A report just issued by the Energy Department and the North American Electric Reliability Corporation, known as Nerc, an industry group that polices the power grid, lists three categories of threats to the grid: coordinated cyber- and physical attacks, pandemic disease and electromagnetic damage.
Grid experts have long worried that the high-altitude detonation of a nuclear weapon would send a damaging pulse of energy to earth. And changes in solar activity have occasionally distorted the earth's magnetic field and generated currents in the rock that have caused blackouts.
What the threats have in common, said Jerry Cauley, the president and chief executive of Nerc, is the "potential to simultaneously impact many assets at once.'' The grid comprises 200,000 miles of transmission lines and millions of digital controls, he pointed out. The study is an attempt to map out preparations for events that are rare or have so far never happened, what the Energy Department calls "high-impact, low-frequency events."
Earth Changes
At the end of the last ice age, atmospheric carbon dioxide levels shot up by nearly 50 per cent. But where did the CO2 come from? This long-standing climatic mystery has now been solved.
Climate scientists have suspected - but never been able to prove - that the CO2 was the result of a huge belch of gas from the oceans. They predicted that the ice age had slowed ocean circulation, trapping CO2 deep within it, and that warmer temperatures reversed this process.
Signs of stagnant CO2-rich water have now been discovered 3700 metres beneath the Southern Ocean's seabed, between Antarctica and South Africa.
Stewart Fallon of the Australian National University in Canberra and his colleagues collected samples from drill cores of the marine crust of tiny marine fossils called foraminifera. Different species of these lived at the surface and the bottom of the ocean. The chemical composition of their shells is dependent on the water they form in and how much CO2 it contains.
Climate scientists have suspected - but never been able to prove - that the CO2 was the result of a huge belch of gas from the oceans. They predicted that the ice age had slowed ocean circulation, trapping CO2 deep within it, and that warmer temperatures reversed this process.
Signs of stagnant CO2-rich water have now been discovered 3700 metres beneath the Southern Ocean's seabed, between Antarctica and South Africa.
Stewart Fallon of the Australian National University in Canberra and his colleagues collected samples from drill cores of the marine crust of tiny marine fossils called foraminifera. Different species of these lived at the surface and the bottom of the ocean. The chemical composition of their shells is dependent on the water they form in and how much CO2 it contains.
© NASA /Gary A Glatzmaier
The geodynamo is a complex mix of fluid and magnetism
The geodynamo is a complex mix of fluid and magnetism
Molten iron flowing in the outer core generates the Earth's geodynamo, leading to a planetary-scale magnetic field. Beyond this, though, geophysicists know very little for certain about the field, such as its strength in the core or why its orientation fluctuates regularly. Researchers do suspect, however, that field variations are strongly linked with changing conditions within the molten core.
As we cannot access the Earth's core directly, researchers look to clues at the Earth's surface. One intriguing suggestion is that changing conditions at the core could have an impact on angular momentum throughout the whole Earth system. The implication is that variation to the flow patterns in the core could have an impact on the Earth's rotation, which could lead to slight variations in the length of a day.
© (AP Photo/Shakil Adil)
A child walks through flood waters caused by torrential rains outside his home in Karachi, Pakistan, Sunday, June 6, 2010. An approaching tropical storm triggered torrential rains in Pakistan's largest city and surrounding areas on Sunday, collapsing mud houses and submerging roads.
A child walks through flood waters caused by torrential rains outside his home in Karachi, Pakistan, Sunday, June 6, 2010. An approaching tropical storm triggered torrential rains in Pakistan's largest city and surrounding areas on Sunday, collapsing mud houses and submerging roads.
Authorities feared worse flooding was to come in and around Karachi and tried to evacuate people from their homes elsewhere along the country's southern coastline. Some villagers refused to move, but several thousand people shifted to higher ground, said Hamal Kalmati, a government minister in Baluchistan province.
He said many mud houses in Gawadar and Pasni districts had already collapsed.
The storm made landfall late Sunday to the east of Karachi, bringing winds as high as 50 miles (80 kilometers) per hour. The meteorological department said ocean storm surges of between 2 and 4 meters were likely in Karachi and other coastal towns.
© AP Photo
A brown pelican is seen on the beach at East Grand Terre Island along the Louisiana coast
A brown pelican is seen on the beach at East Grand Terre Island along the Louisiana coast
It could be an image from a grisly sci-fi movie. But it is not. This bird is a shocking illustration of the catastrophic impact of the Gulf of Mexico oil spill on local wildlife.
The pelican - the official bird of Louisiana - was one of a number that were saved off the coast of the state.
They were barely able to walk or get out of the sea near East Grand Terre island, where officials found around 35 of the birds.
They were treated with detergents to wash off the oil. Many more animals have not been so lucky. More than 400 dead birds have so far been recovered.
Images such as this will only fuel anger towards BP as the spill enters its 46th day and the company struggles to stem the flow of oil from the ruptured Deepwater Horizon well.
Previously, photographs of wildlife coated in an oily sheen were as bad as it got. But now the animals are drowning in the muck, as thick and sticky as treacle, and much, much harder to clean up.
© AP Photo/Paul Sancya
Bethany Millhime looks for personal belongings in the aftermath of tornado damage in Millbury, Ohio Sunday, June 6, 2010.
Bethany Millhime looks for personal belongings in the aftermath of tornado damage in Millbury, Ohio Sunday, June 6, 2010.
Rescue officials in northwest Ohio were still searching through homes Sunday and couldn't say whether anyone else was missing, Lake Township Fire Chief Todd Walters said. Police Chief Mark Hummer flew over the damaged area and said at least 50 homes were destroyed and another 50 severely damaged, as well as six commercial buildings. He estimated a 7-mile path of destruction about 100 yards wide. The storm that hit around 11 p.m. Saturday fell over an area of farm fields and light industry, narrowly missing the heavily populated suburbs on the southern edge of Toledo.
"It's a war zone," Hummer said. "It's pretty disheartening."
Hummer said that among those killed were a person outside the police department and a motorist. He said a young child and two other victims were from nearby Millbury, a bedroom community of roughly 1,200 about 10 miles southeast of Toledo. The National Weather Service had confirmed Sunday afternoon that a Toledo-area tornado was part of the storm, said Meteorologist Marty Mullen of the service's Cleveland office.
Click here to see tornado damage photos.
© AP Photo/Gerald Herbert
Plaquemines Parish coastal zone director P.J. Hahn lifts an oil-covered pelican which was stuck in oil at Queen Bess Island in Barataria Bay, just off the Gulf of Mexico in Plaquemines Parish, La., Saturday, June 5, 2010.
Plaquemines Parish coastal zone director P.J. Hahn lifts an oil-covered pelican which was stuck in oil at Queen Bess Island in Barataria Bay, just off the Gulf of Mexico in Plaquemines Parish, La., Saturday, June 5, 2010.
On Barataria Bay, Louisiana - The wildlife apocalypse along the Gulf Coast that everyone has feared for weeks is fast becoming a terrible reality.
Pelicans struggle to free themselves from oil, thick as tar, that gathers in hip-deep pools, while others stretch out useless wings, feathers dripping with crude. Dead birds and dolphins wash ashore, coated in the sludge. Seashells that once glinted pearly white under the hot June sun are stained crimson.
Scenes like this played out along miles of shoreline Saturday, nearly seven weeks after a BP rig exploded and the wellhead a mile below the surface began belching millions of gallon of oil.
The worst fears of one conservationist may be coming true.
Admiral Thad Allen said Friday that the cap placed over the leaking well was only collecting oil at a rate of 42,000 gallons a day. Recent estimates put the leak's flow at 500,000 to a million gallons a day.
That figure may have increased by 20 percent after the pipe at the top of the blowout preventer was cut off during BP's latest attempt to staunch the flow.
© Reuters/China Daily
Flood in China
Flood in China
The downpour, which hit Guangxi Zhuang region on Monday, has affected over 2 million people, causing excessive damage.
At least 15 freshwater reservoirs have been damaged.
South China is annually stormed by torrential rains, often leading to hundreds of deaths.
Cyclone Phet killed 12 people in Oman before it barrelled on towards Pakistan, Oman's civil defence force said.
The victims included a member of the civil defence force and five other people who were swept away by flood waters caused by rainfall from the cyclone, said a statement carried by the official ONA news agency.
Authorities said Phet had weakened in intensity yesterday before heading at wind speeds of up to 120km/h towards Pakistan, where about 60,000 people have been evacuated from the south coast to safer areas.
The Omani authorities had taken several precautionary measures prior to Phet's arrival, evacuating hotels along the east coast and airlifting the residents of Masirah island to safer areas.
The victims included a member of the civil defence force and five other people who were swept away by flood waters caused by rainfall from the cyclone, said a statement carried by the official ONA news agency.
Authorities said Phet had weakened in intensity yesterday before heading at wind speeds of up to 120km/h towards Pakistan, where about 60,000 people have been evacuated from the south coast to safer areas.
The Omani authorities had taken several precautionary measures prior to Phet's arrival, evacuating hotels along the east coast and airlifting the residents of Masirah island to safer areas.
