- How to Slow Climate Change for Just $15 Billion
- Video: Scientific Drones Take Flight at Earth’s Icy Poles
- Hole in Ionosphere Reveals Clues About North Korean Missile Launch
- Scientists Still Waiting to Hear From Journalists Covering Copenhagen
- First Global Map of Mercury
- Chernobyl Exclusion Zone Radioactive Longer Than Expected
Posted: 16 Dec 2009 07:10 AM PST
Weaning humanity from its fossil fuel habit will take decades, and it will take decades more for global warming to stop. But one simple measure could slow warming in some of Earth's most sensitive regions, effective immediately — and it would cost just $15 billion.
That's a rough price tag for providing clean stoves to the 500 million households that use open fires, fed by wood and animal dung and coal, to heat their homes and cook. Those fires produce one-quarter of all so-called "black carbon," a sooty pollutant that's adding to the planetary heat burden.
"We know how to cook without smoke," said Veerabhadran Ramanathan, a University of California, San Diego climatographer. "A clean stove costs $30. Multiply that by 500 million households, and it's only $15 billion. This is a solvable problem."
After floating to the atmosphere, black carbon mixes with dust to form a solar heat-absorbing particulate layer. Raindrops form around the particles, trapping even more heat. Soot deposited by the rain heats up, too.
The climate dynamics of the black carbon process have been fully described only in the last decade, but scientists now say their short-term impact sometimes rivals that of carbon dioxide. As much as one-half of the 3.4 degree Fahrenheit rise in Arctic temperatures since 1890 is attributed to black carbon. By disrupting weather patterns, it may be responsible for weakening seasonal rains in South Asia and West Africa. And black carbon is also a major reason why Himalayan glaciers, which provide water to hundreds of millions of people, are vanishing.
Unlike carbon dioxide, however, which can hang in the atmosphere for centuries, black carbon returns to Earth in less than a month. And that makes it a ripe target for immediate action. Though Ramanathan is quick to warn that eliminating black carbon is no substitute for controlling carbon dioxide emissions, which in coming centuries could have a far greater effect, he estimates that a 50% reduction in black carbon could delay the onset of severe global warming by one to two decades.
In addition to being emitted by unclean stoves, black carbon also comes from coal-fired power plants, and burning diesel fuel and forests. Halting deforestation and installing filters on power plants and cars will cost more than clean stoves, though the price would likely be small compared to the environmental, agricultural and health benefits.
In the meantime, clean stoves remain a very practical target. Black carbon emissions are not being considered as part of whatever agreement comes from the ongoing United Nations climate conference in Copenhagen, but Ramanathan hopes that regional agreements will address the problem. Many non-governmental organizations are already working to distribute clean stoves.
"We're not talking about a trillion dollar problem. We're talking about a few billion dollars. There's no downside here," said Ramanathan.
Image: Atmospheric black carbon intensity/Nature Geoscience.
Posted: 15 Dec 2009 05:04 PM PST
SAN FRANCISCO — Space is not the only place where special craft can boldly go where no man has gone before.
The earth's polar regions are incredibly difficult places for human beings to do science, so researchers are increasingly turning to unmanned aerial vehicles to make the observations they need to understand important environmental changes.
"Everyone knows researchers who have died trying to get data. Hopefully the worst we're going to have with our unmanned aircraft is we lose a vehicle or two," polar scientist Betsy Weatherhead of the Cooperative Institute for Research in Environmental Sciences at UC Boulder, said Tuesday here at the American Geophysical Union meeting.
Important but poorly understood features of the polar landscape are areas of open water surrounded by sea ice called polynyas. Scientists know that polynyas are key spots for energy transfer between the water, ice and land. They are also "incredibly important for biological activity," Weatherhead said. "Most of the primary productivity occurs right at the polynya and the ice edge."
But despite their importance, key data about what happens in and above them is missing. For example, no atmospheric measurements had been made over the Terra Nova Bay polynya in Antarctica during the winter time. During that season, manned flights are impossible.
In fact, said CIRES polar scientist John Cassano, the only way to measure how the air and water interact over the polynya is to use an unmanned aerial vehicle. And because some scientists have all the luck, the particular unmanned vehicle Cassano uses must be launched from the roof of a speeding pickup truck.
In September 2009, Cassano's team sent Aerosonde UAVs on 16 flights, including eight over Terra Nova Bay. In 130 hours of flying, the planes, which have a wingspan of about 10 feet and weigh under 35 pounds, covered 6,800 miles.
Norwegian and British teams have flown UAVs in Antarctica, but nowhere near as far as Cassano's team.
"These are by far the longest duration flights completed," Cassano said.
It's one of a series of polar research projects made possible by the tiny, unmanned planes. The British Antarctic Survey owns four UAVs and Norwegian researchers are studying albedo in the Arctic with unmanned planes. The Characterization of Arctic Sea Ice Experiment made extensive use of UAVs leaving from Svalbard Island and the Arctic MUltisensor Cryospheric Observation eXperiment (MUSCOX) sent UAVs winging over Greenland to study glacial waters.
"We really kicked the door down in the last few years [on UAV use]," said Whitehead. "I think it's the technologies and now we can get funded doing these things."
In the old days, Whitehead said, UAVs were not a major part of polar scientists' programs. Now, though, the excellent early scientific returns from UAV research have convinced an increasing number of scientists that the technology is ready.
"UAVs are proving themselves, from the start, to be a valuable asset. We're getting science on our first time out with these vehicles," Whitehead said. "And that's primarily because we can't have the data any other way."
UAVs come with a variety of price tags, from kits that only cost a few hundred dollars to fancy military-style drones that can run a million dollars, said Ute Herzfeld, a mathematician at UC Boulder.
Cassano said his team actually rented the Aerosondes. The bill for the entire month-long trip was just $150,000.
Image: CIRES. Videos: 1) John Cassano. 2) Betsy Weatherhead.
Citation: "UAV Observations of an Antarctic Polynya During Winter" by J. Cassano; J. A. Maslanik; S. Knuth. AGU 2009.
Posted: 15 Dec 2009 01:48 PM PST
SAN FRANCISCO — North Korean missile tests may sometimes flop, but their program continues to make strides in building bigger, more powerful projectiles, according to new research presented at the American Geophysical Union meeting Tuesday.
In April of this year, the country launched a Taepodong-2 missile with the intent of placing a satellite in orbit. It does not appear to have done so, though the North Korean government claims it did.
As the missile flew up and over Japan, it punched hole in the ionosphere, the upper-most layer of the Earth's atmosphere. Using the more than 1,000 GPS receivers in Japan, Kosuke Heki, a geodesy specialist at Hokkaido University, was able to compute the trajectory of the rocket by looking at the interactions between its exhaust and the charged oxygen ions in that part of the earth's atmosphere.
While the results don't dispute the conclusion that the launch was a failure, the work does provide some interesting data about the relatively mysterious North Korean missile program. For one, Heki said, their missiles have gotten better since the Taepodong-1 launch 11 years ago, which was recorded with the same dense network of GPS sensors.
Based on the holes the two missiles made in the ionosphere, the Taepodong-2 had eight times as many water molecules in its exhaust.
"This perhaps reflects improvement in the thrust of the Taepodong series," Heki wrote in the abstract for the presentation.
The work is made possible by the sensitivity of the GPS array to reductions of electrons in the ionosphere. Water molecules introduced by rocket exhaust [pdf] become positively charged by the ionosphere's oxygen ions. These H20 molecules then combine with free electrons, depleting the total number of electrons in the area. This is the hole Heki measured, and the bigger it is, the more water was introduced, the larger the rocket.
Geoff Forden, an expert on missile tracking and weapons systems at MIT, said that the technique for tracking ballistic missiles was "very interesting" and probably unprecedented. That said, it's not superior to what government satellites can accomplish.
"Their determination is still very helpful for analysts outside of the US government in determining the trajectory and therefore the missile's capabilities and characteristics, but it is not any better than the U.S. can do with its infrared satellites that observe the exhaust of the rocket during its entire powered trajectory," Forden wrote in an email. " So their method is very exciting for us [non-governmental-organization] people but not so important for governments in determining the missile's capabilities."
Though he emphasized the importance of the technique for people outside the government, Forden also questioned how accurate the GPS-array technique ultimately could be.
His own analysis of the projectile's flight, based on direct observation of a satellite image of the missile's contrail, is one major piece of evidence that the North Korean missile didn't even attempt to reach space. Instead, it took a more horizontal trajectory, consistent with a weapon, not a space launch.
Image: Alaska Department of Military and Veteran Affairs. Ground-based ballistic missile interceptor at the Missile Defense Complex at Fort Greely, Alaska.
Citation: AGU Poster. "Determination of the Trajectory of Ballistic Missiles Using a Dense GPS Array" by K. Heki; M. Ozeki.
Posted: 15 Dec 2009 12:49 PM PST
Around 650 climate scientists have signed up to assist journalists covering the Copenhagen climate talks through an on-call email service. For three different shifts, day and night every day from Dec. 7 to Dec. 18, between three and six experts are available to the media to answer science questions related to the negotiations.
Sounds great, right? When I heard about this service, organized by members of the American Geophysical Union which holds its annual meeting in San Francisco this week, I thought it would be a way to make the job a little bit easier for those of us covering Copenhagen. The problem is, the scientists' email inbox is far emptier than they hoped, save for perhaps some cyber crickets.
"I suppose the pagentry and intrigue of Copenhagen is more mediagenic than a few hundred scientists waiting by their computers," said Mark Henderson, who studies climate and land use in China at Mills College in Oakland, California, in an email. "But explaining the science is important. How will the public judge whether their leaders have done a good job in Copenhagen if they don't know the likely results on the climate of the agreement reached there?"
So many journalists are in Copenhagen (unfortunately Wired Science couldn't be among them) that the U.N. had to stop issuing credentials at one point because there was no more room in the building. But the AGU scientists only heard from around 20 media outlets during the first week of the talks, and some days there were almost no inquiries at all.
Of the many possible explanations for this, one that comes to mind is that journalists may be unaware of the service. This may be part of the problem, but I don't think it's the whole reason. AGU is particularly adept at handling press and routinely attracts a couple hundred journalists and public information officers to its annual meeting, being held this week in San Francisco. I heard about the service from an AGU press release earlier this month, and was reminded of it by one volunteer scientist, Katherine Hayhoe, who was twittering about it.
We can be fairly certain it's not because the science is easy, and journalists don't need much help with it. Though some of us have covered the subject to the point of having a pretty good understanding of the science, none of us understand it all. And there are plenty of journalists who understand very little. Maybe it's possible that the science is so hard to understand that most journalists covering Copenhagen aren't even bothering with it.
One good sign is that the journalists that are taking the scientists up on their offer seem motivated by the possibility of improving the accuracy of climate science coverage in the press, said Stacy Jackson, a climate scientist at UC Berkeley who helped organize the project.
Whatever the reason for the low turnout, I hope it won't discourage the scientists who volunteered to help from reaching out to the media in new ways in the future.
"It's frustrating to spend my days working with data that show clear and alarming trends, then to read that a substantial number of people think that "climate change" is either a hoax or not of concern," Henderson said. "Even after this week is up, I hope the lines of communication between scientists and journalists, and on to the public, might be kept open."
Journalists inquiries should be made here: email@example.com
Image: Press conference at the Copenhagen climate talks./Flickr/UN_Climate_Talks
Posted: 15 Dec 2009 11:51 AM PST
SAN FRANCISCO — The first ever global map of Mercury was released here Tuesday at the American Geophysical Union meeting.
Messenger completed the last of its three flybys of the planet on September 29th. The release of the map marks a new phase of the mission for the spacecraft, which will now orbit the sun's innermost planet for a year.
The U.S. Geological Survey built the map from 917 images of variable resolution and lighting conditions, but sophisticated software was able to match up planetary features from different images to create the near seamless mosaic.
Citation: AGU Poster. "Near Global Mosaic of Mercury" by K. J. Becker; M. S. Robinson; T. L. Becker; L. A. Weller; S. Turner; L. Nguyen; C. Selby; B. W. Denevi; S. L. Murchie; R. L. McNutt; S. C. Solomon.
Posted: 15 Dec 2009 11:32 AM PST
SAN FRANCISCO — Chernobyl, the worst nuclear disaster in the human history, created an accidental laboratory to study the impacts of radiation — and more than twenty years later, the site still holds surprises.
Reinhabiting the large dead zone around the accident site may have to wait longer than expected. Radioactive cesium isn't disappearing from the environment as quickly as predicted, according to new research presented here Monday at the meeting of the American Geophysical Union. Cesium 137's half-life — the time it takes for half of a given amount of material to decay — is 30 years, but the amount of cesium in soil near Chernobyl isn't decreasing nearly that fast. And scientists don't know why.
It stands to reason that at some point the Ukrainian government would like to be able to use that land again, but the scientists have calculated the cesium's ecological half-life — the time for half the cesium to disappear from the local environment — is between 180 and 320 years.
"Normally you'd say that every 30 years, it's half as bad as it was. But it's not," said Tim Jannick, nuclear scientist at Savannah River National Laboratory and a collaborator on the work. "It's going to be longer before they repopulate the area."
In 1986, after the Chernobyl accident, a series of test sites was established along paths that scientists expected the fallout to take. Soil samples were taken at different depths to gauge how the radioactive isotopes of strontium, cesium and plutonium migrated in the ground. They've been taking these measurements for more than 20 years, providing a unique experiment in the long-term environmental repercussions of a near worst-case nuclear accident.
In some ways, Chernobyl is easier to understand than DOE sites like Hanford, which have been contaminated by long-term processes. With Chernobyl, said Boris Faybishenko, a nuclear remediation expert at Lawrence Berkeley National Laboratory, we have a definite date at which the contamination began and a series of measurements carried out from that time to today.
"I have been involved in Chernobyl studies for many years and this particular study could be of great importance to many [Department of Energy] researchers," said Faybishenko.
The results of this study came as a surprise. Scientists expected the ecological half-lives of radioactive isotopes to be shorter than their physical half-life as natural dispersion helped reduce the amount of material in any given soil sample. For strontium, that idea has held up. But for cesium the the opposite appears to be true.
The physical properties of cesium haven't changed, so scientists think there must be an environmental explanation. It could be that new cesium is blowing over the soil sites from closer to the Chernobyl site. Or perhaps cesium is migrating up through the soil from deeper in the ground. Jannik hopes more research will uncover the truth.
"There are a lot of unknowns that are probably causing this phenomenon," he said.
Beyond the societal impacts of the study, the work also emphasizes the uncertainties associated with radioactive contamination. Thankfully, Chernobyl-scale accidents have been rare, but that also means there is a paucity of places to study how radioactive contamination really behaves in the wild.
"The data from Chernobyl can be used for validating models," said Faybishenko. "This is the most value that we can gain from it."
Citation: "Long-Term Dynamics of Radionuclides Vertical Migration in Soils of the Chernobyl Nuclear Power Plant Exclusion Zone" by Yu.A. Ivanov, V.A. Kashparov, S.E. Levchuk, Yu.V. Khomutinin, M.D. Bondarkov, A.M. Maximenko, E.B. Farfan, G.T. Jannik, and J.C. Marra. AGU 2009 poster session.
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