Amazing Science

A species of tropical fish has been shown to be able to distinguish between human faces. It is the first time fish have demonstrated this ability.

First author Dr Cait Newport, Marie Curie Research Fellow in the Department of Zoology at Oxford University, said: 'Being able to distinguish between a large number of human faces is a surprisingly difficult task, mainly due to the fact that all human faces share the same basic features. All faces have two eyes above a nose and mouth, therefore to tell people apart we must be able to identify subtle differences in their features. If you consider the similarities in appearance between some family members, this task can be very difficult indeed.

'It has been hypothesized that this task is so difficult that it can only be accomplished by primates, which have a large and complex brain. The fact that the human brain has a specialized region used for recognizing human faces suggests that there may be something special about faces themselves. To test this idea, we wanted to determine if another animal with a smaller and simpler brain, and with no evolutionary need to recognize human faces, was still able to do so.'

The researchers found that fish, which lack the sophisticated visual cortex of primates, are nevertheless capable of discriminating one face from up to 44 new faces. The research provides evidence that fish (vertebrates lacking a major part of the brain called the neocortex) have impressive visual discrimination abilities.

When plankton on the high seas catch a cold, the whole ocean may sneeze. Viruses hijacking these microbes could be an important overlooked factor in tracing how living things trap — or in this case, fail to trap — the climate-warming gas carbon dioxide.

Plants and other organisms that photosynthesize use energy from the sun to capture CO2 for food. The most abundant of these photosynthesizers on the planet are marine cyanobacteria with hardly any name recognition: Synechococcus and Prochlorococcus.

Now, for the first time, a study looks in detail at what happens when some of the abundant viruses found in the sea infect these microbes. Two viruses tested in the lab hijacked cell metabolism, allowing photosynthesis to continue but shunting the captured energy to virus reproduction. The normal use of that energy, capturing CO2, largely shuts down, David Scanlan of the University of Warwick in England and colleagues report online June 9 in Current Biology. As a result, people could be overestimating by 10 percent the amount of CO2 that photosynthesis in the oceans captures.

On any given day, 1 to 60 percent of these plankton may have picked up a viral infection, researchers have estimated. That means that between 0.02 and 5.39 petagrams of carbon — up to 5.39 billion metric tons — may not be captured by marine organisms a year. The high end of that scenario is equivalent to 2.8 times the CO2 routinely captured annually by all the planet’s salt marshes, coral reefs, estuaries, sea grass meadows and seaweeds put together.

Synechococcus and Prochlorococcus plankton “are organisms that you’ve never heard of but you really should have,” says Adam Martiny of the University of California, Irvine. He studies the same kinds of plankton but wasn’t involved in the new virus research, and what he appreciates about it is the intriguing biology of viral manipulation the new work has uncovered.

Until now, Scanlan says, the prevailing view was that while infected plankton were still alive, they were probably carrying on normal photosynthesis. As early as 2003, researchers had clues that the viruses attacking these tiny marine organisms might manipulate photosynthesis in some way, perhaps keeping the process running in an infected cell. These viruses have genes for proteins used in photosynthesis, even though a virus doesn’t even have its own cell much less a way to photosynthesize.

What the viruses are doing, Scanlan and his colleagues have now shown, is subverting their victim’s photosynthesis. Energy capture, the part of photosynthesis directly involved with light, goes on as usual; the cells carry out the routine electron transport for catching energy. But instead of using those sizzling electrons to capture CO2 and turn it into carbohydrates for basic cell metabolism, the viruses shut down this process (called carbon fixation). The light reactions are the ones that researchers normally measure to estimate how much carbon photosynthesis captures in the oceans, but the covert viral shunting means that estimate could be too high.

Gene drives may wipe out malaria and take down invasive species. But they may be difficult to control.

enies are said to have the power to grant three wishes. But genies recently released from laboratory flasks promise to fulfill nearly any wish a biologist can dream up. End the scourge of insect-borne diseases? Check. Inoculate endangered amphibians against killer fungi? Yes. Pluck invasive species from environments where they don’t belong? As you wish.

These genies aren’t magical; they are research tools known as gene drives — clever bits of engineered DNA designed to propel themselves into the DNA of a pesky or troubled organism. A gene drive is a targeted contagion intended to spread within species, forever altering the offspring.

Gene drive enthusiasts say these genies could wipe out malaria, saving more than half a million lives each year. Invasive species, herbicide-resistant weeds and pesticide-resistant bugs could be driven out of existence. Animals that carry harmful viruses could be immunized with ease.

Scientists have sought the power of gene drives for decades. But only with the emergence of a genetic tool called CRISPR/Cas9 — the bottle opener that unleashed the genie — has gene drive technology offered the prospect of providing a speedy means to end some of the world’s greatest health and ecological scourges.

“Everything is possible with CRISPR,” says geneticist Hugo Bellen. “I’m not kidding.” But genes designed to spread through populations and alter ecosystems could have unforeseen consequences. Researchers have designed ways to keep gene drives confined in the lab, but no such safety nets exist for gene drives released into the wild. A technology to eradicate entire species, even when those species are pests, raises ethical and regulatory issues that scientific and government agencies are just beginning to consider.

New findings by scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) suggest that planet formation in the early universe might have created carbon planets consisting of graphite, carbides, and diamond and that astronomers might find these diamond worlds by searching a rare class of stars.

“This work shows that even stars with a tiny fraction of the carbon in our solar system can host planets,” says lead author and Harvard University graduate student Natalie Mashian. “We have good reason to believe that alien life will be carbon-based, like life on Earth, so this also bodes well for the possibility of life in the early universe.”

The primordial universe consisted mostly of hydrogen and helium, and lacked chemical elements like carbon and oxygen necessary for life as we know it. Only after the first stars exploded as supernovae and seeded the second generation did planet formation and life become possible.

Clues to how life got started in the universe

Mashian and her PhD thesis advisor Avi Loeb examined a particular class of old stars known as carbon-enhanced metal-poor (CEMP) stars. These “anemic” stars contain only one hundred-thousandth as much iron as our Sun, meaning they formed before interstellar space had been widely seeded with heavy elements.

“These stars are fossils from the young universe,” explains Loeb. “By studying them, we can look at how planets, and possibly life in the universe, got started.”

CEMP stars have more carbon than would be expected, given their age. This relative abundance would influence planet formation as fluffy carbon dust grains (from supernovae) clump together to form tar-black worlds.

From a distance, these carbon planets would be difficult to tell apart from more Earth-like worlds. Their masses and physical sizes would be similar. Astronomers would have to examine their atmospheres for signs of their true nature. Gases like carbon monoxide and methane would envelop these unusual worlds.

Computer simulations show that blasting plastic with strong laser pulses could produce gamma rays with unprecedented intensity, good for fundamental physics experiments and possibly cancer treatments.

Intense beams of gamma rays would find a host of uses in fundamental physics research, nuclear fusion, and medicine, but they are hard to produce. A team has now used computer simulations to show that a powerful laser hitting a plastic surface can generate intense gamma-ray emission. In the simulations, the laser light creates a plasma in the plastic and accelerates electrons enough to produce large numbers of gamma-ray photons. The researchers say that the system might work with current technology.

In extreme astrophysical environments, such as near a supermassive black hole, matter and antimatter (electrons and positrons) regularly annihilate, producing gamma rays. Researchers would like to study the reverse process by colliding beams of gamma rays, which should create electrons and positrons, a transformation of light into matter [1]. Gamma-ray beams could also enable a wide range of other fundamental experiments and might have a role in radiation therapy and radiosurgery [2]. Previous attempts to make these beams involved the interaction of a laser beam with an electron beam [3]. But to produce copious gamma-ray photons with energies in the MeV range, the laser beam would need to be more intense than any current device.

Alexey Arefiev at the University of Texas at Austin and his co-workers now propose a different method that requires somewhat less laser power. It involves shining pulses of a petawatt (10**15W) infrared laser onto a carbon-rich, plastic target. The power density of such a pulsed laser can reach around 5×10**22W/cm2, which is about 500 times greater than would be produced by focusing all of the sunlight reaching the Earth onto a pencil tip.

In the team’s scenario, the laser pulse heats the target, creating a plasma of electrons and ions. The electrons in the plasma are high-energy, and according to special relativity, they acquire a large effective mass, making them too sluggish to follow the oscillations of the laser’s electromagnetic field. This effect renders the plasma transparent to the light, so the laser beam can penetrate tens of micrometers into the target, filling it with a dense plasma.

In the team’s simulations, the laser pulse pushes the electrons in this plasma forward, like a leaf blower propelling leaves, and this motion of charge sets up a strong magnetic field that curls around the axis of the laser beam. This field accelerates the electrons forward even more but along zigzag trajectories as they move through the plastic. This electron motion generates so-called synchrotron radiation of very high energy (gamma-ray photons) that is emitted from the rear of the plastic target in the direction of the laser beam.

The simulations that Arefiev and colleagues conducted using the Stampede supercomputer at the University of Texas showed that the method works in principle—but also that propagation of the laser pulse into the target may quickly become unstable and deviate from its original direction. Then the electrons are pushed in random directions, and the multi-MeV photons they emit exit in an uncoordinated spray. “It’s similar to what happens to a garden hose that, when left unattended, can spray water uncontrollably everywhere,” says Arefiev.

Spider silk has lost its record for being the strongest natural material – these limpet teeth are six times as strong.

No wonder it takes a crowbar to detach a limpet from a rock while it’s feeding. The mollusc’s teeth, seen in the above microscope image, are made from the strongest material yet discovered in the natural world.

When Asa Barber from the University of Portsmouth and his team measured the stretching force needed to break the teeth, they found that the material they are made out of is about six times as strong as spider silk – the previous record holder. The material also matches ultra-resistant carbon nanofibers, which are the strongest artificial material.

The teeth are both stretchy and strong thanks to their unique composition. They contain millions of aligned nanofibers, made from a natural mineral called goethite, which are embedded in a softer shell of chitin. Amazingly, samples were stretched to four times their original length without losing their elasticity.

Mimicking the structure of limpets’ teeth could help engineers build sturdier cars, boats and aircraft, says Barber.

Journal reference: Journal of the Royal Society Interface, DOI: 10.1098/rsif.2014.1326

One of the most ambitious endeavors in quantum physics right now is to build a large-scale quantum network that could one day span the entire globe. In a new study, physicists have shown that describing quantum networks in a new way—as mathematical graphs—can help increase the distance that quantum information can be transmitted. Compared to classical networks, quantum networks have potential advantages such as better security and being faster under certain circumstances.

Hip humans aren't the only ones growing outrageous facial hair. Some chickens do, too. And now, geneticists in China have discovered the cause.

A small team of researchers at Harvard University has taken another look at CRISPR and has found that it can be used as a recording device of sorts, keeping track of when and where a given bacterium has been exposed to different viruses. In their paper published in the journal Science, the team describes their study, their findings and the ways such natural recordings might be useful.

CRISPR has been in the news a lot of late, primarily due to its use in gene editing—but lost in all the news is the actual basis of the technology. Like humans, bacteria have a unique immune system, which is known as CRISPR/Cas, and it works by cutting out pieces of DNA (called oligomers) when attacking viruses and integrating those pieces into its own genome, which is later used to give the bacterium historical knowledge when fighting the virus should it appear again. The researchers with this new effort noted that the oligomers that are placed in the genome are done so sequentially, which means they form a record of viral attacks. To see its history, the team reasoned, the genome need only be sequenced.

To test this idea, the researchers used a simplified version of E. coli, which still contained Cas1 and Cas2, the enzymes needed for snipping and adding oligomers, but no other immune system functionality. They then directly exposed it to various DNA sequences over a period of time, allowed it to snip and add to its genome, then sequenced the bacterium to see if the theory held up. The team reports that it did indeed. Taking the idea further they found that by introducing modified versions of Cas 1 and Cas2 that they could actually create different recording modes.

The team suggests this new bit of knowledge regarding CRISPR might be used to aid in creating bacteria that could be used as sensors of a sort, offering recording evidence of a host of different microorganisms in a given environment. Such sensors could prove useful in applications ranging from soil testing, to human gut biome analysis to atmospheric probes.

A new class of lasers developed by a team that included physics researchers at Kansas State University could help scientists measure distances to faraway targets, identify the presence of certain gases in the atmosphere and send images of the earth from space.

These energy-efficient lasers also are portable, produce light at difficult-to-reach wavelengths and have the potential to scale to high-powered versions.

The new lasers were invented by Brian Washburn and Kristan Corwin, both associate professors of physics at Kansas State University's College of Arts & Sciences, along with Andrew Jones, a May 2012 doctoral graduate in physics, and Rajesh Kadel, a May 2014 doctoral graduate in physics. Other contributors include three University of New Mexico physics and astronomy researchers: Wolfgang Rudolf, a Regents professor and department chair, Vasudevan Nampoothiri, a research assistant professor, and Amarin Ratanavis, a doctoral student; and John Zavada, a Virginia-based optic and photonic physicist who brought them all together.

The new lasers are fiber-based and use various molecular gases to produce light. They differ from traditional glass-tube lasers, which are large and bulky, and have mirrors to reflect the light. But the novel lasers use a hollow fiber with a honeycomb structure to hold gas and to guide light. This optical fiber is filled with a molecular gas, such as hydrogen cyanide or acetylene. Another laser excites the gas and causes a molecule of the excited gas to spontaneously emit light. Other molecules in the gas quickly follow suit, which results in laser light.

"By putting the gas in a hollow core, we can have really high intensities of light without having to put such high amounts of power into the laser," Corwin said. "If you had a glass tube of that size and put light in it, the light would escape through the sides. It's actually the structure that makes it work."

The structure also allows for portability. In contrast to traditional lasers, which are fragile and cumbersome to move, the researchers' more durable fiber laser is about the thickness of a single strand of hair and can wrap around itself for compact storage and transportation. "The smallness is nice," Washburn said. "You can wrap up the coil like a string."

The invention process began when Zavada brought Washburn and Corwin, who already had expertise putting gas into hollow fibers, together with Rudolph and Nampoothiri, who were skilled in making optically pumped gas lasers.

"We thought hard about how this would all work together, and after about a year and a half, we came up with this," Corwin said.

Human cells contain 23 pairs of chromosomes that form a loosely organized cluster in the cell nucleus. When cells divide, they must first condense these chromosomes — each of which when fully extended is a thousand times longer than the cell’s nucleus and physically indistinguishable from the others — into compact structures that can be easily separated and packaged into their offspring.

An MIT-led team has now developed a model that explains how cells handle this difficult task. In computer simulations, the researchers demonstrate that certain molecular “machines” can transform chromosomes from a loosely tangled rope into a series of tiny loops that condense each chromosome and allow it to extricate itself from the others. Moreover, the researchers demonstrate that a similar model explains how chromosomes are organized when cells are not dividing, and they hypothesize that loop extrusion by molecular motors splits chromosomes into separate domains, helping to control which genes are expressed in a given cell.

This mechanism, outlined in three recent papers published in Cell Reports, eLife, and Biophysical Journal, suggests that chromosome organization relies on proteins that act as molecular motors that pull strands of DNA into progressively larger loops. The MIT team suggests that two proteins thought to function primarily as “staples” that hold DNA together, cohesin and condensin, can also actively manipulate DNA.

“Nobody has ever directly observed this mechanism of loop extrusion. If it exists, it will solve lots of problems,” says Leonid Mirny, a professor of physics in MIT’s Institute for Medical Engineering and Sciences, who led the research. “We will know how chromosomes condense, how they segregate, how genes talk to enhancers. Lots of things can be solved by this mechanism.”

Teleoperated endolumenal bot can navigate inside the body, image and treat conditions without making incisions.

The U.S. Food and Drug Administration (FDA) has just approved the first medical robot from Auris Surgical, a stealthy startup led by the co-founder of industry leader Intuitive Surgical, makers of the widely-used da Vinci robot.

The teleoperated ARES robot (the acronym stands for Auris Robotic Endoscopy System), was cleared by the FDA at the end of May, and could now be used for diagnosing and treating patients.

Auris, which describes itself only as a “technology company based in Silicon Valley,” was previously thought to be working on a robotic microsurgical system designed to remove cataracts, and the company has in fact filed several patent applications along those lines.

However, an investigation by IEEE Spectrum suggests that the company has greater ambitions, including, according to current and former employees, “building the next generation of surgical robots… capable of expanding the applicability of robotics to a broad spectrum of medical procedures.”

A close reading of recent patent applications filed by Auris scientists shows that the company is focusing on so-called endolumenal (or endoluminal) surgery. This involves surgeons introducing flexible robots via the body’s natural openings (the mouth in particular), to address conditions of the throat, lungs and gastrointestinal system. IEEE Spectrum can reveal that Auris has already carried out at least one successful human trial of such a robot, outside the United States.

Because endolumenal surgery does not involve large incisions or (usually) general anesthesia, it benefits fragile patients who cannot withstand the trauma of normal surgery. The Society for American Gastrointestinal and Endoscopic Surgeons estimates that effective endolumenal therapies for obesity and reflux diseases alone could help more than 1 million patients a year in the United States.

A new study finds that the abandoned nuclear test sites aren't much more radioactive than Central Park.

If you wanted to test a nuclear bomb in the 1940s and 1950s, you could head to one of two hotspots: Los Alamos, New Mexico or the Marshall Islands. The latter was the site of 67 nuclear tests over the years—dangerous experiments that forced islanders to abandon their homes.The Castle Bravo test alone which was performed at the Bikini Atoll was more than 1,000 times more powerful than the bomb the United States dropped on Hiroshima.

But change could be coming for the island exiles. Now, reports Patrick Monahan for Science, a new study shows that the Marshall Islands are becoming less nuclear. A new study published in the journal Proceedings of the National Academy of Sciences​ found that previous estimates of contamination levels across the Marshall Islands are skewed. Researchers measured gamma radiation—electromagnetic radiation from nuclear fallout that is associated with cancer and developmental delays—on six of the over 1,000 islands in the republic where nuclear tests occurred. On five of the six islands studied, gamma radiation levels were below 100 millirem per year. That’s beneath the safe threshold for human habitation and a fraction of the approximately 310 millirem of radiation the average American is exposed to each year from natural sources.

Those measurements fly in the face of prevailing wisdom about radiation on the islands—wisdom that the study’s authors say is based on outdated, decades-old data. The findings could prompt Marshallese who had to flee their home islands to move back. If so, it will be a welcome relief to the evacuated residents forced to cram themselves onto crowded islands with scant resources.

In 2015, the situation on Kili and Ejit Islands became so bad that Marshallese officials petitioned the U.S. government to provide funds to move people away from the islands altogether. Climate change, which caused widespread flooding and inclement weather, was also at play. The U.S. Department of the Interior has since supported pleas to consider fleeing islanders as refugees.

Those efforts are only fair given the effects the U.S. nuclear program had on islanders. Between 1946 and 1958, 23 nuclear devices were detonated at Bikini Atoll. The most memorable of which was a 15-megaton bomb tested in 1954. More than a thousand times more powerful than the bomb dropped on Hiroshima, it was the largest nuclear device the U.S. ever exploded. At the time, unexpected weather patterns caused radioactive fallout to rain over several other islands.

Bikini Island radiation levels were the only ones in the six islands studied to be above safe levels for human habitation. But at 184 millirem per year, the measurement’s weren’t much higher than those taken at a control island or in New York’s Central Park, which receives about 100 millirem of gamma ray radiation per year. Those levels are probably due to granite within the park, writes Monahan.

Now that it’s been established that the islands have become less radioactive, is it finally time for displaced residents to go home? Not so fast—the study’s authors say that they’re not yet sure if the islands are safe for habitation. They write that other exposure pathways, like the fish-heavy diet the Marshallese enjoy, should be studied before a determination is made. But for the island's former residents, eager to ease crowding and go back to their home islands, the study is a hint of hope for achieving a more normal post-nuclear life.

AI expert Neil Jacobstein talks fintech, machine learning, Big Data, and building artificial brains.

Artificial Intelligence (AI) has flown beneath the radar for the first six decades of its development, and just recently it's exploded into public consciousness, according to Neil Jacobstein. The AI & Robotics co-chair at Singularity University and former CEO of Teknowledge Corporation believes the combination of humans, AI, and good business processes is disrupting the very ground we stand on in financial technology (Fintech) and beyond as we already use machine learning tools to augment the power of the human brain.

At Singularity University's Exponential Finance conference today, Jacobstein pointed to examples like Google's AlphaGo wiping the floor with world champion Lee Sedol, and how quickly the world shifted from a state of shock to seizing the scientific opportunity. Soon after seeing its human champion so thoroughly beaten by a machine, South Korea announced a plan to spend $840 million by 2020 to boost AI research and development (R&D), and to create a research institute where six of the country's highest profile tech companies—Samsung, LG, SK Telecom SKT, KT, Naver, and Hyundai—will each invest up to $3 billion in AI R&D.

He also mentioned Facebook's DeepText AI language comprehension and categorization, as well as Viv, saying that calling it another personal assistant misses the point. Viv, Jacobstein explained, is a tool that allows you to delegate work to a computer or an agent. You teach Viv how to do something, and from there it becomes a problem-solving utility akin to Bluetooth or Wi-Fi. It's with us all the time.

"The key point [about Viv] from an outside-in perspective, from a user perspective, is that they are no longer interacting with a system that's just a tool. You don't need to tell it everything you want it to do," Jacobstein told PCMag. "You show it what you want it to do, and then actually delegate work to this intelligent system."

From 2011-2015, over $3 billion was invested specifically in AI-related companies, according to Jacobstein. Beyond the Facebooks and Googles of the world, there are a host of start-ups and open-source initiatives applying next-gen machine learning, AI, and Big Data technologies to real-world business use cases. Jacobstein talked about a few:

Brighterion 
An AI-as-a-Service start-up bringing cloud-based data analysis and predictive analytics to the financial community, cyber-security companies, and industrial Internet of Things (IoT) applications.

Kabbage
A start-up using unconventional data and machine learning to give small to midsize businesses (SMBs) a line of credit up to $100,000 in a matter of minutes.

Feedzai
A machine-learning platform analyzing fraud in each step of financial transactions to identify anomalies with on-demand Big Data processing and AI for banking, e-commerce, payments, and lending.

Experfy
A curated marketplace for AI professionals where companies can post a business problem they're experiencing and bid on an AI-based solution proposed by marketplace professionals. Jacobstein disclosed he's an investor in Experfy, which came out of HarvardX.

Nutonian
A start-up that created Eureqa, a virtual data scientist designed to extract answers from complex data 90 percent faster than traditional predictive models. Jacobstein described Eureqa as an example of how barriers of access to machine learning algorithms and data science tools hurt SMBs.

TensorFlow
Google's open-source software library for machine-learning intelligence; an AI application development toolbox.

OpenAI
The nonprofit research company started by Elon Musk and Y-Combinator founder Sam Altman to put AI algorithms out into the public domain. Thisdemocratization of AI technology has already started with OpenAI Gym, an open-source system for evaluating reinforcement learning algorithms.

The International Union of Pure and Applied Chemistry (IUPAC) opened a public comment period Wednesday for the recommended names of elements 115, 117 and 118.

Lawrence Livermore National Laboratory and the Joint Institute for Nuclear Research in Dubna, Russia (JINR) were credited late last year for discovering elements 115 and 118. LLNL, JINR, Oak Ridge National Laboratory (ORNL), Vanderbilt University and the University of Nevada, Las Vegas were credited with the discovery of element 117.

Moscovium (Mc) is provisionally recommended for element 115 in recognition of the Moscow region and honoring the ancient Russian land that is home to JINR. Moscow is the capital of the region.

Tennessine (Ts) is proposed for element 117, recognizing the contribution of Tennessee research centers ORNL, Vanderbilt and the University of Tennessee to superheavy element research.

The provisional name for element 118 is Oganesson (Og) in recognition of the pioneering contributions of Yuri Oganessian to superheavy element research. Oganessian's vision and determination created this opportunity for the significant expansion of the periodic table and knowledge of superheavy nuclei.

The provisional names will undergo a statutory period for public review before the names and symbols can be finally approved by the IUPAC Council—likely later this year.

"I'm proud of all of the hard work that this group has done over the years performing these experiments," said Dawn Shaughnessy," LLNL's principal investigator for the Heavy Element Group. "It's a huge accomplishment for the entire group that we are recognized for our efforts in accomplishing these highly difficult experiments and for the years of work it takes to successfully create a new chemical element."

LLNL teamed with JINR in 2004 to discover elements 113 and 115 (Japan was credited with the discovery of element 113). LLNL worked again with JINR in 2006 to discover element 118. The LLNL/JINR team then jointly worked with researchers from the Research Institute for Advanced Reactors (Dimitrovgrad), ORNL, Vanderbilt University and the University of Nevada, Las Vegas, to discover element 117 in 2010.

Using NASA's Landsat satellites, researchers conducted the most precise study yet on vegetation growth trends across North America.

In the most precise study yet on vegetation growth trends across North America, researchers from America’s space agency have found that nearly a third of the land cover in Canada and Alaska has greened in recent decades as a result of climate change.

The researchers also found that, while vegetation productivity is on the rise in the tundra regions of the continent, warming temperatures might be having the opposite effect on the Boreal forest, which showed some signs of browning. Overall, three per cent of the land experienced vegetation decline.

The researchers used data from NASA’s Landsat satellites between 1984 and 2012 in order to trace wide-scale changes over the 10.6 million sq-km landscape. Areas characterized by growth – where grasslands became shrublands, or where existing shrublands became bigger and denser – were classified as greening, while those where vegetation declined were classified as browning.

Scott Goetz, deputy director and senior scientist at the Woods Hole Research Center in Massachusetts, said the study shows “a clear distinction” between what’s happening in the tundra and Boreal regions of Canada and Alaska.