November 14, 2013
When it comes to deforestation, Brazil’s Amazon often tops the list of places to worry about. New maps of global forest loss, however, find plenty of other sites throughout the world that should be of even bigger concern
. Angola, Zambia, Bolivia, Paraguay and Malaysia all have high rates of forest loss, but the situation is perhaps worst in Indonesia, where the rate of deforestation may soon exceed that in Brazil.
On a global scale, the planet lost 888,000 square miles of forest and gained 309,000 square miles of new forest between 2000 and 2012, a team of researchers led by remote sensing scientist Matthew Hansen of the University of Maryland College Park report today in Science. That’s a net forest loss equivalent to all the land in Alaska.
“Losses or gains in forest cover shape many important aspects of an ecosystem including climate regulation, carbon storage, biodiversity and water supplies, but until now there has not been a way to get detailed, accurate, satellite-based and readily available data on forest cover change from local to global scales,” Hansen said in a statement.
Hansen’s team began with a collection of more than 650,000 images taken by the Landsat 7 Earth-imaging satellite from 1999 to 2012 and housed in the Google Earth Engine, a cloud-computing platform that was created for just this kind of thing—planetary analyses of environmental characteristics, accomplished at amazing speeds. They tasked the engine to monitor vegetation taller than 16 feet (5 meters) across the globe as it appeared and disappeared through time. The result was a set of highly detailed maps showing forest extent, loss, gain and net change at a resolution of a mere 98 feet (30 meters).
The maps reveal a variety of stories taking place around the world. Tropical forests accounted for nearly a third of global deforestation, as humans stripped forest lands, both legally and illegally. Deforestation in those regions is a particular concern–tropical forests are home to many unique species that can be endangered or lost entirely when their forest homes are destroyed. What’s more, depending on the scale and patchiness of the tree loss, rainfall can either intensify or decrease, either of which can have devastating consequences, such as flood or drought. And the lost vegetation can no longer be a
sink for atmospheric carbon–the carbon stays in the atmosphere and intensifies climate change.
The rate of deforestation recorded by the study varied from nation to nation. Indonesia witnessed a doubling of forest loss in just a decade. In Brazil, by contrast, deforestation slowed from a pace of more than 15,400 square miles per year in 2003 and 2004 to a rate less than half that in 2010 and 2011, confirming that efforts in that country to reduce forest loss, including the combating of illegal logging, are seeing success. Despite the decline, however,
Brazil still suffers a lot of tree loss—the second highest total globally. And when combined with deforestation going on in other nations on that continent, such as Argentina, Bolivia and Paraguay, about half of tropical forest loss occurred in South America, Hansen’s team calculated.
Another way to look at the scope of tropical deforestation is to calculate loss as a percentage of a nation’s total land area. In that ranking, Brazil doesn’t look too bad since it’s a country with a large land area. Malaysia, Cambodia, Cote d’Ivoire, Tanzania, Argentina and Paraguay experienced a much greater loss of forest as a share of all their land.
Determining the extent of forest loss can be helpful for reducing it in the future, the researchers note. “Brazil’s use of Landsat data in documenting trends in deforestation was crucial to its policy formulation and implementation,” they write in their paper. “The maps and statistics we present can be used as an initial reference point for a number of countries lacking such data.”
The maps also reveal the small and large stories of forest growth and loss taking place in other regions around the world, highlighting places such as the American Southeast, where large portions of forest are lost and regrown in short periods of time; the region is a much bigger player in the timber industry than the more famous Northwest U.S. In Alaska, Canada and Russia—home to the world’s greatest extent of forest loss (loss per national area) simply due to that nation’s size—one can see how slowly these high-latitude forests recover from events such as wildfires. The maps even allow the detection of smaller events—such as the mountain pine bark beetle infestation in British Columbia and even a powerful windstorm that leveled forests in southwestern France.
“With our global mapping of forest changes every nation has access to this kind of information, for their own country and the rest of the world,” Hansen said. Whether they follow Brazil’s footsteps and use the data to work towards conserving these important ecosystems will be a question for the future.
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 16, 2013
We often hear about melting sea ice, rising tides and bleached coral reefs, but climate change is poised to reverberate through a broader swath of the marine environment than these headline issues alone might suggest.
According to a new study published in PLoS Biology, “the entire world’s ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity.” As the ocean’s biogeochemistry shifts, the paper reports, so too will its habitats and the creatures living there. This could mean hardship for some 470 to 870 million people–many of whom live in poverty–who depend upon the bounty of the sea to support livelihoods and fill dinner plates. And these impacts are not predicted to occur centuries down the road, either: according to the study, they may transpire as soon as 2100.
Nearly 30 scientists from around the world–including climate modelers, ecologists, biogeochemists and social scientists–co-authored the study. They built upon computer models from the Intergovernmental Panel for Climate Change by compiling data from 31 Earth System Models that included at least one ocean parameter. All told, 27,000 years’ worth of data of the various overlapping, aggregated variables were compiled into their new model.
With those data compiled, they then modeled two different future scenarios: one in which atmospheric carbon dioxide concentrations increase to 550 parts per million, and another in which they hit 900 ppm (the planet currently stands at about 400 ppm, as compared to pre-industrial times, when that measurement was 280 ppm). The former model represents values predicted if mitigation efforts are undertaken, while the latter is predicted for a “business-as-usual” scenario where we maintain current levels of greenhouse gas emissions into the future.
Their model predicted changes in temperature, oxygen levels, increased acidity and productivity (the creation of organic compounds by primary producers like phytoplankton) on both the ocean surface and the sea floor under those two future scenarios. Nearly across the board on the ocean’s surface, they found, their models predicted a continued warming and rise in acidity accompanied by a decline in oxygen and productivity. The only exception was in a small fraction of the sea in polar regions, where the sea surface would experience increased oxygen and productivity. The magnitude of these predicted changes, they write, will be greater than any comparable shifts over the past 20 million years.
“When you look at the world ocean, there are few places that will be free of changes; most will suffer the simultaneous effects of warming, acidification, and reductions in oxygen and productivity,” Camilo Mora, a geographer at the University of Hawaii at Mānoa, said in a press release.
The most drastic impacts, they found, will occur on the ocean’s surface, but the seafloor will also experience its share of smaller but still significant changes. Seafloor temperature and acidity will change only slightly compared to the surface, but there will be large reductions in the influx of carbon, which provides food for many bottom-dwelling organisms. The drop in dissolved oxygen on the sea floor will be similar to that experienced on the surface.
These changes may be enough to disrupt the ocean floor’s delicate ecosystem. ”Because many deep-sea ecosystems are so stable, even small changes in temperature, oxygen, and acidity may lower the resilience of deep-sea communities,” Lisa Levin, an oceanographer at the University of California, San Diego, and co-author of the paper, said in the release. “This is a growing concern as humans extract more resources and create more disturbances in the deep ocean.”
As for the surface, the magnitude of the projected changes will vary by place. The tropics will experience the smallest changes in acidity; temperate regions will suffer the least significant shifts in temperature and productivity; and the Southern Ocean near Antarctica will be spared the least fluctuations in oxygen. But overall, across the board the ocean surface will suffer significant impacts.
With those data in hand, they then overlaid habitat and biodiversity hot spot information for 32 diverse marine environments around the world to see how these changes would impact ocean flora and fauna. Coral reefs, seagrass beds and other shallow areas will suffer the greatest impacts, they found, while deep ocean seamounts and vents will suffer the least.
Humans will not be spared the repercussions of those changes. In a final analysis, they quantified humanity’s dependence on the ocean by analyzing global jobs, revenues and food that comes from the sea. Most of the up to 870 million people who will be affected most by these changes live in some of the world’s poorest nations, they found.
While these predictions are subject to the same limitations that plague any computer model that attempts to represent a complex natural system and project its future fate, the authors believe that the results are robust enough to strongly support the likelihood that our oceans will be very different places in the not-too-distant future. If carbon dioxide levels continue to rise, they write, “substantial degradation of marine ecosystems and associated human hardships are very likely to occur.”
“It is truly scary to consider how vast these impacts will be,” co-author Andrew Sweetman of the International Research Institute of Stavanger, Norway, emphasized in the press release. “This is one legacy that we as humans should not be allowed to ignore.”
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.