November 19, 2013
The North Pole is losing about 30,000 square miles of sea ice per year. Over the past century, average global temperatures have climbed by 1.5 degrees Fahrenheit. And yet, over the past few years, the sea ice that surround the South Pole has steadily been growing.
This past September, at the end of the Southern Hemisphere’s winter, the extent of Antarctica’s sea ice reached 19.51 million square kilometers, breaking a 35-year record that dated back to the start of data being collected in 1978. (In comparison, from 1981 to 2010, the average extent on the same date was just 18.5 million square miles.)
Why are the Arctic and Antarctic such polar opposites? Climate change deniers have pounced upon the unexpected divergence to argue that the planet’s temperature isn’t actually rising. But new research suggests that a different mechanism—unrelated to climate change—is responsible for the ice growth. The real answer, says University of Washington oceanographer Jinlun Zhang, can be found blowing in the wind.
Specifically, according to a study he and colleagues published in the Journal of Climate, the vortex of winds that swirl around the South Pole has both strengthened and converged, a trend that can explain about 80 percent of the growth in ice extent that has been detected in recent years.
Atmospheric scientists had previously observed that these swirling winds had gradually strengthened since the 1970s. Using a computer model, Zhang’s team found that this mechanism drives ice growth—even in the face of rising temperatures—by pushing floating layers of sea ice together, compressing them into thick ridges that are slower to melt.
“Ice ridging increases the amount of open water and areas with thin ice, which are then exposed to cold air in winter, leading to enhanced ice growth,” Zhang says. “Meanwhile, the ridges, driven together by the wind, shrink less during the summer, because thicker ice tends to survive longer.” Based on this mechanism, the model accurately predicted ice growth in the same areas—the Weddell, Bellingshausen, Amundsen and Ross seas—that it’s been most distinctly observed.
Of course, the explanation brings to mind another question: Why is this vortex of swirling winds growing more powerful in the first place? Scientists are still unsure, but a few hypotheses have been put forth.
One possible culprit is the hole in the ozone layer, caused by lingering CFCs that were emitted before their use was phased out by the Montreal Protocol. Because ozone absorbs ultraviolet light from the Sun, missing ozone affects the local balance and transfer of energy, potentially leading to stronger winds. Another possibility is that the strengthened winds can simply be chalked up to natural variability.
Whatever the cause, the observed effect—a growth in Antarctic ice—has been relatively small, especially in comparison to the rapidly melting ice in the Arctic. For now, the winds are causing ice growth, but going forward, that trend is likely to be overwhelmed by a far more potent one: the continued rise in greenhouse gas emissions and the climate change they’re rapidly driving. “If the warming continues, at some point the trend will reverse,” Zhang says.
October 30, 2013
In 2013, if you’re someone who cares about the environment, your first and foremost concern is probably climate change. After that, you might worry about things like radioactive contamination, collapsing honeybee colonies and endangered ecosystems, among other contemporary environmental perils that fill recent news headlines.
But a number of researchers in the field are focused on a problem that has faded out of the news cycle: the piles of garbage that are growing around the world.
A recent World Bank report projected that the amount of solid waste generated globally will nearly double by the year 2025, going from 3.5 million tons to 6 million tons per day. But the truly concerning part is that these figures will only keep growing for the foreseeable future. We likely won’t hit peak garbage—the moment when our global trash production hits its highest rate, then levels off—until sometime after the year 2100, the projection indicates, when we produce 11 million tons of trash per day.
Why does this matter? One reason is that much of this waste isn’t handled properly: Millions of plastic fragments flooding the world’s oceans and disrupting marine ecosystems, and plenty of trash in developing countries is either burned in incinerators that generate air pollution or dumped recklessly in urban environments.
Even if we sealed all our waste in sanitary landfills, however, there’d be a much bigger problem with our growing piles of garbage—all the industrial activities and consumption that they represent. “Honestly, I don’t see waste disposal as a huge environmental problem in itself,” explains Daniel Hoornweg, one of the authors of the World Bank report and a professor at the University of Ontario, who authored an article on peak garbage published today in Nature. “But it’s the easiest way to see how the environment is being affected by our lifestyles overall.”
The quantity of garbage we generate reflects the amount of new products we buy, and therefore the energy, resources and upstream waste that are involved in producing those items. As a result, Hoornweg says, “solid waste is the canary in the coal mine. It shows how much of an impact we’re having globally, as a species, on the planet as a whole.”
This is why he and others are concerned about peak garbage and are attempting to project our trash trends decades into the future. To make such estimates, they rely upon projections of population grown along with a number of established trends in waste: People create much more trash when they move to cities (and begin consuming more packaged products) and when they become wealthier (and increase their consumption overall).
Historical data indicate, though, that a certain point, the per capita amount of garbage generated in wealthy societies tends to level off—apparently, there’s only so much a person can consume (and only so much trash they can produce). As a result, in many of the world’s wealthy countries, the average person produces slightly more than 3 pounds of solid waste per day, and that number isn’t estimated to change significantly going forward.
The amount of people moving to cities and consuming more in the rest of the world, however, is projected to surge over the coming century—and even as the resulting waste production finally levels off in East Asia around 2075, it’ll be offset by continuing increases in the growing urban areas of South Asia and Sub-Saharan Africa, the authors of the Nature article note. As a result, unless we significantly reduce the per capita waste production of wealthy city-dwellers,
the world as a whole won’t hit peak garbage until sometime after 2100, when we’re creating three times as much trash as we are right now.
How can we address our population’s growing consumption problem? One of the main things to consider is that it’s largely driven by people in the developing world voluntarily moving to cities and improving their standard of living, both signs of economic progress in their own right. But even if these demographic shifts continue, the projected rates of garbage growth aren’t entirely inevitable, because there are cultural and policy dimensions to waste production.
The average person in Japan, for example, creates about one-third less trash than an American, even though the two countries have similar levels of GDP per person. This is partly because of higher-density living arrangements and higher prices for imported goods, but also because of norms surrounding consumption. In many Japanese municipalities, trash must be disposed in clear bags (to publicly show who isn’t bothering to recycle) and recyclables are routinely sorted into dozens of categories, policies driven by the limited amount of space for landfills in the small country.
Creating policies that give incentive to people to produce less waste elsewhere, therefore, could be a way of tackling the problem. But, because our garbage is just the end result of a host of industrial activities, some reduction measures will be less important than others. Designing recyclable packaging would be a much less useful solution, for instance, than designing products that don’t need to be replaced as often. Even better, as Hoornweg and his coauthors argue in the article, would be accelerating ongoing increases in education and economic development in the developing world, especially Africa, which would cause urban population growth—and also the amount of trash produced per capita—to level off sooner.
Garbage might seem like a passé environmental issue, but it’s a proxy for nearly all the others—so tripling our global rate of garbage production is a particularly bad idea. “The planet is having enough trouble handling the cumulative impacts that we’re subjecting it to today,” Hoornweg says. “So with this projection, we’re basically looking at tripling the total amount of stress that we’re putting the planet under.”
October 22, 2013
If you traveled to the town of Kalgoorlie, in Western Australia, then headed about 25 miles north, you’d eventually reach a grove of large eucalyptus trees, some more than 30 feet tall, scattered across a dusty, arid landscape. Examining the dirt at your feet would reveal no trace of the gold deposits that lie roughly 100 feet underground, due to the thick layers of clay and rock that sit atop the precious metal.
But, scientists recently learned, if you peered closely enough at the eucalyptus trees—specifically, using X-rays to detect nanoparticles—you’d find that there’s gold in them thar leaves. As detailed in a study published today in Nature Communications, a group of researchers from Australia’s Commonwealth Scientific and Industrial Research Organisation has shown that plants can absorb gold particles deep underground and bring it upward through their tissues—a finding that could help mineral exploration companies mine for gold.
“In Australia, we’re faced with this problem of trying to explore through thick layers of sediments and weathered rock to reach valued minerals,” says Melvyn Lintern, an Earth scientist and lead author of the study. “At the same time, we’d previously heard from mining engineers that, in some places, they’d found eucalyptus roots going down to 30 meters [98 feet] or deeper in the mines.” With this observation in mind, and the knowledge that plants can absorb and transport minerals from the surrounding soil and bedrock all the way up to their leaves, Lintern and his colleagues were struck with an idea: Why not test eucalyptus leaves to see if they could indicate underground gold deposits?
To do so, they visited two Australian sites with known gold deposits deep underground (as revealed by exploratory drilling) that were covered by thick layers of rock and on top of which grew tall eucalyptus trees. When they tested leaves that grew on or had fallen from the large trees in both areas, they indeed found minute traces of gold—up to 80 parts per billion, compared with the 2 parts per billion they found in leaves that had grown 650 feet away from the underground deposit.
Other researchers had detected gold particles in plants and leaf litter before, but it was unclear whether they’d been transported all the way from underground deposits. “We were concerned that the gold might have been occurring as dust particles on the outside of these leaves, so it was important for us to locate the gold within the plant,” says Lintern.
His team did so by analyzing the leaves in even further detail (using a specialized X-ray microprobe located at the Australian Synchrotron research facility) and confirmed that the gold particles were located within the plant’s vascular tissue, indicating that they were moving naturally within the leaves. They also conduced greenhouse experiments and found that eucalyptus saplings, grown in soil laced with similar levels of gold, absorbed it and transported detectable levels into their leaves. These separate streams of evidence, they say, shows that the wild eucalyptus trees were indeed sucking up gold from deep underground.
“The eucalyptus acts like a hydraulic pump,” using its roots to suck ground water upward, crucial in an arid environment, Lintern says. “The plants, of course, are searching for water, not gold, but it just so happens that there’s gold dissolved in it.”
The fact that the gold has been found in the leaves, in fact, might be evidence that the eucalyptus is actively trying to get rid of it—after all, it’s a toxic heavy metal—by transporting it to its extremities. Additionally, the gold particles in the leaves were often found located near calcium oxalate crystals, theorized to be part of the removal pathway for toxic chemicals.
Lintern’s group plans to conduct further research into which plants are capable of transporting gold particles in this way and what environmental factors affect the rate of uptake. Mining companies in Canada, he mentions, have already toyed with the idea of using plants as mineral indicators, so this first scientific evidence for the process is likely to accelerate adoption of the method.
“Essentially, we’re tapping into a natural process,” Lintern says. In an age when most of the readily accessible gold near the planet’s surface has been mined, it makes sense to harness the natural mineral exploration plants are already engaging in when they drive their roots deep into the ground. Doing so might even reduce the number of exploratory mines we’re forced to drill—and consequently, lead to less environmental destruction of these plants’ habitats as a result of mining.
October 14, 2013
In the 20 years since the movie Jurassic Park fantasized about how dinosaurs could be cloned from blood found in ancient amber-trapped mosquitoes, fossil collectors have been on the hunt for a similar specimen. Over the years, a few different groups of scientists have claimed to find a fossilized mosquito with ancient blood trapped in its abdomen, but each of these teams’ discoveries, in turn, turned out to be the result of error or contamination.
Today, it was announced that we finally have such a specimen, a blood-engorged mosquito that’s been preserved in shale rock for around 46 million years in northwestern Montana. The most astounding thing about the discovery? It was made three decades ago by an amateur fossil hunter—a geology graduate student named Kurt Constenius—then left to sit in a basement, and only recognized recently by a retired biochemist named Dale Greenwalt who’s been working to collect fossils in the Western U.S. for the Smithsonian Museum of Natural History.
The specimen, described in a paper Greenwalt published with museum researchers and entomologist Ralph Harbach today in the Proceedings of the National Academy of Sciences, is trapped in stone, not amber, and (unfortunately for Jurassic Park enthusiasts) it’s not old enough to be filled with dinosaur blood. But it is the first time we’ve found a fossilized mosquito with blood in its belly.
The rock-encased specimen was originally excavated sometime during the early 80s, when Constenius, then pursuing a master’s degree in geology from the University of Arizona, found hundreds of fossilized insects during weekend fossil-hunting trips with his parents at the Kishenehn Formation in northwestern Montana, near Glacier National Park. In the years since, they’d simply left the fossils sitting in boxes in their basement in Whitefish, Montana and largely forgotten about them.
Enter Greenwalt, who began volunteering at the museum in 2006, cataloging specimens for the paleobiology department. In 2008, he embarked on his own project of collecting fossils from the Kishenehn every summer, in part because he’d read in an insect evolution textbook an offhand mention of Constenius’ discoveries, which had never been rigorously described in the scientific literature.
In the years since, Greenwalt has collected thousands of specimens from 14 different orders of insects. The collection site is remote—he has to raft the Flathead River that runs along the border of the park to a place where the river has cut down through layers of rock of the Kishenehn Formation, which includes shale that formed the bottom of a lake during the Eocene epoch, some 46 million years ago.
“It is a fantastic fossil insect site, arguably one of the best in the world,” he says, noting that a rare combination of circumstances—thin layers of fine-grained sediment and a lack of oxygen—led to a “mind-boggling degree of preservation.” Working there, he’s made a number of significant finds, collecting specimens that led to the description of two new insect species (pdf).
After Greenwalt met the Constenius family in Whitefish and described his work, they decided to donate their fossil collection to the museum. When he began cataloging the boxes the fossils and came across this particular specimen, “I immediately noticed it—it was obvious that it was different,” he says. He suspected that the mosquito’s darkly opaque abdomen, trapped in a thin piece of shale, might contain 46-million-year old blood.
Staff from the museum’s mineral sciences lab used a number of techniques to scan the specimen up close, including energy dispersive X-ray spectroscopy. “The first thing we found is that the abdomen is just chock full of iron, which is what you’d expect from blood,” Greenwalt says. Additionally, analysis using a secondary ion mass spectrometer revealed the presence of heme, the compound that give red blood cells their distinctive color and allows them to carry oxygen throughout the body. Other tests that showed an absence of these compounds elsewhere in the fossil.
The findings serve as definitive evidence that blood was preserved inside the insect. But at this point, scientists have no way of knowing what creature’s fossilized blood fills the mosquito’s abdomen. That’s because DNA degrades way too quickly to possibly survive 46 million years of being trapped in stone (or in amber, for that matter). Recent research had found it has a half-life of roughly 521 years, even under ideal conditions.
This means that even if we miraculously had some DNA of the ancient creature, there are currently a ton of technical problems that prevent the cloning similar to that in Jurassic Park from becoming a reality. Assembling a full genome from DNA fragments requires us to have an understanding of what the whole genome looks like (which we don’t have in this case), and turning that into a living, breathing animal would necessitate putting that DNA into an ovum of a living species very closely related to the mystery creature that we don’t know in the first place.
So, alas, no resurrected ancient creatures will roam free thanks to this new find. Still, the find is scientifically significant, helping scientists better understand the evolution of blood-feeding insects. Previously, the closest thing to a blood-engorged mosquito that scientists had found was a mosquito with remnants of the malaria parasite inside its abdomen (pdf). Though that provides indirect evidence that mosquitoes fed on blood 15-20 million years ago, this new discovery represents the oldest direct evidence of blood-sucking behavior. It also shows for the first time that biological molecules such as heme can survive as part of the fossil record.
October 9, 2013
Climate change is a global problem, but that doesn’t mean it’s going to hit us all the same time.
If you live in Moscow, scientists estimate that your local climate will depart from the historical norm in the year 2063. In New York, that date is the year 2047. And if you happen to reside in Mexico City or Jakarta, those numbers are 2031 and 2029, respectively.
See a pattern here? These estimates, which all come from a new study published today in Nature by scientists from the University of Hawaii, reflect a concerning trend that some scientists believe will define the arrival of climate change’s effects on the planet: It’ll arrive in tropical, biodiverse areas first.
Most climate models simulate how changes in greenhouse gas concentration will affect the worldwide climate in a given year (most often 2020, 2050 or 2100). But the Hawaii team, led by biologist and geographer Camilo Mora, took an alternate approach—they assumed, in the absence of a global mitigation agreement, greenhouse gas levels will keep rising at a steady rate, and used climate models to track how long it would take for weather events that are currently thought of as extreme to become typical.
When they calculated which year this would occur for a range of cities—defining a deviation from the historical record as the first year when a given month’s coldest day is hotter than any day of that month between 1860 and 2005—our dates of climate departure came far sooner than they were expecting.
“The results shocked us. Regardless of the scenario, changes will be coming soon,” Mora said in a press statement. “Within my generation, whatever climate we were used to will be a thing of the past.”
For all locations on Earth, the average year of departure is 2047, but for some places concentrated in the tropics, that date will come much sooner, in the 2030′s, or in some extreme cases, the 2020′s. In just a few decades, in other words, the coldest day you experience in January will be hotter than the warmest days your parents had in January—and the hottest day you get in July (in the Northern hemisphere) will simply be hotter than any day anyone has ever felt in your city to date.
The fact that these effects would be felt soonest in the tropics, according to the simulation, is also surprising. Thus far, most models have predicted that the most abrupt shifts in temperature will occur at the poles.
The new study actually agrees with that fact, but views it from a different perspective, looking at relative changes compared to the historical record rather than absolute changes in temperature. Because the tropics have less variability in temperature to start with, it takes less of a shift to push temperatures there beyond the norm. On the other hand, temperatures will indeed surge most in the Arctic and Antarctic, but there’s already more natural climate variability at those locales to begin with.
This is a huge concern, because wildlife biodiversity is consistently highest at the tropics, and most of the world’s biodiversity hotspots are located there (tropical rainforests, for instance, are estimated to cover less than 2 percent of the Earth’s surface area yet contain roughly 50 percent of its plant and animal species). If, historically, these ecosystems evolved in the presence of relatively little climatic biodiversity, it follows that they might be less capable of coping with swings in temperature and adapting to survive.
It also happens that a disproportionate amount of the people living in poverty worldwide are located in the tropics. “Our results suggest that countries first impacted by unprecedented climates are the ones with the least capacity to respond,” study author Ryan Longman said. “Ironically, these are the countries that are least responsible for climate change in the first place.”
Despite the bad news, the researchers say they embarked on this alternate sort of climate modeling to empower people. “We hope that with this map, people can see and understand the progression of climate change in time where they live, hopefully connecting people more closely to the issue and increasing awareness about the urgency to act,” said co-author Abby Frazier said.
Towards this goal, the group also put out an interactive map that lets you click on any location and see the projected increase in temperature over time, along with two different years: the one in which you can expect a consistently extreme climate if we keep emitting carbon dioxide at current rates, and the one in which you’ll experience an abnormal climate if we figure out a way to stop.