The 10 best science images, videos, and visualizations of the year

We are all too aware of how hard it can be to explain science. Describing concepts, theories, processes, and phenomena use up a lot of words—and even after careful consideration those words can fall short. That's why for the last three years Popular Science has teamed up with the National Science Foundation to honor the best science visualizations out there.

As part of this year's Vizzies, we're highlighting an intricate illustration of brain neurons and a visual explainer of humming bird tongues. We're celebrating a lexicon of American Sign Language and a photo of how hungry starfish larva move the water around them.

How did we select the best of the best? Experts selected by the National Science Foundation judged hundreds of entries on their impact, ability to make a complex subject easier to understand, and originality. This panel of experts pared down the list to 50 finalists—10 illustrations, 10 interactive designs, 10 photographs, 10 posters and graphics, and 10 videos. Those 50 visualizations were put up for public review. The final result: One experts' choice winner and one people's choice winner per category.

These are our winners:

The "Hungry Starfish" is a fundamentally Californian product. William Gilpin, a PhD candidate in physics at Stanford University, found out the school was offering classes at its marine village on the Pacific Ocean. So he and his fellow researchers headed out, ready for a break from the lab. What they ended up finding surprised them: starfish move using hundreds of elaborate, tube-like feet, and they also seem to control the waters around them.

When they headed back to the lab, they found very little research had been done on the way starfish move the water around them, so they set about finding—and illustrating—the answer themselves. "Hungry Starfish" is essentially an elaborate time lapse photo, created when all of the vortices the starfish makes were imaged and combined into one surprisingly delicate image of the starfish's superpower. Those vortices aren't just for fun: they're for softly pulling algae into a starfish larva's tiny mouth.

Soft robots—ones made entirely out of squishy materials—are about to take over. They're theoretically safer and more resilient than metallic mechanoids, but scientists haven't quite figured out practical ways to make every part of a robot mushy. Octobot is a step (or eight) in the right direction: it's entirely soft, powered by chemical reactions __that push fluid and gas into its limbs.

As Harvard researchers worked to design the bot, they frequently used fluorescent dyes to better visualize its intricate inner-workings. "To us, these dyes always made the 3D printed Octobots so beautiful, and we thought __that they would make for an awesome photograph," says study co-lead Ryan Truby, a PhD candidate in applied physics. "We hope our photograph will appeal to the imaginations of both academic and broader audiences interested in robots and inspire a vision of future entirely soft robots like the Octobot."

It took data from “essentially dozens if not hundreds” of scientific sources to create this intricate image of the brain, says team lead Greg Dunn, a neuroscientist at the University of Pennsylvania.

Combining hand drawings, optical engineering, gilding (the process of etching into gold), and other artistic and technical processes, they created this depiction of about 500,000 neurons hard at work. It’s “a reminder that the most incredible machine in the universe” is inside each of us, the team wrote.

Self Reflected was featured at the Franklin Institute in Philadelphia, with the goal of prompting viewers to consider what looking at an elaborate representation of the brain looks like from inside the brain. In addition to this image of the full brain viewed from the side, Dunn’s team generated a variety of other works with different focuses and resolutions.

Every month, the RCSB Protein Data Bank shares a “Molecule of the Month.” This zika virus had the honor of being the featured image for May 2016.

The zoomed-in illustration reveals something of a topographic map of the infecting agent. It shows not just the envelope that encircles the virus, but also the RNA (in yellow) that lives inside it and allows it to replicate. When the image was first published, scientists had been aware of the virus for almost 70 years, but understanding of the disease was limited. “Study of Zika virus has gained new importance because of the recent spread of the virus in many countries around the globe and its connection to birth defects and a rare neurological disease,” the illustrator wrote at the time.

Shane Loeffler started working on his app, Flyover Country, when he realized his undergraduate studies in geoscience at the University of Minnesota provided him with a unique—and entertaining—view on flying.

“I was flying over the San Rafael Swell,” he says, “and I could look down and I had been down there hitting those rocks with hammers, and now I’m above, reading a Wikipedia article [about the features below].” The app uses GPS signals to show people the topography of the land beneath them, as well as special features, like sites where dinosaur fossils are embedded in the soil. Loeffler, who is working with a small team to further develop the app, says it can also be used to enhance hiking and camping, road trips, and other more earth-bound activities.

American Sign Language is a language like any other—but it can’t be easily organized like a traditional English dictionary. This and other barriers make it hard for parents of deaf children to aid them in language acquisition, says Naomi Caselli, a lecturer on Deaf Studies at Boston University's School of Education.

Caselli and her team decided to take all of the ASL data available to them and organize it in a new way. ASL-LEX organizes 1,000 signs into groups based on things like similar hand shape or movement. What’s more, these little nodes are sized according to their common usage, so words like “book” are a little easier to find than a word like “castle.” It’s already helping hearing teachers and parents communicate with deaf children, and Caselli says the researchers are working hard to ensure that trend continues.

Eleanor Lutz isn't an astronomer—she's pursuing a PhD in biology at the University of Washington—but she loves sifting through the data that NASA makes public. That's how she got the idea to map Mars—with a Victorian twist. "Unlike other planetary maps, this map uses a Victorian style inspired by medieval cartographers," Lutz says. "Victorian-style maps are from a time when most of the world remained a mystery, and travelers only knew about nearby lands. Now that people have mapped the entire globe, I think that Mars has taken over our collective imagination as the next mystery to explore. I wanted to make the geography of Mars more tangible to the general public."

The hardest part? Fact-checking the name of each feature. "Since everything on the map is a proper noun, I had to go through and manually make sure every single landmark name and the name origin were spelled correctly."

When Esther Ng set out to visualize a hummingbird’s tongue, she had no idea where her work would take her. At the time, no one was really sure what a hummingbird tongue looked like, though new discoveries about the little bird’s micro-pumping abilities were all the rage.

“It's so tiny,” says Esther, a student at the University of Illinois focusing on scientific and medical illustrations. “Even with a video, it's very hard to catch.” To fix this, she headed to the Field Museum in Chicago. “They let me borrow [the bird] to look under a microscope, to pull the tongue out and draw how it is,” she says. It was nothing like she imagined, but those surprises are what make her work so enjoyable.

Video: Expert's Choice

Network Earth

"The situation is very tragic," data visualizer Mauro Martino says of climate change. It's so sad, in fact, that on many researchers "you can smell the sadness," Martino adds. It makes sense: they've dedicated decades of their life and career to researching disasters and impending doom. But Martino, the creator and director of IBM's Cognitive Visualization Lab, strives to turn their data into more upbeat, visual stories that people want to watch and share with their friends.

In "Network Earth," Martino and his team created a film that shows the interconnections between all life on Earth. It was created to accompany a research paper on Earth's resilience published in Nature. While the paper was theoretical, Martino says, the video aims to show that "math can be poetically expressed visually" and made to feel real and tangible to viewers around the world.

Video: People's Choice

The hunt for Planet Nine

When astronomers Michael Brown and Konstantin Batygin published the best-ever evidence for the existence of a ninth planet—a massive world orbiting in the farthest reaches of our solar system—the hunt for the mysterious celestial body captured the public's imagination. This video for Chicago's Adler Planetarium uses that fascinating research to show visitors how such scientific explorations unfold.

"Our goal with this show was not to teach people about Planet Nine, and it certainly wasn’t to convince them that Planet Nine exists," says Patrick McPike, a visual engineer at the planetarium. "The show is really about the excitement and process of scientific discovery. We hope that the show gets people more involved in science, whether that is by following science news more closely or by studying it themselves."

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Fertilizer has saved billions of lives, but it also has a dark side

The following is an excerpt from "Pandora’s Lab: Seven Stories of Science Gone Wrong" by Paul A. Offit.

We’re not __that complicated. Although we come in different shapes and sizes, heights and weights, and backgrounds and temperaments, and although we have different genes __that make different proteins and different enzymes, we all boil down to four essential elements: hydrogen, oxygen, carbon, and nitrogen. If any one of these elements becomes unavailable, our time on earth will end. Three of the four elements are easily obtained.

Hydrogen comes from the water we drink, which consists of two hydrogen atoms and one oxygen atom (H 2 O). Oxygen, not surprisingly, comes from the air we breathe (O 2 ). (Only fish, through their gills, can extract oxygen from water.) Carbon also comes from the air. Green plants, in the presence of sunlight, take carbon dioxide (CO₂) from the air and capture it in the form of complex sugars that contain carbon (i.e., photosynthesis). We get our carbon from eating plants or from eating animals that ate the plants. Either way, because air and water are abundant, hydrogen, oxygen, and carbon are also abundant.

The weakest link in the cycle of life is nitrogen, which comes only from soil. When farmers grow crops like corn, wheat, barley, potatoes or rice, they deplete nitrogen from the soil. If they don’t replace it, the soil won’t be rich enough to grow more crops. Farmers replenish nitrogen in three ways. They use natural fertilizers made from decaying plants or animal manure. They rotate their crops with legumes like chickpeas, alfalfa, peas, soybeans, or clover, which harbor bacteria in their roots that take nitrogen from the air and convert it into a usable form in the soil—a process called “nitrogen fixation.” Or they wait for thunderstorms; lightning, as it turns out, can also fix nitrogen from the air.

If every farmer in every country on every continent in the world used every inch of fertile land, sprinkled their fields with natural fertilizers, meticulously rotated their crops, and convinced everyone to eat a vegetarian diet, they could feed about four billion people. But, as of 2016, more than seven billion people roamed the earth. And although pockets of people are starving, the problem isn’t that there isn’t enough food. There’s plenty of food. The problem is that the food isn’t distributed efficiently to those who need it.

So how are farmers able to do this? How are they able to feed so many people? The answer lies in an event that occurred on July 2, 1909. Because of this singular moment, 50 percent of the nitrogen in our bodies comes from natural sources and 50 percent comes from the work of one man—a man who at once saved our lives and sowed the seeds of our destruction. Fritz Haber was born on December 9, 1868, in Breslau, Germany. At the age of twenty-six, Haber attended the University of Karlsruhe, which had an excellent relationship with Badische Anilin & Soda-Fabik (BASF): a large chemical company just a stone’s throw down the Rhine River.

Haber’s task, taking nitrogen from the air and creating a chemical compound that could nourish crops, wasn’t easy. Although air is 79 percent nitrogen, it doesn’t exist as a single atom (N). It exists as two atoms coupled together (N₂) in a triple bond that is essentially unbreakable: the strongest chemical bond in nature. While N₂ in the air can be used to inflate a million balloons, it can’t be used to grow a single stalk of corn.

Because N₂ isn’t commonly broken down by nature, it took an unnatural process to do it: in a sense, an act against nature. The formula is simple:

N₂ + 3H₂ <—> 2NH₃

Reading from left to right, two paired nitrogen atoms combine with three paired hydrogen atoms to form two molecules of ammonia. Ammonia, Haber knew, would be perfect as a synthetic fertilizer.

A series of fortuitous events allowed Fritz Haber to succeed where many before him had failed. First, a young physicist from England named Robert Le Rossignol came to his laboratory. Le Rossignol was a skilled and inventive experimenter, eventually designing a small tabletop apparatus made of quartz and iron capable of withstanding temperatures as high as 1,832 o F, hot enough to melt copper; and pressures as high as 3,000 pounds per square inch, strong enough to crush a submarine. Second, Haber found a catalyst to speed up the reaction: osmium, a rare metal used as a filament in light bulbs. Third, Haber found a way to cool down ammonia quickly so that it didn’t burn up in the high heat. Finally, and most important, Haber’s mentor at Karlsruhe, Carl Engler, persuaded BASF to fund Haber’s experiments; if they worked, BASF would own the patents and Haber would have a commercial partner.

Haber and Le Rossignol tinkered with the fittings and tried different temperatures and pressures. Finally, in March 1909, they had a glimpse of success. Haber was ecstatic. “Come down, you have to see how the liquid ammonia is running out!” he shouted to a colleague, who remembered, “I can still see it. There was about a cubic centimeter of ammonia. It was fantastic.” It wasn’t much—about a fifth of a teaspoon—but it was a start. Within a few months, Haber and Le Rossignol’s apparatus was producing ammonia round the clock.

Ten months after Haber’s demonstration, scientists at BASF built a small prototypic unit in Ludwigshafen, a village not far from Karlsruhe. The plant officially opened on May 18, 1910. Haber’s 2-foot high tabletop apparatus had become a 26-foot high mega-machine. Within two months, the unit had produced more than 2,000 pounds of ammonia. By the beginning of January 1911, it was producing more than 8,000 pounds a day.

Other countries mimicked Haber’s process. By 1963, about 300 ammonia plants were in operation and more than 40 were under construction. Today, about 130 million tons of nitrogen are removed from the air and spread across the earth as fertilizer. More than three billion people alive today—and billions more in the future—owe their existence to Fritz Haber. Never before have so many people enjoyed so much food.

But there’s a dark side.

The largest nitrogen producing plant in the United States is located in Donaldsonville, Louisiana. Every day the plant consumes a million dollars worth of natural gas, boils 30,000 tons of water from a local river into steam, and produces 5,000 tons of ammonia (2 million tons a year). Every day these 5,000 tons of ammonia are loaded onto railcars, placed onto barges, floated down the Mississippi River, and sprinkled onto corn and wheat fields across the land. Not all of the nitrogen contained in ammonia ends up in crops. Only about a third of the nitrogen layered onto a cornfield, for instance, ends up in a kernel of corn. The rest washes into streams and leeches into groundwater.

The Gulf of Mexico, located next to the Louisiana ammonia plant, is a perfect example of what can happen when no one is watching. Every year about 1.5 million tons of nitrogen are dumped into the Gulf. This excess nitrogen has caused an overgrowth of algae that clouds the water and chokes off oxygen and sunlight to other species, like fish and mollusks. Algal overgrowth has killed streams, lakes, and coastal ecosystems across the northern hemisphere. And it’s not just the fish that are dying. The birds that eat the fish are dying, too. Synthetic nitrogen pollution isn’t limited to the waters; it’s also entered the air and come back to earth as acid rain, further damaging lakes, streams, and forests as well as the animals that depend on them. These problems will only worsen.

In the Deutsches Museum in Munich, separated from onlookers by a small barrier, stands the tabletop device built by Fritz Haber and Robert Le Rossignol to fix nitrogen from the air. Onlookers occasionally stop, stare for a few seconds, and walk past, thinking little of this machine that launched the worldwide manufacture of synthetic fertilizer, a process that has given so many people their lives and—due to ongoing contamination of the environment with excess nitrogen—a process that has probably started the clock on their eventual destruction.

Excerpted from the book Pandora's Lab by Paul Offit, published by National Geographic Partners on April 4, 2017.

Paul A. Offit, MD is a professor of pediatrics and director of the Vaccine Education Center at the Children’s Hospital of Philadelphia.

Popular Science is delighted to bring you selections from new and noteworthy science-related books. If you are an author or publisher and have a new and exciting book that you think would be a great fit for our website, please get in touch! Send an email to books@popsci.com.

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Bill Nye is going to march on Washington

Bill Nye, star of the megahit "Science Guy" television show of the 90s, announced his public support of the March for Science in a blog post on Thursday. The April 22 march is billed as a call for the world to support and safeguard science in light of recent policy changes disrupting research at the Environmental Protection Agency, National Institutes of Health, NASA, and more. The event will include a teach-in and rally on the National Mall followed by a march through the streets of D.C.

Nye, whose new Netflix series will drop the day before (an air date set long before the march was planned, but presumably also intended to coincide with Earth Day, which is on April 22), will be at the event as a speaker and honorary co-chair. He explained his support for the march in a blog post for The Planetary Society, a science nonprofit of which he is currently the CEO.

The March for Science aligns with The Planetary Society's values, he said, and evokes the wishes of its late founder Carl Sagan. Nye studied under the legendary science communicator at Cornell, and believes __that marching in April is the right thing to do to uphold Sagan's legacy.

"He was a space science champion, advocate and communicator," Nye wrote. "He inspired the world to experience space science and delight in discoveries: achieved and within reach. His legacy lives on, through us: through you.” Science, Nye added, is universal—and space exploration, which is experiencing a bold new renaissance, brings out the very best in humanity.

“We march to inspire unity," Nye wrote. "When we explore the cosmos, we come together and accomplish extraordinary things. Space science brings people of all walks of life together to solve problems and experience the unparalleled awe of exploration. Everyone—regardless of race, gender, nationality, creed or ability—is welcome in our journey to advance space science.”

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This graphene filter could make it cheaper to drink seawater

A new study released earlier this week in the journal Nature Nanotechnology may be a major step towards making desalinated water—water in which salt is removed to make it safe for drinking—a viable option for more of the world. Researchers from the University of Manchester modified graphene oxide membranes, a type of selectively permeable membrane __that allows some molecules to pass while keeping others behind, to let water through while trapping salt ions. It's essentially a molecular sieve.

Finding new sources of fresh water is important, because roughly 20 percent of the world's population—1.2 billion people—lack access to clean drinking water, according to the United Nations. It’s a number that’s expected to grow as populations increase and existing water supplies dwindle, in part due to climate change. This reality has led some to suggest __that the world’s next “gold rush” will be for water. Others have a less sanguine approach, worrying that the wars of the future will be fought over water. And this concern is not without merit: the war currently raging in Yemen is linked, at least in part, to water conflicts.

But while fresh water is scarce (a scant three percent of the world’s water is fresh) water itself is not. The Earth is more than 70 percent water, but 97 percent is undrinkable because it’s either salt or brackish (a mix of salt and fresh water). The occasional gulp of seawater while swimming aside, drinking saltwater is dangerous for humans—it leads to dehydration and eventually death. Hence the famous lined from the Rhyme of the Ancient Mariner: “water, water everywhere, nor any drop to drink.”

Desalination could be a solution. After all, the technique is already employed in parts of the Middle East and the Cayman Islands. However, the two techniques currently employed—multi-stage flash distillation, which flash heats a portion of the water into steam through a series of heat exchanges, and reverse osmosis, which uses a high-pressure pump to push sea water through reverse osmosis membranes to remove ions and particles from drinking water—have several key drawbacks.

“Current desalination methods are energy intensive and produce adverse environmental impact,” wrote Ram Devanathan a researcher at the Energy and Environment Directorate at Pacific Northwest National Laboratory, in an op-ed that accompanied the study. “Furthermore, energy production consumes large quantities of water and creates wastewater that needs to be treated with further energy input.”

Graphene oxide membranes show promise as a relatively inexpensive alternative, because they can be cheaply produced in a lab—and though water easily passes through them, salts do not. However, when immersed in water on a large-scale, graphene oxide membranes tend to quickly swell. Once swollen, the membranes not only allow water to pass through, but also sodium and magnesium ions, i.e. salt, defeating the purpose of the filtration.

Study author Rahul Nair and his colleagues discovered that by placing walls made of epoxy resin on either side of the graphene oxide, they could stop the expansion. And by restricting the membranes with resin, they were able to fine tune their capillary size to prevent any errant salts from hitching a ride on water molecules.

The next step will be testing it on an industrial scale to see if the method holds up. If it works, many people might just be drinking (a glass of water) to it.

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Even our ancient ancestors had to deal with bed bugs

For about as long as humans have been living in places, bed bugs have been infesting them. In a new study in Journal of Medical Entomology, researchers present evidence of the oldest bed bug ancestors ever uncovered: tiny fragments of insidious insects from some 5,000 to 11,000 years ago.

Cimex lectularius and Cimex hemipterus, the species __that haunt our nightmares (and sometimes, if we're really unlucky, our apartments) are thought to have split from their close relatives at least 98,000 years ago—perhaps even before modern humans hit the scene 200,000 years ago. But we only know __that by turning back the evolutionary clock in their DNA.

"Cimicidae is almost unknown in the fossil record," the researchers wrote in the study. One fossilized bug from a mid-Cretaceous amber deposit in Myanmar is considered a member of the same broader family as Climex, but it's not a close relative—Quasicimex eilapinastes is what's called a stem-group member, which means it descended from an ancestor shared with the bed bug but has no living descendants. Cimex lectularius has been spotted in the remains of wells and latrines from colonial Jamestown and settlements of similar time periods, and once even in 3,500-year-old fossils in Egypt, but the rest of the insect's history is without record.

The newly described ancient insects aren't of the sort that would suck human blood, but they represent the oldest-ever fossilized records of the genus Cimex. Until these bits of Cimex pilosellus, Cimex latipennis, and Cimex antennatus were found, the oldest known bed bugs of any sort were the Climex lectularius specimens found in Egypt in the 1990s.

The fragments described in this new paper belonged to species that feed on bats. But, study author and zooarchaeologist Martin Adams told Live Science, they likely "would have fed on humans if the opportunity presented itself." There are many recorded instances of this in the modern day, the researchers noted.

The insects' location—Paisley Caves in Oregon—played host to humans during the same time period, so it would have been difficult for those settlers to avoid playing host to some bat-loving bed bugs. So why didn't the ancient blood suckers adapt to these convenient sources of nutrition? It seems likely that species such as lectularius branched off from their relatives in the midst of a similar set-up—with humans and bats living alongside one another in caves—tens of thousands of years earlier. Why didn't it happen again, creating new lineages of bed bugs that preferred, well, beds? Not that we're complaining. But it's a puzzle Adams and his colleagues are trying to work out.

"Were the cimicid populations too small to establish themselves outside the caves, or were the host populations too small?" Adams pondered in a statement. "Given that Paisley Caves was only a seasonal occupation area for human hunter-gatherers, did the humans move around too much, or were the bugs not able to withstand the environment outside the caves for very long? Or, were there other constraints involved?"

These questions might sound like an itch not worth scratching if you're not an entomologist. But the more we understand about the common bed bug's lineage, the better equipped we are to keep them from creeping into our modern homes.

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What is climate change?

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Media captionMatt McGrath explains why we should care about climate change

BBC News looks at what we know and don't know about the Earth's changing climate.

What is climate change?

The planet's climate has constantly been changing over geological time. The global average temperature today is about 15C, though geological evidence suggests it has been much higher and lower in the past.

However, the current period of warming is occurring more rapidly than many past events. Scientists are concerned __that the natural fluctuation, or variability, is being overtaken by a rapid human-induced warming __that has serious implications for the stability of the planet's climate.

What is the "greenhouse effect"?

The greenhouse effect refers to the way the Earth's atmosphere traps some of the energy from the Sun. Solar energy radiating back out to space from the Earth's surface is absorbed by atmospheric greenhouse gases and re-emitted in all directions.

The energy that radiates back down to the planet heats both the lower atmosphere and the surface. Without this effect, the Earth would be about 30C colder, making our planet hostile to life.

Scientists believe we are adding to the natural greenhouse effect with gases released from industry and agriculture (known as emissions), trapping more energy and increasing the temperature. This is commonly referred to as global warming or climate change.

The most important of these greenhouse gases in terms of its contribution to warming is water vapour, but concentrations show little change and it persists in the atmosphere for only a few days.

On the other hand, carbon dioxide (CO2) persists for much longer (it would take hundreds of years for it to return to pre-industrial levels). In addition, there is only so much CO2 that can be soaked up by natural reservoirs such as the oceans.

Most man-made emissions of CO2 are through the burning of fossil fuels, as well as through cutting down carbon-absorbing forests. Other greenhouse gases such as methane and nitrous oxide are also released through human activities, but their overall abundance is small compared with carbon dioxide.

Since the industrial revolution began in 1750, CO2 levels have risen by more than 30% and methane levels have risen more than 140%. The concentration of CO2 in the atmosphere is now higher than at any time in at least 800,000 years.

Image caption Source: Nasa GISS

What is the evidence for warming?

Temperature records going back to the late 19th Century show that the average temperature of the Earth's surface has increased by about 0.8C (1.4F) in the last 100 years. About 0.6C (1.0F) of this warming occurred in the last three decades.

Satellite data shows an average increase in global sea levels of some 3mm per year in recent decades. A large proportion of the change in sea level is accounted for by the thermal expansion of seawater. As seawater warms up, the molecules become less densely packed, causing an increase in the volume of the ocean.

But the melting of mountain glaciers and the retreat of polar ice sheets are also important contributors. Most glaciers in temperate regions of the world and along the Antarctic Peninsula are in retreat. Since 1979, satellite records show a dramatic decline in Arctic sea-ice extent, at an annual rate of 4% per decade. In 2012, the ice extent reached a record minimum that was 50% lower than the 1979-2000 average.

The Greenland Ice Sheet has experienced record melting in recent years; if the entire 2.8 million cu km sheet were to melt, it would raise sea levels by 6m.

Satellite data shows the West Antarctic Ice Sheet is also losing mass, and a recent study indicated that East Antarctica, which had displayed no clear warming or cooling trend, may also have started to lose mass in the last few years. But scientists are not expecting dramatic changes. In some places, mass may actually increase as warming temperatures drive the production of more snows.

The effects of a changing climate can also be seen in vegetation and land animals. These include earlier flowering and fruiting times for plants and changes in the territories (or ranges) occupied by animals.

Image copyright AFP

Image caption Climate change could cause more extremes of weather

What about the pause?

In the last few years, there has been a lot of talk about a pause in global warming. Commentators argued that since 1998, there had been no significant global warming despite ever increasing amounts of carbon dioxide being emitted. Scientists have tried to explain this in a number of ways.

These include:

• variations in the Sun's energy output
• a decline in atmospheric water vapour
• greater storage of heat by the oceans.

But so far, there is no general consensus on the precise mechanism behind the pause.

Sceptics highlight the pause as an example of the fallibility of predictions based on computer climate models. On the other hand, climate scientists point out that the hiatus occurs in just one component of the climate system - the global mean surface temperature - and that other indicators, such as melting ice and changes to plant and animal life, demonstrate that the Earth has continued to warm.

In fact, a study published in Science journal in June 2015 doubted there had been a warming hiatus in the first place.

How much will temperatures rise in future?

In its 2013 assessment, the Intergovernmental Panel on Climate Change (IPCC) forecast a range of possible scenarios based on computer modelling. But most simulations indicate that global surface temperature change by the end of the 21st Century is likely to exceed 1.5C, relative to 1850.

A threshold of 2C is generally regarded as the gateway to dangerous warming.

Even if we cut greenhouse gas emissions dramatically now, scientists say the effects will continue because parts of the climate system, particularly large bodies of water and ice, can take hundreds of years to respond to changes in temperature. It also takes greenhouse gases decades to be removed from the atmosphere.

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Media captionHow temperatures have risen since 1884

How will climate change affect us?

The scale of potential impacts is uncertain. The changes could drive freshwater shortages, bring sweeping changes in food production conditions, and increase the number of deaths from floods, storms, heat waves and droughts. This is because climate change is expected to increase the frequency of extreme weather events - though linking any single event to global warming is complicated.

Scientists forecast more rainfall overall, but say the risk of drought in inland areas during hot summers will increase. More flooding is expected from storms and rising sea levels. There are, however, likely to be very strong regional variations in these patterns.

Poorer countries, which are least equipped to deal with rapid change, could suffer the most.

Plant and animal extinctions are predicted as habitats change faster than species can adapt, and the World Health Organization (WHO) has warned that the health of millions could be threatened by increases in malaria, water-borne disease and malnutrition.

As an increased amount of CO2 is released into the atmosphere, there is increased uptake of CO2 by the oceans, and this leads to them becoming more acidic. This ongoing process of acidification could pose major problems for the world's coral reefs, as the changes in chemistry prevent corals from forming a calcified skeleton, which is essential for their survival.

Computer models are used to study the dynamics of the Earth's climate and make projections about future temperature change. But these climate models differ on "climate sensitivity" - the amount of warming or cooling that occurs as a particular factor, such as CO2. goes up or down.

Models also differ in the way that they express "climate feedbacks".

Global warming will cause some changes that look likely to create further heating, such as the release of large quantities of the greenhouse gas methane as permafrost (permanently frozen soil found mainly in the Arctic) melts. This is known as a positive climate feedback.

But negative feedbacks exist that could offset warming. Various "reservoirs" on Earth absorb CO2 as part of the carbon cycle - the process through which carbon is exchanged between, for example, the oceans and the land.

The question is: how will these balance out?

More: BBC News climate change special report

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Trump makes major change to US climate change narrative

Image copyright Getty Images

Image caption Coal fired power plants like this one faced restrictions under President Obama

"This is, I think, one of the most historic attacks on climate and environmental action __that the US has ever seen," said Liz Perera from the Sierra Club.

Her words are certain to cheer Trump supporters everywhere.

Green "job-killing" regulations limiting energy production have long been a red rag for Donald Trump, as candidate and President.

His new energy independence executive order seeks to radically change the US narrative on climate change, its causes and its importance. The best way of fighting global warming according to the new outline is to create prosperity. Environmental regulation should be about air and water. CO2, in this light, is your friend.

Supporters believe __that cutting back Obama climate regulations will create thousands of jobs in the newly liberated oil and gas industries.

His opponents agree the new order will be a job creator - but they'll be jobs for lawyers, not in the coal fields.

Image copyright Getty Images

Image caption President Trump plans may reduce regulations on coal but can't guarantee jobs

Front and centre is practical action on the Clean Power Plan (CPP), the Obama project to cut fossil fuels from electricity production. Although it has long been tied up in the courts, the CPP will be left to fester there while the new administration comes up with a much weaker replacement.

"Undoing the rule will not be straightforward," said Prof Bruce Huber, from the Notre Dame law school.

"For the Environmental Protection Agency (EPA) to reverse course, it will have to propose a new rule, with all the lengthy procedures that entails. When President George W Bush tried to reverse course on some of President Clinton's signature environmental regulations, those efforts took years and were not entirely successful."

In terms of coal, the new executive order will allow the Department of the Interior to lift a moratorium on the sale of new coal leases on federal lands. However, boosting coal as a source of energy, and jobs, will be very difficult.

Many coal plants have shut down not because of Obama's carbon restrictions but because of mercury pollution associated with burning the fuel. Thanks to fracking, cheap natural gas has soared as a source of power generation, and renewables are taking an every bigger share.

Former State department climate adviser Andrew Light now works for the World Resources Institute. Both of his grandfathers were coal miners.

"They were paid by the tonne for the coal they pulled out of the ground, but those jobs are gone, and technology has moved beyond that and I hope it's the case that voters in the coal states will recognise that their jobs aren't magically coming back because of this executive order," he told BBC News.

Image copyright Getty Images

Image caption EPA administrator Scott Pruitt says that CO2 is not a primary contributor to global warming

President Obama sought to put consideration of climate change at the heart of all government policy - but by revising the social cost of carbon measure and encouraging an immediate government review of all rules that inhibit energy production, President Trump is signalling a change in the widely held philosophy that CO2 is the enemy, the main driver of climate change.

While rolling back Obama era ideas like the role of climate change in national security, or how climate change should be considered in relation to the National Environmental Policy Act, the Trump plan does not directly attack the key finding on which much of America's carbon restrictions are based.

Back in 2007, the US Supreme Court ruled that carbon dioxide gas was a pollutant under the Clean Air Act.

In response, the EPA ruled in 2009 that CO2 and other gases were responsible for contributing to climate change which results in a threat to the public health and welfare of current and future generations.

This "endangerment finding" compels the federal government to regulate emissions of CO2. And according to some environmentalists, this finding is the solid rock that Trump's plans will be dashed against.

"The law of the land is that CO2 endangers my public health and welfare," said Liz Perera from the Sierra Club.

"So they have to regulate it. What they are doing now is saying that all the Obama regulations were wrong but that means they are going to have to put something forward in their place and by the law it has to be adequate or we can sue them every step of the way."

Other experts believe that the ultimate goal of this executive order will be to overturn the Supreme Court ruling on CO2 as a pollutant.

They believe that the declaration of EPA administrator Scott Pruitt that CO2 was not a "primary contributor" to climate change is instructive of the direction of travel.

"It is fundamental," said Andrew Light. "I believe that Scott Pruitt wants to go after the endangerment finding. Their argument is that climate change exists, but it is not the case that humans are causing it.

"It is the endangerment finding that draws that tight connection between the fact that humans are making it and the fact that global warming is happening. Once you destabilise that point then you can go for the endangerment finding. That would be the biggest win they could get."

But Liz Perera, for one, believes that won't happen.

"We have the economics on our side, we have the market on our side, we have the public on our side, and we have the law on our side - that this is endangering public health and welfare. They can't change any of those things."

But in many ways, extended court battles are exactly what President Trump and the fossil fuel lobby are looking for.

"Delay is what they want," one green source told me. "Delay is winning."

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How to turn a spinach leaf into a human heart

Spinach could be good for your heart in more ways than one. It’s packed with fiber, vitamin A, and the branching vasculature necessary for cells to absorb nutrients.

Which is why bioengineers at Worcester Polytechnic Institute decided to try growing human heart cells on the scaffolding of a humble spinach leaf. And it worked. They published their results online in the journal Biomaterials in advance of the May 2017 print issue.

When you look at a spinach leaf, you probably see a dark, leafy green __that belongs alongside dried cranberries and apples. A bioengineer sees veins. There’s a central stem with smaller branches peeling off towards the edges, much the same way __that the blood vessels in your heart grow. And though spinach doesn’t have blood, the vasculature in the leaf and in your heart are used for essentially the same purpose: delivering nutrients.

It’s easy to think of your circulatory system as mainly large veins and arteries all connecting in one big loop. But perhaps the most important part of that system are the capillaries, the minuscule tubes that get the blood to that last stage, where a lot of the oxygen and nutrient delivery actually happens. Without the capillaries, you couldn’t survive. The cells in your organs can’t survive very far from a capillary—they have to be within about 100-200 micrometers, or one or two hairs’ width. And because cells have to have this intricate web of capillaries, it’s hard to grow human tissues artificially. It’s actually one of the hardest things about manufacturing organs. Cells have ways of inducing blood vessel growth inside your body, but outside it’s not so easy. And you can’t just transplant a mass of cells into a body and expect them to create their own vasculature, because they’ll die off before they even have a chance. So if you want to create an organ from scratch (or even just a chunk of one), you have to find a way to create at least a simulacrum of blood vessels.

There are a bunch of ideas on how to do this, and spinach scaffolding is just one of them. In 2012, two researchers at the University of Pennsylvania 3D printed “blood vessels” made of sugar, then got liver cells to grow around the network. Once the cells had taken hold, they simply dissolved the sugar away, leaving behind a hollow web of tubes that could function as capillaries. That approach doesn’t have a very natural structure, though, since you’re limited by the geometric way in which 3D printers can lay down threads of sugar.

These bioengineers took a different approach. They dissolved all of the cellular material inside a spinach leaf using detergents, leaving the cellulose background behind. Once they had an empty shell of spinach, they could add in human heart cells and get them to adhere to the structure. The cells could still beat the way a heart should and the vasculature could support blood flow, though the engineers didn’t put real blood into the system—they used a red-dyed liquid meant to look like blood to prove that it worked.

Spinach leaves wouldn’t be suitable scaffolding for all tissues. The branching design is similar to how the vessels in a heart grow, but other organs have different capillary networks, so other plants might work better for different parts of the body. These bioengineers also proved their concept using parsley stems and the little hairy roots on peanuts, and they point out that in theory you could use something like wood to mimic the way bones grow, or a thick-stemmed plant like jewel weed to form a piece of an artery.

They’re not yet sure how well these bits of organ would transplant into an actual human. It’s one thing to grow a piece of a heart and another to get a body to accept that artificial structure as part of itself. Grafts fail to take hold pretty regularly, even when they’re not made from plants. And even Popeye would have trouble becoming one with a spinach leaf. At least for now.

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To save their land, they unveiled the world’s biggest dinosaur footprint

The Goolarabooloo people have been singing about dinosaur footprints for thousands of years—they just don’t call them ‘dinosaurs.’

To the indigenous tribe, those tracks were left by ancient, spiritual beings who walked those lands during the Creation Time. The men tasked with maintaining the laws and rituals for the Goolarabooloo people have passed down lyrical stories about the footprints. These so-called ‘song cycles’ detail the paths __that their supernatural predecessors took, as demarcated by the enormous tracks they left behind. So they’ve known for thousands of years __that these footprints existed, they just weren’t about to open up their homelands to a bunch of outsiders.

That is, until 2008 when the Australian government wanted to build a gas processing plant in the Walmadany area, where most of the dino prints are located. The Goolarabooloo wanted to protect their lands and they knew they might have a bargaining chip up their sleeves. If the prints that their folklore was based on were valuable to paleontologists, then maybe the land would be protected. And they were right.

Salisbury footprint tweet

Leaders from the group reached out to Steven Salisbury, a paleontologist at the University of Queensland in Australia, hoping that he could investigate the tracks. And investigate he did. Salisbury and his colleagues found 21 different types of fossil prints embedded in the sandstone in Walmadany, making it perhaps the most diverse region of dinosaur footprints in the world. The site confirms that the stegosaurus once roamed Australian lands and includes a five-foot-nine-inch long footprint from a sauropod, the largest footprint ever found. Salisbury and his colleagues finally published five years’ worth of research in the Journal of Vertebrate Paleontology on Friday.

The Walmadany region is especially significant for Australian paleontology because there are so few prehistoric fossils in the area. Low, flat plains aren’t ideal for finding fossils. You need areas of rock that are in the process of being unearthed by geological activity, such that you can see the fossils before they’re destroyed by total exposure.

Even these tracks were only visible at low tide, forcing the researchers to brave sharks and crocodiles to reach them. Welcome to Australia.

Fortunately, the land has now been designated a National Heritage site and the gas plant plan fell through, so paleontologists can keep investigating the thousands of tracks in the area. And since they’re significantly older than the fossils found elsewhere in Australia—which are a mere 90 to 115 million years old—these prints could hold clues to more ancient history.

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Bombing Antarctica, flying into hurricanes, and drinking your own pee: Fantastic tales from the field

Jeff Williams, NASA astronaut and U.S. record holder for total days spent in space

"On Earth, not all water tastes the same. Some water is delicious, but some can leave a funny taste in your mouth—the result of a particular mineral or metal. This doesnʼt happen on board the International Space Station, even though youʼre drinking recycled sweat and urine. You donʼt sense any unusual flavors. The water—and the beverages we make from it—consistently tastes pretty good.

The process of treating wastewater up there isnʼt all __that different from the natural water cycle on Earth—the runoff, the evaporation, clouds, and rain. The planetʼs water cycle turns water we might consider nasty into water we consider drinkable; so do the ISSʼs systems. And we test it almost every single day, so weʼre confident __that our drinking water is clean. NASA has very strict standards for it. We joke about it a lot, but we really donʼt think much about what our drinking water used to be. Iʼve been on board with 55 or so different people, and Iʼve never seen anyone hesitate to drink it. We drink the Russian water, and they drink ours."

As told to Sarah Fecht

Rick Gelting, U.S. Public Health Service Officer at the Centers for Disease Control and Prevention

"When you’re in a water emergency, it’s really not the time to try something new. In 2010, when the cholera outbreak hit Haiti, the local government invited us to help implement a water-cleaning system. We had to work quickly to get clean water to small communities fighting against the waterborne disease. But we also couldn’t introduce any new technologies or products that local workers and residents might not be familiar with.

Chlorine was our go-to: It’s available, inexpensive, and incredibly effective. Problem is, there are different types of chlorination, so we had to trace where people got every drop of their water—whether they piped it in, hauled it from wells, or got it elsewhere. This is where local knowledge comes in handy.

For large community water systems, we used locally available materials to drip a liquid chlorine solution directly into storage tanks, a method that Haiti’s national water and ­sanitation agency (DINEPA) developed. But some people were bringing in small batches of water from other places. In those cases, special chlorine tablets and solutions let ­individual households treat their own water.

Working with DINEPA was key because they knew the local conditions and communities better than we did. Local knowledge ­ensures that what you build will sustain itself and make a difference in the long term—­because you will eventually leave."

As told to Claire Maldarelli

Robert Rogers, meteorologist for the National Oceanic and Atmospheric Organization

"When we fly Hurricane Hunter aircraft into cyclones, a lot of the data we gather is to monitor for “rapid intensification.” That’s when a storm increases in strength by 35 miles per hour or more within a 24-hour period, and it’s a big concern for the forecast community. The nightmare scenario is for this to happen to a Category 1 hurricane just before landfall on the U.S. coast: It goes from a Category 1 to a catastrophic Category 4, and no one has any warning.

Back in 2007, during Hurricane Felix, we flew into a Category 2. But at 10,000 feet, I saw flashes—at first I thought someone took a photo, but then I realized it was lightning. When you see lightning in the core of a storm, it’s a sign that it’s really intensifying. We wound up hitting such a strong updraft, maybe 60 miles per hour, that we hit zero g for a couple of seconds. My notebook started to float, and drops of water from the cup next to me were hovering in the air. At that point, the mission switched from collecting data to just getting home safely."

As told to Rachel Feltman

Nick Holschuh, Geophysicist at the University of Washington

"If you were to melt Antarctica, the global sea level would go up by around 60 meters, which would obviously be pretty bad. But to understand how and when the ice sheet might melt, we need to measure its physical properties—the material of the rocks beneath, the temperature of the ice, defects gliding through the system. For something one and a half times the size of the United States, thatʼs a crazy-difficult task.

So how do we do that? Well, if you use a thermometer to measure temperature, youʼre actually measuring the behavior of alcohol or metal within the thermometer itself. I used a similar principle to measure temperature through the ice. We sent sound waves down into the subsurface to get information on physical properties—like temperature—that affected them on the way.

Explosives happen to be a great source of sound. First, we bored a 20-meter hole down into the ice with a hot-water drill. Then we stuffed in a pound of Pentex H boosters and packed them in with snow. We covered the surface in an array of microphones. Then—boom!

After the explosion, we listened for echoes. Logistically speaking, itʼs not the simplest method of measuring the properties of ice, but having a variety of data-collection techniques at our disposal helps us understand how human behavior affects this massive system.

On quieter days, I use radio waves to peek through the ice sheets—to look at the configuration of the ice and the properties of the material itʼs sitting on top of—and I use satellite data to see how the surface is changing over time."

As told to Sophie Bushwick

Emily Sutton, meteorologist and storm chaser at KFOR-TV in Oklahoma City

"When you're chasing a storm, hydro-planing and hail are usually scarier than the tornado itself. It’s like driving on black ice in the middle of nowhere with no cell reception."

As told to Rachel Feltman

Andrea Dietrich, water consultant for utility companies

"About 25 years ago, some people would turn on their ­faucets and smell cat urine. It was one apartment in a building, or one house in a neighborhood. Residents would say, 'We don’t have a cat.' We were stumped for more than a year until a utility employee said, 'It’s not our water; it’s residents’ new carpets.'

He was half right, anyway. At the time, maybe 0.1 percent of utilities in the United States disinfected their water with chlorine dioxide. But chlorine dioxide isn’t water soluble, so when people opened their faucets, it would quickly fill the surrounding air. There, it reacted with chemicals in new carpets to create the signature stench. My colleague and I went to his church, which had a new carpet, to test the theory. We sprayed chlorine dioxide into the air, and sure enough: cat urine."

As told to Sarah Chodosh

These articles were originally published in the March/April 2017 issue of Popular Science, in the “Tales From The Field” section.

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Popular foods that grow in somewhat startling ways

Cherries grow on trees, strawberries on vines, but how do cashews grow? Thanks to our current food system, we can get crops from almost anywhere in the world—vanilla from Madagascar, bananas from Ecuador. Of course, the downside of receiving produce from far-off lands is __that we can’t exactly run into the fields to see how they’re grown. For many, the manner in which fruits and veggies emerge from the earth can be something of a mystery. Here are some of the more unexpected ways plants propagate before they make their way into our meals:

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Groundhog day for a keystone cop-out?

Image copyright Getty Images

Image caption Sections of the pipeline prepared but not yet used for Keystone XL

According to Donald Trump, the Keystone XL will be an "incredible pipeline", but could it be __that the official signing of the permit in the Oval Office will be the high point for this long-winded process?

Let's look at some of the issues __that might see TransCanada, the company behind the project, eventually walk away.

First, making oil from the bitumen-rich Canadian tar sands is a messy and expensive business.

Separating the liquid from the sand requires huge amounts of water and heat, and environmentalists say the process causes about 17% more greenhouse gas emissions than standard oil extraction.

However, both Democrats and Republicans have over recent years supported, however reluctantly, this massive project, which would send more than 800,000 barrels of the tarry oil from Alberta, Canada, to the US Gulf Coast every day.

Back in 2010, then Secretary of State Hillary Clinton said that the Obama administration was "inclined" towards approval, based on an assessment of environmental and economic impacts.

The State department, which carried out the review, believed that there would be at least some jobs created in the short term, and the environmental and safety impacts of diverting that much oil from railroad cars were beneficial.

Environmentalists, though, were aghast at the thought of the overall effect on climate change from endorsing the tar sands source.

But for several years, much to the despair of the green movement, Obama remained conflicted over the project, torn between opting for dirty but secure Canadian oil over cleaner but vulnerable middle-eastern sources.

Problem solved

In November 2015, global warming gave him a way out of the dilemma.

Just a month before the key Paris climate meeting, John Kerry wrote that "moving forward with this project would significantly undermine our ability to continue leading the world in combating climate change". Obama scrapped XL, and it helped persuade the world to sign the Paris Climate Agreement.

Image copyright Getty Images

Image caption President Trump signing the permit to allow the Keystone XL pipeline to go ahead

But the new administration has made clear that jobs and infrastructure top climate change as priorities.

In January, President Trump asked the State department to re-assess the project. It has now found that the economic case makes sense and the pipeline "serves the national interest".

Mr Trump, struggling with healthcare reform, is very keen for a "win" on infrastructure and jobs, and the pipeline fits the bill.

But his rush to approve may actually end up delaying it significantly.

"Trump required the State department to make a decision within 60 days. That didn't allow them to do another environmental review of the project and meet that deadline, as US environmental law requires," said Anthony Swift from the National Resources Defense Council, who are looking to challenge the decision in the courts

"Allowing a decision to be made that flaunts the minimum requirements of our country's environmental laws would set an alarming precedent," he told BBC News.

There are many other complications, most of them centred around the state of Nebraska.

TransCanada has not had a route through the state approved, and that application process will take at least 8-12 months. Many landowners are reluctant to sell to the company and there are ongoing worries about polluting water sources.

"We're living in what feels to be the worst version of Groundhog Day imaginable, as every morning we're waking up to yet another decision made by Trump that would be disastrous for our climate, our communities, and our health," said Michael Brune, from the Sierra Club.

"But Trump will not succeed. The pipeline will pollute our air and water, destroy farmers' and ranchers' property, and enrich the foreign oil barons and corporate polluters that have been stocking Trump's cabinet and pulling his strings from the get-go."

Image copyright Getty Images

Image caption Previous attempts to move forward with Keystone have drawn protests on the streets

The low price of oil makes XL (which stands for export limited and not extra large!) extremely expensive right now and the prospects of getting a good return on that investment is very distant.

As oil companies like Shell look to get rid of their tar sands holdings, a more pressing problem for the pipeline may be getting any oil to put in it.

"The chances of it opening in the next couple of years would appear to be pretty low," said Anthony Swift.

"TransCanada also has to find enough tar sands companies to back the pipeline, to make it economically feasible and in the current market it is hard to see which companies will be willing to commit to that kind of new production for 20-30 years."

And even if Keystone XL is built, it may not fulfil a key Trump requirement - to be constructed with "American steel". It seems that the TransCanada Corp has already ordered sufficient Canadian and Mexican supplies. Oops!

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New 'super yield' GM wheat trial gets go-ahead

Image copyright ROTHAMSTED RESEARCH

Image caption In greenhouse tests, the new wheat has shown increased yields of between 20-40%

The planting of a new experimental crop of genetically modified (GM) wheat will take place this spring after the UK government gave the final go ahead.

The GM wheat has been engineered to use sunlight more efficiently and has boosted greenhouse yields by up to 40%.

Researchers in Hertfordshire now want to see if they can replicate these gains in the field.

Critics say __that boosting wheat yields is not an answer to global food shortages.

Against the grain

Several GM trials of crops have taken place in the UK over the past 20 years, often attracting protesters who have attempted to destroy the plants.

Even when trials managed to avoid disruption, they have not always been scientifically successful.

This latest effort aims to see if the spectacular gains in productivity of 20-40% in GM wheat grown in the greenhouse can be reproduced in the open air.

Last Autumn, the scientists at Rothamsted Research submitted an application to the Department of the Environment, Food and Rural Affairs (Defra) seeking permission to carry out small field trials at a secure site near Harpenden between 2017 and 2019.

After an independent risk assessment and a public consultation, __that permission has now been granted.

The researchers say they want to test newly developed wheat plants that have been modified to carry a gene from a wild relative called stiff brome.

The Rothamsted team, which is working in collaboration with researchers from the University of Essex and Lancaster University, believes this enables the modified wheat to carry out photosynthesis more efficiently, converting more sunlight and CO2 into grain.

Image copyright ROTHAMSTED RESEARCH

Image caption Attempts to improve wheat with GM technology have not yet proved successful

"It makes the plant bigger in the greenhouse, it makes the leaves grow bigger, and that's because you have more of this photosynthesis going on," Dr Malcolm Hawkesford from Rothamsted told BBC News.

"Once you start to produce grain all of that CO2 fixation starts to get targeted into the production of more grain. You end with bigger plants and more grain."

With a rapidly growing global population, food production will need to increase by 70% by 2050 to meet the demand, say researchers.

The problem for wheat is that yields have reached a plateau in recent years and the scientists involved in this new trial say they have gone as far as they can in boosting growth via conventional means.

However, replicating the gains made under glass will not be easy.

"At the moment with traditional methods if you get one percent you are pretty happy," said Dr Hawkesford.

"Anything more than a few percent would be super yielding. I would be happy if we could get 5-10; anything more than that would be absolutely massive."

Feeding the world

But the planned planting is not without its critics.

Around 30 green organisations lodged objections to the plan, pointing to concerns about the potential for the GM wheat to escape into the wild, as has repeatedly happened in the US. Campaigners say they are "disappointed" that the trial is now going ahead.

"People aren't starving because photosynthesis isn't efficient enough; people are starving because they are poor," said Liz O'Neill from GM Freeze.

"Techno-fixes like GM wheat suck up public funding that could make a real difference if it was spent on systemic solutions like waste reduction and poverty eradication. Then we could all enjoy food that is produced responsibly, fairly and sustainably."

But supporters of the technology point out that if the GM wheat boosts yields it could allow farmers to grow greater amounts of the crop with fewer inputs such as nitrogen, decreasing emissions of CO2 as well.

Another concern is that the go-ahead for the new trial signals a different approach to GM as the UK faces up to Brexit. In the House of Commons last autumn, farming minister George Eustice indicated that the government was open to re-examining the position after the UK leaves the EU.

"As part of the preparations for EU exit, the government is considering possible future arrangements for the regulation of genetically modified organisms," he said in a written statement.

"The government's general view remains that policy and regulation in this area should be science-based and proportionate."

Both supporters and critics say the new trial does not signal a change in position.

"I don't believe it will make a huge difference to us," said Dr Hawkesford.

"This whole project was planned prior to Brexit. I honestly don't know if it will influence future trials, but at the moment the British government has its policy, we stick to the rules, and I wouldn't say there's any impact I would definitely see about Brexit."

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Climate may have shaped the evolution of the human nose

In the late 1800s, British anthropologist and anatomist Arthur Thomson posited __that people with ancestral origins in cold, arid climates were likely to have longer, thinner noses, while those who came from warm, humid regions were inclined to have noses __that were shorter and thicker.

His theory was that climate has a profound influence on the shape of the human nose, more so than any other evolutionary factor, because one important job of the nose is to warm and humidify air inhaled through the nostrils. This suggests it is an advantage for people in colder climates to have narrower nostrils, and vice versa.

Over the years, scientists have tested Thomson’s Nose Rule, as it came to be known, with skull measurements, but until recently no one had ever studied these dimensions in live people.

Pennsylvania State University researchers did just that in a study published Thursday in PLOS Genetics, confirming that Thomson was onto something. They concluded that the size and shape of noses evolved, at least in part, as a response to local climate conditions.

“We are primarily interested in understanding how human variation arises,” says Arslan Zaidi, a postdoctoral fellow in biology and the study’s lead author. “The questions we ask are: why do we look different from one another? Why do males and females look different? Why are there differences among humans from different populations? We focused on the nose because there is a huge body of work suggesting that it may have evolved in response to climate.”

The research is important because studying human evolution and adaptation can have significant implications for human health. For example, people of Northern European ancestry — because of their light skin — carry an increased risk of sunburn and skin cancer when they are near the equator. Similarly, dark-skinned individuals carry an increased risk of vitamin-D deficiency at higher latitudes.

“These risks are a direct consequence of our evolutionary history,” Zaidi says. “Dark skin evolved to protect us from overexposure to ultraviolet radiation, and lighter skin evolved to allow us more absorption of UV so that we can synthesize more vitamin D. If nose shape evolution has indeed been driven by climate, does moving to a different climate increase our risk of respiratory disease? This is unclear at this point, but important to pursue.”

The researchers looked at a variety of nose measurements. Using three-dimensional facial imaging, they examined the width of the nostrils, the distance between nostrils, the height of the nose, nose ridge length, nose protrusion, external area of the nose, and the area of the nostrils. They focused on individuals of four different ancestries: South Asian, East Asian, West African and Northern European.

They asked two questions: Are some aspects of nose shape more varied across populations than expected with genetic drift? (Genetic drift is a random evolutionary process leading to differences among populations over a long period of time, simply by chance.) If so, can this variation be explained by climate?

“In other words, if two populations are isolated for a long time, we expect their noses to look different just by chance, because of genetic drift,” Zaidi says. “We needed to rule this out to show that the variation among human populations was more than that expected just by genetic drift. Out of the seven measurements describing nose shape, we found two measurements related to the width of the nose to be significantly more differentiated among populations than expected by genetic drift. This means that the difference in nose width among human populations is more than is expected by random chance.”

Researchers found a positive correlation between nostril width and temperature and humidity, suggesting that natural selection likely plays a significant role in human nose evolution. Natural selection is the process by which organisms that are well adapted to their environment tend to survive and pass their traits to succeeding generations, while ill-adapted organisms tend to die off.

But humans have always moved around, and these days it's not uncommon for someone from a long line of cold climates to live by the equator. They'll likely sport the narrow nostrils of their forbears.

“Evolution takes a long time,” Zaidi says. “If nose shape has evolved in the past to adapt to local climate, it likely took tens of thousands of years. So, my great-great-great grandkids are likely still going to have wider noses — I’m Pakistani — even if they continue to live in a colder climate, as long as they continue to marry other South Asians.”

Moreover, “human variation does not agree with notions of race,” he adds. “There are more similarities among humans from different populations than there are differences, both genetically and phenotypically. Traits such as skin pigmentation and nose width appear more different because they are examples of external traits that are exposed to the environment, and have evolved faster than most other human traits. They are an exception rather than the rule. This is an important caveat to make, because people often tend to focus on differences and ignore the similarities.”

The researchers also noted that other factors may also be involved, such as gender differences. Men tend to be larger than women, for example, so their noses tend to be larger as well. Other variations emerge because people may prefer mates with smaller or larger noses. Still, concepts of beauty may be related to how well-adapted a nose is to the local climate, according to the scientists.

As for the future of the schnoz, Zaidi says that evolution is “a wildly random” process, making it difficult to predict what will happen to the human nose in response to global warming.

“Human evolution, at this point, is very different from evolution in the past,” he says. “Our lifestyles aren’t what they used to be, and we move around the world way too much. That makes it very complicated to predict the future evolutionary trajectory of the nose with the changing climate.”

Marlene Cimons writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture.

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Introducing the world's oldest plant-like fossil

When you think fossils, you probably think of impressively preserved bones; the last remains of dinosaurs __that strolled (or flew) across the Earth eons ago.

But it took evolution a long time to work up to dinosaurs. Or any kind of animal, for __that matter. For about 2 billion years in Earth’s early history (give or take a few hundred million years) single-celled organisms ruled the planet. Then, life started branching out.

In a paper published Tuesday in PLOS Biology, researchers from the Swedish Museum of Natural History announced the discovery of the earliest known evidence of plants in the fossil record; 1.6 billion-year-old red algae that lived alongside mats of bacteria in our planet's shallow waters.

These particular fossils were found in India. “Back in the days when they were living and growing this would have been a shallow marine system with plenty of sunlight,” says study co-author and geobiologist Therese Sallstedt.

Instead of frolicking fish or even decorative corals, these sunny, warm waters were filled with a different life form: vast mats of photosynthesizing, slimy cyanobacteria—single-celled organisms that grow in colonies.

And among these cyanobacteria were at least two different kinds of red algae, one forming thin threads, and one forming a fleshy mass.

Sallstedt was originally studying the cyanobacteria, which are preserved in bulbous formations of rock known as stromatolites, when she came across the fossils.

The algae are tiny—the thread-like fossils are microscopic, and the tissue-like organisms only a few millimeters across—but for Sallstedt, it was a big find in more ways than one.

“I’m used to studying cyanobacteria, which is even smaller,” Sallstedt says, laughing. At least one of the algae fossils is visible to the naked eye, if only barely. “Usually my stuff is a lot smaller than that,” she says.

And finding fossils of such an advanced age is no small feat. At 1.6 billion years, they outstrip the next oldest red algae specimens by 400 million years.

“From what we know today, these are the oldest red algae ever found,” Sallstedt says.

That also makes them the oldest plant-like fossils—with distinct cell structures like walls and tiny organelles (likely chloroplasts) that are distinct to red algae—ever found.

These fossils fit into an interesting period of evolutionary history, long before the eruption of biodiversity known as the Cambrian explosion 550 million years ago. Both bacteria and algae met their end in a sudden event—perhaps a rapid burial—that preserved their little ecosystem for 1.6 billion years. This portrait was painted in phosphate, a mineral that can help preserve even tiny details of a cell’s structure.

The minuscule fossils of a time long-past might not seem to have much of an influence on your daily life. But in reality, we owe these pioneering lifeforms a huge debt. Though tiny, organisms like cyanobacteria and the red algae eventually altered our world entirely.

“[Cyanobacteria] changed forever the state of the atmosphere, releasing oxygen that we breathe,” Sallstedt says. “As did plants, in a way. They didn’t invent photosynthesis, but they took it to the next level.”

Remember that the next time you ponder the plants in your yard or algae in a pond. It’s not mere scum: it’s next-level biology, with the potential to change the world.

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Plagued by predators in the sea, these fish are moving onto land

On the remote Pacific island of Rarotonga, some fish are fleeing to land.

Scientists have long suspected __that blenny fish leapt out of water to escape the many sea creatures __that seek to eat them, but the blennies' true motivations remained a mystery. Now, in a study published this week in The American Naturalist, researchers show that these sausage-shaped fish were over three times more likely to be devoured in the sea than on land, giving credence to this theory.

"It turns out the aquatic environment is a nasty place for blennies, full of enemies wanting to eat these small fish. But life is less hostile on the rocks, with birds their main worry,” says Terry Ord, the study’s lead author and evolutionary ecologist from the University of New South Wales, in Sydney, Australia.

Amphibious blenny fish leaping about on an intertidal rock ledge on Guam

To find out, Ord and his team visited Raratongo Island, where several species of blenny are regularly found lying on the ground near the water. The team fashioned 250 fake plastic blennies, about 2.5 inches long, with lifelike colorings and patterns. Half of the mimics were put in the water, and the other half were fully exposed on dry land. Predatory attacks on the mimics were observed over eight days, and the results suggest that blennies are much safer on land. “There were at least three times more attacks on our model blennies placed in the water than there were on models positioned on land,” says Ord.

So although being hacked to death by predatory seabirds surely isn’t a great way to go, it seems the blennies prefer that alternative to whatever ravenous creatures lurk in the sea.

The team also observed the behaviors of real-life blennies. At low tide, most of the blennies migrated to the rocky shelves above the water. And as the tide rose, they moved with it, taking refuge at higher ground, “apparently to avoid being eaten by aquatic predators coming in with the rising water,” explains Ord.

Ord doesn’t think this is just a survival technique, like mountain lions and bears scrambling up trees when they sense danger. He thinks that blennies are in the process of moving out of the sea and colonizing land on a more permanent basis.

Although lacking legs, they do seem comfortable on the ground. They don’t just spend a considerable amount of time there (although Ord notes it's difficult to measure how much time each blenny spends out of water), they also hop around to different rock crevices and socialize with each other, explains Ord. Perhaps most compelling, there’s a blenny species that hangs out on the same rocks as the truly amphibious fish, and “spends its entire adult life out on the rocks in the splash zone,” he says.

What’s more, the land-seeking habits of the blenny are seen in disparate places around the world. Ord cites Guam and Japan in the North Pacific, Tahiti and Rarotonga in the South Pacific, and Mauritius and Seychelles in the Indian Ocean as examples.

The blenny has a long way to go before it’s a full-fledged land-dweller, but it’s doing pretty well—for a legless fish. They breathe mostly through their gills, but can get some oxygen through their skin, says Orb. And they’re “reasonably agile out of water because of their general sausage-shaped body, and by use of their tails to shuffle and even hop across intertidal rocks,” he says.

In time, we’ll see if the blennies continue their march towards dry land, a place where they’re less likely to be chomped and munched on. For now, let’s keep mum about their ambitions, lest more predatory sea birds—or Guam’s two million snakes—catch on to the scheme.

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A simulated tornado, ghosts at NASA's Goddard Space Flight Center, and other amazing images of the week

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