How Will Clouds Respond to Climate Change?

Clouds will respond to climate change in ways that further heat the planet, a new study suggests.

The research, published yesterday in the journal Science, appears to solve one of of the biggest remaining mysteries in climate science: How well do computer climate models predict the behavior of clouds?

That's important because clouds can work to cool or heat the Earth, depending on the type of cloud and where it sits in the atmosphere. Clouds cool the planet by reflecting incoming radiation from the sun. They heat it by trapping outgoing radiation from the planet's surface. The question scientists have been struggling to answer is which of these two effects will dominate as climate change intensifies.

"Clouds are really, I would say, the biggest uncertainty in understanding how much warming we're going to get in the future," said study author Andrew Dessler, an atmospheric scientist at Texas A&M University. "And up until my paper, all we really had were the models. We had no idea if the models were completely wrong."

Computerized climate models vary widely in their predictions of how clouds will respond to long-term climate change. A few models predict clouds will be neutral players, neither compounding warming nor counteracting it, while others predict clouds will exacerbate warming.

Some climate skeptics have alleged that models "got clouds completely wrong," Dessler said. He believes that his paper, which suggests long-term climate change will create a positive feedback from clouds that produces additional heating of the planet, "shows that models are doing a reasonable job as a group."

A bolt from Cancun
One of those skeptics is Roy Spencer, a climatologist at the University of Alabama, Huntsville. He issued a statement yesterday attacking Dessler's study, calling its "central evidence weak at best, misleading at worst."

Spencer has published a paper arguing that clouds will cool the planet and counteract warming. He drew on that work to argue that Dessler's study confuses the cause and effect of warming by failing to take into account the idea that changes in clouds drive temperature, rather than temperature changes driving cloud behavior.

Dennis Hartmann, a professor of atmospheric sciences at the University of Washington, agreed with Dessler.

"I do think it's very significant that this analysis shows that a strongly negative, short-term cloud feedback is very unlikely, based upon the evidence, and that positive cloud feedback is more likely," said Hartmann, who did not contribute to the new study. "Current climate models vary widely on their assessments of cloud feedback. But if you were forced to draw consensus on what models are saying so far, they're saying that cloud feedback is moderately positive."

The new analysis is based on the first 10 years of data collected by an instrument flying aboard NASA's Terra satellite that monitors how much radiation is entering and leaving Earth's atmosphere. The instrument, known as CERES (short for "Clouds and Earth's Radiant Energy System"), began collecting information in March 2000.

Dessler used the data to determine how the El Niño-Southern Oscillation weathercycle affected the amount of radiation leaving the atmosphere over a 10-year period -- an indirect measurement of cloud behavior and the ensuing climate response.

A 10-year glimpse of cloud behavior
That's not a precise analogue for cloud behavior in response to long-term climate change, he said.

The latter "is really what we care about," Dessler added. "In order to understand how clouds are going to respond to long-term warming, you have to wait until there is long-term warming. That will take decades. Looking at the short-term is the best we can do right now."

Hartmann noted that the warming observed during an El Niño cycle of a year or two is different than the long-term climate change prompted by human activities that produce greenhouse gases like carbon dioxide.

El Niño warms the tropics, whereas climate change driven by greenhouse gases warms the planet up everywhere, Hartmann said. But the scientist said he thought Dessler's approach still amounted to a "useful diagnostic tool" for trying to understand whether climate models' representation of clouds is on the right track.

Meanwhile, Dessler said his next step is aimed at identifying how well individual climate models do predicting cloud behavior, by examining their output for different regions of the globe -- such as land versus ocean, or high latitudes versus low latitudes.

"This is a significantly harder problem, and it's a tougher test of the models," he said. "My hope is that looking at the spatial distribution will allow me to say, 'These models are doing a good job. These models are doing a terrible job.'"

Interfering with skeptics' 'negative impact'?
In his statement attacking Dessler's study, Spencer also said he suspected, but had no proof, "that Dessler was under pressure to get this paper published to blunt the negative impact our work has had on the [Intergovernmental Panel on Climate Change]'s efforts."

Spencer appeared in Cancun accompanied by Marc Morano, founder of Climate Depot, which regularly attacks mainstream climate change science, and Lord Christopher Monckton, a British skeptic who asserted the Kyoto Protocol threatens national sovereignty and individual freedom.

In a response posted yesterday afternoon on the blog "RealClimate," Dessler said his disagreement with Spencer stemmed from their very different views about the cause of the El Niño-Southern Oscillation (ENSO), quoting an e-mail exchange with Spencer.

"My position is the mainstream one, backed up by decades of research," Dessler wrote on the blog. "This mainstream theory is quite successful at simulating almost all of the aspects of ENSO. Dr. Spencer, on the other hand, is as far out of the mainstream when it comes to ENSO as he is when it comes to climate change. He is advancing here a completely new and untested theory of ENSO -- based on just one figure in one of his papers (and, as I told him in one of our e-mails, there are other interpretations of those data that do not agree with his interpretation)."

He added: "And as far as my interest in influencing the policy debate goes, I'll just say that I'm in College Station this week, while Dr. Spencer is in Cancun."

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

Kathie and Graeme's Christmas Party 2010

Baby aspirin cuts risk for prostate cancer mortality

According to a new report in The Lancet, just published on line, a daily aspirin regimen reduces deaths due to several common cancers — including those caused by prostate cancer.

The report by Rothwell et al., in this week’s issue of The Lancet, is based on data from eight randomized trials (including 25,570 patients and 674 cancer deaths). These trials were originally designed to evaluate the impact of aspirin therapy on risk for cardiovascular events.

We can summarize the data from these trials as follows:

• When data from all eight trials are considered), patinets randomized to aspirin therapy had a statistically signifciant reduction in risk of death due to any form of cancer (odds ratio [OR] = 0.79).
• When individual patient data — available from seven of the eight trials (23 535 patients, 657 cancer deaths) — were analyzed , benefit was apparent only after 5 years’ follow-up.
  • For all cancers, the hazard ratio [HR] was 0.66.
  • For gastrointestinal cancers, the hazard ratio was 0·46.
• The 20-year risk of cancer death (based on 1,634 deaths in 12,659 patients in three trials) remained lower in the aspirin groups than in the control groups.
  • For all solid tumors, HR = 0·80.
  • For gastrointestinal cancers, HR = 0·65
• The time to evidence of an effect on deaths (the “latent period”) was about 5 years for oesophageal, pancreatic, brain, and lung cancers, but was longer for stomach, colorectal, and prostate cancers.
• The overall effect on 20-year risk of cancer death was greatest for adenocarcinomas (HR = 0·66), and the vast majority of prostate cancers areadenocarcinomas.
• The benefit of aspirin therapy was unrelated to aspirin dose (75 mg upwards), sex, or smoking, but increased with age.
• The absolute reduction in 20-year risk of cancer death was 7·08 percent (range, 2·42 to 11·74 percent) at age 65 years and older.

Now we should be clear that daily aspirin therapy — even with a “baby” dose of aspirion each day of 75 mg — is not risk-free. Long term aspirin therapy is associated with such side effects as gastrointestinal bleeding and with strokes. Men who wish to consider daily aspirin therapy as a means to lower their risk for cardiovascular disorders and cancer should always consult with their physician prior to initiating such a regimen.

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Tooth decay to be a thing of the past? Enzyme responsible for dental plaque sticking to teeth deciphered

ScienceDaily (Dec. 4, 2010) — The Groningen professors Bauke Dijkstra and Lubbert Dijkhuizen have deciphered the structure and functional mechanism of the glucansucrase enzyme that is responsible for dental plaque sticking to teeth. This knowledge will stimulate the identification of substances that inhibit the enzyme. Just add that substance to toothpaste, or even sweets, and caries will be a thing of the past. The results of the research have been published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

The University of Groningen researchers analysed glucansucrase from the lactic acid bacteriumLactobacillus reuteri, which is present in the human mouth and digestive tract. The bacteria use the glucansucrase enzyme to convert sugar from food into long, sticky sugar chains. They use this glue to attach themselves to tooth enamel. The main cause of tooth decay, the bacterium Streptococcus mutans, also uses this enzyme. Once attached to tooth enamel, these bacteria ferment sugars releasing acids that dissolve the calcium in teeth. This is how caries develops.

Three dimensional structure

Using protein crystallography, the researchers were able to elucidate the three dimensional (3D) structure of the enzyme. The Groningen researchers are the first to succeed in crystallizing glucansucrase. The crystal structure has revealed that the folding mechanism of the protein is unique. The various domains of the enzyme are not formed from a single, linear amino acid chain but from two parts that assemble via a U-shaped structure of the chain; this is the first report on such a folding mechanism in the literature.

Functional mechanism

The unravelling of the 3D structure provided the researchers with detailed insight into the functional mechanism of the enzyme. The enzyme splits sucrose into fructose and glucose and then adds the glucose molecule to a growing sugar chain. Thus far the scientific community assumed that both processes were performed by different parts of the enzyme. However, the model created by the Groningen researchers has revealed that both activities occur in the same active site of the enzyme.

Inhibitors

Dijkhuizen expects that specific inhibitors for the glucansucrase enzyme may help to prevent attachment of the bacteria to the tooth enamel. Information about the structure and functional mechanism of the enzyme is crucial for developing such inhibitors. Thus far, such research has not been successful, states Dijkhuizen: 'The various inhibitors studied not only blocked the glucansucrase, but also the digestive enzyme amylase in our saliva, which is needed to degrade starch.'

Evolution

The crystal structure also provides an explanation for this double inhibition. The data published by the Groningen scientists shows that glucansucrase proteins most likely evolved from amylase enzymes that degrade starch. 'We already knew that the two enzymes were similar', says Dijkhuizen, 'but the crystal structure revealed that the active sites are virtually identical. Future inhibitors thus need to be directed towards very specific targets because both enzymes are evolutionary closely related.'

Toothpaste and sweets

Dijkhuizen points out that in future glucansucrase inhibitors may be added to toothpaste and mouthwash. 'But it may even be possible to add them to sweets', he suggests. 'An inhibitor might prevent that sugars released in the mouth cause damage.' However, Dijkhuizen doesn't expect that toothbrushes have had their day: 'it will always be necessary to clean your teeth.'

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Groningen.

Dim Stars Triple the Universe’s Stellar Tally

Dim Stars Triple the Universe’s Stellar Tally: "


There are more dim bulbs in the universe than even the most hardened pessimist might have imagined.

Astronomers who examined eight relatively nearby galaxies have found evidence of a surprisingly high abundance of faint, low-mass stars — each has about 10 times as many as the Milky Way. Those elderly galaxies are so chock-full of faint stars that the researchers extrapolate that the heavens contain up to three times the total number of stars previously estimated.

The profusion of stars also suggests that the early history of the cosmos may need a rewrite, perhaps doubling previous estimates of the total mass of stars in many of the universe’s first, massive galaxies. If so, those early galaxies would have forged stars at a much more prodigious rate, says Pieter van Dokkum of Yale University. He and Charlie Conroy of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., describe their study in a paper appearing online in Nature on December 1.

Van Dokkum and Conroy set out to determine whether spiral galaxies like the Milky Way have a different mix of low-mass and high-mass stars than is found in elliptical galaxies, which tend to have an older stellar population. Such differences had long been suspected but never proven.



Because even the sharpest telescopes can’t resolve individual faint stars in galaxies millions of light-years beyond the Milky Way, the team examined light from the central portion of each of eight massive elliptical galaxies — four in the Coma cluster and four in the Virgo cluster. Such galaxies are thought to account for one-third of the stellar mass in the universe. Massive galaxies that existed during the first billion or so years of cosmic history are believed to be the early ancestors of these ellipticals.

Spectra of light from the galaxies revealed two chemical fingerprints, absorption by sodium atoms and by iron hydride, which are unusually strong in faint red dwarf stars that have less than one-third the sun’s mass. The strength of the absorption features indicates that red dwarfs account for 80 percent of the number of stars in elliptical galaxies and 60 percent of the total stellar mass in those galaxies.

“Extrapolating from the central regions of these eight galaxies to the entire universe is somewhat hazardous, but if the galaxies are typical examples of their class it may well lead to a tripling” of the total number of stars in the cosmos, van Dokkum says.

One caveat, says Richard Ellis of Caltech, is that the researchers assumed that red dwarfs in the elliptical galaxies have the same chemical composition as red dwarfs in the Milky Way. It’s possible, he notes, that the strong absorption signals don’t indicate a very large population of the dwarfs. Instead, those measurements might be explained by a smaller population of red dwarfs that happen to be richer in sodium and iron hydride than red dwarfs in the Milky Way.

Nonetheless, the study provides “the most convincing observational test” that the mix of stars — heavyweights and lightweights — varies dramatically from one type of galaxy to another, says Ellis. Instead of using the assortment of high- and low-mass stars in the Milky Way as a standard template, such differences need to be taken into account when astronomers estimate the stellar mass and star-formation rates of galaxies from the early universe, van Dokkum and Conroy note.



Images: 1) The elliptical galaxy ESO 325-G004, which may harbor 10 times as many dim stars as the Milky Way. Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) 2) Astronomers examined the chemical signature of small, dim stars called red dwarfs (right) in eight elliptical galaxies and found that they are much more numerous than red dwarfs in the Milky Way (left). The finding suggests that the total number of stars in the universe could be up to three times higher than previously thought. Credit: Yale University

See Also:

• Calling All Amateur Astronomers: Help Solve a Mystery
• Odds of Finding Earth-Size Exoplanets Are 1-in-4
• Early Galaxies Formed Stars Fast Because They Had More Gas
• Sharpest Image Yet of Massive Galaxy Collision
• Milky Way May Fizzle Out Sooner Than Expected
• Galaxies Discovered in Their Awkward Teen Phase

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Could This Be How Stonehenge Was Actually Built?

Could This Be How Stonehenge Was Actually Built?: "

One of the most puzzling mysteries is how Stonehenge, the prehistoric circle of stones in England, came to be. We know it was built around 4500 years ago, and the stones came from Wales, some 250km away… but how?

Of course, back then, it wasn’t so easy to transport stuff around the country – especially not 60 bluestones which are said to weigh between two and four tons each. Several theories have been bandied about over the years of how the stones were transported, including sledges; rafts along the rivers; and that Merlin himself used his magic to gather the stones there.

This week, an engineer and former BBC TV presenter, Garry Lavin, tested his theory that wicker baskets made from willows were used to roll the stones all 250kms from the quarry in Preseli Hills, Wales, to Salisbury, in Wiltshire, England. He built one himself, using willow and alder saplings, and enlisted several friends to help roll a one-ton boulder along the ground.

He thinks oxen might’ve helped roll the baskets in some parts, and that rivers could have floated them downstream. But it’s the baskets which Lavin is sure had a huge part in the formation of Stonehenge – and as he’s currently building a maxi-basket to move a five ton stone, we may soon find out the answer. Unless aliens decide to show up and show us otherwise, of course. [Daily Mail]

Tagged:

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Your Next Computer Chip Revolution Unveiled by IBM: Sexy Blend of Lasers, Electrons

IBM's just unveiled a new breakthrough chip tech: CMOS Integrated Silicon Nanophotonics. Confused? It's actually pretty astonishing, promising chip-sized supercomputer power in the near future. Now you're interested....
We've known for a while that optical technology is going to be the next big revolution in computing--it's simply faster than pure electronics, and means you can get even greater performance with lower power demands from similar-sized devices. The trick is about blending optical technology at a nanoscopic scale with existing silicon electronics--and this is where CMOS ISN has achieved a breakthrough. It means thanks to research at IBM's research facility, it's now possible to integrate optical computing technology and conventional electronics onto a single slice of silicon.
Optical signals can carry more information more swiftly than electronics can manage--it's why Intel's fiber-optic Light Peak connection cables may quickly supersede newcomer USB3--and the associated electronics can eat less power than normal silicon tech. This means when you mix the systems together on chips, you can get up to ten times more integration density than is possible with current chip fabrication tech. Putting a bunch of them together results in a computer that shoots data around at rates that would seem incredible compared to current designs.
IBM's trick requires no particularly hefty refits of existing CMOS production plants, and means all the nanoscopic optical equipment like modulators and photodetectors can be built right in to a more conventional chip--meaning there's no need to add in extra-special chips to access the benefits of optical tech when you're building an integrated optical computer.
Still confused? The upshot: Chips can be significantly faster, and still consume less electrical power. Enough that IBM thinks the chips could build an exascale supercomputer, roughly 1,000 times faster than the fastest machine that exists. The side effect of this, of course, will be consumer-level systems that could be as powerful as today's research supercomputers. Your laptop in several years may be driven by chips packed with frikking laser beams, people.
To read more news on this, and similar stuff, keep up with my updates by following me, Kit Eaton, on Twitter.

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