Monday, February 11, 2013

We could refreeze the Arctic, should we?

By Bob Weber

A record loss of Arctic sea ice and faster-than-expected melting of Greenland’s ice cap made worldwide headlines in 2012, but research published in major science journals in the fall suggest warming in the North doesn’t have to continue.

We could refreeze the Arctic, proposed a paper in Nature Climate Change. It wouldn’t even cost that much, said an affiliated study in Environmental Research Letters.

The question is should we?

“In terms of pure technical capacity, any significant nation in the world could do it,” said David Keith, a Calgarian and professor of applied physics at Harvard University, one of the lead authors in both studies.

“The really hard questions here aren’t mostly technical. They’re questions about what kind of planet we want and who we are.”

In a world that seems unable to come to grips with carbon dioxide emissions driving climate change, manipulating the Earth’s climate to cool it down has some calling geoengineering a bad idea whose time has finally come.

Scientists have long theorized that injecting reflective particles of some kind into the high atmosphere could reduce the amount of sunlight reaching the Earth’s surface and compensate for the greenhouse effect. High CO2 levels would continue to trap heat, but with less energy coming in to begin with, temperatures on the surface would go down.

Keith’s paper used climate models to cautiously suggest that the method could be adapted to engineer regional effects. The right amount of aerosols in the right place at the right time could restore the Arctic’s frozen glory.

“With an average solar reduction of only 0.5 per cent, it is possible to recover pre-industrial sea ice extent,” the paper says. “Decisions involving (solar radiation management) do not need to be reduced to a single ‘global thermostat.’”

A separate paper concluded that it could all be done with a few modified Gulfstream jets widely available on the used market. Annually, it could cost somewhat less than $8 billion — about the price of a major oil pipeline.

While Keith believes emissions should be cut, he doesn’t advocate such a plan, at least not yet.

He suggested geoengineering may be a viable response to a “climate emergency” — a sudden collapse of ice sheets or a killing drought.

“If your primary view is pragmatic, and you want to reduce the risk to Asian farmers who might get hit by high temperatures that make their crops not germinate, then the answer is you should do whatever is actually safe and controllable and produces the outcomes.”

Some environmentalists are starting to think there may be something to that.

“We all agree: mitigation, that’s the thing you should do,” said Steve Hamburg, chief scientist of the U.S.-based Environmental Defense Fund. “But everyone also recognizes that even if we did that, we may have climate surprises. We’d be irresponsible not to try and understand what our options are.

“It’s easy to dismiss this as too radical a solution, but that does a disservice to what we don’t know. We need to be prepared with information to understand what our options are or aren’t depending on how things play out.”

If we don’t at least understand the risks, a desperate situation may lead to a disastrous decision, Hamburg said.

Keith Allott, head of climate change for the World Wildlife Fund UK, agrees that research is needed.

“We do see the need for a grown-up conversation about the type of research that may be acceptable at this stage,” he said.

The United Nations, through its Convention on Biological Diversity, has ruled out open-air or large-scale geoengineering experiments. Current research, including some that Environment Canada is involved in, is restricted to using models to better understand how the Earth’s climate might respond to manipulation.

Hamburg said discussions on everything from how research is conducted to who gets to set the global thermostat are just beginning.

He’s part of the Solar Radiation Management Governance Initiative, a partnership between his group and several scientific academies from around the world.

“Everybody has to feel like their interests are represented,” he said.

“It can’t be about North American and European voices. It has to be about global voices and global communities being aware of it so that there is some kind of consensus that ignorance is our enemy.”

Peter Mooney of the Ottawa-based Etc Group, an environmental technology watchdog, is skeptical of anyone’s ability to manage geoengineering.

“There’s a marvellous naivete to it all,” he said. “We need to prepare for this horrible thing of Plan B because governments have proved themselves incapable of addressing the real problem. Therefore, we need to have governments go ahead and do Plan B.”

But that thinking is flawed, he suggested.

“The governments who screwed up in the first place can’t be expected to take something like planetary systems management and do a better job of it.”

Others hold that geoengineering is just more of the same kind of thinking that caused the problem — a reliance on technical fixes instead of looking at causes.

“They kind of like the fact the problem is hard to solve because it gives you a lever to say we have to make these deep reforms in consumer culture, which I personally would like to see,” said Keith.

But really, he asks, what is society but one technical fix after another? Sanitation, for example, is a technical fix for cities producing sewage.

Mooney feels it’s asking too much of governments to expect they’ll make science-based unbiased decisions.

“It’s naive to think that once Plan B becomes a political option that governments won’t just take it on and interpret it as they wish. They will always find scientists who will give them the spin that they want.

“(We shouldn’t be) opening up the back door for politicians to creep out of, claiming that, ‘Don’t worry folks. We don’t need to do anything because we have technological fixes that we can deploy on short notice.’”

Allott, too, is concerned that geoengineering could become a way to excuse the continued consumption of CO2-causing fossil fuels.

“There are some unfortunate overlaps between parts of the geoengineering community and parts of the fossil fuel lobby,” he said. “That’s not OK.”

He also points out that no plan to manage solar radiation does anything to address ocean acidification, another byproduct of CO2 emissions. The best way forward, he said, is to reduce the emissions in the first place.

“People talk about this as if (geoengineering) is an easy option. That ain’t true.”

Geoengineering isn’t likely to become a reality any time soon. There are no aerosol-laden planes on a tarmac waiting for clearance to take off.

But the debate is coming, predicted Hamburg.

“We’re not going to put the genie back in the bottle … (We need) a robust and broad conversation about how to govern research in this area with widely agreed-upon rules of the road.”

Even then, said Keith, we need to cut CO2 emissions.

“If we do this and we do not cut emissions, we just walk further and further off the cliff, like Wile E. Coyote.”


Sunday, February 10, 2013

the Ants Are Talking

By Carrie Arnold


If you want to survive as an ant, you'd better get ready to make some noise. A new study shows that even ant pupae—a stage between larvae and adult—can communicate via sound, and that this communication can be crucial to their survival.

"What's very cool about this paper is that researchers have shown for the first time that pupae do, in fact, make some sort of a sound," says Phil DeVries, an entomologist at the University of New Orleans in Louisiana who was not involved in the study. "This was a very clever piece of natural history and science."

Scientists have known for decades that ants use a variety of small chemicals known as pheromones to communicate. Perhaps the most classic example is the trail of pheromones the insects place as they walk. Those behind them follow this trail, leading to long lines of ants marching one by one. However, the insects also use pheromones to identify which nest an ant is from and its social status in that nest. Because this chemical communication is so prevalent and complex, researchers long believed that this was the primary way ants shared information.

However, several years ago, researchers began to notice that adults in some ant genuses, such as Myrmica, which contains more than 200 diverse species found across Europe and Asia, made noise. These types of ants have a specialized spike along their abdomen that they stroke with one of their hind legs, similar to dragging the teeth of a comb along the edge of a table. Preliminary studies seemed to indicate that this noise served primarily as an emergency beacon, allowing the ants to shout for help when being threatened by a predator.

Larvae and young pupae have soft outer skeletons, which means their specialized spikes haven't yet formed and they can't make noise. However, as the pupae mature, their covering hardens into a tough exoskeleton like that found in adult ants. These older pupae do have fully functional spikes but were generally thought to be silent.

Karsten Schönrogge, an entomologist at the Centre for Ecology & Hydrology, Wallingford, in the United Kingdom, thought it odd that mature pupae would have the capability to produce sound but remain silent. So he and his colleagues listened in to a group of Myrmica scabrinodis ants. These 4- to 5-millimeter-long, reddish-brown ants are commonly found in northern Europe, in low-lying areas like peat bogs.

Using an extra-sensitive microphone that would pick up on the faint acoustic signals, the researchers measured the sounds produced by 10 differentM. scabrinodis larvae, six immature pupae, and six mature pupae. Whereas the larvae and immature pupae were completely silent, the mature pupae produced brief pulses of sound, the team reports online today in Current Biology.

Further analysis of this noise showed that it was a simplified version of the more complex adult sound. It was as if the mature pupae were saying, "Help!" while the adults were saying "Hey, I'm over here! Please come help! It's your friend!"

To test the function of these noises in the mature pupae, the researchers first played back the sounds made by either the mature pupae or adult M. scabrinodis. Adult worker ants responded the same way to both recordings, such as walking over to the speaker, rubbing their antennae against it, and guarding it. They didn't show these responses when Schönrogge and colleagues played white noise. These behaviors, which represent a worker ant's attempts to protect its nestmates, indicate that acoustic communication served to bring assistance in both mature pupae and adult ants.

To see how the ants used this acoustic communication, the team removed the abdominal spike from some of the mature pupae in a nest. The researchers then disturbed the nest, spilling out larvae, pupae, and adult workers into an experimental arena. Normally, the adult ants rescue their nestmates in a specific order: mature pupae, immature pupae, and, finally, the larvae. In the experiments by Schönrogge and colleagues, the adult workers indeed rescued the unmuted mature pupae first. However, the adult ants completely ignored the muted ants. It was as if the mute mature pupae simply didn't exist.

"The sounds they make rescue them by signaling their social status," Schönrogge says. "There is complex information in these signals," that combine with chemical signals to provide an array of information about the individual. Researchers have yet to decode everything the ants are communicating by sound and how the ants interpret these signals. Acoustic communication may be especially important in mature pupae because they don't yet produce the full array of adult pheromones, but they also don't smell and behave like larvae, either.

DeVries cautions that the discovery doesn't mean that chemical communication in ants is less important. "Ants live in these enormously sophisticated societies," he says. "Acoustic signaling adds another gorgeous piece to what we know about how insect societies communicate."



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