Archive for the ‘global warming’ Category

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Mirkwood comes to Midland

September 1, 2007

The New York Times reports that a state park in Texas has become home to a spider web several acres in size.

Sheets of web have encased several mature oak trees and are thick enough in places to block out the sun along a nature trail at Lake Tawakoni State Park, near this town about 50 miles east of Dallas.
The gossamer strands, slowly overtaking a lakefront peninsula, emit a fetid odor, perhaps from the dead insects entwined in the silk. The web whines with the sound of countless mosquitoes and flies trapped in its folds…
Mr. Dean and several other scientists said they had never seen a web of this size outside of the tropics, where the relatively few species of “social” spiders that build communal webs are most active…

The Times doesn’t mention the possibility, but one predicted consequence of global warming is that tropical species will extend their ranges northward. Maybe the spiders have congregated to reward all those Texas oilmen for providing them with new habitat.

The Grey Lady is also mum on the explanation I find most likely: once both Tom DeLay and Karl Rove headed back to the Lone Star State for good, word went out on the grapevine that the nucleus had formed for a creepy crawler flash mob.

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Reducing your photon footprint

May 15, 2007

Black may be the new green.

The usual form of computer screen text display, black characters on white background, uses 60 or 70% more wattage than white on black display. So one teensy favor you can do to mother earth is to move your web searches to blackle, which uses the Google engine but presents the results in the more efficient format.

Some tell me it makes them squint. After the years I spent in the seventies and early eighties on those Apple II and IIe dot marix, no-descender text screens, it feels to me just like coming home. See what you think. From what we all learned in the IIe days, though, and subsequently forgot, I’ve got two words for the blackle techies: Think Gold.

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Your garden is full of quantum computers

April 24, 2007

It hasn’t made a big splash in the media, but the revelation about photosynthesis in Nature two weeks ago might be the sleeper science story of the year. (You’ll need a subscription or an academic account to follow the link.)

Photosynthesis has always posed a conundrum. It’s unreasonably efficient. While materials scientists struggle to get solar cells up to 30% efficiency, green plants everywhere chug happily along, converting photons to bound chemical energy with effiiciencies topping 95%.

How on earth do they manage it? That solar cell just converts a photon’s energy to charge, in a single step, and then drains off the charge. But in the light-eating organism, the photon excites an electron in one atom, and the excitation goes through a long cascade of other atoms in a complex molecule like chlorophyll, presumably losing energy all the way, until it finally creates a high-energy bond in a carbohydrate at the other end.

In a world run according to classical physics, not much energy could trickle through that whole process. But direct measurements have now indicated that what passes through the photosynthesizing molecule isn’t a series of distinct particles. It appears to be a single quantum wave, which doesn’t lose its coherence.

Let me unpack that just a bit more. In the two-slit experiment, the textbook example of a quantum process, an electron passes through a shield with two openings to land on a target plane. And what we learned in the ’20s and ’30s is that the electron will act like a wave which passes through both slits at once. The peaks and troughs of the wave passing through one slit will intefere with those of the wave passing through the other slit. At some points on the target plane the two parts of the wave will reinforce each other – the electron will be more likely to show up at those places – and at some they’ll cancel each other out, so the electron can’t show up there at all. Until the rest of the world interacts somehow with the electron, forcing the wave to collapse into a particle, it will retain this wavy character. The wtave state is said to be “coherent”, until such time as a collapse makes it decohere.

What Nature tells us is, that the excited electron at one end of the photosynthetic complex remains coherent, taking all possible paths through the molecule to the other end. And it appears that the complex is so cunningly arranged, that the inefficient, energy-losing paths cancel each other out, while the efficient paths enhance one another. As a result, hardly any energy is lost. It’s a process analogous to the “try all possible answers” method by which quantum computers are expected to filter out all but the right answer to a difficult factorization problem.

Such sustained coherence isn’t supposed to be possible very far from absolute zero. Thermal disturbances ordinarily force decoherence. But it seems that evolution, that clever artificer, has found some way to fend it off.

What does all this signify?

Weird as it is, quantum mechanics really does undergird the seemingly solid physical world. Over the years, we’ve grown used to quantum effects, whether we know it or not, since transistors – and with them our whole panorama of blinking, beeping, mousing, clicking, vlogging consumer electronics world – would be so much dead silicon in a classical Newtonian world.

Every so often some maverick will come along (Roger Penrose being the most credentialed) to suggest that something about our mental lives, from free will to consciousness itself, rests in some vaguely defined fashion on quantum strangeness. And those mavericks are generally laughed out of court, with very little hearing. Brains, neurons, proteins, are so big, and quanta are so small!

Now, the likes of Frank Capra may not deserve much hearing. But the bald assertion that quantum effects can’t figure in to the workings of the brain, because neurons, and even neural synapses, are several orders of magnitude larger than elementary particles, never really made sense. Geiger counters are several orders of magnitude larger still, but their macroscopic behavior will differ, depending on how the Schroedinger wave cookie crumbles.

Thanks to this article, the notions that free will, or consciousness itself, might be quantum-generated effects within the brain, have instantly become orders of magnitude more respectable.

In amore practical terms, the new result raises the faint possibility that plants and microbes may eventually teach us how to triple the efficiency of our solar systems. Why faint? Precise calculation of the quantum states of something as simple as a lithium atom push the limits of today’s supercomputers. To model the green sulphur bacterium’s “Fenna-Matthews-Olsen antenna complex” , its chlorophyll cradled by the attendant chromophores that maintain its subtle balances, would push the limits of Douglas Adams’ Deep Thought.

Some enterprising bioengineer may find an ingenious workaround to avoid brute force calculation. But unless she does, chlorophyll will keep most of its quantum secrets until long after we humans have either solved our CO2 problems by other means, or brought our own quantum computer technology into its full maturity , or descended into barbarism.

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Teachers’ organization finds a truth inconvenient

November 27, 2006

The producer of An Inconvenient Truth offered to distribute 50,000 copies of the DVD to schools for free. The National Science Teacher’s Association refused to accept the gift.

Why? Because it might jeopardize the funds Big Oil regularly pumps into science curricula. See, this is why the private sector is where you should always turn for things like education. Unlike that nasty gummint, the private sector is altruistic, and wholly free of any agenda. Especially from those icky liberal agendas, like telling kids stuff that scientists know.

Poor Al Gore. He shoulda made sure to have lots of product placement for Coca Cola in the film, then maybe he and his producer could have snuck a little science into our science classes.

[Update: in view of a NSTA press release pointed out by commenter “anonymous”, the first para should have said “offered 50,000 free copies of the DVD to NSTA for distribution”. The sticking point appears to have been the distributing, rather than the acceptance of the gift.]

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The Cheese Stands Alone

November 14, 2006

The U.S. is now the only holdout. The world’s deputy global warming bad boy, Australia, has joined the reality-based community, and will start playing the Kyoto side of the fence. As America’s biggest G-W Denier, Senator Inhofe (R-Toto), is forced to take his fingers out of the ears of the Senate Environment Committee, Barbara Boxer (D-Green as Grass) will pick up the gavel and a megaphone. Perhaps even the High Sheriff Global Warming Bad Boy will put some chips down in the game now.

About time would have been six years ago. But I’ll take it.

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Carbon return desk II

August 27, 2006

So, as I posted a couple of days ago, the standard – and surprisingly well developed – technique for carbon sequestration is to stick it way under the ground, in deep aquifers.

But there’s another contender out there accruing its fan base: sticking it onto the ground.

More specifically, there are marvelously productive soils out there, typified by the terra preta of the Amazon, which are a couple of feet deep and which turn out turnips and whatnot twice the size of those that come up in ordinary soil. It turns out this class of rich black earths is anthropogenic. Armed with the right know-how, any farmer or gardener can have it. And fight global warming withal.

The chief evangelist for terra preta was the late peripatetic Dutchman Wim Sombroek. As Nature reported on August 10:

Sombroek was born in the Netherlands in 1934 and lived through the Dutch famine of 1944 — the Hongerwinter. His family kept body and soul together with the help of a small plot of land made rich and dark by generations of laborious fertilization. Sombroek’s father improved the land in part by strewing it with the ash and cinders from their home. When, in the 50s, Sombroek came across terra preta in the Amazon, it reminded him of that life-giving ‘plaggen’ soil, and he more or less fell in love. His 1966 book Amazon Soils began the scientific study of terra preta.Since then trial after trial with crop after crop has shown how remarkably fertile the terra preta is. Bruno Glaser, of the University of Bayreuth, Germany, a sometime collaborator of Sombroek’s, estimates that productivity of crops in terra preta is twice that of crops grown in nearby soils

Sure enough, the Brazilian soils had been built up by Brazilian locals over centuries, with bone and manure and – chiefly – charcoal, which is the source of the black color. For a sense of the soil’s productivity, compare the photo of preta corn on the left, normal soil corn on the right, and like they say in the Sure commercial, your left side will convince your right side.The charcoal tends to absorb water and assorted nutrients that would otherwise sink into the aquifer. That in turn encourages massive growth of microorganisms, who not only further enrich the soil, but bind an astonishing quantity of carbon in subsoil biomass. Three feet of terra preta, it is claimed, will support a biomass equal to the rain forest above the same ground.

Expertise is still slim (What’s the optimal mix of char with other ingedients, and how does it change with climate? How compatible is formation of these soils with other green practices like no-till farming?), but it’s growing. In addition to the Bayreuth project, Danny Day runs a working production facility in Athens, Georgia, which turns farm waste like peanut shells half into biofuels and half into char. Free hydrogen is another byproduct. At Iowa State University Ames, Robert Brown is doing something similar with corn rather than peanuts. In New South Wales, Biomass Energy Services and Technology has constructed a series of char-producing engines at increasing scales.

The bottom line? Brown estimates that the U.S. corn crop alone could be used to sequester a quarter of a billion tonnes of carbon a year.

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The carbon return desk

August 21, 2006


Last week’s Nature had a fascinating pair of news features on carbon sequestration. There is, of course, no silver bullet for beating global warming. It’s going to take, you should pardon the expression, an energetic attack across several simultaneous fronts. But I had been imagining that sequestering CO2 was no more than a bit of blue-skying. Turns out all of the technology is well established, and it may solve a goodly fraction of the puzzle.

The zine’s first piece, The hundred billion tonne challenge, concerns the standard plan: capture the carbon dioxide from coal as it burns, and then inject it into deep aquifers, where it will be stabilized under pressure in dissolved form. Three ongoing industrial scale projects already exist, in Canada, Algeria, and Norway. The Norwegian plant is already economically viable, because of Norway’s hefty carbon tax, set at $50 a tonne as compared to the EU’s timid $20. A scaled-up project is under construction in Ketzin, Germany, which will stuff 60,000 tonnes of CO2 away over two years.

It had better scale up a lot further. In order to keep from shooting past the doubling mark for carbon dioxide concentrations, we’ve got 175 gigatonnes of Chevron’s favorite gas to make vanish over the next 50 years. The potential storage capacity of deep aquifers, though, is from 1,000 to 10,000 gigatonnes.

For CCS (Carbon Capture and Sequestration) to become a significant chunk of the solution worldwide will take around $80 billion in capital investment. When a coal plant is built from scratch to accommodate the integrated gasification combined cycle (IGCC), you have to pay out 20% more up front. If it has to be retrofitted, the cost gets steeper. Then there are operating costs, the IGCC burns up some energy itself, and you still only recover half the carbon dioxide the coal gives off. The bottom line: IGCC will add about 3 cents per kilowatt hour to the production costs of a coal plant, a bit under double. Enough to make you swallow hard, but when compared to the costs of global warming, not particularly alarming. As a side benefit, the technique also scours such pollutants as sulfur from the plant’s stacks.

It’s a two-step process.

In IGCC plants, the fuel — coal, fuel oil or biomass — is introduced into a hot gasifier along with oxygen and steam. This produces a fuel gas consisting mainly of carbon monoxide and hydrogen. The carbon monoxide then goes through a second ‘shift’ reaction with steam, making carbon dioxide and more hydrogen. The carbon dioxide can be relatively easily separated at this point.

The magazine’s second article dangles its limbs a little bit out into blue sky territory, but there’s some good science behind it. More next time…