A device that gets scorching hot as it captures and traps much of the sun's energy using a greenhouse-like approach could usher in an era of inexpensive electricity from the sun.

The breakthrough comes from a sunlight-absorbing material made of photonic crystals that are arranged to prevent the escape of most of the energy it captures from direct sunlight.

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The concept is similar to the way carbon dioxide molecules in the atmosphere trap the sun's energy, which keep the planet warmer than it would be if all the energy escaped to space.

In this case, infrared radiation from the sun enters the device through holes in the surface, but the reflected rays are blocked when they try to escape, explains Peter Bermel, an electronics researcher working on the device at the Massachusetts Institute of Technology. 

This blockage is achieved by a geometry that limits re-radiation of the sun's rays to a narrow range of angles — the solar disk and region right around the sun. The rest of the rays stay in the device and heat it up.

All this concentrated heat is focused on the production of high-energy photons, which are used to generate electricity via a thermophotovoltaic device.

Conventional photovoltaic cells are limited in their ability to convert sunlight into electricity due to the inefficient conversion of the broad spectrum of sunlight that hits the cells. 

This limit, known as Shockley-Queisser, is 31 percent. 

"What we're doing is a way around that limit … we are taking a very broad spectrum and then we are squeezing it, in some sense," Bermel told me.

That's because heat is absorbed across a broad range of wavelengths and then tailored to generate the high-energy photons needed to generate electricity. The approach, Bermel said, could reach efficiencies of 35 to 36 percent, which is higher than the Shockley-Queisser limit.

Thermophotovoltaic devices have existed since the 1950s, but the concentration of sunlight is traditionally done with giant and expensive arrays of mirrors. Bermel's approach, by contrast, can be made with inexpensive chip-manufacturing technology, he said.

A major expense, though, will come in the equipment needed to track the sun so that the device is always getting direct sunlight to take advantage of the selective-angle approach.

Other solar concentrators, such as the luminescent solar concentrators we reported on in November, get around the outlay for tracking technology by absorbing diffuse sunlight and pumping it to conventional solar cells.

However, some sunlight is still reabsorbed in the LSC technology and control of the wavelengths is difficult, Bermel noted.

"The nice thing about our angle-selective approach is that it can keep losses to extremely low levels, relatively speaking," he said.

What's more, the higher efficiencies of the thermophotovoltaics, in theory, could make up for the added costs of the tracking, he added.

To get there, though, will require more work on optimizing the angular selectivity of their material to reach the theoretical efficiencies.

"I don't want to oversell the research and say we've already figured it all out and it is going to be in your home in the next year or two," Bermel said. "That's not realistic."

Nevertheless, finding new ways to concentrate sunlight to generate electricity is welcome news as global concentrations of carbon dioxide reach new highs, raising worries about that other greenhouse effect.

More on solar energy breakthroughs:

• Ant frying tech could make solar cheap
• Technology could streamline solar power
• Pentagon may study space-based solar power
• Green energy ideas so crazy they just might work

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Bermel and colleagues describe their work in the journal Nanoscale Research Letters. 

John Roach is a contributing writer for msnbc.com. To learn more about him, check out his website. For more of our Future of Technology series, watch the featured video below.

Parts of the global oceans may get smellier thanks to global warming, according to a recent study.

The culprit is increased production of a sulfur-containing compound by marine plankton called dimethyl sulfide, or DMS. The sea-air smell is described variably as like cabbage or fishy and tangy.

Its link to marine plankton has been known for a while, and in 2007 scientists identified the genes responsible for its production.

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Climate scientists are interested in the smelly gas for more reasons than just tickling their inner child: it is a major precursor for aerosols that trigger cloud formation and reflect sunlight back to space.

The new study finds that "DMS is locally much more sensitive to climate change than in previous modeling studies," Philip Cameron-Smith, a researcher at the Lawrence Livermore National Laboratory in California, said in a news release.  

"The shift in emissions will change the heating patterns." 

To find out how the marine plankton and production of the gas will respond as concentrations of the greenhouse gas carbon dioxide rise, scientists plugged present day values (355 parts per million) and a future value (970 parts per million) into a global ocean biogeochemical model. 

In the future scenario, the team found that DMS emission to the atmosphere was 150 percent higher than current levels in the Southern Ocean. The plankton there benefit from melting sea ice and other ecosystem changes, which will open up cold water where they thrive.

The increased production of the plankton in the Southern Ocean, in particular a species called Phaeocystis, will compensate for a decline in production in warming waters that stunt growth, Cameron-Smith said.

Going forward, the researchers said that they may need to factor in how ocean acidification from increased levels of carbon dioxide in the oceans will affect the plankton community, and thus DMS production.

For a preview on this issue, check out the video below:

More on climate change and the oceans:

• Scientists figure out origins of sea smell 
• Plankton, base of ocean food chain, in big decline 
• Warming alters Antarctic food web, study finds 
• Arctic ice melt sparks plankton blooms 
• Scientists unravel recipe for ocean's biological blooms 

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Findings are published in the journal Geophysical Research Letters. In addition to Cameron-Smith, co-authors include Scott Elliot and Matthew Maltrud of the Los Alamos National Laboratory; David Erickson of the Oak Ridge National Laboratory; and Oliver Wingenter of the New Mexico Institute of Mining and Technology.

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

At a glance, images of the forest fire raging in Arizona and the volcano erupting in Chile seem to suggest they are filling the atmosphere with gases and debris that will mess with the global climate, but experts say this week's events, in isolation, aren't much to worry about. 

The Willow fire in Arizona has charred at least 336,000 acres so far, filling the atmosphere with smoke, soot, and the greenhouse gas carbon dioxide. It joins a string of fires that have raged elsewhere in the U.S., including Texas and Florida.

The amount of greenhouse gases from these types of fires "can be quite substantial," Matt Hurteau, a forest ecologist at Northern Arizona University told me today. 

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To illustrate how substantial, he pointed to work led by Christine Wiedinmyer at the National Center for Atmospheric Research in Boulder, Colorado, that shows forest fires in the U.S. between 2001 and 2008 accounted for six to eight percent of total annual U.S. greenhouse gas emissions.

One fire alone, however, is a blip compared to the emissions from burning fossil fuels such as oil and coal to power the global economy.

"A common misconception is that fire emissions are huge compared to fossil fuel emissions," Beverly Law, a forest ecologist at Oregon State University told me today. "They are not, really. Fossil fuel emissions trump everything."

Fire projections
But the fires burning in Arizona and elsewhere along the southern tier of U.S. do fit projections from models of global climate change that suggest the buildup of greenhouse gases in the atmosphere will cause the southwest, over the long term, to become drier, Law added.

"We just can't say there is a direct cause and effect right there," she said.

In fact, historical forest management decisions in Arizona play a major role in the severity of fires there, Hurteau said. In the ancient past, the ponderosa pine forests burned frequently and, as a result, were open and had a grassy understory. The grass, in turn, served as fuel for forest fires.

Beginning in the 1800s, pioneer settlers moved west and grazed the forests with their livestock, which reduced the fuels. Then, in the 1900s, a policy of fire suppression led to increased forest density. "Now we've got these really dense forests that are prone to this type of wildfire event," he said.

The effect of this management on forest fire ecology is independent of the climate signal. What's more, it is the weather on any given day that drives the severity of fire.

"To say that climate change is causing that weather on that day, we can't do that because climate is the longer term trend," Hurteau said.

Nevertheless, long term climate trends suggest the southwest will become drier, thus more prone to wildfire. More wildfire, in turn will put more greenhouse gases into the atmosphere, which should lead to more changes in the global climate, he noted.

Volcanoes and cooling
Volcanoes, on the other hand, can potentially cool the climate by spewing the gas sulfur dioxide into the stratosphere where it blocks sunlight from reaching Earth, thus causing cooling. The eruption of the Puyehue-Cordón Caulle volcano in Chile, however, doesn’t appear to have done that.

"It wasn't a massive injection of SO2," Alan Robock, an environmental scientist who studies the connection between volcanoes and climate, told me today. "While it shut down air traffic over Argentina and Chile because of the ash, we won't be able to see the climate effect."

The last time a volcanic eruption cooled the climate was the 1991 eruption of Mt. Pinatubo in the Philippines, which caused global temperatures to cool by about half a degree Celsius for a couple of years.

The dramatic images of the Puyehue-Cordón Caulle show a giant ash cloud. The particles will fall out quickly, creating havoc locally, but they don't have a long-term climate effect.

A cooling effect will eventually comes from an explosive eruption that puts sulfur into the stratosphere, Charles Stern, a geologist at the University of Colorado at Boulder told me today.

"And that's good, we could use a little cooling right now," he said.

In fact, scientists have begun to discuss the idea of intentionally filling the stratosphere with sulfur to mimic the cooling effect of a Pinatubo-style eruption. Stern and Robock, though, said this geoengineering approach isn't a good idea due to the costs and other side effects.

"I think we are just going to have to wait for a volcano to do it," Stern said.

More stories on fires, volcanoes and climate change

• Photos: Puyehue-Cordon Caulle volcano eruption seen from space
• Photos: Raging Arizona fire continues to blaze
• Volcano could mean cooling, acid rain 
• Could warming trigger volcanoes, quakes
• U.N.: Warming makes for bigger forest fires
• Forests in flames: Scientists see warming ties 

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John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

A team of U.S. researchers has developed a model to identify technologies that are on the fast track to constant improvement. When applied to energy, it could help investors and policymakers sort out which ones will help us avoid catastrophic climate change.

"That is certainly an inspiration for this kind of work," Jessika Trancik, an assistant professor of engineering systems at the Massachusetts Institute of Technology, told me on Wednesday. 

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International climate negotiators have set a goal of limiting climate warming to 2 degrees Celsius, which will require keeping a lid on concentrations of the greenhouse gas carbon dioxide in the atmosphere to between 450 and 550 parts per million.

"If you look at the international goals that have been set limiting greenhouse gas emissions, you can see that we really need to move quickly," Trancik said.

Design complexity
In theory, the model she and colleagues developed can be used to pinpoint which technology designs will have the sort of fast improvement over time (think Moore's law and the evolution of computer chips) to make a realistic dent in emissions.

Essentially, they found the greater a technology's complexity, the more slowly it changes and improves over time, MIT explains in a news release. Complexity here relates to design complexity.

The model mathematically breaks a system down into its individual components and then maps all the interconnections between these components. The team found that certain patterns of interconnection can create bottlenecks that cause a technology's improvement to go in fits and starts.

Previously, researchers have compared things such as which energy technologies are moving faster by looking at their experience curve — the cost of an item against its cumulative production, James McNerney, a graduate student at Boston University, explained to me.

Technologies with the steepest slope are seen as the best investment because they are the ones that respond most to increases in production. Make more widgets more quickly and you bring down the cost of the widget.

A better basis for prediction is needed, according to McNerney, who is the lead author of the paper published May 12 in the Proceedings of the National Academy of Sciences.

"I think our paper marks the first progress on that problem in a long while by offering one possible better basis for prediction — the engineering design of the technology as expressed by its design structure matrix," he told me in an email.

Energy technologies
According to McNerney, the model isn't ready to make any prognostications on which energy technology design is primed to help humans curb climate change, partly because the full data set to make the comparisons hasn't been collected.

("The team has collected large data sets on experience curves for energy technologies. They also have data on design structure matrices, but this harder to come by," Trancik noted).

"That data is probably out there, but stuck in textbooks, papers, diagrams, or engineers' heads, and needs a grad student willing to dive into all that," he said in his email. "Unfortunately, I haven't had time to do that yet!"

General trends in experience curves, though, are already notable, said Trancik. For example, the cost of electricity from solar power has come down "dramatically" over the lifetime of the industry whereas the cost of coal-fired electricity has been stagnant in recent decades.

"Those two I would say are at opposite ends of the spectrum in terms of rate of improvement," she said.

Of course, she added, the cost of coal-fired electricity is already low, which makes it an economically attractive technology for today.

"It is not just about making the best decisions for today, right now," she said. "You can think about balancing today against tomorrow in terms of rate of the improvement of these technologies, which I think is something that is very important for both designing technologies and investing in technologies."

Note: Post updated on Oct. 11, 2011 to more accurately reflect the scope of the data review.

More on energy and climate change:

• Ten hot green-energy trends to watch
• Green-energy ideas so crazy they might just work
• Climate change panel drafts renewable energy paper
• Obama's climate card: nuclear power
• Report: China, India seen as key to energy, climate

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John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

 

 

What will the planet's climate be like by the end of this century? The answer may lie in really, really old rocks, according to a new report that urges a coordinated research effort to study them.

Scientists have already pieced together a comprehensive record of Earth's changing climate from studies of rocks and ice that stretches back about 2 million years. The problem is that the amount of carbon dioxide already pumped into the atmosphere is 25 to 30 percent higher than at any point in that record.

"If we continue to emit CO2 into the atmosphere and don't do something about abating those emissions, by the end of this century we are looking to be where we were 35 million years ago," Isabel Montañez, a geologist at the University of California at Davis, told me.

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To understand what that amount of the greenhouse gas in the atmosphere will do to the global climate in the future, scientists are keen to study what it did to it in the deep past. Existing studies already paint a worrisome picture, noted Montañez, who chaired the team behind the National Research Council's new report.

"Those past times of higher CO2 were much warmer … and there were processes operating that don't operate in our current climate. And they lead to amplified change, accelerated warming, changes in ice sheets, things like that," she said.

For example, a massive burst of volcanic eruptions about 55 million years ago filled the atmosphere with carbon dioxide and pushed global temperatures higher. This, in turn, warmed the oceans, which released massive amounts of methane, another greenhouse gas, into the atmosphere. The methane release, in turn, accelerated the warming. The event triggered an extinction event known as the Paleocene-Eocene Thermal Maximum. Scientists view this period as a good analog to what could happen today.

Montañez and colleagues want to study this and other transitions between "icehouse" and "greenhouse" states at various sites around the world to gain a deeper understanding of these transitions in the climate. They can do this by studying cores of rock and dirt.

These sediment cores are full of shells, minerals and plants that scientists can correlate to levels of carbon dioxide and temperature.

"These are all proxies [and] the technology that allows us to define these proxies has been revolutionized in the last decade in terms of its ability to do that and to actually read time in old sediments and rocks," Montañez said.

In the distant future, scientists may look at rocks and sediment from today to better understand the transition to what geologists are starting to call the Anthropocene, or the age of man. They'll be looking for similar things.

"If you go to the end of the Anthropocene, maybe 80,000 years from now, it would look just like many of those intervals in the past," she said. "The difference is, it is just a snippet in geologic time. But for those of us living in it now, is is much more than just a snippet."

More about climate and extinction:

• Study says sixth mass extinction looms, but is preventable
• Climate change wiped out woolly mammoths, scientists say
• Lizards can't take the heat ... some are going extinct
• Glaciers played a role in ancient mass extinction
• Interactive: Trace Earth's geological turning points

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John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

If anyone thinks that climate scientist Michael Mann has been cowed by last year's controversy over stolen e-mails, known as Climategate ... or by last week's election, which could lead to congressional hearings that target Mann and his colleagues ... well, think again.

"They can threaten whatever they want," the Penn State professor told me on Sunday, after his talk at the New Horizons in Science meeting at Yale University. "I'm quite confident to fight those sorts of witch-hunt attempts."

Mann is already fighting an investigation by Virginia's attorney general, who has been pressing the University of Virginia to provide copies of Mann's e-mail correspondence from the years when he was a professor there. And at least some House Republicans have signaled that they want to mount their own investigation of climate scientists.

Although Mann didn't exactly say "Bring it on," he did note that "those on the other side of the aisle will see this as an opportunity." He doesn't think scientists will be pushed on the defensive by their congressional critics.

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"We should look at this as an opportunity for offense," he said.

What's all the fuss about?
Those House Republicans, as well as Virginia Attorney General Ken Cuccinelli, may be anxious to expose the "climate hoax." But the way Mann sees it, there's not much question that greenhouse-gas levels are going up, that global average temperatures are rising, and that industrial activity is playing a role in that rise. "You might not gather that from the nature of the discourse today," he admitted.

During Sunday's talk, he traced the chain of evidence once again, as he and fellow scientists did in research published by the Proceedings of the National Academy of Sciences. Mann's modeling of climate data shows what's known as a "hockey stick" of rapidly rising temperatures. That statistical jump has been hotly contested by climate skeptics, but Mann said the sharp rise shows up in at least a dozen other studies. "It's not a hockey stick -- it's a hockey league," he joked.

At the same time, he acknowledged that there have been uncertainties in the data, as well as missteps in the way those data have been presented.

For example, one study that became the focus of the Climategate e-mail debate used tree-ring measurements as a proxy for temperatures up to 1960, but switched to a different data set after that point. Mann said that the tree-ring data stopped reflecting true temperatures 50 years ago for reasons that are not yet fully known -- but he added that it was a mistake not to show the data anyway. "That was bad," he said. (A British inquiry into Climategate criticized the "misleading" portrayal of tree-ring data as one of the few scientific lapses in the scientists' conduct. One of the researchers said in an e-mail that he picked up the tree-ring "trick" from Mann.) 

The uncertainties have more to do with exactly how hot things will get if current trends continue, rather than whether or not global temperatures will heat up. Mann said it's not known just how much of a positive feedback effect a warmer, moister atmosphere and the increased cloud cover might have -- which is why projections for the global temperature rise by 2100 vary by several degrees. Also, it remains to be seen how well scientists are modeling the effect of weather patterns such as El Nino and La Nina. If the models are off, "maybe we can't trust what they're predicting" when it comes to climate change on a region-by-region level.

But under any scenario, the models point to "an array of potentially deleterious effects" that will accompany rising global temperatures, ranging from stronger storms to the loss of polar ice sheets.

"The ice sheets are not Republican or Democrat," Mann said. "They don't have a political agenda as they disappear."

During his talk, Mann flashed a picture of his daughter and a polar bear at a zoo. "I can't imagine having to tell my daughter when she's grown up that polar bears became extinct ... because we didn't act soon enough to combat a problem that we knew was real, but we couldn't convince the public because we faced so much opposition from a very well-funded, very well-organized effort to distract the public," Mann said.

What is to be done?
Mann said scientists "can do our best to call out the disinformation where we see it." One example of this was how Mann reacted to a Climategate op-ed written by former GOP vice-presidential nominee Sarah Palin for The Washington Post. He persuaded the Post to publish his own op-ed, responding to Palin's claims.

Mann praised the American Geophysical Union for providing resources to help set the record straight on climate science. He said journalists also should exercise their traditional role as a "critical and independent arbiter" of the policy debate, particularly in the midst of "politically motivated inquiries that we haven't seen in this country since the 1950s."

It might sound as if Mann relishes the fight, but he acknowledged that life after Climategate has not been easy for him. His routine now includes dealing with veiled death threats as well as investigations such as the one in Virginia. (The University of Virginia has reportedly run up a legal tab totaling $350,000 to fend off the state attorney general.) Mann is doing less research, and more speaking and writing. (For example, he's one of the scientists behind the RealClimate blog.)

"I spend quite a bit of time these days on what I might generously describe as outreach," he told me. "I think not every scientist should be doing this -- but more scientists should."

Update for 12:10 a.m. ET Nov. 9: During his talk, Mann praised the AGU for its role in the climate change debate, but some of that praise may have been based on reports about a campaign against global warming skeptics -- reports that the AGU later said were "inaccurate." In my report, I've revised the reference to the AGU role to reflect what the AGU says that role actually is.

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The New Horizons in Science meeting is part of ScienceWriters 2010 and is organized by the Council for the Advancement of Science Writing. I'm CASW's treasurer.

To learn more about climate change, Mann recommends the Skeptical Science website, which offers mobile apps and browser add-ons. My recommendation? Msnbc.com's climate change coverage, naturally.

Connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.