On Thursday, 2 June 2011, the IAEA provided the following information on the status of nuclear safety in Japan:

Overall, the situation at the Fukushima Daiichi nuclear power plant remains very serious.

The IAEA receives information from various official sources in Japan through the Japanese national competent authority, the Nuclear and Industrial Safety Agency (NISA). This Update Brief is based on information issued by the IAEA Incident and Emergency Centre up to 16:00 UTC on 31 May 2011.

On 13 May TEPCO commenced the preparatory work for the installation of a cover for the reactor building of Unit 1. The reactor building cover will be installed as an emergency measure to prevent the dispersion of radioactive substances until mid- to long term measures, including radiation shielding, are implemented.

TEPCO has reported that information obtained after calibration of the reactor water level gauges of Unit 1 shows that the actual water level in the Unit 1 reactor pressure vessel was lower than was indicated, showing that the fuel was completely uncovered. The results of provisional analysis show that fuel pellets melted and fell to the bottom of reactor pressure vessel at a relatively early stage in the accident.

TEPCO reported that “most part of the fuel is considered to be submerged in the bottom of reactor pressure vessel and some part exposed.” TEPCO also reported that leakage of cooling water from the reactor pressure vessel is likely to have occurred. However, TEPCO considers that the actual damage to the reactor pressure vessel is limited, on the basis of the temperatures now being measured around the reactor pressure vessel.

The results of the analysis are provisional; TEPCO will continue to conduct investigations. Similar analyses will be conducted for Units 2 and 3 when radiation levels allow calibration of the instrumentation.

The daily monitoring of the deposition of caesium and iodine radionuclides for 47 prefectures is continuing. Since 17 May, deposition of I-131 has not been observed. Low levels of Cs-137 deposition were reported in a few prefectures on a few days since 18 May; the reported values range of from 2.2 to 91 Bq/ m2 for Cs-137.

Gamma dose rates values for all 47 prefectures are reported daily by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. On 31 May the gamma dose rate reported for Fukushima prefecture was 1.5 µSv/h. In all other prefectures, reported gamma dose rates were below 0.1 µSv/h; with a general decreasing trend. Meanwhile, the decrease of the gamma dose rate has slowed down, since the short-lived radionuclides have decayed away.

Gamma dose rates reported specifically for the monitoring points in the eastern part of Fukushima prefecture, for distances of more than 30 km from the Fukushima Daiichi plant, showed a general decreasing trend, ranging from 0.1 µSv/h to 17 µSv/h, as reported for 31 May.

On-site measurements at the west gate of the Fukushima Daiichi plant indicate the presence of I-131 and Cs-137 in the air in the close vicinity of the plant (within approximately 1 km). The concentrations in air reported for 29 May were about 3 Bq/m3 for I-131 and about 9 Bq/m3 for Cs-137. The values observed in the previous days show daily fluctuations with an overall decreasing tendency.

NEW YORK – hunger in the Horn of Africa is still expanding and will soon spread to a further six regions in Somalia, said Valerie Amos, head of humanitarian operations the United Nations.

She said that the assistance is urgently needed by 12.4 million people in Kenya, Ethiopia, Somalia and Djibouti, and explained that the situation is constantly deteriorating.

UN declared a state of hunger in the two regions in southern Somalia, where 3.7 million people affected. Residents of Somalia are coming to the north of Kenya, mainly to take refuge from violence in recent months and to find food.

“Today we issue a warning that hunger will extend for another five or six regions, if the humanitarian response does not become significantly more massive,” said Amos.

She pointed out that tens of thousands of Somalis have died and that hundreds of thousands are hungry, which may have consequences for the entire region. Amos said it is urgent to collect 1.4 billion dollars to save lives.

She recalled that the African soil was hit by the biggest drought in 60 years, given the amount of rainfall, number of affected people and countries, and the number of dead cattle.

Tepco sticks to timetable for ‘cold shutdown’, despite revelations plant suffered greater damaged than previously thought

The firm at the centre of Japan’s worst nuclear accident insisted on Tuesday it would bring stricken reactors at the Fukushima Daiichi power plant under control by January 2012, despite evidence that the complex is more seriously damaged than previously thought.

Is nuclear power the answer to the energy crisis? Ian Sample explains how it works – and how we get the awful side-effects of bombs and waste

Nuclear power

The world’s first large-scale nuclear power plant opened at Calder Hall in Cumbria, England, in 1956 and produced electricity for 47 years.

Police evacuate residents as Mississippi river spreads to six times its usual span, threatening the city’s blues district

The city of Memphis, Tennesee has been put on alert for record flooding as the waters of the Mississippi river reached a historic peak.

Police went door-to-door to evacuate people from low-lying neighbourhoods after forecasters said the river could reach its peak of 14.6 metres (48ft) by Monday evening.

Hamaoka nuclear plant, which sits near a major fault line, to be made more resistant to earthquakes and tsunamis

The operator of Japan’s “most dangerous” nuclear plant has said it will comply with a government request to temporarily close the facility and carry out work to improve its ability to withstand earthquakes and tsunamis.

Experts fear it might happen regularly, turning forest into warming source

RIO DE JANEIRO — A widespread drought in the Amazon rain forest last year was worse than the “once-in-a-century” dry spell in 2005 and may have a bigger impact on global warming than the United States does in a year, British and Brazilian scientists said on Thursday.

More frequent severe droughts like those in 2005 and 2010 risk turning the world’s largest rain forest from a sponge that absorbs carbon emissions into a source of the gases, accelerating global warming, the report found.

Trees and other vegetation in the world’s forests soak up heat-trapping carbon dioxide as they grow, helping cool the planet, but release it when they die and rot.

“If events like this happen more often, the Amazon rain forest would reach a point where it shifts from being a valuable carbon sink slowing climate change to a major source of greenhouse gases that could speed it up,” said lead author Simon Lewis, an ecologist at the University of Leeds.

The study, published in the journal Science, found that last year’s drought caused rainfall shortages over a 1.16 million square-mile expanse of the forest, compared with 734,000 square miles in the 2005 drought.

It was also more intense, causing higher tree mortality and having three major epicenters, whereas the 2005 drought was mainly focused in the southwestern Amazon.

As a result, the study predicted the Amazon forest would not absorb its usual 1.5 billion metric tons of carbon dioxide from the atmosphere in both 2010 and 2011. In addition, the dead and dying trees would release 5 billion metric tons of the gas in the coming years, making a total impact of about 8 billion metric tons, according to the study.

In comparison, the United States emitted 5.4 billion metric tons of carbon dioxide from fossil fuel use in 2009.

The combined emissions caused by the two droughts were probably enough to have canceled out the carbon absorbed by the forest over the past 10 years, the study found.

The widespread drought last year dried up major rivers in the Amazon and isolated thousands of people who depend on boat transportation, shocking climate scientists who had billed the 2005 drought as a once-in-a-century event.

The two intense dry spells fit predictions by some climate models that the forest will face greater weather extremes this century, with more intense droughts making it more vulnerable to fires, which in turn could damage its ability to recover.

Under the more extreme scenarios, large parts of the forest could turn into a savannah-like ecosystem by the middle of the century with much lower levels of animal and plant biodiversity. Although human-caused deforestation in Brazil has fallen sharply in recent years, scientists say the forest is still vulnerable.

A crucial question is whether the droughts are being driven by higher levels of greenhouse gases or are an anomaly, Lewis said. If they are driven by global warming, a vicious cycle of warmer temperatures and droughts could conceivably lead to a large-scale transformation of the forest over a period of decades.

“You could quite rapidly move to a much drier Amazon with less forest there,” Lewis told Reuters.

The research was a collaboration among scientists at the University of Leeds and the University of Sheffield in Britain and Brazil’s Amazon Environmental Research Institute.

Experts test waters to see if salinity levels have been altered

The loss of a massive “tongue” of glacial ice on the Antarctic coast — a natural protective barrier nearly four times the size of New York City — could affect ocean circulation patterns and be a harbinger of changes to come from global warming, scientists on a mission to the frozen continent say.

Last February, the tongue of Antarctica’s Mertz Glacier was rammed by a huge iceberg, causing the tongue section to break away and itself become an iceberg.

The tongue, sticking out into the Southern Ocean, had acted like a dam, preventing sea ice from moving into a permanently open section of water to the west.

But now, with the tongue gone due the collision, scientists fear it could trigger changes to the behavior of a major part of global ocean circulation patterns that shift heat around the globe via myriad currents at the surface and along the bottom.

The area around the glacier tongue, since halved in length by the collision, and to the west are one of the few places around Antarctica where dense, salty water is formed and sinks to the depths of the ocean, said mission leader Steve Rintoul.

This dense “bottom water” is a key driver of the global overturning circulation that includes the current that brings warm Atlantic waters to western Europe.

But he said there was a risk the area could now be less effective in producing the bottom water that feeds the deep ocean currents, which influence global climate patterns.

“This is one of the few places around Antarctica where the sea surface is made dense enough to sink to the deep ocean,” Rintoul said from the icebreaker Aurora Australis.

“If the area is less effective in forming less dense water, then that salinity now should be lower than it was in the past.”

Rintoul is leading an international team of nearly 40 scientists on a voyage studying the impacts of the loss of the glacier tongue as well as changes to ocean temperatures, salinity and acidity.

Oceans act as a brake on climate change by soaking up large amounts of heat and carbon dioxide, the main greenhouse gas, from the atmosphere. But the more CO2 the oceans take up, the more acidic they become, making it harder for animals such as sea snails to make their shells.

Rintoul, an oceanographer with the Antarctic Climate and Ecosystems Cooperative Research Centre in Hobart, Australia, said the area around the glacier remains free of ice all winter. Such areas are called polynas.

“It remains free of ice because the winds blowing off the continent are so strong it blows the ice away as rapidly as it forms,” he said.

“So in that sense, it is kind of a sea-ice factory and the more sea ice that is formed, the saltier the water beneath the sea ice becomes,” leading to the creation of dense, salty water, he added.

“We think the presence of the glacier tongue was part of what made this a very active polyna,” he said, adding he expected it would be less effective now there was no ice tongue.

A Japanese-led study published earlier this month estimated that the loss of the ice tongue led to nearly 25 percent less dense water formation.

Rintoul’s team have been taking samples in the area measuring salinity, temperature, oxygen and carbon and the results will be studied over the coming weeks.

Studying the damage to the Mertz Glacier would help efforts to project future changes in climate, he said.

“It allows us to explore how sensitive the formation of that dense water is to things like the shape of the continent and change in the effectiveness in these polynas,” he said.

As the oceans heated up, warmer water would likely increase the rate these floating tongues of ice melted, he said, exposing glaciers on the continent to warmer seas. This risked faster rates of melting and discharge of ice into the ocean, raising sea levels.

A new discovery described by a team of international scientists, including Carnegie Museum of Natural History paleontologist Christopher Beard, suggests that anthropoids — the primate group that includes humans, apes, and monkeys — "colonized" Africa, rather than originally evolving in Africa as has been widely accepted.

According to the paper published in the journal Nature, what is exceptional about these new fossils — discovered at the Dur At-Talah escarpment in central Libya – is the diversity of species present: the site includes three distinct families of anthropoid primates that lived in North Africa at approximately the same time.

This suggests that anthropoids underwent diversification, through evolution, previous to the time of these newly discovered fossils, which date to 39 million years ago. The sudden appearance in the African fossil record of diverse anthropoid families can be answered in one of two ways, the paper’s authors say. It could be the result of a striking gap in the African fossil record prior to this period. This is unlikely to be the case as Northern Africa’s Eocene sites have been well sampled over the past century, and no diversity of anthropoid fossils has yet been discovered that predates the new Libyan specimens. Therefore, the paleontologists suggest, it is more likely that several anthropoid species "colonized" Africa from another continent 39 million years ago — the middle of the Eocene epoch. Since diversification would have occurred over extreme lengths of time, and likely leave fossil evidence, the new fossils combined with previous sampling in North Africa leads the paper’s authors to surmise an Asian origin for anthropoids, as proposed by Beard and his colleagues in earlier work, rather than a gap in the fossil record.

"If our ideas are correct, this early colonization of Africa by anthropoids was a truly pivotal event — one of the key points in our evolutionary history," says Christopher Beard, Curator of Vertebrate Paleontology at Carnegie Museum of Natural History and an author on the paper. "At the time, Africa was an island continent; when these anthropoids appeared, there was nothing on that island that could compete with them. It led to a period of flourishing evolutionary divergence amongst anthropoids, and one of those lineages resulted in humans. If our early anthropoid ancestors had not succeeded in migrating from Asia to Africa, we simply wouldn’t exist."

Beard has done extensive research on anthropoid origins, including his work on the primate Eosimias. His book, The Hunt for the Dawn Monkey, has been critical in positing Asia, not Africa, as the place of origin for anthropoids. The search for information regarding the origins of man’s earliest anthropoid ancestors remains one of the most hotly pursued subjects in paleontology.

"This extraordinary new fossil site in Libya shows us that in the middle Eocene, 39 million years ago, there was a surprising diversity of anthropoids living in Africa, whereas few if any anthropoids are known from Africa before this time," says Beard. "This sudden appearance of such diversity suggests that these anthropoids probably colonized Africa from somewhere else. Without earlier fossil evidence in Africa, we’re currently looking to Asia as the place where these animals first evolved.

New research has settled decades of scientific debate about a puzzling aspect of space weather. Researchers from the University of California (UCLA) and British Antarctic Survey (BAS) have found the final link between electrons trapped in space and the glow of light from the upper atmosphere known as the diffuse aurora.

The research, published in the latest issue of the journal Nature, promises to further understanding of space weather, with benefits for the satellite, power grid and aviation industries, and how space storms affect the Earth’s atmosphere from the top down.

Scientists have long understood that the ‘diffuse aurora’ is caused by electrons striking the upper atmosphere. However, the electrons are normally trapped much higher up in the Earth’s magnetic field through a long chain of events starting with the Sun. The problem is to understand how these electrons reach the atmosphere.

Since the 1970s scientists have debated whether very low frequency (VLF) radio waves could scatter the trapped electrons into the atmosphere. Two types of VLF waves were identified in space as the possible cause of the ‘diffuse aurora’, but despite years of argument and research no conclusive result had been possible. The new research shows, without doubt, that VLF waves known as ‘chorus’ are responsible; so-called since the signals detected by ground-based recording equipment sound like the bird’s dawn chorus when played back through a loud speaker.

Through detailed analysis of satellite data the authors were able to calculate the effects on the trapped electrons and identify which radio waves were causing the scattering.

Lead author Professor Richard Thorne from UCLA says: "The breakthrough came when we realised that the electrons being lost from space to the Earth’s atmosphere were leaving a signature, effectively telling a story about how they were being scattered. We could then analyse our satellite data on the two types of VLF waves and by running calculations on them — including the rate at which the electrons were being lost to the Earth’s atmosphere — we could clearly see that chorus waves were the cause of the scattering."

Professor Richard Horne from British Antarctic Survey says: "Our finding is an important one because it will help scientists to understand how the diffuse aurora leads to changes in the chemistry of the Earth’s upper atmosphere, including effects on ozone at high altitude, which may affect temperature right through the atmosphere.

"We are also including the VLF waves into computer models to help predict ‘space weather’ which not only affects satellites and power grids, but also the accuracy of GPS navigation and high frequency radio communications with aircraft on polar routes."

The ‘diffuse aurora’, is not the same as the ‘discrete aurora’ known as the northern and southern lights. ‘Discrete aurora’ look like fiery moving curtains of colourful light and can be seen by the naked eye, whereas the diffuse aurora is much fainter but more extensive. The ‘diffuse aurora’, which typically accounts for three-quarters of the energy input into the upper atmosphere at night, varies according to the season and the 11 year solar cycle.

Notes:

*Chorus waves: Very low frequency radio waves coming from space and first detected on the ground. So-called because when played back through a loud speaker they sound like the bird’s dawn chorus.

*Diffuse aurora: caused when electrons that are trapped in the Earth’s magnetic field are funnelled towards the polar atmosphere. Light is emitted when the electrons collide with neutral atoms in the upper atmosphere. The diffuse aurora is not generally visible to the naked eye but is well captured in satellite images.

*Discrete aurora: known as the Aurora Borealis at the North Pole (above the Arctic circle) and Aurora Australis at the South Pole (above Antarctica). They look like fiery, moving curtains of colourful light and can be seen by the naked eye whereas the diffuse aurora is much fainter but is more extensive and can cover the whole sky.