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Top 11 warmest years have occurred in the last 13 years

Fri, 14 Dec 2007 06:09:00 -0500

Top 11 warmest years have all occurred in the last the 13 years, according to preliminary global temperature figures for 2007 released by the University of East Anglia and the Met Office’s Hadley Centre.

The preliminary global figure for 2007 is based on climate data from January to November, which presently places the year as the seventh warmest on records dating back to 1850.

The declaration comes as the Secretary-General of the World Meteorological Organization (WMO), Michel Jarraud spoke at the Conference of the Parties (COP) in Bali.

Researchers and politicians have been in Indonesia discussing plans to cut greenhouse gas emissions that have been associated with rising global temperatures.

“The last few days have provided an important platform for debate and confirms the need for swift action to combat further rises in global temperatures because of human behaviour,” Dr Vicky Pope from the Met Office Hadley Centre has been attending the conference and said.

The last time annual mean global temperatures were below the 1961-1990 long term average was in 1985. Since then, mean surface air temperatures have continued to demonstrate a warming trend around the world. 2007 has been no exception to this, even though there has been a La Nina event, which usually reduces global temperatures.

Professor Phil Jones, Director of UEA’s Climatic Research Unit, said: “The year began with a weak El Nino – the warmer relation of La Nina - and global temperatures well above the long-term average. However, since the end of April the La Nina event has taken some of the heat out of what could have been an even warmer year”.

In January, the Met Office, in conjunction with the University of East Anglia, predicted that 2007 could record global temperature well above the long-term average. There was also a 60 percent probability that 2007 could be the warmest on record and the expected temperature for 2007 is within the range predicted.

“2007 was warmer in the Northern Hemisphere, where the year ranks second warmest, than the Southern Hemisphere, where it ranks ninth warmest,” Professor Jones said.

Met Office Climate Scientist David Parker added: “This year has also seen sea-ice extent in the Northern Hemisphere below average in each month of 2007, with record minima sea-ice reported in July, August and September. In the Southern Hemisphere, sea-ice coverage has remained close to average”.

Global 10 Warmest Years Mean Global temperature (°C) (anomaly with respect to 1961-1990)

1998 0.52

2005 0.48

2003 0.46

2002 0.46

2004 0.43

2006 0.42

2007(Jan-Nov) 0.41

2001 0.40

1997 0.36

1995 0.28

(ANI)

Global warming sounding death knell for coral reefs

Fri, 14 Dec 2007 06:09:00 -0500

A study has revealed that most coral reefs will not survive the drastic increases in global temperatures and atmospheric CO2 unless governments act immediately to combat current trends.

The study, conducted by Dr. Bob Steneck, of the University of Maine and 16 other marine scientists from several countries, stated the effects rising ocean temperatures are having on the world’s coral reefs.

The study showed a bleak picture of a future without all but the most resilient coral species if atmospheric CO2 levels continue on their current trajectory.

It warned that the marine biodiversity, tourism and fishing industries and the food security of millions are at risk.

Steneck said that the time was right for international leaders to commit to meaningful action to save the world’s coral reefs.

“The science speaks for itself. We have created conditions on Earth unlike anything most species alive today have experienced in their evolutionary history. Corals are feeling the effects of our actions and it is now or never if we want to safeguard these marine creatures and the livelihoods that depend on them,” Steneck said.

Coral skeletons are made of calcium, and reef development requires plenty of carbonate ions to build these skeletons, a process called calcification.

When carbon dioxide is absorbed in the ocean, the pH level drops, along with the amount of carbonate ions, slowing the growth of coral reefs.

Atmospheric CO2 levels are currently at 380 parts per million (ppm) and the researchers of the study calculated that once levels reach 560ppm, the calcification process could be reduced by up to 40 percent.

The scientists also suggested that by 2100 the oceans would be so acidic that 70 percent of the habitat for deep-water corals, once considered relatively safe from the effects of climate change, will be uninhabitable.

Ocean acidification is just one example of the threats corals are facing. Bleaching, a process that is triggered when summer sea temperatures rise above normal for weeks at a time causes corals to expel the algae that gives them their colour and nutrients.

Another threat is that consumer demand has also placed corals at risk. Popular products include coral jewellery, home decor items and live animals used in home aquaria.

Fernanda Kellogg, president of The Tiffany & Co. Foundation, said, “Tiffany & Co. is committed to obtaining precious materials in ways that are socially and environmentally responsible. We decided to stop using real coral in our jewellery and feel that there are much better alternatives that celebrate the beauty of the ocean without destroying it.”

The study, titled ‘Carbon Crisis: Coral Reefs under Rapid Climate Change and Ocean Acidification’ is published in Science. (ANI)

Milky Way's two stellar halos have opposing spins

Fri, 14 Dec 2007 06:09:00 -0500

We call it home, but the Milky Way can still surprise us. It does not have just one halo of stars, but two.

According to Daniela Carollo of the Torino Observatory in Italy and her colleagues, the discovery was made while measuring the metal content and motion of 20,000 stars in the Milky Way through the Sloan Digital Sky Survey.

Carollo and her team found that the halo can be divided into two distinct regions, rotating in opposite directions, and containing stars of different chemical composition.

The team found that the inner halo is flattened and extends out to about 4.6 x 1017 kilometres from the galactic centre, rotating at 20 kilometres per second, in the same sense that the Sun travels round the galactic centre.

The outer halo is spherical, stretching out to over 6.0 x 1017 kilometres and spinning in the opposite direction at about 70 kilometres per second.

By examining the spectrum of light emitted by the stars, the team also calculated that the inner-halo stars contain three times more heavy atoms than the outer-halo stars, raising questions about when the two halos formed.

"The two haloes appear to have been formed at different times by different mechanisms," believes Carollo.

"This result throws out all our current models of galaxy formation," Carollo reports in her study published in Wednesday’s issue of the journal Nature. (ANI)

Hotspot under EarthÃ¢â‚¬â„¢s crust dangerously melting GreenlandÃ¢â‚¬â„¢s ice: Experts

Fri, 14 Dec 2007 06:09:00 -0500

A thin spot in the Earth's crust is enabling underground magma to melt Greenland’s ice, scientists at the Ohio State University feel.

According to them, the "hotspot" is located in the northeast corner of Greenland -- just below a site where an ice stream was recently discovered.

The researchers don't yet know how warm the hotspot is, but if it is warm enough to melt the ice above it even a little, it could enable the ice to slide more rapidly out to sea.

To measure actual temperatures beneath the ice, scientists will have to drill boreholes down to the base of the ice sheet-- a mile or more below the ice surface. The effort and expense make such measurements few and far between, especially in remote areas of northeast Greenland.

"The behaviour of the great ice sheets is an important barometer of global climate change," said Ralph von Frese, leader of the project and a professor of earth sciences at Ohio State University.

"However, to effectively separate and quantify human impacts on climate change, we must understand the natural impacts, too,” he added.

Von Frese's team combined gravity measurements of the area taken by a Naval Research Laboratory aircraft with airborne radar measurements taken by research partners at the University of Kansas.

The combined map revealed changes in mass beneath the Earth's crust, and the topography of the crust where it meets the ice sheet.

According to the researchers, below the earth’s crust is the mantle, the partially molten rocky layer that surrounds its core.

The mantle is so hot that temperatures just a few miles deep in the crust reach hundreds of degrees Fahrenheit, von Frese explained.

"It could be that there's a volcano down there. But we think it's probably just the way the heat is being distributed by the rock topography at the base of the ice," he said.

The ice thickness, the temperature at the base of the ice, and ground topography all contribute to the forming of an ice stream -- a river of ice that flows within a larger ice sheet.

In recent years, Greenland ice streams have been carrying ice out to sea faster, and ice cover on the island has been diminishing.

Once the ice reaches the sea, it melts, and global sea levels rise.

"Where the crust is thicker, things are cooler, and where it's thinner, things are warmer. And under a big place like Greenland or Antarctica, natural variations in the crust will make some parts of the ice sheet warmer than others," von Frese added.

The ice sheet in northeast Greenland is especially worrisome to scientists. It had no known ice streams until 1991, when satellites spied one for the first time.

Dubbed the Northeastern Greenland Ice Stream, it carries ice nearly 400 miles, from the deepest interior of the island out to the Greenland Sea.

The newly discovered hotspot is just below the ice stream, and could have caused it to form, the researchers concluded. But what caused the hotspot to form?

"It could be that there's a volcano down there. But we think it's probably just the way the heat is being distributed by the rock topography at the base of the ice," said von Frese.

Collaborator Kees van der Veen, a visiting associate professor of geological sciences and research scientist at Byrd Polar Research Center at Ohio State, said: "Our map is the first attempt at quantifying spatial variations in geo-heat under Greenland -- and it explains why the Northeast Greenland Ice Stream is where it is."

For now, the researchers are combining theories of how heat flows through the mantle and crust with the gravity and radar data, to understand how the hotspot is influencing the ice.

Once they finish searching the rest of Greenland for other hotspots, they hope to turn their attention to Antarctica.

Timothy Leftwich, von Frese's former student and now a post-doctoral engineer at the Centre for Remote Sensing of Ice Sheets at the University of Kansas, presented the study's early results on Thursday at the American Geophysical Union meeting in San Francisco. (ANI)

New rubber may soon see face masks that change shape to fit any face

Fri, 14 Dec 2007 06:01:00 -0500

It won’t be long before there will be a face mask that may change its shape to fit any user, or a lens that does the same, for scientists have developed a new class of shape-memory rubber, that can be stretched to a new shape and regain its original shape when heated.

This rubber, developed by the researchers at the University of Rochester, may enable applications as diverse as biomedical implants, conformal face-masks, self-sealing sutures, and "smart" labels.

This unique invention owes its credit to Mitchell Anthamatten, assistant professor of chemical engineering and inventor of the material.

After stretching to any desired shape, these materials, also known as shape-memory polymers, when heated will revert to their initial shape.

These materials, unlike conventional shape-memory polymers are however transparent, rubbery, and most importantly, will allow engineers to control the speed at which it returns to its original shape.

The other shape memory polymers utilize crystallization to hold a temporary shape, which often makes them opaque, hard, and brittle in their frozen states, which limits their use.

"At higher temperatures the material stretches like a rubber band, but, at lower temperatures, it stiffens up," said Mitchell Anthamatten.

He added: "This property can be used to temporarily hold the material in a deformed shape; and its original shape can be recalled by heating. Imagine an optical lens that can be triggered to change shape, a face-mask that can fit any user, or a biomedical implant that changes shape slow enough for a surgical procedure."

This new rubber has different functioning than conventional shape-memory materials by using "sticker groups"—hydrogen bonding groups that form temporary bonds.

Such sticker groups break and reform constantly. It's same as tearing a net apart only to discover new knots that have been formed between different strands.

As the material is stretched, new bonds are formed that hold the material, temporarily, in its deformed shape.

The rate at which the rubber returns to its original shape can be controlled through creating the rubber with varied amounts of sticker groups. Because of this control, Anthamatten foresses applications, that today's shape-memory polymers simply can't fulfill.

"The pressure at which you hold together a sutured wound determines a lot about how it will heal," said Anthamatten.

He added: "This polymer could be made into a thread that responds precisely to body temperature, tightening the sutures to the perfect pressure."

This unique discovery was described in the journal Advanced Materials. (ANI)

Scientists find why size matters in nature

Fri, 14 Dec 2007 05:53:00 -0500

Researchers at the John Innes Centre in Norwich have shed light on the beauty of nature by explaining the mechanism behind the uniformity of leaf and flower size in individual plants.

Investigating how plants arrive at these aesthetic proportions, the team discovered that cells at the margins of leaves and petals play a key role in setting their size.

“The remarkable uniformity of leaves and flowers helps us to tell different species apart, such as daisies and marguerites, which look very similar otherwise. We are now uncovering how the genetic blueprint of a species tightly controls the size of leaves and flowers”, said lead author Dr. Michael Lenhard.

The cells at the margins appear to ooze a mobile growth signal that keeps the cells throughout the leaf dividing. The more of this signal is produced, the larger the leaves and flowers get, the team found.

Surprisingly, the authors said, this signal seems to be different from the classical and well-studied plant hormones that are known to influence growth and development.

“As the signal only seems to come in from the margins, we suggest it gets diluted as the leaf or petal grows. Once the concentration falls below a certain threshold, the cells in the leaf or petal stop dividing. Dr. Lenhard said.

“This would be a simple way of measuring the size of a growing organ. It’s a bit like adding more and more tonic to a gin and tonic until you can no longer taste the gin,” he added.

He further said that noticeably, animals seem to use the same principle of dilution for measuring size, for example of the wings in a fly, although the molecules used are very different.

Efforts are in progress to use this finding to boost leaf growth in biofuel crops for the production of sustainable energy and to increase the yield of fruits and seeds.

The study was published in Developmental Cell. (ANI)

Now, a Bamboo bridge thatÃ¢â‚¬â„¢s strong enough for 8-ton trucks

Fri, 14 Dec 2007 05:53:00 -0500

The world's first bamboo bridge that can carry the weight of trucks has been built in a village in the central province of Hunan in China.

The ten-metres-long bridge was designed by Yan Xiao, a professor at the University of Southern California Viterbi School of Engineering.

The bridge, made from pre-fabricated structural elements, was erected within a week by a team of eight workers without heavy construction equipment.

Trucks have already driven via the bridge, which was officially opened up for traffic on Dec 12.

While traffic on the bridge will be limited to the 8-ton design capacity, preliminary tests on a duplicate bridge erected on the campus of Hunan University have shown much higher strength.

The new bridge is the latest instalment in research on structural bamboo being carried on by Xiao, who in addition to his appointment at the USC Sonny Astani Department of Civil and Enviornmental Engineering holds an appointment at the College of Civil Engineering of the Hunan University, China.

Prof. Xiao expects his modern bamboo bridge technology to be extensively used in pedestrian crossing, large number of bridges in rural areas in China, as a environmental friendly and sustainable construction material. (ANI)

Unprecedented 5 degree heating of part of Arctic Ocean due to global warming

Fri, 14 Dec 2007 05:53:00 -0500

A new research has indicated that sea surface temperatures in one section of the Arctic Ocean have risen up to 5 degree Celsius above average, due to the effects of global warming.

A major reason for this increase in temperature in the particular area of the Arctic Ocean is the record-breaking amounts of ice-free water, which has deprived the Arctic of more of its natural “sunscreen” than ever in recent summers.

“Such superwarming of surface waters can affect how thick ice grows back in the winter, as well as its ability to withstand melting the next summer,” said Michael Steele, an oceanographer with the University of Washington's Applied Physics Laboratory.

“The extra ocean warming also might be contributing to some changes on land, such as previously unseen plant growth in the coastal Arctic tundra, if heat coming off the ocean during freeze-up is making its way over land,” adds Steele.

According to the research, warming is particularly pronounced since 1995, and especially since 2000. The spot where waters were 5 Celsius above average was in the region just north of the Chakchi Sea. The historical average temperature there is -1 C.

But this year, water in that area warmed to 4 C, for a 5-degree change from the average.

That general area, the part of the ocean north of Alaska and Eastern Siberia that includes the Bering Strait and Chukchi Sea, experienced the greatest summer warming.

Temperatures for that region were generally 3.5 C warmer than historical averages and 1.5 C warmer than the historical maximum.

“Such widespread warming in those areas and elsewhere in the Arctic is probably the result of having increasing amounts of open water in the summer that readily absorb the sun's rays,” said Steele.

The warming also may be partly caused by increasing amounts of warmer water coming from the Pacific Ocean, something scientists have noted in recent years.

The Arctic was primed for more open water since the early 1990s as the sea-ice cover has thinned, due to a warming atmosphere and more frequent strong winds sweeping ice out of the Arctic Ocean via Fram Strait into the Atlantic Ocean where the ice melts.

“Now the situation could be self-perpetuating,” said Steele.

For example, he calculates that having more heat in surface waters in recent years means 23 to 30 inches less ice will grow in the winter than formed in 1965. Since sea ice typically grows about 80 inches in a winter, that is a significant fraction of ice that's going missing, he says.

Then too, higher sea surface temperatures can delay the start of freeze-up because the extra heat must be discharged from the upper ocean before ice can form.

"The effect on net winter growth would probably be negligible for a delay of several weeks, but could be substantial for delays of several months," said the authors. (ANI)