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terça-feira, 25 de agosto de 2015
sábado, 22 de agosto de 2015
CHINA IS NOT 'SO BAD' AS IPCC USED TO THINK, ABOUT POLLUTION
The research, published today in Nature, shows that from 2000 to 2013 China produced 2.9 gigatonnes less carbon than previous estimates of its culmulative emissions, meaning that its true emissions may have been around 14% lower than calculated.
Meanwhile, with a population of almost 1.4 billion, China's energy consumption grew 10% faster during 2000-12 than reported by its national statistics.
As the world's biggest greenhouse gas emitter, China's recent pledge to peak its emissions by 2030 has been praised as responsible leadership on the climate issue, but its faster-than-expected energy consumption growth means meeting this target may present an even bigger challenge.
The researchers, led by Dabo Guan, of UEA's School of International Development, used independently assessed data on the amount of fuel burned, and new measurements of emissions factors to re-evaluate emissions of two major sources of China's carbon dioxide emissions - the burning of fossil fuels and cement production - from 1950-2013.
Guan said the new estimates were compiled by considering fuel quality when establishing emissions inventories - something that had previously been overlooked by the Intergovernmental Panel on Climate Change (IPCC) and most international data sources.
"While China is the largest coal consumer in the world, it burns much lower-quality coal, such as brown coal, which has a lower heat value and carbon content compared to the coal burned in the US and Europe", said Guan.
Counting coal
According to the paper, "We find that total energy consumption in China was 10 per cent higher in 2000-2012 than the value reported by China's national statistics, that emission factors for Chinese coal are on average 40 per cent lower than the default values recommended by the Intergovernmental Panel on Climate Change, and that emissions from China's cement production are 45 per cent less than recent estimates.
"Altogether, our revised estimate of China's CO2 emissions from fossil fuel combustion and cement production is 2.49 gigatonnes of carbon in 2013, which is 14 per cent lower than the emissions reported by other prominent inventories. Over the full period 2000 to 2013, our revised estimates are 2.9 gigatonnes of carbon less than previous estimates of China's cumulative carbon emissions."
Pep Canadell, Executive director of the Global Carbon Project at CSIRO, who was not involved in the study, said a lack of research resources meant that estimates of China's emissions relied on default values from global databases.
Guan's research team "visited thousands of mines and by actually exploring the coal they found there was less emissions", Canadell said.
This is a process done by many countries, but for developing nations like China the important task of compiling detailed emissions inventories has historically been too expensive.
"The default values can be quite far away from the real values", Canadell said. "In the future we would need real values for other places such as India."
Corinne Le Quéré, director of the UAE Tyndall Centre for Climate Change Research, said there were a lot of uncertainties in China's data, especially given the discrepancies between national and provincial figures.
"The strong message here is that as we refine our estimates of carbon emissions we get closer to an accurate picture of what is going on and we can improve our climate projections and better inform policy on climate change."
The good news and the bad news
The new findings are a positive step towards accurately measuring emissions, but their effect on climate policy requires acknowledging the negatives - China's rapidly growing energy needs.
Frank Jotzo, director of the ANU Centre for Climate Economics and Policy, described continued work on primary data as important but said the findings that emissions were overestimated does not change the challenge China faces in moving away from coal.
"For global climate change mitigation to succeed, a shift from coal to other energy sources in China is essential." he said. "China is making good progress towards that goal."
With the Paris meeting of the UNFCCC in November this year, China's pledge to peak emissions from all activities by 2030 requires addressing its demand for electricity generation in production, transport and industrial systems.
According to Canadell, cement production accounts for about 5% of global greenhouse emissions, but because China is "building so much" it is a much bigger fraction. China produces more than half of global production of steel and cement. Yet China's cement emissions, as the study found, are 45% lower than previously estimated.
"I don't think this news is making it easier or harder" for China to meet its climate targets, said Canadell. "The most important thing is to measure the speed and trends of energy consumption."
The paper: 'Reduced carbon emission estimates from fossil fuel combustion and cement production in China' is by Zhu Liu et al, and published in Nature.
Eliza Berlage is Editor at The Conversation.
This article was originally published on The Conversation. Read the original article.
segunda-feira, 17 de agosto de 2015
HOW DO DRONES AFFECT WILDLIFE? BUT...THEY CAN SCARE REAL BIRDS IN INCONVENIENT PLACES LIKE AIRPORTS, FARMS...
First there were electronic sheepdogs. Now flapping robotic drones disguised as birds of prey could act as another form of futuristic farming device, thanks to a Dutch inventor and his flying machine.
The two models being developed might confuse birdwatchers from a distance as they are designed to resemble a peregrine falcon and a bald eagle, but are made of a lightweight and rugged glass fibre nylon composite.
The remote-controlled, battery-powered invention, known as the Robird, has been designed as a kind of flying scarecrow to scare real birds away from places like airports, farms and landfills where they cause a nuisance.
Farmers could soon be going very hi-tech, following reports this week of an experiment involving GPS tracking of sheepdogs to discover how they herd their flocks, research which could feasibly lead to robotic replacements.
The man behind the new flying machine is 27-year-old Nico Nijenhuis, who became interested in robotic birds after asking his advisor for ideas when he was trying to come up with an topic for his master’s thesis at the Technical University of Twente in the east of Holland.
His advisor handed him a crude mechanical bird off the shelf and told him to figure out how it works and make it better. This was easier said than done.
“From a scientific point of view, we don’t truly understand flapping wing flight,” Mr Hijenhuis told Wired magazine, adding that fixed wings are simple by comparison.
“But the minute wings start moving, we really have a problem. It’s all about very complex, three-dimensional flow. What a bird actually does is so complex that it’s incredibly difficult to mimic,” he added.
The latest model of his Robird combines a basic up and down flapping motion from a single joint in each wing with a rotating movement and mixes in some on-board sensors and sophisticated stabilisation software.
For the robot bird to do its job properly it has to fool the species around it that it is for real. Two qualities are needed to trigger the other birds “flight instinct”: a silhouette and wing movement, Mr Hijenhuis said. “If it doesn’t look like a predator, they don’t care. And if it doesn’t move like a predator, they don’t care either.”
The Robirds are currently being trialled in the Netherlands. One landfill has recorded a 75 per cent decline in bird visits, while those that do return do so with a swivelling head, said Mr Hijenhuis.
Although bright lights and bangs will scare away birds in the short-term, robotic drones will provide a much longer-term deterrent, he said.
Mr Hijenhuis has set up a company called Clear Flight Solutions to develop the product and is current testing remote-controlled birds, which can only be operated by an experienced aircraft pilot. He is also working on an autopilot system which would make the bird autonomous and hopes to complete this version by the end of the year.
After that he will begin marketing the products to companies in industries such as aviation and waste management.