Geoengineering — the deliberate manipulation of climate to counteract global warming — might not be taking off just yet, but the push to fund more research into it is increasing. Read the full story here on Nature News. And that wraps up our coverage of the 2009 Ecological Society of America meeting.
Roughly 100 billion cubic meters of groundwater is overexploited around Beijing. Nine years ago, that figure was 8 billion cubic meters.
Such were the dire numbers coming out of a presentation today by Ge Sun, a hydrologist at the US Department of Agriculture in Raleigh, North Carolina, on the state of China’s water crisis. In the Daxing district of Beijing along, the water table has dropped 1.3 meters per year between 2001 and 2007. (I checked my notes three times to make sure that ‘meters’ is correct there, hard as it seems to believe.) More than 1,000 natural lakes have vanished. Forty percent of the country’s rivers have become ephemeral. The rivers that manage to hang on are, more than half of them, polluted.
The factors are many: among them are population growth, mismanagement of land, increasing urbanization and low efficiency of using water, Sun said. And it was hard to miss the sense of urgency in his voice. Water resource issues and environmental disasters have become so rote in China over the past decades that it can be difficult — at least for me, a jaded journalist — to comprehend them getting any worse. But the economic boom in China is a whole new matter. Look at that number again of overexploited water in Beijing: 8 billion cubic meters in 2000, 100 billion cubic meters today. Where will we be in 2020?
Image: The 2,000-year-old Dujiangyan irrigation system in Sichuan province
Day and night are not equal when it comes to warming, Shiqiang Wan of the Chinese Academy of Sciences’ Institute of Botany reminded the audience today.
Since 2005 Wan has been part of a team looking at how ecosystems change in Inner Mongolia, along the gradient that runs from meadow to typical (grassy) to desert steppe. They’ve set up big experimental plots (right) that alter precipitation, temperature, and other inputs, then see what happens. The idea is to simulate how climatic change might affect various ecosystem responses.
Among many questions they tackled a fairly thorny one: what difference it makes whether warming occurs during the night or during the day. Many computer models, Wan told the meeting, rely on a 24-hour average to sum up the expected effects of warming. His team, however, split out these factors, warming some of their plots during the day only, some during the night only, and some during a 24-hour cycle.
The differences were fairly dramatic, his team reports in a paper in press in Biogeosciences. Plots warmed only during the night turned from being a net carbon source to a net carbon sink; the extra warming at night stimulated leaf respiration rates, which meant they sucked down more carbon than before.
The take-home message? It might sound familiar: climate change could affect the world’s ecosystems in unpredictable and currently little-understood ways.
When will society let go of a land that’s lost? Not until long after it should, as I was reminded by a talk by Robert Twilley of Louisiana State University.
Twilley is an expert on the vast delta of the Mississippi River that feeds Louisiana coastal wetlands with both freshwater and rich sediment. Or rather, it used to — until decades of water diversions choked off much of the water supply. Hurricanes such as Katrina and Rita in 2005 have also wiped out hundreds of square kilometres of land. Sea level rise, and land subsidence, conspire further to threaten to drown much of the coast.
A Nature Geoscience paper published in June argues that relative sea level rise will wipe out 10,000 to 13,500 square kilometres of coastal land by the year 2100 — and there’s apparently nothing we can do about it. The Mississippi River has simply been too dammed up and altered for it to ever provide enough sediment back to the delta to rebuild coast or even counter much of the decline. In other words, Twilley told the ESA meeting, we’re past the point of no return. “We’ve decreased the capacity to adapt,” he said. “We are now outside of the adaptation envelope because of the way we’ve mismanaged the river.”
What’s left to do? One idea is to look at how much coast could be restored if we tried as hard as we could. The Wax Lake Delta (pictured) started forming from sediments around about 1973, as a result of water diversions along Louisiana’s Atchafalaya River. Studying how it builds up over time provides one test system to understand the land-building capacity of the coast, Twilley says. Moving a model of how Wax Lake is built to the Mississippi, he says, suggests that 1,000 square kilometres of wetlands could be created in the next century if sea level rise and land subsidence together amount to 7 millimeters per year — a sort of middle-of-the-road estimate.
Society has put its mind to greater tasks, Twilley argues. Whether battling a vanishing coastline is worth it is a difficult question, however. Restoring Louisiana could be a great environmental triumph — or a great societal folly. What do you think?
Image: National Center for Earth-surface Dynamics
The exhibit hall here at the ecological meeting seems oddly empty — or maybe that’s just because I hit it at a down time when free beer wasn’t being offered. I did spend some time flipping through the fancy new materials at the unstaffed booth of the Encyclopedia of Life (EOL), the ambitious effort to catalogue the planet’s species onto a one-page-per-species website.
The site is still in its early days — a little browsing uncovers skimpy entries for many species, but such is the nature ofa work in progress. But I was intrigued by one new social-networking push to get more content. If you’ve got a Flickr account, you can add your pictures of various animals and plants to the EOL. Just join the EOL group, upload your pix, and change the license. You then tag the photo with the common and/or genus and species name of the organism in the picture. Et voila!
One thing not clear to me: what happens if you misidentify your critter?
Image: Canis lupus familiaris, common name Angie
In the largest experiment of its kind to date, ecologists have found that the wetter the Arctic tundra becomes, the more carbon dioxide it gives off. See the full story on Nature News here.
Powerpoint presentations at ecology conferences are usually dominated by pretty landscapes: flowering plants, cute little pikas, soaring mountain vistas. So it was a bit of a shock today to sit through pictures of corpses at the Civil War battle of Gettysburg, American warplanes spraying deadly Agent Orange on Vietnam, and refugees lining up at camps in Darfur. 
The cheerful topic of the morning: warfare ecology, a newly-dubbed sub-field of ecology. Gary Machlis, an ecologist at the University of Idaho, gave an impassioned lecture about why all scientists should care about warfare and why ecologists should help figure out how to restore devastated landscapes.
The litany of environmental disasters was depressing: General Patton scarring the delicate landscape of California’s Mojave desert with thousands of tanks. Bombings of chemical plants in Serbia that sent pollutants coursing downstream into non-combatant nations. Saddam Hussein draining the marshlands of Iraq to destroy the livelihoods of the Marsh Arabs there. Elephants that stampeded over the border from Uganda into the Congo, then back, as war raged back and forth.
But in his oddly infectious, impassioned-professor sort of way, Machlis seemed to get the audience – primarily younger researchers, with a smattering of military types – inspired. “Like conservation biology in the 1970s, or restoration in the ecology in the 1980s, warfare ecology reflects an interdisciplinary approach to a global challenge,” he said, pacing back and forth. “The scientific community must continually evaluate its ethical responsibility toward warfare.”
Ecologists might engage, he said, by figuring out how to build a refugee camp with the right resources to save lives. Or supporting swords-to-ploughshares restoration efforts like restoring the Korean demilitarized zone. Or working with remote sensing to better monitor war’s impacts on civilian populations. Only then, Machlis argued, can scientists truly be responsible.
What do you think? What responsibility do scientists have to salve society’s ills? And how best might they go about it?
Image: Car bomb in Iraq, DoD
The always-controversial notion that a comet or asteroid slammed into North America some 13,000 years ago got a severe tongue-lashing today from a Wisconsin researcher. 
The idea, put forth two years ago, suggests that an extraterrestrial impact somewhere over the Laurentide ice sheet abruptly terminated the last ice age and lead to the extinction of the continent’s great mammals, like mammoths (right), and some early peoples. A recent paper in Science proposes that physical evidence of the impact has been found in the form of nanodiamonds scattered across the continent. But both impact experts and paleoecologists have been reluctant to accept the idea.
Jacquelyn Gill, a graduate student at the University of Wisconsin in Madison, laid into what she called the “impact” (with quote marks heavy in her voice) today. Sediment cores at two locations in Indiana, and one in Ohio, are ideally located to preserve evidence of the environmental chaos such an impact would have caused. But no such traces are present, she reported at the meeting. In fact, declines in the abundance of a particular spore marker appears to take place more than 1,500 years before the purported impact would have happened, she says.
“We don’t see a real trend here that would suggest a physical impact,” she said.
Supporters of the impact idea have argued that no physical evidence of the impact itself — eg a crater — might be expected to remain. But evidence of massive environmental disturbance seems also remarkably slim, at least to researchers like Gill.
Image: Royal BC Museum, Victoria, Canada (where you can listen to a mammoth!)
While the idea of green roofs sounds lovely and eco-friendly, keeping those plants alive on your rooftop is easier said than done. That’s the message given the ecology meeting today by Colleen Butler, who’s been growing experimental green-roof plots at Tufts University in Boston for the past few years. 
Atop the campus library she’s been planting various species to see which ones do best. “People assume that if it grows in your garden, it’ll grow on your roof,” she says. But the high temperatures and variable rainfall can often do in even the best-meant plants. One that seems to do well is the Sedum species of low-growing flowering plants. In fact, Sedum might even be bullying out its neighbors in certain circumstances.
Butler’s test plots suggest that when drought comes, Sedum might help its neighbouring plants survive. But in normal rainfall years, it seems to out-compete its neighbours and hog the green roof all to itself. The lesson, she says? Be sure you know what you’re planting up there.
Image: The California Academy of Sciences’ green roof, in San Francisco
Nature reporters Alexandra Witze and Emma Marris will be in Albuquerque, New Mexico, from Aug. 3-7, 2009, to cover the annual meeting of the Ecological Society of America. They’ll be posting updates here on In the Field, Nature’s news team blog from conferences and events.