where the money is: large passenger planes (Boeing 777) and cutting-edge military aircraft (F-22 or A400M), not general aviation or small regional passenger planes.
Building a supersonic electric airplane is certainly ambitious, but far from impossible.
On the other hand, building a practical and economically useful supersonic electric airplane with current technology is impossible. Hydrocarbon-powered supersonic planes still run out of fuel quickly, even after hundreds of billions of dollars of investment in the concept. A battery-powered model will certainly not have useful endurance.
Your analysis assumes that the purpose of an airplane engine is to produce shaft power (the subject of the Wiki article you linked). This is incorrect, especially for jets (which ought not to be confused with turboprops).
The true purpose of an airplane engine is to add kinetic energy to the airplane. The effectiveness of jets at this task relative to piston-driven propellers is far higher than your shaft-power based comparison would suggest.
First, because jets (unlike turboprops) are intended to derive a significant portion of their thrust directly from the high-velocity exhaust stream, like a rocket. In a turbojet, shaft power is mostly used to drive the compressor. While turbofans are more similar to propeller engines in this respect, they are still distinct in that they deliberately leave a lot of energy in the exhaust stream.
Thus, for a given shaft power rating a jet will produce much greater thrust than any propeller based system. Moreover, the higher the ambient airspeed, the greater the proportion of thrust that is derived from the exhaust stream, rather than the fan. Ignoring the exhaust stream when analysing the fuel efficiency of a jet engine will yield wildly incorrect results for turbojets at any speed, and for turbofans at cruising speed.
Second, because sustaining the same amount of thrust at a higher airspeed adds linearly more kinetic energy to the aircraft. Consider:
Prop: A 10 ton airplane is cruising at [125 m/s], maintaining constant altitude and speed using a piston-driven propeller exerting [20 kN] of force. The kinetic power imparted to the airplane is therefore [20 kN] * [125 m/s] = [2.5 MW].
Jet: A 10 ton airplane is cruising at [250 m/s], maintaining constant altitude and speed using a jet exerting [20 kN] of force. The kinetic power imparted to the airplane is therefore [20 kN] * [250 m/s] = [5 MW]. (Yes, a jet can sustain a higher speed using the same amount of thrust - the plane just has to fly higher, where the air is thinner and creates less drag.)
At the same effective specific impulse (Isp, a better measure of jet efficiency than the BSFC you linked), a jet can achieve greater practical fuel efficiency (fuel burned per unit distance) than a propeller plane, simply by flying faster and higher. This effect is very large - enough so to overcome significant differences in Isp as compared to a prop plane.
TL;DR: The purpose of a jet is to move the airplane, not to spin a shaft. It's efficiency should be evaluated on that basis.
The Russians plod on with steam-era rockets, which are practical but are a fallback to pre-V2-technoliogy.
That's a pretty ridiculous and insulting exaggeration.
Up until SpaceX announced the Merlin 1C less than a decade ago, Russia was the unquestioned leader in Kerosene-Oxygen engine technology. There's a good reason that United Launch Alliance selected the Russian RD-180 for the Atlas V. More generally, Russian technology is competitive with (I do not say equal to) that of the West in many areas, such as rocketry, jet engines, airframes, avionics, weaponry, etc.
Dismissing all of that as "pre-V2 technology" is nonsensical propaganda: facing off against a military limited to actual pre-V2 tech, the Russian military would absolutely dominate.
I think the biggest problem is that the low altitude environment is pretty hostile - waves, birds, floating obstructions etc. In principal though they are more efficient than airplanes.
That, and the high air density at sea level requires a lower cruising speed to be efficient. The military, who funds much of the world's aerospace research, values speed more than efficiency. (They are only interested in efficiency mostly because it limits range, which is also important to them.)
Jets are actually less efficient, but the lighter weight more than makes up for that.
"Efficient" is a meaningless term, unless one specifies which two metrics are being compared.
Jet engines generally have considerably better thermodynamic efficiency than piston engines: they convert a larger percentage of the chemical energy in the fuel into mechanical energy, and waste less in the form of unused heat and partially burned exhaust.
They have inferior thrust efficiency at low speeds (less thrust is generated per unit fuel per second), but superior thrust efficiency at high speeds (trans-sonic and up). In fact, normal piston-driven propellers don't produce any (net) thrust at all at the normal operating speeds for many jets, and so are perfectly inefficient.
With a good flight profile, burning through fuel faster in order to fly faster generally does not hurt the plane's overall fuel efficiency, as measured in fuel units burned per unit distance. What it does do is complete the journey faster, freeing the vehicle and its passengers/cargo to move on to another task, thus improving economic efficiency. The only reason that airplanes don't just fly as fast as they possibly can, is that drag increases sharply for airspeeds above Mach 1.
TL;DR: Jets are used on nearly all large planes because they are more efficient in the metrics that count, not just because of their weight.
with a significant percentage of the need for lift and thrust cancelled by positive-buoyancy gas cells,
As has already been pointed out, buoyancy cells reduce the need for lift, but increase the need for thrust at a given speed. The square-cube law favours larger airships for lower drag.
most or all of the electricity coming from photo-voltaic cells covering the upper hull/fuselage and lifting/control surfaces.
The power that can be collected via solar cells scales with surface area, but the power required scales with mass (and therefore volume). Thus, the square-cube law also favours smaller airships for greater power-to-weight, if solar power is the primary energy source.
lifting-body design and surface-effect-cushion aerodynamics at just a few meters altitude above the sea, possibly, rather than lifting to a multiple-kilometers altitude?
The volume of buoyancy cell required to lift a given mass increases exponentially with altitude, so a low cruising altitude is desirable to keep the size reasonable. However, deliberately cruising at "just a few meters altitude" is a very bad idea: many of the worst airship accidents in history were caused by the wind suddenly pushing on the vehicle's massive surface area in an unexpected direction, easily overwhelming the engines, ground handlers, etc. You need to cruise at a high enough altitude that a single unexpected down draft doesn't kill everyone on board.
If a ticket from London to Tokyo or Singapore to LA took two days but cost around the $100USD price point or even lower...
I don't think this will ever happen. At least in the USA, two nights in a cheap motel costs at least $100 (often much more). It seems safe to say that a flying motel will never be cheaper than one built on the ground. Also, the need to provide overnight accommodations, and room for people to stretch their legs, imposes a large weight penalty on passenger airships compared to airplanes.
This is a fundamental reason that airships are unlikely to replace airplanes for general passenger service: life is expensive, and people's time is valuable. The richer the world gets, the less likely that a new, slower form of long-distance air travel will catch on, even if it is more energy efficient.
Those concerns don't apply to cargo though, so the idea is still very much worth exploring.
I'm basically typing a 'stream-of-consciousness' here as I consider the problem.
Watts' headline is based on comparing Scenario A to observations but in reality Scenario B is closest to reality but slightly higher than observations.
Hansen's scenario A has mankind's CO2 output rising exponentially at 1.5% per year (see the second paragraph on page 5 of the original paper) since 1988, but the actual rate of increase has been substantially higher - about 2% per year based on this graph from the Union of Concerned Scientists.
Hansen's scenario A has the average global surface temperature rising over 1 C between 1988 and 2014 (see figure 3 on page 7 of Hansen's paper). The actual temperature rise during that period was somewhere between 0.2 C and 0.4 Cdepending on which of the many data sets you believe.
Since Hansen's basic hypothesis was "more CO2 emissions = faster warming", scenario B certainly was not "closest to reality"; in fact none of his scenarios is at all realistic, since (empirically) he completely failed to accurately predict the relationship between CO2 and temperature - which was the entire point of his paper.
Hansen's model also had too high a value for climate sensitivity (around 4.2 IIRC) while subsequent research came up with a value around 3.2.
[1 C] * [3.2/4.2] = [0.76 C], which is still about double the observed temperature rise.
There is a reason that so much effort has been invested by alarmists into trying to make excuses for the lower-than-predicted temperatures - it's because temperatures have been lower than they predicted! That's still true, even if you use more recent models with less dramatic sensitivity to CO2.
There are already cities like Miami and Norfolk, VA that are flooding in areas when the king tides occur.
Don't be ridiculous - Miami (1.8 m) and Miami Beach (1.2 m) were both built practically at sea level to begin with; they have always been highly vulnerable to flooding since their founding. The sea level has only risen perhaps 0.25 m since that time, whereas the natural range of tides + waves + storm surges is 5+ m (especially in hurricane country!).
Norfolk, Virginia is likewise built at such a low elevation (2.1 m) that flooding problems are inevitable, although in their case the founding was long enough ago (1682) that the danger may be due to subsidence and pre-AGW sea level rise, rather than it originally being an obviously bad location.
If you look closely that EPA graph does show some acceleration.
Hardly, unless you want to count the little bump at the end which is too short to be statistically significant given how chaotic the climate system is.
In the Guardian article I think you misread "several meters" as "7 meters".
No, the original paper contains numerous statements along these lines: "Sea level reached 6–9 m in the Eemian, a time that we have concluded was probably no more than a few tenths of a degree warmer than today."
The introduction also makes reference to an earlier paper: "This uncertainty is illustrated by Pollard et al. (2015), who found that addition of hydro-fracturing and cliff failure into their ice sheet model increased simulated sea level rise from 2 to 17 m, in response to only 2 C ocean warming and accelerated the time for substantial change from several centuries to several decades."
Several meters of sea level rise this century is impossible to rule out. We don't know much about the dynamics of ice
People keep talking as though the islands were destroyed primarily by sea level rise, plus some other lesser factors. However, even the original paper basically acknowledges that the actual dominant causes of land area loss in the Solomon Islands were things like wave erosion (driven mainly by changes in regional weather patterns, not sea level rise), local human activities such as dredging, and seismic activity.
The effects of the tiny sea level change over the studied period (even taking into account the higher-than-average rise in the Solomon Islands), seem to have been completely dwarfed by those other effects. In order to have some excuse to blame AGW anyway, the paper speculates - but never offers any real evidence for - a non-linear increase in wave erosion due to the small sea level rise.
A more accurate title for the paper would have been, "Wave-Driven Erosion in (a few of) the Solomon Islands, with Many Gratuitous References to Anthropogenic Global Warming".
If you paid attention to actual time scales in actual published scientific papers instead of sexed up headlines you wouldn't be saying that.
The predicted high rate of warming from the early work of NASA and the IPCC has already been falsified. This is why more recent IPCC reports forecast much lower rates of warming (while still predicting catastrophe).
For instance observed sea level rise has always been faster than predicted in any of the IPCC reports.
The sea level is hardly rising at all right now; it is plain to see from the actual data that a massive acceleration in the rise would be required to fulfil the predictions of flooded cities and so forth. Moreover, those dramatic predictions come from sensational numbers like 7 meters, but these days the IPCC is predicting a rise of less than 1 meter over the next century, which would be more than usual, but still not terribly exciting in the grand scheme of things.
I'm not going to make an exhaustive list, but I will offer a few sources.
1) The predictive record:
a) Temperature and CO2: James Hansen - one of the most prominent climate scientists in the world, and former head of the NASA Goddard Institue for Space Studies - gave highly influential testimony to the United States Congress in 1988 based on his efforts at numerical modeling of future AGW. The actual increase in temperature is approximately that of his best-case scenario, in which he assumed far lower CO2 emissions than have actually occured; the actual increase in CO2 since that time has exceeded his worst-case scenario.
(Despite this unambiguous falsification of his models, Hansen continues to prophesy CO2-induced doom real soon now to this day - and the media still takes him seriously.)
b) Sea level rise: "A senior environmental official at the United Nations, Noel Brown, says entire nations could be wiped off the face of the earth by rising sea levels if global warming is not reversed by the year 2000. Coastal flooding and crop failures would create an exodus of "eco-refugees," threatening political chaos, said Brown, director of the New York office of the U.N. Environment Program." - San Jose Mercury News (June 30, 1989)
2) Vague, mutually contradictory models: Amusingly, this very thread contains a fine example about sea level rise - phantomfive's "real, peer reviewed scientific paper" predicts seven meters of sea level rise in the near future (and I have seen other papers predicting even larger rises), but both the Guardian article he linked, and the Solomon Islands paper in the OP have other climate scientists are predicting a rise of less than one meter.
Another good example of the self-contradictory nature of the "settled science", is the myriad efforts to explain away the unpredicted 15+ year long "pause" in statistically significant global warming that has occured since about 2000 (although the strong El Nino this year may finally end it, at least temporarily): there are now 50+ official excuses, ranging from "the missing heat is hidden in the oceans" and "excess volcanic dust is dimming the sun", to "the pause isn't real; it's just an error in the measurements". Many of these excuses are mutually contradictory - the pause cannot be just a measurement error and also have a real physical cause.
(Suspiciously missing from the above, is any serious consideration of the possibility that the models were just wrong about the magnitude of the climate's sensitivity to CO2.)
3) Low quality data: There are two main problems with the data sets upon which modern climate science is based. The first is that claims about the long-t
For it to be a lie it has to be a knowing untruth. What evidence do you have that the writer knew it was untrue?
For a start, how about the fact that the actual research paper never says anywhere that the islands which disappeared did so due to man-made climate change? The summary plainly states:
A paper published in the journal Environmental Research Letters says five of the Solomon Islands have completely submerged underwater due to man-made climate change, and six more have experienced a dramatic reduction in shoreline.
The bolded part above is simply a lie, as several others in this thread who read the original paper (including pro-AGW people) have pointed out.
It's not just the Slashdot summary either; the linked ABC news article also lies about the content of the paper:
Five of the Solomon Islands have submerged underwater and six more have experienced a dramatic reduction in shoreline due to man-made climate change, according to a paper published in the journal Environmental Research Letters.
You could suggest that the writers never actually read the paper - but how is it not a lie to open with a definitive statement about the contents of a paper that they never even read?
And for the record, I've seen numerous public statements by Solomon islanders and their government, that they believe sea levels are rising and that AGW causes it. They may not be right but that doesn't make them liars.
I didn't call the Solomon islanders liars. I called the writers of the Slashdot summary and the ABC news article liars.
This is how science works. You don't start from scratch every time, proving basic physics and maths until you build up to your main point.
Sure. But it would be nice if their paper actually had anything new to say, at all, with respect to its titular topic. I could not find anything new in the entire paper about the "Interactions between sea-level rise and wave exposure on reef island dynamics", except the unsupported "can", "may be", and "further work is required".
From the Key Points sidebar on that page: "After a period of approximately 2,000 years of little change (not shown here),...."
I saw that. It's basically made up though - there is no global tide gauge data going back that far, and certainly no satellite data. The graph starts when it does because any numbers before that are basically speculation.
(Yes, archaeology and historical records can have some interesting things to say on the subject, but it's extremely difficult to reliably differentiate between the sea rising, versus the land subsiding or eroding without the modern measurement methods. Many scientists and archaeologists claim to have found evidence that the sea level was rising slowly during that period, just like it is now.)
1880 is pretty close to being the end of the Second Industrial Revolution. That graph doesn't show what you think it does.
It shows an almost perfectly steady (by the standards of nature), linear rise in sea level since 1880. Do you really think the sea level was static before that, and just suddenly started rising at a constant rate the minute people started burning coal?
Moreover, the CO2 levels in the air have been rising exponentially since 1800 or so; they are now about 10x greater than they were in 1880, at the start of the EPA sea level graph. How does an exponential rise in CO2 emissions produce a smooth linear rise in sea level? (And if an exponential rise in emissions does produce only a very slow linear rise in sea level, why should we worry about it?)
They don't have a mean but it really looks to me like the mean would be negative.
As I said: pay attention to the axes. Notice how all the shrinking islands are on the left side of the graph? That means it's the small islands that are shrinking. The large islands on the right are mostly growing. Moreover, it is a logarithmic scale, so the islands on the right are 100x the size of the islands on the left. That means that a single growing island on the right cancels out many shrinking islands on the left.
So legRoom, this comment where you say "That's a bold faced lie..." was posted before you read the entire paper.
I quoted the part I was arguing against, which was from the summary. Why am I only allowed to pick on the original paper, and not the summary? Are we supposed to just accept bogus headlines, summaries, and news articles (the ABC news article linked says the same wrong stuff as the summary) without comment now?
Also, I did look at the paper before posting; I just didn't read it in detail - because my original comment was directed primarily at the summary and the ABC news article, not the paper.
It's not a strange summary, because it's not obvious to anyone who hasn't studied the math, science, and engineering of it that direct solar power is unlikely to ever work for a 747 (or a Cessna 188) replacement. The point of the article is for the author to say, "Hey! I did the math, and now I'm going to tell you what I learned from that."
Is this an article paid for by Exxon-Mobile or something?
Because basic physics is a conspiracy by the oil companies?
Truth has value, whether it is politically pleasing to your or not. Even if all you care about is renewable technologies, pointing out which are obvious dead ends is still highly beneficial, because it preserves the movement's engineering and political credibility, and frees up resources to pursue other ideas that have more merit - such as synthetic fuels, airships, etc.
so what you're saying is that someone needs to explain to you, once again, the difference between a global average and a regional or local value, which can be markedly different from said average?
The "sea level rise" in the Solomon Islands was much larger than the global average. However, since gravity will naturally distribute melt water evenly across the world's oceans, that greater local rise cannot logically be attributed to global warming melting the ice caps.
What is causing it then? Often the land itself rises or sinks considerably faster than the actual sea level does; the original paper, for example, mentions that one of the islands studied sunk by 60 cm due to a large earthquake. The paper also says that by far the majority of the observed land area lost appears to have been due to erosion via wave action, often exacerbated by local construction activity, like dredging.
Shifts in regional weather patterns can also cause rapid changes in local sea level - however, these changes are bounded because the larger the local change, the harder gravity fights against it to return the water to the global average sea level. Thus, changes in weather patterns cannot, by themselves, cause long-term, sustained sea level rise; increased melting of the ice caps is the only plausible climate-related mechanism.
The paper mentions the Pacific Decadal Oscillation (PDO) as a likely major contributor to the rise in the Solomon Islands. AGW advocates will, of course, always attempt to blame any and every change in climate on mankind's CO2 emissions, but variation in the PDO is not new - that's why it has "Oscillation" in the name. Moreover, it has a cycle time measured in decades, and our (non-junk, direct observation-based) records of it only extend back a hundred years of so, so realistically we simply haven't observed it in detail for long enough to be able to tell whether the recent PDO cycle was within the normal range or not.
hell, you even named the cause of the main threat: storm surge.
even if the rise WAS limited to 10 inches, that 10 inches can cause an increase in storm surge volume of 30-60%, or more.
The sea level has been rising at about the same rate for the entire period over which we have been measuring (since 1880). AGW is alleged not to have reached a measurable strength until some time after World War II. The rate of rise has not accelerated meaningfully since then; the reasonable conclusion (regardless of what may happen in the future) is that, as of today, all observed sea level rise has been natural in origin.
(The warnings of sea level rise-induced doom are all based upon a predicted - but not yet observed - rapid increase in the rate of sea level rise over the next hundred years or so; few people could say with a straight face that another 8 inches will destroy Florida or whatever.)
if I remember my sunday school the "deal" with christians is that they believe all men are fundamentally messed up
Yes, this is a foundational teaching of both the Hebrew Old Testament, and the Christian Bible as a whole.
"As it is written: 'There is none righteous, no, not one; There is none who understands; There is none who seeks after God. They have all turned aside; They have together become unprofitable; There is none who does good, no, not one.'"
- Paul, an Apostle of Christ, refering to the ancient Jewish king and prophet David
Now, that may sound absurd at first, because we're used to lowering the moral standard down to the level of our performance - butchersong said it well:
The alternative of course is simply to adjust your moral and ethical compass to reflect the limitations of man.
But, what is meant by "perfect"? What is "goodness"? "What is truth?"
As mankind's Creator and Judge, God reserves the right to answer these questions for us. He made us with a purpose: "Then God said, 'Let Us make man in Our image, according to Our likeness; let them have dominion over the fish of the sea, over the birds of the air, and over the cattle, over all the earth and over every creeping thing that creeps on the earth.' So God created man in His own image; in the image of God He created him; male and female He created them. Then God blessed them, and God said to them, 'Be fruitful and multiply; fill the earth and subdue it; have dominion over the fish of the sea, over the birds of the air, and over every living thing that moves on the earth.'"
Mankind was designed to reflect God's nature, character, and glory:
"Jesus said to him, ''You shall love the Lord your God with all your heart, with all your soul, and with all your mind.' This is the first and great commandment. And the second is like it: 'You shall love your neighbor as yourself.' On these two commandments hang all the Law and the Prophets.'
Slashdot Mirror
So does Google actually scan the store or what?
Due to the Halting Problem, reliable automated detection of malware is theoretically impossible. This doesn't mean antivirus software is useless, but it is simply inevitable that it will miss stuff. Human security experts will always need to be involved, but humans are expensive, slow, and make more mistakes compared to machines - so it's inevitable that we'll miss stuff, too.
The best long-term route to increasing computer security for society seems to be limiting the capabilities of a program's execution environment to a less dangerous subset of the full range of possible capabilities via air gaps, sand boxing, fine-grained permissions, etc. However, between the continual efforts of three-letter agencies to poke holes in the sand boxes, and the universality of the critical PEBKAC vulnerability, I think the internet is doomed to remain a dangerous place until Judgment Day comes. :-(
If you don't think the software matters, you don't understand big-O notation.
No matter how advanced the software is, it cannot overcome hard theoretical limits on complexity. For example, it has been mathematically proven that no general-purpose sorting algorithm can ever have a time complexity better than O(N * log(N)) on a Turing Machine; even "real AI" cannot change that. This also means that any algorithm which includes such a sort - even just one - can never be faster than O(N * log(N)).
60 microseconds (his allotted time per generation) is a very short span of time: it's not even enough to stream the full source code of a really large program (such as the Linux kernel) through a single CPU core, let alone actually do anything with all that data.
And if you think major breakthroughs in the design of computer hardware are impossible, you're just not paying attention.
Moore's Law (which has officially ended already, by the way) has brought us exponential improvements in throughput, primarily (but not exclusively) through increasing parallelism in the past ten years. However, 60 microseconds is such a short period of time that latency becomes a problem, as well. Latency within the CPU and memory has not improved much at all in the past ten years, because it is limited by the speed of light.
Any estimate for this task is fine considering it'll take several generations of both Moore's Law and software engineering to get to the stage that the computation is even feasible.
Neither computer software nor computer hardware is magic. There are known theoretical limits to how fast either can get, barring a fundamental physics breakthrough or (possibly) the advent of a stronger computational model than the Turing Machine.
Quantum computers are likely to improve things on the software side - but only for certain algorithms; many would be no faster on a quantum computer than on a standard Turing Machine. On the hardware side, latency in quantum computers will still be limited by the speed of light.
10,000,000 generations (about 10 minutes?)
10 minutes is an utterly absurd estimate for this task, to anyone who understands how modern computers actually work. Completing even one generation in that time span would be an amazing achievement. 10,000,000 is simply impossible, barring a major breakthrough in the design of computer hardware (regardless of how advanced the software used is).
Define 'much higher'? The areas I've been in where the sidewalk was right up against the road was always 25 mph or less.
The Los Angeles basin has places where the sidewalk is right next to a road with a limit of 45 mph or more.
As for 'right', well, the goal isn't to only hit pedestrians when they're following the rules, but to avoid hitting them as much as possible. Which means that you have to assume jaywalking, people pushing other people into the street, etc...
Yes. That's why I was surprised by your "25 mph" claim. I presume it's true (or close enough) wherever you live, but it certainly isn't where I am.
What utter nonsense. Lithium is not burning via some Li + Li --> Li_2 reaction in the absence of other elements.
That is true, but in the case of Lithium batteries the required oxidizer is an essential component of the battery itself. No outside chemical input is required for the battery to burn or explode; the military has investigated the use of lithium batteries as improvised grenades.
The problem with water ingress would not necessarily be that it serves as a concentrated oxidizer, but rather that it may short out the batteries, causing sufficient local heating to trigger a self-sustaining chain reaction within the batteries themselves.
In numerous studies it has been found that stopping is pretty much the universal solution
The shift toward electric drive trains (whether hybrid, or pure battery powered) may help with this: the combination of regenerative and mechanical breaking shortens the emergency stopping distance meaningfully, when sufficient traction is available. In particular, the recently unveiled Nikola One hybrid-electric tractor design claims to halve the distance.
Given a sidewalk where people can unexpectedly enter the road, the speed limit should be around 25 mph
Perhaps you mean "where people have the right to unexpectedly enter the road"? Because there are lots of places (in the USA, at least) with much higher speed limits than that, and no barrier - or even strip of grass/trees - between pedestrians and the road.
the new ShenWei (roughly translates to The Wrath of God in Mandarin)
Umm... what? Got an official source for that translation? Because that sounds like propagandistic nonsense to me.
1) China is an officially atheist state, and on that basis alone I doubt they would choose such a name.
(China did have an ancient tradition of monotheism, but it ceased to be the dominant religion a long, long time ago. Moreover, in ancient times it was closely associated with the position of the emperor, considered an enemy of the people under Communism. In modern times, it is associated with Christianity and Islam, both regarded as dangerous (albeit in somewhat different ways) foreign ideas by the government.)
2) A naive effort using Google translate suggests that the actual translation is something more like "Extend Prestige" which sound far more plausible, coming from a (nominally) Communist government. Translating the other way, starting from the English "The Wrath of God", doesn't yield anything remotely resembling ShenWei.
If you have an external medium to move (air), you want a low exhaust velocity (about the same as the aircraft speed).
You seem to have skipped the most important parts of my posts. Even a jet that burns more fuel per unit thrust, can still be more efficient at actually moving the airplane from origin to destination, because the higher top speed means that it doesn't need to sustain that thrust as long to complete the journey.
There is a little thrust from the jet exhaust, but that is low efficiency because its velocity is so much higher than the aircraft efficiency.
Subsonic turbofans typically have a bypass ratio somewhere between [5:1] and [10:1]. Taking into account the mass of the fuel being mixed into the core air stream, this means that you are ignoring between [21.2%] and [10.5%] of the mass flow.
Moreover, that portion of the mass flow is ejected at considerably higher speed, so you are actually ignoring an even greater percentage of the thrust - perhaps [30%] to [15%]? Maybe more at cruising speed, given that the rate of thrust lapse is higher for the fan output, than for the core. (My quick search didn't turn up any hard numbers on the speed of the core exhaust, specifically.)
That difference in thrust is of the same magnitude as the shaft power efficiency difference for your turboprop example, and must not be neglected if you want the comparison to be meaningful.
In turbines the maximum combustion temperature has to be within the operating range of the turbine blades.
Finally, that one random turboprop you picked as the point of comparison isn't very efficient compared to a lot of modern turbines. Hard numbers are not easy to find, but even the 1966 [Rolls-Royce/Snecma Olympus 593](https://en.wikipedia.org/wiki/Rolls-Royce/Snecma_Olympus_593) had a thermodynamic efficiency of [43%]. This beats any of the airplane engines in your shaft power comparison.
While the Concorde was an exotic, bleeding-edge design, materials science has advanced considerably since then, and modern high-end turbines have higher pressure ratios and peak temperatures. If you want to see good examples of this, you need to go look where the money is: large passenger planes (Boeing 777) and cutting-edge military aircraft (F-22 or A400M), not general aviation or small regional passenger planes.
Building a supersonic electric airplane is certainly ambitious, but far from impossible.
On the other hand, building a practical and economically useful supersonic electric airplane with current technology is impossible. Hydrocarbon-powered supersonic planes still run out of fuel quickly, even after hundreds of billions of dollars of investment in the concept. A battery-powered model will certainly not have useful endurance.
Your analysis assumes that the purpose of an airplane engine is to produce shaft power (the subject of the Wiki article you linked). This is incorrect, especially for jets (which ought not to be confused with turboprops).
The true purpose of an airplane engine is to add kinetic energy to the airplane. The effectiveness of jets at this task relative to piston-driven propellers is far higher than your shaft-power based comparison would suggest.
First, because jets (unlike turboprops) are intended to derive a significant portion of their thrust directly from the high-velocity exhaust stream, like a rocket. In a turbojet, shaft power is mostly used to drive the compressor. While turbofans are more similar to propeller engines in this respect, they are still distinct in that they deliberately leave a lot of energy in the exhaust stream.
Thus, for a given shaft power rating a jet will produce much greater thrust than any propeller based system. Moreover, the higher the ambient airspeed, the greater the proportion of thrust that is derived from the exhaust stream, rather than the fan. Ignoring the exhaust stream when analysing the fuel efficiency of a jet engine will yield wildly incorrect results for turbojets at any speed, and for turbofans at cruising speed.
Second, because sustaining the same amount of thrust at a higher airspeed adds linearly more kinetic energy to the aircraft. Consider:
Prop: A 10 ton airplane is cruising at [125 m/s], maintaining constant altitude and speed using a piston-driven propeller exerting [20 kN] of force. The kinetic power imparted to the airplane is therefore [20 kN] * [125 m/s] = [2.5 MW].
Jet: A 10 ton airplane is cruising at [250 m/s], maintaining constant altitude and speed using a jet exerting [20 kN] of force. The kinetic power imparted to the airplane is therefore [20 kN] * [250 m/s] = [5 MW]. (Yes, a jet can sustain a higher speed using the same amount of thrust - the plane just has to fly higher, where the air is thinner and creates less drag.)
At the same effective specific impulse (Isp , a better measure of jet efficiency than the BSFC you linked), a jet can achieve greater practical fuel efficiency (fuel burned per unit distance) than a propeller plane, simply by flying faster and higher. This effect is very large - enough so to overcome significant differences in Isp as compared to a prop plane.
TL;DR: The purpose of a jet is to move the airplane, not to spin a shaft. It's efficiency should be evaluated on that basis.
The Russians plod on with steam-era rockets, which are practical but are a fallback to pre-V2-technoliogy.
That's a pretty ridiculous and insulting exaggeration.
Up until SpaceX announced the Merlin 1C less than a decade ago, Russia was the unquestioned leader in Kerosene-Oxygen engine technology. There's a good reason that United Launch Alliance selected the Russian RD-180 for the Atlas V. More generally, Russian technology is competitive with (I do not say equal to) that of the West in many areas, such as rocketry, jet engines, airframes, avionics, weaponry, etc.
Dismissing all of that as "pre-V2 technology" is nonsensical propaganda: facing off against a military limited to actual pre-V2 tech, the Russian military would absolutely dominate.
I think the biggest problem is that the low altitude environment is pretty hostile - waves, birds, floating obstructions etc. In principal though they are more efficient than airplanes.
That, and the high air density at sea level requires a lower cruising speed to be efficient. The military, who funds much of the world's aerospace research, values speed more than efficiency. (They are only interested in efficiency mostly because it limits range, which is also important to them.)
Jets are actually less efficient, but the lighter weight more than makes up for that.
"Efficient" is a meaningless term, unless one specifies which two metrics are being compared.
Jet engines generally have considerably better thermodynamic efficiency than piston engines: they convert a larger percentage of the chemical energy in the fuel into mechanical energy, and waste less in the form of unused heat and partially burned exhaust.
They have inferior thrust efficiency at low speeds (less thrust is generated per unit fuel per second), but superior thrust efficiency at high speeds (trans-sonic and up). In fact, normal piston-driven propellers don't produce any (net) thrust at all at the normal operating speeds for many jets, and so are perfectly inefficient.
With a good flight profile, burning through fuel faster in order to fly faster generally does not hurt the plane's overall fuel efficiency, as measured in fuel units burned per unit distance. What it does do is complete the journey faster, freeing the vehicle and its passengers/cargo to move on to another task, thus improving economic efficiency. The only reason that airplanes don't just fly as fast as they possibly can, is that drag increases sharply for airspeeds above Mach 1.
TL;DR: Jets are used on nearly all large planes because they are more efficient in the metrics that count, not just because of their weight.
with a significant percentage of the need for lift and thrust cancelled by positive-buoyancy gas cells,
As has already been pointed out, buoyancy cells reduce the need for lift, but increase the need for thrust at a given speed. The square-cube law favours larger airships for lower drag.
most or all of the electricity coming from photo-voltaic cells covering the upper hull/fuselage and lifting/control surfaces.
The power that can be collected via solar cells scales with surface area, but the power required scales with mass (and therefore volume). Thus, the square-cube law also favours smaller airships for greater power-to-weight, if solar power is the primary energy source.
lifting-body design and surface-effect-cushion aerodynamics at just a few meters altitude above the sea, possibly, rather than lifting to a multiple-kilometers altitude?
The volume of buoyancy cell required to lift a given mass increases exponentially with altitude, so a low cruising altitude is desirable to keep the size reasonable. However, deliberately cruising at "just a few meters altitude" is a very bad idea: many of the worst airship accidents in history were caused by the wind suddenly pushing on the vehicle's massive surface area in an unexpected direction, easily overwhelming the engines, ground handlers, etc. You need to cruise at a high enough altitude that a single unexpected down draft doesn't kill everyone on board.
If a ticket from London to Tokyo or Singapore to LA took two days but cost around the $100USD price point or even lower...
I don't think this will ever happen. At least in the USA, two nights in a cheap motel costs at least $100 (often much more). It seems safe to say that a flying motel will never be cheaper than one built on the ground. Also, the need to provide overnight accommodations, and room for people to stretch their legs, imposes a large weight penalty on passenger airships compared to airplanes.
This is a fundamental reason that airships are unlikely to replace airplanes for general passenger service: life is expensive, and people's time is valuable. The richer the world gets, the less likely that a new, slower form of long-distance air travel will catch on, even if it is more energy efficient.
Those concerns don't apply to cargo though, so the idea is still very much worth exploring.
I'm basically typing a 'stream-of-consciousness' here as I consider the problem.
Same here.
Watts' headline is based on comparing Scenario A to observations but in reality Scenario B is closest to reality but slightly higher than observations.
Hansen's scenario A has mankind's CO2 output rising exponentially at 1.5% per year (see the second paragraph on page 5 of the original paper) since 1988, but the actual rate of increase has been substantially higher - about 2% per year based on this graph from the Union of Concerned Scientists.
Hansen's scenario A has the average global surface temperature rising over 1 C between 1988 and 2014 (see figure 3 on page 7 of Hansen's paper). The actual temperature rise during that period was somewhere between 0.2 C and 0.4 C depending on which of the many data sets you believe.
Since Hansen's basic hypothesis was "more CO2 emissions = faster warming", scenario B certainly was not "closest to reality"; in fact none of his scenarios is at all realistic, since (empirically) he completely failed to accurately predict the relationship between CO2 and temperature - which was the entire point of his paper.
Hansen's model also had too high a value for climate sensitivity (around 4.2 IIRC) while subsequent research came up with a value around 3.2.
[1 C] * [3.2/4.2] = [0.76 C], which is still about double the observed temperature rise.
There is a reason that so much effort has been invested by alarmists into trying to make excuses for the lower-than-predicted temperatures - it's because temperatures have been lower than they predicted! That's still true, even if you use more recent models with less dramatic sensitivity to CO2.
There are already cities like Miami and Norfolk, VA that are flooding in areas when the king tides occur.
Don't be ridiculous - Miami (1.8 m) and Miami Beach (1.2 m) were both built practically at sea level to begin with; they have always been highly vulnerable to flooding since their founding. The sea level has only risen perhaps 0.25 m since that time, whereas the natural range of tides + waves + storm surges is 5+ m (especially in hurricane country!).
Norfolk, Virginia is likewise built at such a low elevation (2.1 m) that flooding problems are inevitable, although in their case the founding was long enough ago (1682) that the danger may be due to subsidence and pre-AGW sea level rise, rather than it originally being an obviously bad location.
If you look closely that EPA graph does show some acceleration.
Hardly, unless you want to count the little bump at the end which is too short to be statistically significant given how chaotic the climate system is.
In the Guardian article I think you misread "several meters" as "7 meters".
No, the original paper contains numerous statements along these lines: "Sea level reached 6–9 m in the Eemian, a time that we have concluded was probably no more than a few tenths of a degree warmer than today."
The introduction also makes reference to an earlier paper: "This uncertainty is illustrated by Pollard et al. (2015), who found that addition of hydro-fracturing and cliff failure into their ice sheet model increased simulated sea level rise from 2 to 17 m, in response to only 2 C ocean warming and accelerated the time for substantial change from several centuries to several decades."
Several meters of sea level rise this century is impossible to rule out. We don't know much about the dynamics of ice
People keep talking as though the islands were destroyed primarily by sea level rise, plus some other lesser factors. However, even the original paper basically acknowledges that the actual dominant causes of land area loss in the Solomon Islands were things like wave erosion (driven mainly by changes in regional weather patterns, not sea level rise), local human activities such as dredging, and seismic activity.
The effects of the tiny sea level change over the studied period (even taking into account the higher-than-average rise in the Solomon Islands), seem to have been completely dwarfed by those other effects. In order to have some excuse to blame AGW anyway, the paper speculates - but never offers any real evidence for - a non-linear increase in wave erosion due to the small sea level rise.
A more accurate title for the paper would have been, "Wave-Driven Erosion in (a few of) the Solomon Islands, with Many Gratuitous References to Anthropogenic Global Warming".
If you paid attention to actual time scales in actual published scientific papers instead of sexed up headlines you wouldn't be saying that.
The predicted high rate of warming from the early work of NASA and the IPCC has already been falsified. This is why more recent IPCC reports forecast much lower rates of warming (while still predicting catastrophe).
For instance observed sea level rise has always been faster than predicted in any of the IPCC reports.
The sea level is hardly rising at all right now; it is plain to see from the actual data that a massive acceleration in the rise would be required to fulfil the predictions of flooded cities and so forth. Moreover, those dramatic predictions come from sensational numbers like 7 meters, but these days the IPCC is predicting a rise of less than 1 meter over the next century, which would be more than usual, but still not terribly exciting in the grand scheme of things.
I'm not going to make an exhaustive list, but I will offer a few sources.
1) The predictive record:
a) Temperature and CO2: James Hansen - one of the most prominent climate scientists in the world, and former head of the NASA Goddard Institue for Space Studies - gave highly influential testimony to the United States Congress in 1988 based on his efforts at numerical modeling of future AGW. The actual increase in temperature is approximately that of his best-case scenario, in which he assumed far lower CO2 emissions than have actually occured; the actual increase in CO2 since that time has exceeded his worst-case scenario.
(Despite this unambiguous falsification of his models, Hansen continues to prophesy CO2-induced doom real soon now to this day - and the media still takes him seriously.)
The temperature predictions of the early IPCC reports have also been falsified; over time the group has gradually lowered their estimation of the climate's sensitivity to CO2, while maintaining that doom is as imminent as ever (or more so).
b) Sea level rise: "A senior environmental official at the United Nations, Noel Brown, says entire nations could be wiped off the face of the earth by rising sea levels if global warming is not reversed by the year 2000. Coastal flooding and crop failures would create an exodus of "eco-refugees," threatening political chaos, said Brown, director of the New York office of the U.N. Environment Program." - San Jose Mercury News (June 30, 1989)
2) Vague, mutually contradictory models: Amusingly, this very thread contains a fine example about sea level rise - phantomfive's "real, peer reviewed scientific paper" predicts seven meters of sea level rise in the near future (and I have seen other papers predicting even larger rises), but both the Guardian article he linked, and the Solomon Islands paper in the OP have other climate scientists are predicting a rise of less than one meter.
Another good example of the self-contradictory nature of the "settled science", is the myriad efforts to explain away the unpredicted 15+ year long "pause" in statistically significant global warming that has occured since about 2000 (although the strong El Nino this year may finally end it, at least temporarily): there are now 50+ official excuses, ranging from "the missing heat is hidden in the oceans" and "excess volcanic dust is dimming the sun", to "the pause isn't real; it's just an error in the measurements". Many of these excuses are mutually contradictory - the pause cannot be just a measurement error and also have a real physical cause.
(Suspiciously missing from the above, is any serious consideration of the possibility that the models were just wrong about the magnitude of the climate's sensitivity to CO2.)
3) Low quality data: There are two main problems with the data sets upon which modern climate science is based. The first is that claims about the long-t
For it to be a lie it has to be a knowing untruth. What evidence do you have that the writer knew it was untrue?
For a start, how about the fact that the actual research paper never says anywhere that the islands which disappeared did so due to man-made climate change? The summary plainly states:
A paper published in the journal Environmental Research Letters says five of the Solomon Islands have completely submerged underwater due to man-made climate change, and six more have experienced a dramatic reduction in shoreline.
The bolded part above is simply a lie, as several others in this thread who read the original paper (including pro-AGW people) have pointed out.
It's not just the Slashdot summary either; the linked ABC news article also lies about the content of the paper:
Five of the Solomon Islands have submerged underwater and six more have experienced a dramatic reduction in shoreline due to man-made climate change, according to a paper published in the journal Environmental Research Letters.
You could suggest that the writers never actually read the paper - but how is it not a lie to open with a definitive statement about the contents of a paper that they never even read?
And for the record, I've seen numerous public statements by Solomon islanders and their government, that they believe sea levels are rising and that AGW causes it. They may not be right but that doesn't make them liars.
I didn't call the Solomon islanders liars. I called the writers of the Slashdot summary and the ABC news article liars.
This is how science works. You don't start from scratch every time, proving basic physics and maths until you build up to your main point.
Sure. But it would be nice if their paper actually had anything new to say, at all, with respect to its titular topic. I could not find anything new in the entire paper about the " Interactions between sea-level rise and wave exposure on reef island dynamics", except the unsupported "can", "may be", and "further work is required".
From the Key Points sidebar on that page: "After a period of approximately 2,000 years of little change (not shown here),...."
I saw that. It's basically made up though - there is no global tide gauge data going back that far, and certainly no satellite data. The graph starts when it does because any numbers before that are basically speculation.
(Yes, archaeology and historical records can have some interesting things to say on the subject, but it's extremely difficult to reliably differentiate between the sea rising, versus the land subsiding or eroding without the modern measurement methods. Many scientists and archaeologists claim to have found evidence that the sea level was rising slowly during that period, just like it is now.)
1880 is pretty close to being the end of the Second Industrial Revolution. That graph doesn't show what you think it does.
It shows an almost perfectly steady (by the standards of nature), linear rise in sea level since 1880. Do you really think the sea level was static before that, and just suddenly started rising at a constant rate the minute people started burning coal?
Moreover, the CO2 levels in the air have been rising exponentially since 1800 or so; they are now about 10x greater than they were in 1880, at the start of the EPA sea level graph. How does an exponential rise in CO2 emissions produce a smooth linear rise in sea level? (And if an exponential rise in emissions does produce only a very slow linear rise in sea level, why should we worry about it?)
Figure 7?
Yes.
They don't have a mean but it really looks to me like the mean would be negative.
As I said: pay attention to the axes. Notice how all the shrinking islands are on the left side of the graph? That means it's the small islands that are shrinking. The large islands on the right are mostly growing. Moreover, it is a logarithmic scale, so the islands on the right are 100x the size of the islands on the left. That means that a single growing island on the right cancels out many shrinking islands on the left.
So legRoom, this comment where you say "That's a bold faced lie..." was posted before you read the entire paper.
I quoted the part I was arguing against, which was from the summary. Why am I only allowed to pick on the original paper, and not the summary? Are we supposed to just accept bogus headlines, summaries, and news articles (the ABC news article linked says the same wrong stuff as the summary) without comment now?
Also, I did look at the paper before posting; I just didn't read it in detail - because my original comment was directed primarily at the summary and the ABC news article, not the paper.
Seriously, what a strange summary.
It's not a strange summary, because it's not obvious to anyone who hasn't studied the math, science, and engineering of it that direct solar power is unlikely to ever work for a 747 (or a Cessna 188) replacement. The point of the article is for the author to say, "Hey! I did the math, and now I'm going to tell you what I learned from that."
Is this an article paid for by Exxon-Mobile or something?
Because basic physics is a conspiracy by the oil companies?
Truth has value, whether it is politically pleasing to your or not. Even if all you care about is renewable technologies, pointing out which are obvious dead ends is still highly beneficial, because it preserves the movement's engineering and political credibility, and frees up resources to pursue other ideas that have more merit - such as synthetic fuels, airships, etc.
so what you're saying is that someone needs to explain to you, once again, the difference between a global average and a regional or local value, which can be markedly different from said average?
The "sea level rise" in the Solomon Islands was much larger than the global average. However, since gravity will naturally distribute melt water evenly across the world's oceans, that greater local rise cannot logically be attributed to global warming melting the ice caps.
What is causing it then? Often the land itself rises or sinks considerably faster than the actual sea level does; the original paper, for example, mentions that one of the islands studied sunk by 60 cm due to a large earthquake. The paper also says that by far the majority of the observed land area lost appears to have been due to erosion via wave action, often exacerbated by local construction activity, like dredging.
Shifts in regional weather patterns can also cause rapid changes in local sea level - however, these changes are bounded because the larger the local change, the harder gravity fights against it to return the water to the global average sea level. Thus, changes in weather patterns cannot, by themselves, cause long-term, sustained sea level rise; increased melting of the ice caps is the only plausible climate-related mechanism.
The paper mentions the Pacific Decadal Oscillation (PDO) as a likely major contributor to the rise in the Solomon Islands. AGW advocates will, of course, always attempt to blame any and every change in climate on mankind's CO2 emissions, but variation in the PDO is not new - that's why it has "Oscillation" in the name. Moreover, it has a cycle time measured in decades, and our (non-junk, direct observation-based) records of it only extend back a hundred years of so, so realistically we simply haven't observed it in detail for long enough to be able to tell whether the recent PDO cycle was within the normal range or not.
hell, you even named the cause of the main threat: storm surge. even if the rise WAS limited to 10 inches, that 10 inches can cause an increase in storm surge volume of 30-60%, or more.
The sea level has been rising at about the same rate for the entire period over which we have been measuring (since 1880). AGW is alleged not to have reached a measurable strength until some time after World War II. The rate of rise has not accelerated meaningfully since then; the reasonable conclusion (regardless of what may happen in the future) is that, as of today, all observed sea level rise has been natural in origin.
(The warnings of sea level rise-induced doom are all based upon a predicted - but not yet observed - rapid increase in the rate of sea level rise over the next hundred years or so; few people could say with a straight face that another 8 inches will destroy Florida or whatever.)
if I remember my sunday school the "deal" with christians is that they believe all men are fundamentally messed up
Yes, this is a foundational teaching of both the Hebrew Old Testament, and the Christian Bible as a whole.
"As it is written: 'There is none righteous, no, not one; There is none who understands; There is none who seeks after God. They have all turned aside; They have together become unprofitable; There is none who does good, no, not one.'"
- Paul, an Apostle of Christ, refering to the ancient Jewish king and prophet David
Now, that may sound absurd at first, because we're used to lowering the moral standard down to the level of our performance - butchersong said it well:
The alternative of course is simply to adjust your moral and ethical compass to reflect the limitations of man.
God is not impressed when we "proclaim each his own goodness"; He refuses to settle for anything less than true goodness. Jesus Christ commanded his followers, "Therefore you shall be perfect, just as your Father in heaven is perfect."
But, what is meant by "perfect"? What is "goodness"? "What is truth?"
As mankind's Creator and Judge, God reserves the right to answer these questions for us. He made us with a purpose: "Then God said, 'Let Us make man in Our image, according to Our likeness; let them have dominion over the fish of the sea, over the birds of the air, and over the cattle, over all the earth and over every creeping thing that creeps on the earth.' So God created man in His own image; in the image of God He created him; male and female He created them. Then God blessed them, and God said to them, 'Be fruitful and multiply; fill the earth and subdue it; have dominion over the fish of the sea, over the birds of the air, and over every living thing that moves on the earth.'"
Mankind was designed to reflect God's nature, character, and glory:
God "cannot lie", and so mankind is forbidden to lie.
God is holy (that is, pure and separate from evil), and so mankind must be holy.
God is faithful, and so we must be also - toward God, and to each other.
"God is love", and the whole law of God is ultimately based on just two commands:
"Jesus said to him, ''You shall love the Lord your God with all your heart, with all your soul, and with all your mind.' This is the first and great commandment. And the second is like it: 'You shall love your neighbor as yourself.' On these two commandments hang all the Law and the Prophets.'