Dhaka, Nov 24 (UNB) - Scientists are proposing an ingenious but as-yet-unproven way to tackle climate change: spraying sun-dimming chemicals into the Earth’s atmosphere.
The research by scientists at Harvard and Yale universities, published in the journal Environmental Research Letters, proposes using a technique known as stratospheric aerosol injection, which they say could cut the rate of global warming in half, reports CNN.
The technique would involve spraying large amounts of sulfate particles into the Earth’s lower stratosphere at altitudes as high as 12 miles. The scientists propose delivering the sulfates with specially designed high-altitude aircraft, balloons or large naval-style guns.
Despite the technology being undeveloped and with no existing aircraft suitable for adaptation, the researchers say that “developing a new, purpose-built tanker with substantial payload capabilities would neither be technologically difficult nor prohibitively expensive.”
They estimate the total cost of launching a hypothetical system in 15 years’ time at around $3.5 billion, with running costs of $2.25 billion a year over a 15-year period.
The report does, however, acknowledge that the technique is purely hypothetical.
“We make no judgment about the desirability of SAI,” the report states. “We simply show that a hypothetical deployment program commencing 15 years hence, while both highly uncertain and ambitious, would indeed be technically possible from an engineering perspective. It would also be remarkably inexpensive.”
The researchers also acknowledge potential risks: coordination between multiple countries in both hemispheres would be required, and stratospheric aerosol injection techniques could jeopardize crop yields, lead to droughts or cause extreme weather.
The proposals also don’t address the issue of rising greenhouse gas emissions, which are a leading cause of global warming.
And despite the conviction of the report’s authors, other experts were skeptical.
“From the point of view of climate economics, solar radiation management is still a much worse solution than greenhouse gas emissions: more costly and much more risky over the long run,” said Philippe Thalmann of the École Polytechnique Fédérale de Lausanne, an expert in the economics of climate change.
David Archer of the Department of Geophysical Science at the University of Chicago said, “The problem with engineering climate in this way is that it’s only a temporary Band-Aid covering a problem that will persist essentially forever, actually hundreds of thousands of years for fossil fuel CO2 to finally go away naturally.
“It will be tempting to continue to procrastinate on cleaning up our energy system, but we’d be leaving the planet on a form of life-support. If a future generation failed to pay their climate bill they would get all of our warming all at once.”
Los Angeles, Nov 24 (Xinhua/UNB)-- Scientists have proposed a new way to tackle climate change by spraying sun-dimming chemicals into the Earth's atmosphere, according to a study published Friday.
Scientists at Harvard and Yale universities have proposed using a technique known as Stratospheric Aerosol Injection (SAI), which they believe could cut the rate of global warming by half, according to a paper published in the journal Environmental Research Letters.
The technique would involve spraying large amounts of sulfate particles into the Earth's lower stratosphere at altitudes as high as 12 miles (19.3 km).
However, no existing aircraft design -- even with extensive modifications -- can reasonably fulfill this mission, said the paper.
The scientists propose developing a new purpose-built high-altitude tanker with substantial payload capabilities to deliver the sulfates.
The estimated cost of deploying material is about 2.25 billion U.S. dollars a year over 15 years, according to the paper. Scientists calculate the number of flights at 4,000 for the first year, linearly increasing by 4,000 a year.
The report also acknowledges that the technique is purely hypothetical.
"We make no judgment about the desirability of SAI. We simply show that a hypothetical deployment program commencing 15 years hence, while both highly uncertain and ambitious, would indeed be technically possible from an engineering perspective. It would also be remarkably inexpensive," the paper said.
San Juan, Nov 22 (AP/UNB) — A rarely seen shark embryo. Corals up to 7 feet (2 meters) high. Sponges with sharp edges.
These were among the hundreds of findings reported by U.S. scientists who have wrapped up a 22-day mission exploring waters around Puerto Rico and the U.S. Virgin Islands in the deepest dives ever recorded in the region. Guided by other land-based scientists watching live feeds, they collected 89 samples and will now start to analyze them, Daniel Wagner, expedition coordinator with the U.S. National Oceanic and Atmospheric Administration, told The Associated Press on Wednesday.
"When they tell you, 'I've never seen that before,' it's a good indication that it's a new species or something that's new to this region," he said.
It will take several years for scientists to establish whether any new species were discovered, but in the meantime, they will ship all the coral branches, pieces of sponge, brittle starfish and rocks they collected to the Smithsonian National Museum of Natural History, Wagner said.
Scientists aboard the 224-foot (68-meter) Okeanos Explorer also identified some 30 species of fish, including some in areas where previously they hadn't been spotted. These include commercially popular fish such as snappers and groupers, which were seen about 100 meters (330 feet) deeper than reported to exist.
"That's a great thing," Wagner said.
In addition, they mapped geological features up to 3 miles (5,000 meters) deep, covering an area close to 15,000 square kilometers (5,800 square miles), he said.
The 19 dives performed by remotely operated vehicles over 145 hours were streamed live and drew a lot of online attention. One especially popular video was that of a catshark embryo attached to a coral branch some 800 feet deep near an uninhabited island off Puerto Rico's west coast.
Overall, the ecosystems appeared healthy, although scientists also saw pieces of trash on a few dives and the occasional fishing line, he added.
"It's a sad thing, but a healthy reminder that our things go down to the deep sea," he said.
The sites explored were chosen from a list of 80 submitted by scientists worldwide, including the location of a 1918 earthquake that generated a tsunami, killing more than 100 people in Puerto Rico.
Sydney, Nov 19 (Xinhua/UNB) -- Four blind Australians have had their vision partially restored through the implantation of bionic eyes, the company responsible for the technology announced on Monday.
Bionic Vision Technologies ran a trial for patients who had lost vision due to Retinitis Pigmentosa, making them able to sense light and dark but unable to see a hand waving in front of them.
Now the company said patients can perceive the world around them in "pixelated grayscale", meaning they are able to navigate without the need for a guide dog, cane or other assistance.
Lead researcher Associate Professor Penny Allen told local media that the technology could have a dramatic effect on the lives of the one-in-4000 Australians who suffer from the currently incurable genetic condition.
"We've been very happy with how they're progressing and they're really happy; and that is the best thing of all," Allen said.
The system works by capturing images through a camera attached to a pair of glasses, and then feeding the information via an external processing unit, to the patient's scalp, and then to the implanted device in the patient's eyes.
Following the success of initial tests in a laboratory setting, researchers hoped that subjects would be able to take the devices home and start applying them to their everyday lives.
"We are working with them to identify things they want to do at home, normal tasks we all do," Allen said.
"One patient is sorting washing, colours from whites, and one patient wishes to be able to navigate independently to some things in the backyard, like the lemon tree."
Versailles, Nov 17 (AP/UNB) — In a historic vote, more than 50 nations unanimously approved an overhaul of the international measurement system that underpins global trade and other human endeavors, uniting Friday behind new definitions for the kilogram and other units in a way they fail to do on many other issues.
Scientists, for whom the update represented decades of work, clapped, cheered and even wept as delegates gathered in Versailles one by one said "yes" or "oui" to the change, hailed as a revolution in how humanity measures and quantifies its world.
The redefinition of the kilogram, the globally approved unit of mass, was the mostly hotly anticipated change. For more than a century, the kilogram has been defined as the mass of a cylinder of platinum-iridium alloy kept in a high-security vault in France. That artefact, nicknamed "Le Grand K," has been the world's sole true kilogram since 1889 .
Now, with the vote, the kilogram and all of the other main measurement units will be defined using numerical values that fit handily onto a wallet card. Those numbers were read to the national delegates before they voted. The update will take effect May 20.
Scientists at the meeting were giddy with excitement: some even sported tattoos on their forearms that celebrated the science.
Nobel prize winner William Phillips called the update "the greatest revolution in measurement since the French revolution," which ushered in the metric system of meters and kilograms.
The Grand K and its six official copies, kept together in the same safe on the outskirts of Paris and collectively known as the "heir and the spares," will be retired but not forgotten. Scientists want to keep studying them to see whether their masses change over time.
The update will have no discernable impact for most people. Bathroom scales won't suddenly get kinder and kilos and grams won't change in supermarkets.
But the new formula-based definition for the kilogram will have multiple advantages over the precision-crafted metal lump that set the standard from the 19th century to the 21st, through periods of stunning human achievement and stunning follies, including two world wars.
Unlike a physical object, the formula for the kilo, now also known as "the electric kilo," cannot pick up particles of dust, decay with time or be dropped and damaged, but will be easier to share.
"If we stay where we are, and someone did accidentally drop the kilogram or if there was a contamination that we couldn't control, then the whole system has got no head. We're in chaos," said Barry Inglis, a scientist from Australia. "That's the thing that's really been worrying us, I think, for maybe 15 years or more is just how vulnerable the system is, by depending just on that one little piece of platinum-iridium."
The redefined kilo is expected to allow for more accurate measurements of very, very small or very, very large masses and help usher in innovations in science, industry, climate study and other fields. In humankind's efforts to quantify and understand the world, stretching back centuries to when ancient Babylonians measured mass with stones, the vote marked a major milestone, scientists agreed.
"Those units, those constants chosen now, include everything we know, everything we have always known and provide that springboard for us to go pursue those things that we don't know," said Jon Pratt of the U.S. National Institute of Standards and Technology. He said Friday's gathering "was just leaving me in a puddle of tears."
Updated definitions for the ampere, kelvin and mole also were approved Friday.
Humanity uses seven main measurements units: the meter for length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the mole for the amount of a substance and the candela for luminous intensity.
Of the seven, the kilo was the last still based on a physical artefact, Le Grand K. With time, as the science behind the new kilo definition becomes more accessible and affordable, the update should also mean that countries won't have to send their own kilograms back to France to be checked occasionally against Le Grand K, as they have done until now, to see whether their mass was still accurate.
"We future-proofed the system," said Martin Milton, director of the International Bureau of Weights and Measures.
The bureau is the guardian of the system, as well as of Le Grand K and its copies, which are stored in a vault that requires three keys, kept by three different people, to unlock. Very rarely have they seen the light of day.
"We put in place a system that doesn't depend on something that is 140 years old," Milton said.