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2014. október 14., kedd
Climate change: Models 'underplay plant CO2 absorption'
Leaves absorb significantly more CO2 than climate models have estimated
Global climate models have underestimated the amount of CO2 being absorbed by plants, according to new research.
Scientists say that between 1901 and 2010, living things absorbed 16% more of the gas than previously thought.The authors say it explains why models consistently overestimated the growth rate of carbon in the atmosphere.
But experts believe the new calculation is unlikely to make a difference to global warming predictions.
The research has been published in the journal Proceedings of the National Academy of Sciences.
Working out the amount of carbon dioxide that lingers in the atmosphere is critical to estimating the future impacts of global warming on temperatures.
About half the CO2 that's produced ends up in the oceans or is absorbed by living things.
But modelling the exact impacts on a global scale is a fiendishly complicated business.
In this new study, a team of scientists looked again at the way trees and other plants absorb carbon.
By analysing how CO2 spreads slowly inside leaves, a process called mesophyll diffusion, the authors conclude that more of the gas is absorbed than previously thought.
Between 1901 and 2100 the researchers believe that their new work increases the amount of carbon taken up through fertilisation from 915 billion tonnes to 1,057 billion, a 16% increase.
"There is a time lag between scientists who study fundamental processes and modellers who model those processes in a large scale model," explained one of the authors, Dr Lianhong Gu at Oak Ridge National Laboratory in the US.
"It takes time for the the two groups to understand each other."
Scientists monitor carbon dioxide levels near trees to work out how much is absorbed
"The atmospheric CO2 concentration only started to accelerate rapidly after 1950," said Dr Gu.
"So the 17% bias was achieved during a period of about 50 years. If we are going to predict future CO2 concentration increases for hundreds of years, how big would that bias be?"
Model revamp Other researchers believe the new work could help clarify our models but it may not mean any great delay in global warming as a result of increased concentrations of the gas.
"The paper provides great new insights into how the very intricacies of leaf structure and function can have a planetary scale impact," said Dr Pep Canadell from the Global Carbon Project at CSIRO Australia.
"It provides a potential explanation for why global earth system models cannot fully reproduce the observed atmospheric CO2 growth over the past 100 years and suggests that vegetation might be able to uptake more carbon dioxide in the future than is currently modelled.
"Having more carbon taken up by plants would slow down climate change but there are many other processes which lay in between this work and the ultimate capacity of terrestrial ecosystems to remove carbon dioxide and store it for long enough to make a difference to atmospheric CO2 trends."
Many experts agree that the effect is interesting and may require a recalibration of models - but it doesn't change the need for long-term emissions cuts to limit the impact of carbon dioxide.
"This new research implies it will be slightly easier to fulfil the target of keeping global warming below two degrees - but with a big emphasis on 'slightly'," said Dr Chris Huntingford, a climate modeller at the UK's Centre for Ecology and Hydrology.
"Overall, the cuts in CO2 emissions over the next few decades will still have to be very large if we want to keep warming below two degrees."
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Rosetta mission: Philae comet lander pictures its target
The Philae robot, soon to try to land on Comet 67P, has taken another dramatic image of its quarry.
Philae views 67P (top) from its
attachment point on the Rosetta "mothership" (left). One of Rosetta's
rectangular solar wings extends outwards
The picture is very similar to the one it acquired in mid-September - only this one is much closer, snapped from a distance of just 16km.
Also new in this picture is 67P's activity. Jets of gas and
dust can be seen streaming away from the "neck" region of the rubber
duck-shaped comet. Philae is due to make its historic landing attempt on 12 November.
It is currently riding piggyback on its "mothership", the Rosetta probe.
You can just see the corner of this spacecraft on the left of the image, with one of its 14m-long solar wings dominating the foreground.
The plan is for Rosetta to eject Philae towards 67P just after 0830 GMT on the 12th.
The small gravitational tug from the 4km-wide comet should be enough to pull the robot on to its surface in a descent that is likely to take about seven hours to complete.
If the lander survives this fall, it will be a first. Never before in the history of space exploration has a soft touchdown been made on one of these "ice mountains".
David Shukman takes a close-up look at the Philae lander
This allowed the very different contrast conditions to be balanced across the entire vista.
Philae acquired the frames on 7 October. It will be the last view from the robot's CIVA camera system until just after separation from Rosetta.
The plan is for Philae to grab a "goodbye" shot of Rosetta as the pair start to recede from each other.
Assuming the landing succeeds, CIVA will then take a full 360-degree panorama of its touchdown location.
This is a relatively flat terrain on the "head" of the duck, currently dubbed "Site J" after its position in a list of possible destinations in the site selection process.
Mission planners were due to meet on Tuesday to give a final confirmation to the J target. This ought to have been a formality.
The big caveat is if Rosetta has seen a "showstopper" in its recent close-in mapping campaign. This would have to be an extremely dangerous surface feature that had gone unrecognised in previous, lower-resolution imaging.
If a no-go situation has been indentified, planners would then move their attention to a back-up landing target on the "body" of the duck called "Site C".
Rosetta, Philae and Comet 67P are currently moving through space some 480 million km from Earth.
Comet 67P/Churyumov-Gerasimenko
- Named after its 1969 discoverers Klim Churyumov and Svetlana Gerasimenko
- Referred to as a "Jupiter class" comet that takes 6.45 years to go around the Sun
- It gets as close as 180 million km from our star, and as distant as 840 million km
- The icy core, or nucleus, is about 4km across and takes 12.4 hours to rotate
- Rosetta has measured 67P to have a mass of roughly 10 billion tonnes
- Its volume is 25 cu km, giving it a bulk density of 0.4g/cc - similar to some woods
Italy pushes ahead with 'next generation' biofuels from waste
The Crescentino facility is one of the first to turn waste into fuel on a commercial scale
Italy will become the first country in Europe to legally require "advanced biofuels" in cars and trucks, the BBC has learned.
Made from waste, the new fuels are said to reduce the amount of land taken out of food production.The world's first commercial scale plant making fuel from straw opened in Italy last year.
From 2018, all fuel suppliers in the country will have to include 0.6% advanced biofuel in petrol and diesel.
The use of fuels made from crops has been a controversial issue across the EU in recent years.
A Renewable Energy Directive, adopted in 2009, required that 10% of energy used within the transport sector came from renewable sources.
Amid concerns that land was being converted from food production to grow crops for biofuels, the EU ultimately reduced this to 5.75%.
At the same time, the European Parliament voted to require a 2.5% target for advanced biofuels by 2020.
However European Council of energy ministers diluted this to a non-binding goal of 0.5% much to the dismay of the biofuels industry.
Now the Italian government have given the enterprise a shot in the arm.
A ministerial decree, seen by the BBC, requires 0.6% of all petrol and diesel contain advanced biofuels from 2018. This rises to 1% by 2022.
Straw and other agricultural waste products are used in second generation biofuels
The Italians recently announced plans to open three further plants in the south of the country.
Novozymes, one of the companies involved in the Crescentino initiative welcomed the government's decision to make it legally binding on fuel suppliers to include advanced biofuels in their petrol and diesel.
"We applaud the Italian government decision to establish a national mandate for advanced biofuels - the very first of its kind in Europe," said Sebastian Søderberg, from the company.
"After years of dithering and stalemate on biofuels policy in Europe, it is very encouraging that a large member state is ready to lead by example.
"This is most needed to spark investors' interest, and should be a source of inspiration for the Council and the new Parliament to come together in adopting an ambitious, EU-wide mandate for advanced biofuels by 2020 and beyond," he added.
In the United States, the Environment Protection Agency has reduced the level of advanced biofuels it requires for use in transport over concerns that it was increasing imports of fuel made from Brazilian sugarcane. Despite this, a number of new second generation biofuels plants have recently opened.
"This is quite an exciting time, things are finally starting to happen," said Chris Malins from the the International Council on Clean Transportation.
"This shows Italy taking a real leadership role in Europe. It will be an example and a signal to other countries that are interested in this."
However while the new technologies are less likely to spur a shift from using land for food production, there are still questions over their long term sustainability. Farmers may decide to grow "waste" crops.
"In and of itself the fact that you are using cellulosic technology doesn't get a way from land completely - there are still land use and sustainability questions , but there's no doubt that the concerns about impacting food markets are much much less with these technologies than it is with first generation fuels." Follow @janos0314
2014. október 12., vasárnap
Nicki Minaj fails to snatch solo UK number one single
Nicki Minaj is due to release her album The Pink Print later this year
Nicki
Minaj has failed to capture the first UK solo number one single in her
own right as her song Anaconda was beaten into third place in the chart.
The US singer was routed by Meghan Trainor, who galvanised pole position with All About That Bass.Bang Bang - Minaj's joint effort with Jessie J and Ariana Grande - was ahead of her solo record, remaining steady at number two.
George Ezra retained top spot in the album chart with his debut collection.
The singer-songwriter was ahead of Ed Sheeran, Sam Smith and Barbra Streisand in the rundown.
Smith's album The Lonely Hours clocks up its 20th week in the chart this week.
Irish musician Hozier scored the highest new entry at five with his self-titled collection.
A large number of other new
entries peppered the chart, including Canadian star Caribou at eight,
former Smiths guitarist Johnny Marr at nine, with electro-house duo
Gorgon City rounding out the top 10.
Another Canadian, Bryan Adams, was just outside at 11 with his 11th studio album.Elsewhere in the singles chart, Taylor Swift was at four with Shake It Off, which was the most-streamed track of the week.
US R&B star Jeremih went in at number five with Don't Tell 'Em.
A cover of Beach Boys classic God Only Knows - covered by 27 artists including Coldplay's Chris Martin and Sir Elton John - made number 20 after just four days on sale.
A lavish music video was unveiled to launch BBC Music this week, with proceeds of sales going to Children In Need.
Robert Redford to receive New York career honour
Robert Redford is being recognised for his screen roles and work for the film industry
Hollywood
actor and director Robert Redford is to receive a lifetime achievement
award from New York's Film Society of Lincoln Centre.
The 77-year-old's career highlights will be celebrated at a gala in the city next April.The society, which organises the annual New York Film Festival, said that Redford's "impact is hard to measure in many ways".
Recent Chaplin Award recipients include Barbra Streisand and Nicole Kidman.
The honour is given to the movie industry's most notable talents, and has also lauded Martin Scorsese, Alfred Hitchcock and Charlie Chaplin, after whom the award is named.
He was the first recipient in 1972, while last year's winner was director Rob Reiner.
Lesli Klainberg, the film society's executive director, said that Redford's contribution as an actor has been significant, but also pinpointed his work as founder of the Sundance Film Festival.
"Without the Sundance Institute and Sundance Film Festival, we'd likely have a different industry. And they continue to have a huge impact," she said.
"Obviously he's a star that many of us have grown up watching from his films in the early '60s to his current work.
"I happen to think he's also had some of the greatest co-stars ever, from Natalie Wood to Faye Dunaway, Barbra Streisand, and, of course, his great bromance with Paul Newman," added Ms Klainberg.
Redford starred in All is Lost in 2013, which was shown at the New York Film Festival. His performance was greeted with a standing ovation at its Cannes Film Festival premiere last year.
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