Best of our wild blogs: 8 Apr 13

Latest Green Jobs in Singapore [1 - 7 Apr 2013]
from Green Business Times

Have You Seen These Creatures in the Wild ? -Part 2
from Beauty of Fauna and Flora in Nature

Story of a Baby Oriental Pied Hornbill
from Nikita Hengbok

Australian Red-claw Crayfish
from Monday Morgue

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Changi goes green with recycled concrete

Royston Sim Straits Times 8 Apr 13;

AIRCRAFT parking spaces at Changi Airport are being ripped up and replaced with recycled concrete mix as part of an ongoing drive to go green.

Thirty-one of the 80m by 80m spaces - officially termed stands - will be repaved over the next 10 years.

Concrete aggregates extracted from the spaces, which are nearing the end of their lifespan, are used to form a new mixture. This material - which is as good as new, will be used to replace the 31 stands at Terminal 1, Terminal 2 and the cargo area. There are a total of 146 aircraft parking stands at the airport.

Mr Teoh Eng San, assistant vice-president for engineering and development at Changi Airport Group, said the company "has to be prudent and rehabilitate our parking stands at appropriate times".

He added that the pavement has an average lifespan of about 20 to 25 years, depending on factors such as usage, and wear and tear.

The stands at the airport have been in use for more than 30 years - longer than average - because of high-quality construction and rigorous maintenance work.

The airport engaged engineering experts from the National University of Singapore (NUS), who developed a mix in which 20 per cent was recycled concrete.

Eight parking stands were replaced using it under phase one of the project.

The Building and Construction Authority has set a benchmark of 20 per cent to encourage wider use of recycled materials in the construction industry.

With the backing of Changi Airport Group, the NUS team went a step further and formulated a new mix that had 40 per cent of recycled concrete aggregates - a first here.

NUS professor Fwa Tien Fang, a consultant for the project, said the high quality of the concrete used in Changi's stands makes it suitable for recycling.

As parking stands are key airport structures, Prof Fwa said rigorous testing was done to ensure the new mixture was as strong and long-lasting as fresh concrete.

"When we use recycled material, we must make sure there is no compromise on quality," he said.

Mr Teoh said the main advantages of using recycled concrete include alleviating waste disposal issues in land-scarce Singapore and moving towards environmental sustainability.

He added that the cost of using recycled concrete to repave the parking stands is about the same as if fresh concrete was used.

However, he noted: "A major consideration for the team is the pursuit of green measures in using recycled concrete aggregates and doing our part to preserve the environment."

The project consists of four phases and should be completed in 2019. The second phase, which will see 10 parking stands repaved with the new 40 per cent mix, is currently under way.

New aircraft stands will also be constructed at Terminal 4, and Changi Airport Group has announced plans to convert a 38ha land plot into an aircraft parking area. These measures will increase Changi's parking capacity by more than a fifth.

Mr Teoh said the group will consider using recycled concrete for new construction projects where feasible.

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Oceans may explain slowdown in climate change: study

Alister Doyle Reuters Yahoo News 7 Apr 13;

OSLO (Reuters) - Climate change could get worse quickly if huge amounts of extra heat absorbed by the oceans are released back into the air, scientists said after unveiling new research showing that oceans have helped mitigate the effects of warming since 2000.

Heat-trapping gases are being emitted into the atmosphere faster than ever, and the 10 hottest years since records began have all taken place since 1998. But the rate at which the earth's surface is heating up has slowed somewhat since 2000, causing scientists to search for an explanation for the pause.

Experts in France and Spain said on Sunday that the oceans took up more warmth from the air around 2000. That would help explain the slowdown in surface warming but would also suggest that the pause may be only temporary and brief.

"Most of this excess energy was absorbed in the top 700 meters (2,300 ft) of the ocean at the onset of the warming pause, 65 percent of it in the tropical Pacific and Atlantic oceans," they wrote in the journal Nature Climate Change.

Lead author Virginie Guemas of the Catalan Institute of Climate Sciences in Barcelona said the hidden heat may return to the atmosphere in the next decade, stoking warming again.

"If it is only related to natural variability then the rate of warming will increase soon," she told Reuters.

Caroline Katsman of the Royal Netherlands Meteorological Institute, an expert who was not involved in the latest study, said heat absorbed by the ocean will come back into the atmosphere if it is part of an ocean cycle such as the "El Nino" warming and "La Nina" cooling events in the Pacific.

She said the study broadly confirmed earlier research by her institute but that it was unlikely to be the full explanation of the warming pause at the surface, since it only applied to the onset of the slowdown around 2000.

THRESHOLD

The pace of climate change has big economic implications since almost 200 governments agreed in 2010 to limit surface warming to less than 2 degrees Celsius (3.6 F) above pre-industrial levels, mainly by shifting from fossil fuels.

Surface temperatures have already risen by 0.8 C. Two degrees is widely seen as a threshold for dangerous changes such as more droughts, mudslides, floods and rising sea levels.

Some governments, and skeptics that man-made climate change is a big problem, argue that the slowdown in the rising trend shows less urgency to act. Governments have agreed to work out, by the end of 2015, a global deal to combat climate change.

Last year was ninth warmest since records began in the 1850s, according to the U.N.'s World Meteorological Organization, and 2010 was the warmest, just ahead of 1998. Apart from 1998, the 10 hottest years have all been since 2000.

Guemas's study, twinning observations and computer models, showed that natural La Nina weather events in the Pacific around the year 2000 brought cool waters to the surface that absorbed more heat from the air. In another set of natural variations, the Atlantic also soaked up more heat.

"Global warming is continuing but it's being manifested in somewhat different ways," said Kevin Trenberth, of the U.S. National Center for Atmospheric Research. Warming can go, for instance, to the air, water, land or to melting ice and snow.

Warmth is spreading to ever deeper ocean levels, he said, adding that pauses in surface warming could last 15-20 years.

"Recent warming rates of the waters below 700 meters appear to be unprecedented," he and colleagues wrote in a study last month in the journal Geophysical Research Letters.

The U.N. panel of climate scientists says it is at least 90 percent certain that human activities - rather than natural variations in the climate - are the main cause of warming in recent decades.

(Reporting by Alister Doyle, Environment Correspondent; Editing by Peter Graff)

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