J. Bradford DeLong's Blog, page 2092
February 15, 2011
Yet Another Hockey Stick
Joe Romm:
Temperatures of North Atlantic “are unprecedented over the past 2000 years and are presumably linked to the Arctic amplification of global warming” : Study after study finds recent warming is unprecedented in magnitude and speed and cause. The anti-science crowd keeps trying to debunk one or two old Hockey Sticks, but new ones crop up faster than a speeding puck. Science just published a new one, “Enhanced Modern Heat Transfer to the Arctic by Warm Atlantic Water” (subs. req’d), news release here, “Warming North Atlantic water tied to heating Arctic, according to new study.” I have pulled out the key graph — and it is one heck of a Hockey Stick.... derived from “planktic foraminifers in a sediment core.... This astonishing warming in the past century is clearly not, as the anti-science crowd likes to say, some sort of recovery from the so-called Little Ice Age (see “A detailed look at the Little Ice Age“), which, in any case, is barely noticeable in this data. The lead author, Robert Spielhagen of the Leibniz Institute of Marine Sciences said, “Such a warming of the Atlantic water in the Fram Strait is significantly different from all climate variations in the last 2,000 years.” The fact is, over 90% of human-caused warming is going into the oceans — and it is melting ice whereever it goes (see “Deep ocean heat is rapidly melting Antarctic ice“).
Air temperatures in Greenland have risen roughly 7 degrees F in the past several decades, thought to be due primarily to an increase in Earth’s greenhouse gases, according to CU-Boulder scientists. “We must assume that the accelerated decrease of the Arctic sea ice cover and the warming of the ocean and atmosphere of the Arctic measured in recent decades are in part related to an increased heat transfer from the Atlantic,” said Spielhagen.
Here are the abstract and conclusion:
The Arctic is responding more rapidly to global warming than most other areas on our planet. Northward-flowing Atlantic Water [AW] is the major means of heat advection toward the Arctic and strongly affects the sea ice distribution. Records of its natural variability are critical for the understanding of feedback mechanisms and the future of the Arctic climate system, but continuous historical records reach back only ~150 years. Here, we present a multidecadal-scale record of ocean temperature variations during the past 2000 years, derived from marine sediments off Western Svalbard (79°N). We find that early–21st-century temperatures of Atlantic Water entering the Arctic Ocean are unprecedented over the past 2000 years and are presumably linked to the Arctic amplification of global warming….
Although we cannot quantify from our data the variability of previous AW inflow to the Arctic by volume, our temperature data series and the above observational link suggest that the modern warm AW inflow (averaged over two to three decades) is anomalous and unique in the past 2000 years and not just the latest in a series of natural multidecadal oscillations. Both effects—a temperature rise as well as a volume transport increase—introduce a larger heat input into the Arctic Ocean. Although there is no direct contact of the AAWL [Arctic Atlantic Water Layer] with the ocean surface in the Arctic, such an increased heat input has far-reaching consequences. The strong AW warming event in the Arctic Ocean in the 1990s caused a shoaling of the AW core and an enhanced heat flux to the surface , concurrent with decreasing sea ice. Recent oceanographic data from the Laptev Sea continental margin indicate the impact of warm AW-related water masses on the shallow (<50 m) shelf, a feature not observed before in a >80-year time series. The data also provide evidence for a significant heat flux to the overlying shelf waters. Even without any modification of the vertical heat transfer processes, the enhanced temperature contrast between the AW and the surface sea water freezing point (increased from ~5 to 7 K as identified here) leads to an increase in the vertical heat flux of ~40%. Any positive-feedback mechanism will magnify the effect of this flux increase on the ice cover. Complementing the strong feedback between ice and atmospheric temperatures, warming of the AW layer, unprecedented in the past 2000 years, is most likely another key element in the transition toward a future ice-free Arctic Ocean.
Liveblogging World War II: February 15, 1941
CNO Stark:
Op-30Cl-AJ
(SC) N20-12.
Serial 09330.
NAVY DEPARTMENT
OFFICE OF THE CHIEF OF NAVAL OPERATIONS
WASHINGTON, Feb. 15, 1941.
From: The Chief of Naval Operations
To: The Commander-in-Chief, Pacific Fleet
Subject: Anti-torpedo baffles for protection against torpedo plane attacks, Pearl Harbor.
1. Consideration has been given to the installation of A/T baffles within Pearl Harbor for protection against torpedo plane attacks. It is considered that the relatively shallow depth of water limits the need for anti-torpedo nets in Pearl Harbor. In addition the congestion and the necessity for maneuvering room limit the practicability of the present type of baffles.
2. Certain limitations and considerations are advised to be borne in mind in planning the installation of anti-torpedo baffles within harbors, among which the following may be considered:
(a) A minimum depth of water of seventy-five feet may be assumed necessary to successfully drop torpedoes from planes. One hundred and fifty feet of water is desired. The maximum height planes at present experimentally drop torpedoes is 250 feet. Launching speeds are between 120 and 150 knots. Desirable height for dropping is sixty feet or less. About two hundred yards of torpedo run is necessary before the exploding device is armed, but this may be altered.
(b) There should be ample maneuvering room available for vessels approaching and leaving berths.
(c) Ships should be able to get away on short notice.
(d) Room must be available inside the baffles for tugs, fuel oil barges and harbor craft to maneuver alongside individual ships.
(e) Baffles should be clear of cable areas, ferry routes, and channels used by shipping.
(f) Baffles should be sufficient distance from anchored vessels to insure the vessels' safety in case a torpedo explodes on striking a baffle.
(g) High land in the vicinity of an anchorage makes a successful airplane attack from the land side most difficult.
(h) Vulnerable areas in the baffles should be so placed as to compel attacking planes to come within effective range of anti-aircraft batteries before they can range their torpedoes.
(i) Availability of shore and ship anti-aircraft protection, balloon barrages, and aircraft protection.
(j) Availability of naturally well protected anchorages within a harbor from torpedo plane attack for a number of large ships. Where a large force such as a fleet is based, the installation of satisfactory baffles will be difficult because of the congestion.
3. As a matter of interest the successful attacks at Taranto were made at very low launching heights at reported ranges by the individual aviators of 400 to 1300 yards from the battleships, but the depths of water in which the torpedoes were launched were between 14 and 15 fathoms. The attacks were made in the face of intensive and apparently erratic anti-aircraft fire. The eastern shore line of the anchorage and moorings were protected by numerous balloon barrages, but there was no trawler borne balloon barrage to the west. The torpedoes were apparently dropped inside of the nets, probably A/T nets.
4. It is considered that certain large bays and harbors, where a fleet or large force of heavy ships may be anchored and exposed with a large body of water on an entire flank, should have that flank protected by a series of baffles if the water is deep enough for launching torpedoes. The main fleet anchorage at Scapa Flow, for instance, has an A/T net extending slightly to the north of a line between Calf of Flotta and Cava Island protecting the main fleet anchorage. The depth of water where this net is laid is approximately 17 fathoms. On the other hand constricted harbors, in which practically all available space is taken up by anchorages, and which is relatively deep probably must depend upon other defense measures. It might be possible and practicable to provide in some places, which are not protected by relatively shallow water, anti-torpedo baffles practically surrounding a limited number of berths or large ships, such as battleships or carriers. An extreme example of this is furnished at the present time by the French at Dakar, where double nets surround the Richelieu; she is placed similarly as in a dry dock, and evidently would have to open a section of the net to be hauled clear. The depth of water at Dakar, however, is very shallow.
5. The present A/T nets are very expensive extremely heavy, their heavy anchors and moorings take up about 200 yards space perpendicular to the line of the net, take a long time to lay, and are designed to stand up under heavy weather conditions. There is apparently a great need for the development of a light efficient torpedo net which could be laid temporarily and quickly within protected harbors and which can be readily removed. It is hoped that some such net can be developed in the near future.
6. Recommendations and comments of the Commander-in-Chief are especially desired.
(s) H. R. Stark.
H. R. STARK.
Copy to
CinC Atlantic Fleet.
CinC Asiatic Fleet.
Mark Kleiman Watches the Train Wreck...
MK:
Left hand, meet right hand « The Reality-Based Community: Volokh Conspirator Jonathan Adler makes fun of me for imagining that libertarian principles might not allow the government to spend tax money to protect the planet from an incoming asteroid. Apparently we need an affirmative action program to hire conservative academics in order to cure my gross ignorance of right-wing thought. Volokh Conspirator Sasha Volokh admits that his principles would not allow the government to spend tax money to protect the planet from an incoming asteroid. After all, taxation is a violation of rights, and can only be justified if it avoids still graver rights violations. And the asteroid, not being sentient or directed by a sentient being, can do damage but can’t violate rights. Ergo, it would be illegitimate to use the coercive power of the state to raise money for asteroid defense.
I’m glad that Adler agrees with me – and disagrees with many Tea Party lunatics, including some recently elected to the Senate and the House – that there’s no actual Constitutional question about funding the Department of Education or National Public Radio. That, of course, was my point.
I’m also glad that Sasha is standing by his guns, thus demonstrating that my argument was not directed at a mere straw man, though his objection to spending is philosophical rather than Constitutional.
Sasha worries that his honest and forthright response might confirm me in my belief that “libertarians are loopy.” That’s certainly a reasonable concern. But I would have thought that a bigger concern would be that the conclusion is, in fact, obviously loopy...
Sean Carroll: Is Relativity Hard?
Sean Carroll:
Is Relativity Hard? | Cosmic Variance | Discover Magazine: Brad DeLong, in the course of something completely different, suggests that the theory of relativity really isn’t all that hard. At least, if your standard of comparison is quantum mechanics.
He’s completely right, of course. While relativity has a reputation for being intimidatingly difficult, it’s a peculiar kind of difficulty. Coming at the subject without any preparation, you hear all kinds of crazy things about time dilating and space stretching, and it seems all very recondite and baffling. But anyone who studies the subject appreciates that it’s a series of epiphanies: once you get it, you can’t help but wonder what was supposed to be so all-fired difficult about this stuff. Applications can still be very complicated, of course (just as they are in classical mechanics or electrodynamics or whatever), but the basic pillars of the theory are models of clarity.
Quantum mechanics is not like that. The most on-point Feynman quote is this one, from The Character of Physical Law:
There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics.
“Hardness” is not a property that inheres in a theory itself; it’s a statement about the relationship between the theory and the human beings trying to understand it. Quantum mechanics and relativity both seem hard because they feature phenomena that are outside the everyday understanding we grow up with. But for relativity, it’s really just a matter of re-arranging the concepts we already have. Space and time merge into spacetime; clocks behave a bit differently; a rigid background becomes able to move and breathe. Deep, certainly; inscrutable, no.
In the case of quantum mechanics, the sticky step is the measurement process. Unlike in other theories, in quantum mechanics “what we measure” is not the same as “what exists.” This is the source of all the problems (not that recognizing this makes them go away). Our brains have a very tough time separating what we see from what is real; so we keep on talking about the position of the electron, even though quantum mechanics keeps trying to tell us that there’s no such thing.
America's Two Economies
RR:
Robert Reich (The Jobs Report, and America's Two Economies): At a time when corporate profits are through the roof, the Dow is flirting with 12,000, Wall Street paychecks are fat again, and big corporations are sitting on more than $1 trillion in cash, you’d expect jobs be coming back. But you’d be wrong.
The U.S. economy added just 36,000 jobs in January, according to today’s report from the Bureau of Labor Statistics. Remember, 125,000 are needed just to keep up with the increase in the population of Americans wanting and needing work. And 300,000 a month are needed — continuously, for five years — if we’re to get back to anything like the employment we had before the Great Recession.
In other words, today’s employment report should be sending alarm bells all over official Washington. Granted, unusually bad weather may have accounted for some of the reluctance of employers to hire in January. But even considering the weather, the economy is still terribly sick. (Technical note: The official rate of unemployment fell to 9 percent from 9.4 percent, but that’s because more workers have left the labor market, too discouraged to continue looking for work. The official rate reflects how many people are actively looking for work.)
We have two economies. The first is in recovery. The second remains in a continuous depression.
The first is a professional, college-educated, high-wage economy centered in New York and Washington, that’s living well off of global corporate profits. Corporations continue to make money by selling abroad from their foreign operations while cutting costs (especially labor) here at home. Wall Street is making money by taking the Fed’s free money and speculating with it. The richest 10 percent of Americans, holding 90 percent of all financial assets, are riding the wave. And their upscale spending has given high-end retailers and producers a bounce.
The second is most of the rest of America, and it’s still struggling with a mountain of debt, declining home prices, and job losses. In coming months most Americans will also be contending with sharply rising prices of food and fuel.
Our representatives in Washington see and hear mostly the first economy. The business press reports mainly on the first economy. Corporate and Wall Street economists are concerned largely with the first economy.
But the second economy will determine our politics in 2012 and beyond.
And not even the first can be sustained permanently on its own. Corporate profits cannot continue to rise on the basis of foreign sales (which are slowing as Europe adopts austerity and China raises interest rates), the purchases of the richest 10 percent of Americans (which are dependent on a rising stock market), and cost-cutting measures at home (which are necessarily limited). Without a strong and broadly-based middle-class recovery, America’s big money economy will fall in on itself. A major stock market “correction” is a certainty.
Empirical Proof that America's Libertarians Are Completely Insane...
The intellectual train wreck is truly astonishing. Matthew Yglesias sends us to Sasha Volokh, who writes:
The Volokh Conspiracy » Asteroid defense and libertarianism: I think there’s a good case to be made that taxing people to protect the Earth from an asteroid... is an illegitimate function of government from a moral perspective.... [I]t’s O.K. to violate people’s rights (e.g. through taxation) if the result is that you protect people’s rights to some greater extent (e.g. through police, courts, the military). But it’s not obvious to me that the Earth being hit by an asteroid (or, say, someone being hit by lightning or a falling tree) violates anyone’s rights....
[I]f you could show that, once the impending asteroid impact became known, all hell would break loose and lots of rights be violated by looters et al. during the ensuing anarchy, I could justify the taxation as a way of preventing those rights violations; but this wouldn’t apply if, say, the asteroid impact were unknown to the public...
So not only does Sasha Volokh claim that it is immoral to tax people to blow up an asteroid (or install lightning rods, or mandate lightning rods, or pay for a tree-trimming crew on the public roads), but it is immoral to tell people of an approaching asteroid so they can scramble to safety because it will cause violations of rights through looting.
Wow.
Why Oh Why Can't We Have a Better Press Corps? (New York Times Making-S--t-Up Department
Outsourced to Paul Krugman:
Lifestyles Of The Rich But Not Famous - NYTimes.com: Today, David Brooks suggests that economic growth has slowed because these days the affluent are more into self-improvement and life quality... we’re suffering from a decline in materialism. My immediate reaction was that this is all wrong — that people like David’s hypothetical Jared are actually rare, that the reality is that we’re more into the rat race than ever before. What I always think about is the commuter trains. When I was growing up on Long Island, there was a clear social hierarchy in terms of when people went to work: take a 7:30 train and it was full of blue-collar workers, take a 9:00 train and it was full of men in good suits, heading in to spend a couple of hours pushing papers around before taking their three-martini lunches. Today, the highest-paid also put in enormous hours — and you can find plenty of them on that 7:30 train, or even earlier.
But dueling anecdotes only get you so far. What about data?
Well, Google “hours worked per family” and you get this Minneapolis Fed paper (pdf) on the subject... what it all suggests is that most American families are working more, and that
When we compare households with different skill mixes, we also find dramatic differences in the time paths, with higher skill households having the largest increase in average hours over time.
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