Many climate models also assume that the airborne fraction will increase. Because understanding of the airborne fraction of carbon dioxide is important for predicting future climate change, it is essential to have accurate knowledge of whether that fraction is changing or will change as emissions increase.

To assess whether the airborne fraction is indeed increasing, Wolfgang Knorr of the Department of Earth Sciences at the University of Bristol reanalyzed available atmospheric carbon dioxide and emissions data since 1850 and considers the uncertainties in the data. In contradiction to some recent studies, he finds that the airborne fraction of carbon dioxide has not increased either during the past 150 years or during the most recent five decades.

Recently hacked emails from the University of East Anglia's Climate Research Unit expose a plot to eliminate the Medieval Warm Period, a 400-year era that began around AD 1000, the Financial Post's Lawrence Solomon reports. The warming period is said to have improved agriculture and increased life spans, but scientists at the center of the Climategate email scandal believed the era undermined their goal of spreading concern about global warming as it pertains to today's climate.

Solomon noted the warming period presented a dilemma long before the Climategate email scandal. A 1995 email predating the recent Climate Research Unit scandal was sent to geophysicist David Deming. A major climate-change researcher told Deming, "We have to get rid of the Medieval Warm Period." Some scientists later expressed concern about erasing the period.

Solomon revealed that Connolley, one man in the nine-member team who is a UK scientist, a software engineer and Green Party activist, took control of Wikipedia's entries to see that any trace of the true climate history would be erased. Beginning in February 2003, Connolley rewrote Wikipedia entries on global warming, the greenhouse effect, the instrumental temperature record, the urban heat island, on climate models and on global cooling, according to the report. In February, he began editing the Little Ice Age. By August, he began to rewrite history without the Medieval Warm Period. In October, he turned to the hockey-stick chart.

The Obama Administration, caught out by the Christmas Day attempt to blow up a Northwest Airlines aircraft, is reviewing every possible response and has not ruled out military strikes if targets linked directly to the failed attack by Umar Farouk Abdulmutallab can be identified. In line with the terms of a secret military assistance pact agreed last year, Abu Bakr al-Qirbi, the Yemeni Foreign Minister, insisted yesterday that any attacks on al-Qaeda targets in Yemen would be by Yemeni government forces.

He acknowledged, however, that Yemen would need technical and intelligence information to carry out such attacks and senior Pentagon sources told CNN that fresh target lists were being drawn up in case President Obama called for them. The US has never publicly acknowledged the rapid build-up of its military presence in and near Yemen since last year but sources say that attacks already mounted by Yemeni government forces on al-Qaeda training camps would have been impossible without American hardware and knowhow. Future strikes could involve the use of US drones, fighter jets and ship-launched cruise missiles.

"We are going to work with allies and partners to seek out terrorist activity [and] al-Qaeda," Bryan Whitman, a Pentagon spokesman, said. The US military has formidable firepower on permanent standby in the form of carrier battle groups stationed in Bahrain, and unimpeded access to Yemen from bases in Djibouti and the Indian Ocean island of Diego Garcia.

I'm dying, he told himself, "because when you cough blood, it's something really bad." It was really bad, and not just for him. Doctors say Juarez's incessant hack was a sign of what they have both dreaded and expected for years - this country's first case of a contagious, aggressive, especially drug-resistant form of tuberculosis. The Associated Press learned of his case, which until now has not been made public, as part of a six-month look at the soaring global challenge of drug resistance.

Juarez's strain - so-called extremely drug-resistant (XXDR) TB - has never before been seen in the US, according to Dr David Ashkin, one of the nation's leading experts on tuberculosis. XXDR tuberculosis is so rare that only a handful of other people in the world are thought to have had it.

"He is really the future," Ashkin said. "This is the new class that people are not really talking too much about. These are the ones we really fear because I'm not sure how we treat them."

Debates over the state benefit programs have erupted in South Carolina, Nevada, Kansas, Vermont and Indiana. And the budget gaps are expected to spread and become more acute in the coming year, compelling legislators in many states to reconsider their operations. Currently, 25 states have run out of unemployment money and have borrowed $24 billion from the federal government to cover the gaps.

By 2011, according to Department of Labor estimates, 40 state funds will have been emptied by the jobless tsunami. "There's immense pressure, and it's got to be faced," said Indiana state Representative David Niezgodski (Democrat), a sponsor of a bill that addressed the gaps in Indiana's unemployment program. "Our system was absolutely broke."

And last week, a state task force in Kentucky recommended cutting benefits about 9 percent and imposing a week's delay in their payment. The average benefit check there is about $309 a week. The task force also proposed raising taxes. State unemployment-compensation funds are separated from general budgets, so when there is a shortfall, only two primary solutions are typically considered - either cut the benefit or raise the payroll tax.

Since the end of last year, China has sent four flotillas to the Middle East in order to take part in anti-piracy operations together with US, European, Indian and Russian warships. The latest mission, which departed from China in October, involved two missile frigates. Mr Yin said a permanent base in the region would help supply Chinese ships. "We are not saying we need our navy everywhere in order to fulfil our international commitments," he said, cautiously. "We are saying to fulfil our international commitments, we need to strengthen our supply capacity."

His words, which came just a few days after China rescued 25 sailors from Somali pirates, were posted in an interview on the Defence ministry website. China is reported to have paid a US$4 million (2.5 million pounds) ransom to free the De Xin Hai, a coal carrier. Mr Yin, who is a senior researcher at the navy's Equipment Research centre, pointed out that the first Chinese ships in the Gulf of Aden spent 124 days at sea without docking, a logistical challenge. However, Chinese ships have since been permitted to dock at a French base.

"If China establishes a similar long-term supply base, I believe that the nations in the region and the other countries involved with the (anti-pirate) escorts would understand," he said. "I think a permanent, stable base would be good for our operations." Yin added he was aware that Chinese naval ships in the waters near the Gulf have aroused suspicions, but believed other nations understood Beijing's intention was to counter pirates. As the world's largest importer of oil, China is believed to want to establish bases throughout the Indian Ocean and South China Sea to protect its tankers.

Dr al-Qirbi said: "Of course there are a number of al-Qaeda operatives in Yemen and some of their leaders. We realise this danger. They may actually plan attacks like the one we have just had in Detroit. There are maybe hundreds of them - 200, 300." Dr al-Qirbi said it was the "responsibility" of countries with strong intelligence capabilities to warn states such as Yemen about the movements of terror suspects.

The United States, Britain and the European Union could do a lot to improve Yemen's response to militants on its own soil, he added. "We have to work in a very joint fashion in partnership to combat terrorism," he said. "If we do, the problem will be brought under control."

"There is support, but I must say it is inadequate. We need more training, we have to expand our counter-terrorism units and provide them with equipment and transportation like helicopters." Mr Abdulmutallab is said to have told US agents that there were more people "just like him" ready to carry out attacks.

Wildfires are common during the summer, and experts had warned that this year's fires could be particularly bad after one of the warmest winters on record. Some parts of the country have also been suffering from years of drought, making them more susceptible to fire damage.

Two major blazes broke out on Tuesday afternoon local time in a wheat- and sheep-farming district, forcing the evacuation of Toodyay, a township, and threatening a second town, Badgingarra, further north. The state Fire and Emergency Services Authority (Fesa) said at least 37 houses had been destroyed.

Australia is still recovering from "Black Saturday" in February, when 173 people died and more than 2,000 homes were lost in the state of Victoria in the country's worst natural disaster of modern times. In the aftermath of "Black Saturday", officials issued a new level of "catastrophic" fire warning. Parts of Western Australia were given this "catastrophic" rating earlier on Wednesday.

Umar Farouk Abdulmutallab flew from Lagos to Amsterdam before changing planes for a flight to Detroit on which he allegedly tried to detonate a bomb. The Netherlands is to introduce body scanners on US flights within weeks.

Dutch Interior Minister Guusje Ter Horst said Mr Abdulmutallab did not raise any concerns as he passed through Amsterdam's Schiphol Airport to board the flight. She said the airport would be able to use body scanners on all flights to the US from the airport in three weeks, adding that they would be a permanent fixture.

US President Barack Obama has said security failures were unacceptable. He has said a systemic failure allowed Mr Abdulmutallab, a Nigerian, to fly to the US on 25 December despite family members warning officials in November that he had extremist views.

He was overpowered by some of the 278 passengers and 11 crew. Reports say he burnt his leg. Police in London are searching a house where the man is thought to have lived. The suspect is believed to have studied at a university in the city. President Barack Obama, on holiday in Hawaii, has ordered increased security for air travel. Nigeria has ordered its security agencies to investigate the incident and verify the suspect's identity and motives. It has also said they will "co-operate fully" with the US investigations.

Officials have described the device the suspect allegedly tried to ignite as a mixture of powder and liquid which failed to go off properly. One terrorism expert said it looked as though a new way of concealing explosives on the body was involved. The suspect's name was in a database indicating "a significant terrorist connection" although it did not appear on a "no-fly" list, said Mr King. Fellow passenger Melinda Dennis said the man had been severely burned on one leg, and a fire extinguisher and water were used to put out the fire.

The suspect later told the US authorities he had had explosive powder taped to his leg and used a syringe of chemicals to mix with the powder that was to cause an explosion, the ABC television network reports. Dr Sally Leivesley, an adviser on terrorism and public protection, told the BBC: "This has looked as though it's a first attempt of a new way to use the body to conceal explosives. They may be concealing the explosives on the human body - but on the inside upper leg, and we only know this by seeing a very badly burnt leg on the suspected perpetrator."

"The storm is spanning two thirds of the country," said Chris Vaccaro, a spokesman for the National Weather Service. "Its effects run the gamut from severe thunderstorms in the Gulf Coast to ice in New England to really what is a raging blizzard in the lower plains," he added.

Parts of at least 10 central states, stretching from North Dakota to Oklahoma in the south, are now under blizzard warnings. The storm knocked out power to more than 10,000 homes and businesses in the state, officials said. The capital, Oklahoma City was hit by 14in (35cm) of snow by Thursday night, eclipsing the record of 2.5in set in 1914.

Winds of up to 50mph (80kph) buffeted central Kansas, while gusts of up to 65mph in Texas left 5ft (1.5m) snow drifts in some areas. The storm began in the south-west on Tuesday before spreading to the east and north. The Midwest storm comes as the East Coast recovers from record snowfall last weekend, which brought much of the capital, Washington DC, to a standstill.

"We do not wish for war. We wish for calm and peace for our people," Abu Ubaida, spokesman for Hamas's armed wing, the Izz el-Deen al-Qassam Brigades, said late on Wednesday from the cover of an orchard in the Gaza Strip. "But if any battle is imposed on us, we are ready with all our manpower and equipment to confront any Zionist war, any crime and any attack regardless of scale."

Israel has said the brigades, which some observers estimate have 25,000 fighters, have been seeking Syrian and Iranian help to upgrade their rocket capabilities and put the Israeli heartland and the commercial capital of Tel Aviv within range.

The Senate's rare Christmas Eve vote, 60-39, follows House passage last week and raises the debt ceiling by $290 billion. The vote split mainly down party lines, with Democrats voting to raise the limit and Republicans voting against doing so. There was one defection on each side, by senators whose seats will be on the ballot next year: GOP Senator George Voinovich of Ohio and Democratic Senator Evan Bayh of Indiana.

"I would not support raising the debt ceiling because Congress has not adopted a credible process to restrain spending and eliminate red ink," Bayh said in a statement after the vote. The bill permits the Treasury Department to issue enough bonds to fund the government's operations and programs until mid-February. The Senate will vote again on the issue January 20.

Obama must sign the measure into law to prevent a market-rattling, first-ever default on US obligations. The government piled up a record $1.4 trillion deficit in 2009 to counter a meltdown in financial markets and help bring the nation out of its worst recession in seven decades.

The Vatican said the 82-year-old Benedict was unhurt in the fall and that his busy Christmas schedule would remain unchanged. French Cardinal Roger Etchegaray, an 87-year-old Vatican diplomat, fractured his hip in the commotion and will be operated on at Rome's Gemelli hospital, Vatican spokesman the Reverend Federico Lombardi said.

Lombardi identified the woman who toppled Benedict as Susanna Maiolo, 25, a Swiss-Italian national with psychiatric problems. He said Maiolo, who was not armed, was taken to a clinic for necessary treatment.

She was the same woman involved in a similar incident at last year's Midnight Mass, Vatican officials said. In that case, Maiolo jumped the barricade but never managed to reach the pope and was quietly tackled by security. In both cases she wore a red sweatshirt.

The most expensive law is the Working Time Directive, passed in 1998, costing £3.5 billion annually. The law has been widely criticised for imposing expensive rules on working hours, rest periods, pay and holiday entitlements, and a Government-funded report published last month also partly blamed the regulation for an increase in hospital deaths by breaking the continuity in NHS patients' care and cutting the time available for training some operating theatre staff.

Other expensive legislation includes the noise at work regulations, seen as excessively intrusive, particularly for restricting the work of noisy orchestras. Its cost is forecast to hit £586m. Open Europe's Mats Persson was quoted in the Sunday Times saying, "Far too many [EU laws] are OVERLY PRESCRIPTIVE AND UNNECESSARILY BURDENSOME for business, the public sector and individuals."

"SEVENTY-TWO PER CENT OF THE COST OF REGULATION IN THIS COUNTRY STEMS FROM EU LAWS. An incoming government must take a radical new approach to EU over-regulation and must be much tougher and smarter when negotiating in Europe."