Extreme weather aside, what will climate change do to nice, mild days?
On average, Earth will have 10 fewer days of mild and mostly dry weather by the end of the century, researchers estimate.
January 23, 2017 —Climate scientist Sarah Kapnick said her friends kept asking her for help selecting a wedding date in hopes of finding fair weather. That experience, despite her inability to make such precise forecasts months or more in advance, inspired Dr. Kapnick to take part in a first-of-its-kind study to reframe broad climate change findings with more relatable terms.
Instead of highlighting an anticipated increase in extreme weather events, such as hurricanes, droughts, floods, and blizzards, she worked with a research team to focus on the impact climate change will have on "pleasant" weather days. Their study, published online Wednesday by the journal Nature Climate Change, used high-resolution computer modeling to predict that Earth will see an average decrease of four fair-weather days per year by 2035 and an average decrease of 10 such days by the end of the century – creating fewer opportunities for enjoyable outdoor nuptials.
The researchers defined mild weather as between 64 and 86 degrees Fahrenheit with low humidity and little to no rain.
"It's the type of weather where you can go outside and do something fun," the study's lead author, Karin van der Wiel, a meteorology researcher at Princeton University and the National Oceanic and Atmospheric Administration (NOAA), told the Associated Press. "It's not too cold. It's not too hot. It's not too humid."
These Goldilocks-approved weather conditions have occurred an average of 74 days per year globally during the past three decades – a figure that is expected to drop to 64 during the final two decades of the century. But localized changes will vary widely based on season and region, the study found. In the United States, for instance, summer will likely lose nine mild days by the century's end, but it could regain nearly as many mild days in the winter, spring, and fall. Other parts of the world, however, face extreme losses in "pleasant" weather.
"The changes are more dramatic in parts of the developing world, where you have high concentrations of populations," said Kapnick, who coauthored the study with Dr. van der Wiel and NOAA's Gabriel Vecchi. The team relied on middle-of-the-road projections for global warming and ran computer simulations without dramatic reductions in carbon emissions.
They found that tropical regions and most of Africa, eastern South America, South Asia, and northern Australia are projected to see the most pronounced loss in mild weather. Rio de Janeiro, for instance, is expected to lose an average of 40 mild days, while Seattle and cities in northern Europe could see an increase in mild weather days. Since shifts in good weather can impact a wide array of business activity, including tourism and construction, this uneven impact of climate change could bring uneven economic changes as well.
In a separate study, Kapnick joined with economist Derek Lemoine to study the socioeconomic impacts of the latest projections. They found that future warming trends could "raise the expected rate of economic growth in richer countries, reduce the expected rate of economic growth in poorer countries, and increase the variability of growth by increasing the climate's variability," suggesting that climate scientists need to shift their focus.
In their study, Kapnick, van der Wiel, and Dr. Vecchi wrote that their findings use data that is "highly relatable to the public" to describe the near-term impact of climate change.
"The presented information may therefore be used to communicate climate variability and climate change impacts to a broad audience," they wrote.
Even so, some fellow scientists have questioned the purpose behind the study's focus on mild weather.
"It is in the extremes when things break and damage occurs," Chris Field, a Stanford University climate scientist who led an international study of extreme weather, told the Associated Press.
Gerald Meehl, a scientist with the National Center for Atmospheric Research who also studies extreme weather, noted that, although a decrease in mild weather may not cause as much economic hardship as extreme weather, there are other factors worth considering, including tourism "or simple human enjoyment."
This report includes material from the Associated Press.
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Larson C fracturing: Only 12 miles connect massive ice shelf to Antarctic
The giant rift in the Larsen C ice shelf has advanced more than 6 miles since January 1st, the MIDAS project announced on Friday.
January 23, 2017 —What might become one of the largest icebergs ever hangs by a thread from Antarctica's Larsen C ice shelf.
The vast rift has grown more than 6 miles longer since January 1, leaving an area reportedly the size of Delaware connected to the main shelf by a mere 10 percent of the total length, the British MIDAS project announced Thursday. Its loss threatens to destabilize the fourth-largest Antarctic ice shelf.
When exactly that will be is unknowable, according to project leader and Swansea University glaciologist Adrian Luckman: "Although you might expect any extension to hasten the point of calving, it actually remains impossible to predict when it will break because the fracture process is so complex," he told BBC News. "My feeling is that this new development suggests something will happen within weeks to months, but there is an outside chance that further growth will be slow for longer than that.”
This break has been a long time coming, as The Christian Science Monitor reported earlier this week: what began as a tiny crack in the 1960s is now 90 miles wide, and almost one-third of a mile deep. Most of that change has taken place in just the past few years.
While many instinctively assume that the calving is a result of global climate change, that may not necessarily be the case: It’s cracking, not melting. "This is probably not directly attributable to any warming in the region, although of course the warming won't have helped," Dr. Luckman told NPR. "It's probably just simply a natural event that's just been waiting around to happen."
This distinction differentiates it from its two companions, Larsen A and B, whose respective breakups in 1995 and 2002 appear to have been hastened by a series of warm summers.
Nor will this cracking directly contribute to the rise of the seas, as the Larsen C shelf already floats in the ocean. It can't affect water levels any more than a melting ice cube can cause a glass to overflow. Ice shelves do, however, play an indirect role.
Glaciers are dynamic rivers of ice that flow under the pressure of their own weight. Without the dams of floating ice shelves to hold them back, the glaciers that cover much of the Antarctic continent would be freer to flow into the ocean, displacing water and raising ocean levels.
Even after the rift tears through, as much as 90 percent of Larsen C will remain. However, the loss has the potential to destabilize the entire shelf. Previous work by the MIDAS project analyzed this risk, and scientists worry that Larsen C may eventually follow the example of its neighbor Larsen B, which “splintered and collapsed in just over one month,” according to the NASA Earth Observatory.
In such an event, all the ice held back by the shelf could raise global sea levels by as much as four inches, the BBC reported earlier this month.
If Larsen C goes the way of A and B, it will join a dozen other major ice shelves that have either broken up or significantly retreated in the last few decades, including Prince Gustav Channel, Larsen Inlet, Wordie, Muller, Jones Channel, and Wilkins, the BBC reports.
on: Today at 06:19 AM
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'Consensus' on climate change: what that does and doesn't mean
Agreement on basics of climate science is very strong, while there is much less certainty about specifics such as how fast temperatures or sea levels can be expected to rise.
By Amanda Paulson, Staff writer
Boulder, Colo. — Discussions of climate change often pit two polarized sides talking past each other, split along partisan political lines.
Little wonder that it can seem hard to sift the answer to a fundamental question: Just how certain is the science, and how much do scientists agree?
The answer isn’t simple in all its details, because climate itself isn’t a simple thing. But the answer is also in many ways less complicated than the media rhetoric implies.
Listen to climate scientists themselves, and what emerges is that consensus about the basics of climate science is very strong, while there is much less certainty about specifics such as how fast temperatures or sea levels can be expected to rise.
When it comes to core concepts of climate change on a global scale, the scientific agreement is broad and clear-cut: Climate change is happening. The Earth is getting warmer. Human activity is largely responsible.
“Our climate system is far simpler than people think,” says James White, director of the Institute of Arctic and Alpine Research at the University of Colorado in Boulder. He likes to remind people that there are basic laws of physics at play, as immutable as the law of gravity. Global climate depends on how much energy we get from the sun, how much energy is reflected back to space, and the amount of greenhouse gases in the atmosphere.
“It’s not a belief issue,” says Professor White. Fossil fuels have been pumping more carbon dioxide into the atmosphere, and “We don’t know of any example in which greenhouse gases don’t absorb the Earth’s radiation and therefore warm the Earth up.”
That doesn’t mean the impacts of human activity are the only factor affecting climate.
Long before humans began burning fuels, Earth has seen ice ages and warm periods that scientists attribute to small shifts in the planet’s tilt and modest variations in its orbit around the sun, among other things.
Now, however, climate scientists say a warming trend is occurring even though natural factors don’t seem to predict it.
When people talk about the “97 percent” consensus among international scientists, this is the fundamental issue to which they’re referring: that human-caused climate change is already occurring.
Where the consensus starts to disappear is when it comes to more specific questions and predictions – how much and how quickly will temperature rise? How much and how quickly will sea level rise? What will the local climate effects be for specific regions? Have we passed a point of no return, or can the changes be halted? The foundation of science, after all, is skepticism, and climate models can become extraordinarily complicated very quickly.
Another issue is time frame, notes Richard Alley, a geologist at Pennsylvania State University who specializes in climate research. People tend to be interested in predictions a year or a decade out, but right now, any climate predictions for that time scale are clouded by what he calls “noise:” natural phenomena that affect climate and are impossible to know in advance. These include El Niño and La Niña, volcanic eruptions, and small changes in the sun’s brightness.
“Looking out some distance, the natural variability is still important,” says Professor Alley. “It’s in a few decades that our decisions [around how much carbon dioxide we’re adding to the atmosphere] become really important.”
For now, here’s where some of the consensus – and disagreement – lies on some fundamental issues.
Again, the basic scientific consensus here is pretty clear: Sea level is already measurably rising, the pace is increasing, and it will continue to rise. In the past century, Global Mean Sea Level has risen between 4 and 8 inches, and in the past couple decades, the rate of increase has roughly doubled.
Scientists say this is one of the easiest effects of global warming to predict: As water heats up (as is happening) it expands, and as glaciers recede and ice sheets melt, their runoff contributes to the rise.
The biggest impact, however, is expected to come from melting land ice in Greenland and Antarctica, if that occurs in large amounts. The uncertainty around that land ice – along with uncertainty on the pace of change – is what leads to very different predictions.
The National Climate Assessment, which summarizes risks to the US, projects that sea level will rise between 1 and 4 feet (0.3 to 1.2 m) by 2100. According to the most recent report by the International Panel on Climate Change (IPCC), sea levels will rise between .26 meters and .82 meters by 2100 (roughly a 2-foot rise), depending on how emissions continue. That’s an estimate that most scientists see as very conservative, particularly given the amplification that can occur, if a triggering event happens to make a large chunk of an ice sheet break off.
“You can imagine our climate system is like a pot of water on the stove, and we’re turning up the heat, but the water’s not heated up yet,” says White.
Ultimately, he, along with many scientists, agree that the current levels of carbon dioxide in the atmosphere will lead to sea level rises between 10 and 20 meters – but it may take many centuries for that to happen. “We disagree on how high sea level will go at 400 ppm, and we disagree on where the thresholds are that would give you enough carbon dioxide to melt all of Antarctica,” explains White.
Natural disasters and regional change
One of the most controversial areas of climate change involves natural disasters. Will the world see more hurricanes and storms? More droughts and floods? Are we already seeing these impacts, and is climate change to blame for recent disasters?
The research is murky. The IPCC says that “it is very likely that heat waves will occur more often and last longer, and that extreme precipitation events will become more intense and frequent in many regions.”
But there’s less data to back up increased frequency of hurricanes or tornadoes, and it can become very difficult to tease out, for any one natural disaster, whether a portion of its intensity is attributable to climate change.
And depending who you talk to, scientists offer very different predictions for regional change. “In a warmer planet, the atmosphere holds more moisture, and the potential for big rainfall gets larger and larger, so both floods and droughts increase,” says White. But which areas will get drier? Which might have more floods? “This is where the models struggle. Getting the hydrologic cycles right in a model is not easy,” he says.
How quickly will the planet warm?
Scientists have created varied complex models to make climate forecasts, and there is no consensus about how much, or how rapidly, the planet will warm. The most conservative models, assuming the lowest emissions, give an average temperature increase of about 2 degrees F over this century, while higher-emissions models suggest an increase of more than 11 degrees F over the century.
Even within a single baseline of assumptions about emissions, temperature forecasts can vary based on things like how global cloud cover will change under a given model.
Warming is likely to be more extreme at higher latitudes, and most models predict that summer sea ice will be gone from the Arctic by the end of the century.
Part of the reason for the disparity lies in the uncertainty about how carbon emissions may change over the coming century, and part lies in the complex ways in which small changes can have an amplifying effect, or a certain threshold can be crossed that leads to rapid change in a short period of time.
“We are raising CO2, [and] CO2 is having a warming effect on the climate: That’s as close to fact as scientists ever get,” says Alley. “There’s such an interwoven fabric of evidence at this point that any argument about it is noise.” And asking scientists about those basic facts gets 97 percent or more to agree pretty consistently, he says. “But if you write anything specific [around detailed predictions] you’ll find somebody will object to it, because there are several studies and they’re all slightly different.”
The debate among climate scientists isn't always just about the details of specific forecasts. A few scientists worry aloud that a kind of groupthink and peer pressure is compromising public confidence in the quality of published research, as academics see their careers as tied to toeing acceptable lines.
But that critique isn't widely shared. In fact, given all the inquiry into different climate issues, many scientists say the big need is actually to help the public get a better sense of the strong consensus that exists on the core points that global warming is real and that it threatens significant harm to ecosystems and human societies.
on: Today at 06:16 AM
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Calculating your role in melting Arctic sea ice: How the CO2 emissions add up
Climate scientists have calculated just how fast humans' carbon emissions are melting Arctic sea ice in a new study. Just 75 miles in a fossil-fuel powered car equals one square foot of ice melted Arctic ice.
By Eva Botkin-Kowacki, Staff writer 1/23/2017
Sorry polar bears, the Arctic Ocean might be free of sea ice before 2050.
According to new calculations, for every metric ton of carbon dioxide emitted, about three square meters (approximately 32.3 square feet) of Arctic summer sea ice disappears. And, with humans currently emitting about 35 to 40 million tons of CO2 each year, the future doesn't look very frozen.
It's not hard to rack up those emissions. About 2,433 miles of driving – roughly the distance from Washington, DC to Las Vegas – or just one seat on a return flight from New York to London – on average produces a metric ton of CO2 emissions. Or, for those who aren't long-distance travelers, just over 75 miles of driving in a typical fossil-fuel powered car produces enough emissions to melt one square foot of ice.
That's according to Dirk Notz, head of a research group at the Max Planck Institute for Meteorology in Germany that studies sea ice. Dr. Notz calculated the relationship between CO2 emissions and the loss of Arctic summer sea ice as lead author of a paper published Thursday in the journal Science.
"Our study now provides individuals with the sense that their own individual actions make a difference," Notz tells The Christian Science Monitor in a phone interview. "If I decide to drive my car a little less or to buy a car that uses less fuel, for example, all these little actions will make a difference for sea ice."
Technically, Notz has calculated when there will be less than 1 million square kilometers (386,000 square miles) of Arctic sea ice left in September, after summer melting, a measurement commonly used to define sea ice free conditions. Winter temperatures will continue to freeze parts of the Arctic Ocean.
That 1 million square kilometers "seems like quite a lot of ice," says Walter Meier, a sea ice researcher at the NASA Goddard Space Flight Center who was not part of the study. "But in reality it's not that much."
"The Arctic Ocean will be for all intents and purposes a blue Arctic Ocean" when that happens, he says.
Dr. Meier says Notz's calculations oversimplify the relationship between carbon emissions and Arctic sea ice loss. "The climate system is, in reality, a lot more complex than that," he says in a phone interview with the Monitor.
Kevin Trenberth of the the Climate Analysis Section at the National Center for Atmospheric Research, who also was not part of the research, agrees. "I think it's too simple because it doesn't deal with ocean transports and it doesn't deal with atmospheric transports," he says in a phone interview with the Monitor. Furthermore, Dr. Trenberth says, seasonal variations complicate trends so the calculated relationship between CO2 and sea ice loss could be off.
Although he questions their methods, Trenberth agrees with the researchers that the Arctic will see an ice-free September. And, he says, it could be as soon as in the 2030s.
What would a world with a blue Arctic look like?
"We're changing ice that has been around for many years to, mostly, ice that forms every year," James Overland, an oceanographer at the NOAA Pacific Marine Environmental Laboratory who was not part of the study, tells the Monitor in a phone interview. In decades past, ice would build up and become thicker through the winter. While some of that ice would melt during the summer, most would remain to accumulate more ice year after year.
Animals like polar bears and walruses use those thicker sheets of ice as a sort of home base when hunting. Thinner and more fragmented ice could destroy their lifestyles. And that's not just true for animals; a disrupted icy ecosystem could make it more difficult for native human populations to hunt and forage too.
But loss of Arctic sea ice probably won't just have a local impact.
"Arctic sea ice regulates the temperature of our planet by cooling the Atlantic and Pacific waters," David Barber, a sea ice and climate scientist at the University of Manitoba, who was not involved in the research, writes in an email to the Monitor.
Some research has suggested that less Arctic ice could lead to a weakening of the jet stream, an atmospheric system that affects the global climate. This shift could be leading to more extreme weather events, like flooding, freezing, and even droughts, already.
And on top of that, Arctic sea ice serves as a sort of refrigerator for the planet, Notz explains. When the summer sun rays hit the vast, bright ice, much of that energy is reflected back. But the dark waters of a blue ocean will absorb that heat, leading to even more warming and melting.
Then, warmer, more wave-filled waters can eat away at other geological features, including glaciers, coastlines, and permafrost, in a spiral of changes.
It is important to note, however, that melting Arctic sea ice will not directly raise sea levels. Like melting ice in a soda glass, the oceans won't spill over from ice that is already floating in water. But as ice on land, such as the Greenland ice sheet, melts as an indirect effect of the disappearing sea ice, that water will flow into the oceans and raise sea levels.
Saving the ice
The Paris climate agreement is set to go into effect Friday with the aim of meeting an ambitious goal: preventing global temperatures from rising 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial levels.
But, by Notz's calculations, Arctic summer sea ice will already be gone if temperatures reach that threshold. That sea ice could survive, however, if the more aggressive target of 1.5 degrees Celsius warming is attained.
Further complicating things, the Arctic is heating up faster than the rest of the world, perhaps two or three times faster, Notz says.
Trenberth points out that greenhouse gas emissions can also have a delayed effect. So even if humans suddenly stopped emitting carbon altogether, temperatures likely still would rise. And, he says, although scientists have been discussing ways to extract CO2 from the atmosphere, "this is an extremely difficult thing to really achieve."
Looking at the sea ice loss in the Arctic is "a really stark indicator of climate change," Meier says.
"We think of the Arctic as a cold place, but in a lot of ways it's relatively warm," he says. During the summer, many sections sit on the cusp of the freezing point. So, while the difference between 80 and 82 degrees Fahrenheit might not make a huge difference in Washington D.C., Meier explains, if you go from 31 to 33 degrees in the Arctic, it's the difference between ice skating and swimming.
While this study doesn't really add new information for scientists, Meier says, with Arctic sea ice far from most people's everyday lives and carbon emissions, "it really helps people understand and visualize the impact."
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125,000 years of ocean warming in 50 years: What does it mean for sea levels?
The last time the Earth's oceans were this warm, the water level was two to three stories higher than it is today, according to a new research paper.
January 23, 2017 —What do Boston, Miami, and New Orleans have in common? All three may be almost completely underwater someday, if the results of a recent research paper are accurate.
The last time surface ocean temperatures were as warm as they are today, sea levels were 20 to 30 feet higher, according to findings published Friday in the journal Science. Using data from a wide range of locations, the study was able to measure regional temperature changes and concluded that recent models may be underestimating warming trends.
Earth’s climate features cyclical ice ages, when temperatures drop and ice sheets spread, causing ocean levels to fall. We currently enjoy the mild climate of what’s known as an “interglacial period,” when warmer temperatures melt ice, raising the seas. To better understand how our climate may develop in the future, experts consider the last interglacial period, 129,000 years ago, to be of great importance.
Getting a snapshot of what was going on so long ago isn’t easy, but scientists have a few tricks up their sleeves, such as measuring the makeup of ancient ice cores. This study used the composition of plankton shells (which depends on surface temperature) found in ocean sediments from 83 sites worldwide to compare our current interglacial period to the last one.
While it took a tipping of the planet’s axis 125,000 years to raise ocean temperatures by 0.9 degrees F., as The Los Angeles Times explained, current conditions have seen similar warming in less than 50, the paper found.
One degree may not seem like much in terms of the daily weather forecast, but it can have an outsized impact on sea levels. “The last interglacial is extremely interesting because it’s the last time period in recent Earth history when global temperatures were a little bit higher and global sea level was about 6 to 9 meters (20 to 30 feet) higher,” lead author Jeremy Hoffman told The LA Times.
“This tells us that the big ice sheets are really sensitive to just a little bit of warming,” Rob DeConto, a climate scientist at the University of Massachusetts, Amherst, who was not involved in the research, explained to The Guardian. “That’s a really powerful message.”
It’s also a familiar lesson to anyone who’s noticed how much faster ice cubes melt in a room-temperature drink than in a cold one.
Previous papers have predicted similar 20-foot ocean level rises, but this study paints a more nuanced picture of the past climate by drawing on data from dozens of locations, rather than just a few. Researchers concluded that climate change during the last interglacial period was uneven, with different regions warming, or even cooling, at different rates, something that mirrors what we’re seeing today.
The researchers also found that current climate models predicted less warming, on average, during the last interglacial period than the amount they actually measured, which has alarming consequences for future trends.
“This refined picture really clearly identifies that the modelling experiments do not create enough warming during the last interglacial,” Dr. Hoffman told The Guardian. “We think there might be some process missing that we’re just not capturing,” he continued. “If we’re missing something from this period of the Earth’s history, what might we be missing from future projections?”
Global sea rise is already underway: some 8 inches over the last century. The United Nations expects another 5 to 26 inches by 2050. If the current temperature has the same melting effect it did last time, 30 feet of rising waters could displace 643 million people worldwide – almost twice the population of the United States.
If there is a silver lining, it’s the long timescale: no risk of a "Day After Tomorrow" style insta-flood. “The good news is that with luck it will continue to rise slowly, so that we have time to adapt, but the bad news is that eventually all our present coastal city locations will be inundated,” University of Exeter climate scientist Andrew Watson told The Guardian.
But only if we use the time well. “We are rapidly approaching ocean conditions that haven’t been really seen on this planet for over 120,000 years,” Hoffman told The LA Times. “That’s a very relevant thing as we head into the next couple decades, and we start making policy decisions to turn this train around.”
You can check out how your city would handle 20 feet of water with nonprofit news organization Climate Central’s simulation.
on: Today at 06:09 AM
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With satellite launch, US has new eyes to watch for missile threats
On Friday night, the Air Force launched the latest member of a satellite network designed to spot missile threats. How could it keep the US safe from missile attack?
January 23, 2017 —The US military now has a fresh set of eyes on an unstable world.
At 7:42 p.m. EDT Friday, the Air Force’s GEO-3 surveillance satellite was launched from Cape Canaveral in Florida. The Atlas V rocket carried the latest satellite to join the GEO-1 and GEO-2 satellites – launched in 2011 and 2013, respectively – in geosynchronous orbit. From this vantage point, 22,300 miles above a fixed point on Earth, it will use infrared sensors to watch for missile launches.
Together, these three satellites, along with two older ones in different orbits, make up the Space-Based Infrared System (SBIRS), the latest hardware in a global surveillance system that has been evolving since the early days of the cold war. Its mission: detect missile launches around the world, and notify US forces in time for them to respond.
Since it was approved in 1996, the cost of SBIRS has swelled from $5.2 billion to almost $19 billion. And with three more GEO satellites planned, that price tag may rise even more. But the system’s architects insist that it’s needed to keep the Unites States safe from potential missile attack.
“The Space Based Infrared System is considered one of the nation’s highest priority space programs and is designed to provide global, persistent, infrared surveillance capabilities to meet 21st century demands in four national security mission areas,” Lockheed Martin, which built the satellite, says in its Mission Overview. Those four areas include “Missile Warning,” “Missile Defense,” “Technical Intelligence,” and “Battlespace Awareness.”
The military can set this broad mission for GEO-3 thanks to its hardware. The satellite’s two infrared sensors work independently, meaning that while one focuses on a particular region the other can scan an entire hemisphere.
When either sensor sees an unusual blip of heat, the military’s National Air and Space Intelligence Center can check it against a database of “heat signatures” created by a wide range of missiles and other military hardware.
The greater coverage afforded by GEO-3 will speed this process up, making for faster detection of missile launches and prediction of their direction. Military planners hope that this will increase the effectiveness of missile-defense systems, such as the THAAD batteries in Guam.
Beyond the system’s core mission of missile defense, SBIRS data has also been used to investigate the July 2014 downing of Malaysian Airlines Flight 17 by insurgents in Ukraine, and the disappearance of MH370 in March of that year, according to Aviation Week’s Amy Butler.
on: Today at 06:07 AM
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Able navigators: How desert ants know which way to go when walking backward
Ants may be more sophisticated marchers – and navigators – than often thought, according to new research.
January 23, 2017 —The ants go marching … backward.
Desert ants forage alone, each carrying the snacks they find back to their nest. But sometimes the little insects find meals too massive to lift up in their jaws, and they have to drag their prize home, backward.
Now researchers have an idea how the ants figure out where to go without looking where they're going. The little insects might combine visual memories with cues from the sky to follow the right path, even if they can't see it every step of the way. And these findings, published Thursday in the journal Current Biology, suggest that individual ants are much more sophisticated than often assumed.
"I think we've underestimated the individual ant in terms of what it can do," Brian Fisher, an entomologist and curator at the California Academy of Sciences who was not involved in this research, tells The Christian Science Monitor.
Researchers have long studied the forward navigational abilities of desert ants. "We know that these ants rely on vision," says study co-author Antoine Wystrach of the French National Center for Scientific Research, Toulouse III University, and the University of Edinburgh. "Each individual has its own visual memory that can be used to navigate back and forth between the food and the nest."
But research has suggested that this visual memory is egocentric, meaning that the ants see snapshots of their environment just from their perspective, Dr. Wystrach explains in an interview with the Monitor. "They learn by basically seeing the visual scene as projected on their retina, which means that their body orientation is very important for navigating."
In other words, the ants learn the route home based on how it looks when they're walking forward. But if they're facing another direction, such as backward, while walking, the ants get an entirely different view.
Wystrach and his colleagues, and others, had previously observed desert ants walking backward and successfully navigating back to their nests, so they wondered how they could do it without their view of the environment matching their visual memories of the route.
To find out, the researchers built a walled path for the ants to navigate in their natural habitat. They first trained individuals of the desert ant species Cataglyphis velox to follow that one path, and then the ants were presented with either a small morsel of food that they could carry normally or a larger one that had to be dragged backward.
While the ants with the smaller cookies took off down in the correct direction right away, the backward-walking ants had a little more trouble. The researchers saw that some of these ants missed a sharp right turn built into the route. But others periodically stopped, put down their cookie, turned around to face forward – presumably to reorient themselves – and then turned back around to resume dragging their cookie, continuing along the right route.
Because of the way the researchers think the ants' visual memories work, such a simple peek forward wouldn't have been enough for the backward-traveling ants to find the accurate path again. Instead, the scientists suspect that the ants were combining multiple cues to keep themselves on track.
When they peeked forward, Wystrach explains, they needed to memorize the vision from the forward-facing body orientation but then apply it to the backward-facing body orientation. So what, then, were the ants using as a frame of reference?
"We suspected they use an external directional cue," he says. "We suspected celestial cues because ants, and insects in general, are famous for using celestial cues."
The idea is that the ants would note the location of the sun in the sky, for example, and use that to reframe their visual memory of the route so they know which way to walk.
"To me it shows that the ants use different navigational strategies, and they can integrate those strategies" as needed, Adrian Smith a myrmecologist at the North Carolina Museum of Natural Sciences and North Carolina State University who was not involved in the study, tells the Monitor.
These ants "have a representation of direction and of space that is much more sophisticated than we thought," Wystrach says. "It's not just, 'I see a stimulus and I have a typical response,' " he says speaking from an ant's perspective. " 'No, I can store a lot of different information, some long-term for my life, like the view of the scenery, some short-term, like I just dropped my cookie behind but I keep that in mind.' And all that can interact to make a very flexible behavior … rather than just a little automaton, a little machine."
And this could help inform engineers actually building little intelligent machines, Wystrach and Dr. Fisher both suggest. Studying these ants could give those engineers ideas as to how to build neural networks for small computers that allow robots to navigate environments like the ants'. Perhaps this could yield better search-and-rescue robots, Dr. Smith suggests.
Not sniffing their way around in groups?
The classic image of ants is of them marching, two-by-two or otherwise, along pheromone trails as they go back and forth from a food source to their nest. But, for these desert ants, pheromones are not a factor.
That's because of the insects' foraging strategy, Wystrach explains. In the hot, dry desert, ants forage for insects that have roasted in the sun, he says. As such, the food isn't all in a pile for a bunch of worker ants to retrieve. Because the food is scattered across the sand and an individual can typically carry or drag it back in one trip, they don't need pheromone trails to signal to the other workers where to go.
And, Wystrach adds, even the ants that use pheromone trails have also been found to rely on visual memories when they lose the pheromone trail or if it gets disrupted.
Ants have been known to accomplish incredible feats of engineering and agriculture, but that's with an entire colony acting as one superorganism. This research shows individual worker ants in a different light, all three scientists say.
"It's true that if you look at the collective behavior, ... what can emerge at the colony level is more than the sum of what the individual ants can do," Wystrach says. "But that doesn't mean the individual ants are stupid."
"We have our assumptions about how these animals work, how intelligent they might be, how sophisticated they might be," Smith says. "But when we do these experiments, it makes us reconsider just how sophisticated the tiniest parts of life all around us are."
on: Today at 06:05 AM
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Cassini spies shy moon nestled among Saturn's rings
Cassini took the clearest images yet of Saturn's mini-moon Daphnis, shedding light on ring structure and behavior.
January 23, 2017 —Mini-moon Daphnis is literally making waves, and NASA caught it on camera.
NASA probe Cassini snapped its crispest images yet of the five-mile wide moon Daphnis, as it performed another “ring grazing” pass of Saturn’s outer rings on Monday. The pictures provide a close-up look at some previously indirectly observed ring features as the spacecraft approaches the final phase of its two-decade mission.
Daphnis, named for a poet-shepherd in Greek mythology, inhabits the Keeler Gap. Fifty percent wider than the Grand Canyon, this dust-free band in the outermost A Ring of Saturn is thought to be kept clear by the moon’s orbit around the gas giant.
Due to Cassini’s low-to-the-ring perspective, a foreshortening effect makes Daphnis appear to take up most of the gap, but a top-down look would show the band to be five times wider than the moon, according to a NASA press release.
The unprecedented detail reveals features such as horizontal ridges circling the moon’s equator, paralleling Saturn’s rings. Scientists believe these bands could be a sign of the ring-particles that pile up on the surface as the body sweeps through the Keeler Gap, like dust on a car driving down a dry, dirt road.
Cassini may have even caught the planet in the act of dust disturbance, as a faint tendril appears to follow Daphnis, hugging its lower left boundary. NASA speculates the moon’s gravity may have pulled this wispy material from its ring out into the gap, which explains its nickname, wavemaker.
This gravitational disruption can be seen in the form of waves spanning the lower edge of the gap, which sends a reminder that Saturn’s rings are not the static 2-D disks they seem in pictures but rather full 3-D objects with their own internal structure and movement.
Daphnis’s gravity disturbs the 30-foot-thick rings surrounding it in more ways than one. In addition to the horizontal waves visible in this new image, another shot taken in 2009 shows vertical ones as well. Invisible against the bright backdrop, the up to one-mile tall waves revealed themselves indirectly as shadows cast against the outer rings during Saturn’s equinox.
And Daphnis isn’t the only ring-denizen to be caught by Cassini’s cameras. Also taking advantage of the 2009 equinox, when the low angles of sun rays cause out-of-ring objects to cast dramatic shadows, the probe discovered evidence of 100-meter wide moonlets hiding in the rings themselves. While not directly visible, the moonlets reveal themselves in the propeller-shaped swirls they produce moving through the rings, as well as the resulting shadows.
A joint project between NASA and the European Space Agency, among others, Cassini launched from Earth in 1997. Originally intended for a four-year mission, two extensions have brought discoveries such as methane rivers on Titan in addition to the unprecedented views of the rings.
After exploring the inner space between Saturn and its rings, the probe’s extraordinary 20-year career will come to a close on September 15 of this year, when it intentionally dives into the clouds of the gas giant, burning up.
on: Today at 06:04 AM
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NASA scientists prepare for life on Mars ... in Hawaii
Four men and two women will spend eight months in a dome on a Hawaiian volcano, as part of a human behavior study designed to help NASA prepare astronauts for the journey to Mars.
January 21, 2017 —The eight-month journey to Mars is expected to be arduous, with its cramped conditions, isolation, and monotony. By simulating Mars-like conditions on Earth, NASA hopes to learn how to mitigate the challenges.
On Thursday, the latest simulation began. Four men and two women – carefully selected from over 700 applicants – moved into a vinyl-coated pod just below the summit of Mauna Loa, the world’s largest active volcano. During their eight-month stay, which mimics the journey to and life on Mars, they will eat primarily freeze-dried foods, have limited personal space, and experience a 20-minute lag in communications (the length of time it takes a message to travel from Mars to Earth).
Each simulation provides valuable data about the human experience, and the knowledge gained is integrated into future simulations. During this expedition, researchers hope to investigate how much self-direction the space travelers will need to promote group cohesion: do they feel most positively toward one another under conditions of autonomy, or when instructions come from mission control on Earth?
“I think sending people to Mars would be an inspiring and valuable thing to do, so I’m happy to be able to contribute to the knowledge necessary for that to happen,” former simulation participant Zak Wilson told Space.com in an interview in 2015.
In October, President Obama set a goal of sending humans to Mars – and returning them safely to Earth – by the 2030s. Elon Musk, CEO of Tesla and SpaceX, announced in June that he planned to send humans to Mars by 2024. And in September, ahead of his speech at the International Aeronautical Conference in Guadalajara, Mr. Musk released a simulation video detailing his plans to establish a city of 1 million people on the planet.
Five groups making private space flight a reality
Much of the technology that humans will need for the journey already exists. The new National Geographic miniseries, “MARS,” for which Musk was a consultant, spotlights some of these technologies, including ways to cultivate plants and recycle water.
But the greatest challenges may be psychological: getting a small group of people to work together, and remain productive, while in a confined space over a long period of time. With that in mind, numerous programs worldwide have run simulations of Martian conditions, including the Haughton Mars Project on Canada's Devon Island and the Mars-500 Project in Russia.
The Hawaii Space Exploration Analog and Simulation (HI-SEAS), at the University of Hawaii-Manoa, which is running this simulation, is one of the most successful. After its first project, NASA gave HI-SEAS a $1.2 million grant for its next 3 missions, and continues to fund missions.
“This is the best and most obvious place to do this research,” said Kim Binsted of HI-SEAS in a University of Hawaii video, pointing to the similar geological conditions and the availability of top astronomers.
“Astronauts” on these missions have tested out strategies for food preparation, worked to combat sensory deprivation, and grappled with the ever-present challenge of isolation.
One thing researchers think might help: control. So the amount of autonomy that participants have will change over time, NPR reported. Researchers will keep careful track of how their moods – and their relationships with other group members – shift in response.
All participants are equipped with instruments that measure their moods and proximity to others, according to the Associated Press. They can also try to improve their moods using virtual reality devices that simulate the familiar surroundings from with they are now distant.
The goal of the simulation: to find the optimal combination of factors for maintaining the group’s positivity and cohesion. That’s important for any Mars mission, as well as current astronauts. Crew members on the International Space Station have experienced a drop in performance as a result of the isolation, The Christian Science Monitor’s Joseph Dussault reported in August.
Though researchers expect the latest simulation to bring new challenges to light, the simulations have left participants optimistic about journeys to Mars in the future.
“I can give you my personal impression, which is that a mission to Mars in the close future is realistic,” Cyprien Verseux, who participated in the last mission, HI-SEAS IV, told the Associated Press. “I think the technological and psychological obstacles can be overcome.”
Material from the Associated Press contributed to this report.
on: Today at 06:02 AM
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Another Earth just 14 light years away? Maybe not, says new study
A rocky world orbiting Wolf 1061 falls within the potentially-habitable 'Goldilocks zone.' But a new study shows that it might be too close for comfort.
January 23, 2017 —Two years after astronomers found a “super-Earth” in our cosmic neighborhood, another scientist sees reason for caution.
In December 2015, a research team at Australia’s University of New South Wales announced the discovery of three rocky planets orbiting the star Wolf 1061. One of these planets, dubbed Wolf 1061c, fell within the circumstellar habitable zone, sometimes called the "Goldilocks zone": the area not too hot and not too cold for liquid water, considered an essential ingredient for life.
Located about 14 light years from Earth, Wolf 1061c is close by cosmic standards. Proxima Centauri b, discovered in August 2016, is the closest rocky exoplanet at 4 light years.
Discoveries of these “Earth-like” worlds have stirred hopes of discovering life beyond our solar system. But after taking a closer look at Wolf 1061c, Stephen Kane has his doubts about whether we’ll find it there.
“It’s close enough to Wolf 1061 where it’s looking suspiciously like a runaway greenhouse,” Professor Kane, an astrophysicist at San Francisco State University, told Sci News on Friday.
A “runaway greenhouse” effect took place on Venus. Scientists believe that Earth’s inner neighbor once had oceans of its own, but the planet's massive volcanoes flooded the air with carbon dioxide. Intense sunlight could then heat the planet until the oceans boiled away, leaving a thick atmosphere that keeps the planet’s temperature at a toasty 880 degrees Fahrenheit.
Kane thinks that a similar process may be at work on Wolf 1061c. His research, whose results will be published in an upcoming issue of the Astrophysical Journal, examined the planet’s host star.
"The previous estimate used models of what the [star’s] radius could be," he explains in a phone interview, "whereas this is a direct estimate of what the radius is."
Kane and his team measured Wolf 1061 using six networked telescopes at the Center for High Angular Resolution Astronomy in California. They used their measurements to revise previous estimates of its “Goldilocks zone.”
The Australian team that first discovered the three planets estimated “conservative habitable zone limits of 0.092 to 0.18 AU and optimistic limits of 0.073 to 0.19 AU.” (1 AU, or astronomical unit, equals the distance from Earth to the sun, about 93 million miles.)
Kane’s group pushed the habitable zone’s boundaries outward, estimating them at 0.11 to 0.21 AU. That, he explained, means that Wolf 1061c is dangerously close to the inner edge, and prone to a Venus-like fate.
Even if Wolf 1061c escaped a “runaway greenhouse” effect, it might pose other obstacles to life. “If we find a planet in the habitable zone, it doesn’t mean everything is as it seems,” Kane tells The Christian Science Monitor. He explains that the planet displays “very interesting oscillations in its orbit” that make it difficult to determine what kind of climate – if any – it could have.
But those hoping to find extraterrestrial life may not want to write off Wolf 1061c just yet. A new generation of telescopes could reveal more about the planet. A solar system this close, Professor Kane explained, “presents an opportunity for direct imaging of the planet. That’s something that will have to wait until the 2020s.”
He mentioned two upcoming NASA missions – the James Webb Space Telescope and the Wide Field Infrared Survey Telescope – that will make it possible to examine the light reflected through nearby planets’ atmospheres for the chemical signatures of life.
“The planets will appear as nothing more than a speck of light,” he predicts. “And that’s all we really need.”