Japan's meteorological agency said the 7.0 magnitude quake hit off the country's southern coast, near to the island of Okinawa.

The tsunami warning was quickly downgraded to an advisory and there were no immediate reports of casualties.The quake occurred at a depth of 6.2 miles (10 kilometers) at 5:31am local time.

At first the agency predicted a tsunami up to 3 feet (1 metre) near the Okinawan coast but said later it had observed only a small swelling of tide.

Ryota Ueno, a town official in the Nishihara district of Okinawa, said: "I was fast asleep when the quake hit and I jumped out of bed. "It felt like the shaking lasted forever."

Japan is one of the world's most earthquake-prone countries. (Sky News)

A leading scientist has revealed that Europe could be just five years away from the start of a new Ice Age.

While climate change campaigners say global warming is the planet's biggest danger, renowned physicist Vladimir Paar says most of central Europe will soon be covered in ice.

The freeze will be so complete that people will be able to walk from England to Ireland or across the North Sea from Scotland to northern Europe.

Professor Paar, from Croatia's Zagreb University, has spent decades analysing previous ice ages in Europe and what caused them.

"Most of Europe will be under ice, including Germany, Poland, France, Austria, Slovakia and a part of Slovenia," said the professor in an interview with the Index.hr. 

Every form of travel was miserable if not impossible. More than 1,000 flights were canceled, bus service across northern New Jersey was knocked out and roads from Ohio to West Virginia to Maine were closed. State troopers used snowmobiles to reach motorists stranded for hours on an eastern New York highway.

"We're buried," said Graham Foster, highway superintendent in the town of Wappinger, one of the hardest hit areas in upstate New York. "My men have been out since 7 yesterday morning and we're not making much headway because there are so many trees down and wires down."

The US is heading for a debt-driven “financial meltdown” within five to seven years, according to Judd Gregg, the outgoing Republican senator for New Hampshire.

In a robust and at times testy video interview for the Financial Times’s View from DC series, Mr Gregg also complimented China for showing rising alarm about the US’s mounting levels of public debt. (Source : Financial Times )

In 1800, there was just one city with more than a million people - Beijing. Now there are 381 urban areas with at least 1 million inhabitants. Urbanization crossed a threshold last year when, for the first time, more people lived in city settings than rural ones. About 403 million people live in cities that face significant seismic hazard, according to a recent study by seismologist Roger Bilham of the University of Colorado.

Where could the next big Earthquake be?

The next Big One could strike Tokyo, Istanbul, Tehran, Mexico City, New Delhi, Kathmandu or the two metropolises near California's San Andreas Fault, Los Angeles and San Francisco. Or it could devastate Dhaka, Jakarta, Karachi, Manila, Cairo, Osaka, Lima or Bogota. The list goes on and on.

The world's most stunning coral reefs will have dissolved within 100 years, a new study claims.

Scientists say rising levels of acid in the seas and warmer ocean temperatures are wiping out the spectacular reefs enjoyed by millions of divers, tourists and wildlife lovers.

The destruction would also be a disaster for tropical fish and marine life which use coral reefs as nurseries and feeding grounds.

Forecasting a solar flare is a bit like predicting the path of a tornado: It's a lot easier once it makes an appearance.

Yet early warning is crucial. Solar flares can trigger disruptions and errors in GPS signals and other equipment receiving radio waves that bounce off or travel through the ionosphere — the layer of charged particles surrounding Earth's atmosphere that gets kicked up by solar activity.

That's a concern for activities requiring precision navigation, such as landing planes. Solar flares can even affect power grids on Earth.

"You get this faster, twisting motion that then slows down to almost nothing and then the flare. It tells us how big the flare is going to be and that it's coming — maybe a day or two in advance," said Alysha Reinard, a solar physicist with NOAA in Boulder, Colo.

The world’s most powerful investors have been advised to buy farmland, stock up on gold and prepare for a “dirty war” by Marc Faber, the notoriously bearish market pundit, who predicted the 1987 stock market crash.

The bleak warning of social and financial meltdown, delivered today in Tokyo at a gathering of 700 pension and sovereign wealth fund managers.

Dr Faber, who advised his audience to pull out of American stocks one week before the 1987 crash and was among a handful who predicted the more recent financial crisis, vies with the Nouriel Roubini, the economist, as a rival claimant for the nickname Dr Doom.

Speaking today, Dr Faber said that investors, who control billions of dollars of assets, should start considering the effects of more disruptive events than mere market volatility.

“The next war will be a dirty war,” he told fund managers: "What are you going to do when your mobile phone gets shut down or the internet stops working or the city water supplies get poisoned?”

The study is an overview of work into one of the scariest yet also one of the least understood aspects of climate change.

Known in the Atlantic as hurricanes and in eastern Asia as typhoons, tropical storms are driven by the raw fuel of warm seas, which raises the question about what may happen when temperatures rise as a result of greenhouse gases.

Tom Knutson and colleagues from the UN's World Meteorological Organisation (WMO) looked at peer-reviewed investigations that have appeared over the past four years, when the issue began to hit the headlines. Their benchmark for warming is the "A1B" scenario, a middle-of-the-road computer simulation which predicts a global average surface temperature rise of 2.8 degrees Celsius (5.4 degrees Fahrenheit) over the 21st century.

"It is likely that the global frequency of tropical cyclones will either decrease or remain essentially unchanged," says the paper. But storms could have more powerful winds -- an increase of between two and 11 percent -- and dump more water, it warns.

Scientists have been forced to withdraw a study on projected sea level rise due to global warming after finding mistakes that undermined the findings.

The study, published in 2009 in Nature Geoscience, one of the top journals in its field, confirmed the conclusions of the 2007 report from the Intergovernmental Panel on Climate Change (IPCC). It used data over the last 22,000 years to predict that sea level would rise by between 7cm and 82cm by the end of the century.

At the time, Mark Siddall, from the Earth Sciences Department at the University of Bristol, said the study "strengthens the confidence with which one may interpret the IPCC results". The IPCC said that sea level would probably rise by 18cm-59cm by 2100, though stressed this was based on incomplete information about ice sheet melting and that the true rise could be higher.