Radio communications, satellites and power grids could face potential interruptions or damage, however.

Solar flares send radiation to Earth within minutes. Some are also accompanied by coronal mass ejections (CME), clouds of charged particles that arrive in a day or two. This flare unleashed a strong CME that's aimed squarely at Earth.

"It's got all the right stuff," Kunches said.

However, one crucial component to the storm is unknown: its magnetic orientation. If it lines up a certain way with Earth's magnetic field, then the storm essentially pours into our upper atmosphere. If the alignment is otherwise, the storm can pass by the planet with fewer consequences.

Kunches and his team are advising satellite operators and power grid managers to keep an eye on their systems. In the past, CMEs have knocked out satellites and tripped terrestrial power grids. Engineers have learned to limit switching at electricity transfer stations, and satellite operators sometimes reduce operations or make back-up plans in case a craft is damaged.

Another aspect of a CME involves protons that get pushed along by the shock wave. Sometimes these protons break through Earth's protective magnetic field and flood the outer reaches of the atmosphere-where the space station orbits-with radiation. The science of it all is a gray area, Kunches said. But the best guess now is that there will only be a slight increase in proton activity. That's good news for the astronauts.

"When the shock goes by, we don't expect significant radiation issues," he said.

The astronauts were ordered to a protective area of the space station as a precaution last night.

Now that sunspot number 930 has flared so significantly-after several days of being quiet-the forecast calls for a "reasonble chance" of more major flares in coming days, Kunches said.

When magnetic fields in the Sun coalesce in dark regions called sunspots they can explode sending a blast of radiation. Such solar flares reach Earth within minutes.

This is followed by a cloud of plasma or coronal mass ejection (CME) that takes a day or so to reach Earth.

The flare and CME alter the ionosphere, the outermost part of Earth's atmosphere, and cause problems with communication systems.

Unpredictable

Although solar explosions are random, they are more likely to happen when the Sun is most active, during what is called a solar maximum that happens every 11 years. But there is currently a solar minimum.

Cole says solar flares are hard to predict because there are no models of how they work.

While Coles' agency suspected something might happen when they saw a sunspot pointing directly at the Earth and a build up in magnetic fields, they couldn't tell exactly if or when an explosion would occur.

"It's like someone snapping their fingers, you don't know when they're going to do it," he says.

GPS and short-wave communications blocked

Cole says the solar flare that reached the Earth mid-week, had possibly the strongest emission at 1.4 gigahertz ever seen, matching almost exactly the wavelength GPS satellites use.

He says communication with GPS navigation satellites in the lower ionosphere was blacked out for up to two hours.

Short-wave radio communications, used by defence forces, aviation and emergency services, were also affected, says Cole. Such communications pass through or bounce off the ionosphere.

But Cole stresses air traffic control does not rely on short-wave communication.

Fire fighters affected?

Another CME reached Earth today and Cole predicts its effects on short-wave communications will last throughout the weekend.

It might also affect short-wave communication of some personnel currently fighting Australia's severe bushfires.

He says his agency will let such emergency services know which frequencies will be unaffected by the CME so they can use these instead.

Cole says electricity grids close to the poles could also be disrupted today by the CME.

Cole says the same sunspot produced caused less serious explosions earlier this month and may cause another in around two weeks time.

Spacewalkers take cover

While humans on Earth are protected from the effects of solar explosions, those in space are vulnerable, says Cole.

For instance this week astronauts on the shuttle Discovery and the International Space Station have been sleeping in protected areas and may need to cut planned spacewalks short if radiation levels get too high.

"Do you think the preparedness level kept going up? No. The preparedness level at home, work and school went down, down and down," Ninness said.

Most of us only think about earthquakes when we feel a tremor. Near Eldorado in January there was a quake measuring 3.4 on the Richter scale that caught people's attention.

"Those little ones should be reminders to us the big one is out there," Ninness said.

One of the first things people need to realize when preparing for "the big one" is that they will probably be stuck on their property for several days and their house may not be safe enough to stay in. Roads may be too damaged to drive on, bridges may be out, there may be no water or electricity and police and firefighters will likely have too much to do to help out.

People will likely be living in tents in their yards. How do people decide on the emergency items to keep in a preparedness kit?

"Move into your front yard for a week and everything you want with you, that's what you need in the kit," Ninness said.

A few necessary items include a flashlight, battery powered radio and plenty of batteries. Ninness said people should keep at least five days supply of food and water, but more is better.

"The area of devastation could be rather large. There could be a 300 mile circle of devastation," Ninness said.

People should not plan on getting any kind of help very soon.

He said everyone needs a family communications plan. They need to know how they will communicate and reunite.

"You might plan to meet back at the house, but may not be able to get to the house so you want a secondary meeting spot," Ninness said.

Families should have an out of state contact so if they are seperated, all family members know to call that person to exchange information. The earthquake could knock out local telephone service, but long distance service may not be interrupted.

People should plan on there being debris, including broken glass, everywhere, so it is a good idea, especially for women who wear heels, to keep an extra pair of sneakers in the trunk of the car.

Ninness said everyone needs to know how to turn off water, gas mains and electrical utilities in the case of a leak. But he said not to shut off the gas unless there is a leak because it may be needed.

Water heaters should be secured to walls. The water heaters could come in quite handy even if the power is off. They contain about 40 gallons of water you may need for drinking.

Bolt woodburning stoves down and keep heavy objects on the lower shelves.

Ninness said people need to pay attention to the objects that are around them in the places they spend most of their time. For many, those places are a desk at an office and in bed.

"I have two bookshelves that are going to fall on me in the basement of the courthouse," Ninness said.

Around beds there are often mirrors and picture frames that could fall on people during the night if they are not firmly secured to walls.

When the quake happens, people should try to seek cover under a desk, bed or in a doorway immediately. Once the shaking stops they should try to get outside which may be easier said than done.

"Debris is going to be everywhere. I imagine walking through this room would be like walking throug a plate full of spaghetti. There is going to be stuff everywhere," Ninness said.

Under the bed is a good place to keep a duffel back of clothing and emergency supplies.

There may be aftershocks. When the shaking is done, people need to check for fire hazards and structural damage after each aftershock. In checking damage it is not a good idea to use candles in the house because of the fire potential, especially in houses using natural gas.

If driving, people will likely only feel a very large earthquake. If so, he said drivers should pull over, get out of traffic and try not to stop under an overpass or under power lines. Stay with the vehicle and listen to the radio for emergency broadcasts.

Ninness said any open containers could contain shards of glass. People can strain liquids through a handkerchief to make sure they don't ingest glass. Food in the refrigerator should be eaten first, freezer second and cupboard third because of the risk of spoiling.

Don't use the telephone except genuine emergency calls, Ninness said. He recalls one local quake that resulted in 911 calls in the thousands.

"It was people calling to ask if it was an earthquake. Don't do that, please. Turn on the radio. Don't pick up the phone and call somebody and say, 'Did you feel that?' It ties up the lines," Ninness said.

Ninness said other don't include rumor spreading and sightseeing following the quake.

Ninness also said emergency crews will be needing and asking for help. People should be prepared to help in whatever way they are needed at that moment.

SIC President Dr. Ray Cummiskey asked for advice on what should be done at the college. It is a large campus and there are many people there at any given time.

Ninness said personnel should be trained on the college's earthquake emergency plan.

"You have to be self-sufficient. Mutual aid has been taken away from us," Ninness said.

"There is a very huge possibility you will have to stay here a while."

Ninness said the college should consider earthquake drills and exercises.

"They are hard to do, it takes time away from class time, but it can also save you," Ninness said.

About two-thirds of people polled thought they would experience moderate or severe effects, with 21% plumping for the worst case scenario. In contrast to the earlier finding, the most concerned age group questioned were the 18-24s (with 28% classing the likely impact as severe). Overall, a pessimistic 13% thought that rising sea levels meant that the home they currently live in would be underwater within 40 years - with 21% of Londoners believing they face catastrophic submergence by 2046.

How do those results sit with the science? Sea levels first, and the Londoners can breathe (relatively) easily. Sea levels will not get anywhere near high enough to inundate the city unless the mighty Greenland and Antarctic ice sheets melt, which even the most pessimistic forecasts rule out for several centuries at least. Most sea level rise over the coming century will be driven by thermal expansion: the water gets bigger as it warms.

By the 2050s seas around most of England could be 30cm higher, with the rise in the north-west and Scotland not as severe - the entire UK is slowly tilting (southeast down) as the bedrock it sits on recovers from the most recent ice age.

How will this affect us? Scientists are reluctant to simply morph sea level changes on to contour maps, because it is unrealistic to expect no action to be taken to defend valuable land. In other places, the sea could be allowed to advance in a managed retreat.

With sea level higher, the risk of flooding will increase. Vulnerable areas will be underwater more often, and places with no history of floods could be threatened.

By the 2080s, sea levels could be 70cm higher at the southern end of the UK and some 50cm up along the north-western coast. An estimated 2 million extra people will be at risk of flooding and there will be a 17-fold increase in the flood risk along the east coast. London could face a £25bn clean-up bill after a freak storm surge that would overwhelm the Thames barrier. Higher sea levels mean deeper coastal water and more powerful waves battering the shore, which will break down defences and erode soil.

As far as the wider impacts of climate change, then it is hard to escape the evidence that some are already upon us. This year's July and September were the hottest ever and air temperatures across the globe are on the rise. In the Arctic, the mass of sea ice that surrounds the north pole has reached a series of record lows since 2002 and the sea off the Antarctic peninsula is warming so quickly that experts have sounded the alarm over whether its fragile marine species can adapt in time.

Closer to home, warmer winters and a longer growing season have baffled wildlife and disrupted the delicate natural rhythms that drive food availability. Contrary to some over-excited headlines, individual weather events like this summer's heatwave cannot be pinned on global warming, but they are exactly in line with what climate scientists predict.

In 2004 Peter Stott, a Met Office expert, and scientists at Oxford University showed that human emissions of greenhouse gases had more than doubled the risk of record-breaking heatwaves such as the one that is reckoned to have killed 27,000 people across Europe in 2003.

Perhaps the 31% of the poll respondents, who do not foresee any impact, care little for ice and wildlife at the ends of the world, and view changing weather patterns as par for the course. Maybe they are waiting for an impact on their own lives. David Miliband, environment secretary, may have provided it earlier this year. Speaking on possible solutions to climate change, Mr Miliband floated the idea of carbon rationing - which could force consumers to carry a swipe card that records their personal carbon allocation.

Under the scheme, all UK citizens would be allocated an identical annual carbon allowance, stored as points on an electronic card similar to Air Miles or supermarket loyalty cards. Points would be deducted at point of sale for every purchase of non-renewable energy, such as petrol or flight tickets. People who did not use their full allocation, such as families who do not own a car, would be able to sell their surplus carbon points into a central bank. A pilot scheme is on the drawing board. The potential impact on all our lives is beyond dispute.

John Schellnhuber, distinguished science advisor at the Tyndall Centre for Climate Change Research in the United Kingdom, has identified 12 global warming tipping points, such as the deforestation of the Amazon rainforest or the melting of the west Antarctic ice sheet. Any of these, if triggered, will likely initiate sudden changes across the planet, as cataclysmic as any asteroid strike. So what will it take to trigger what we might call the 13th tipping point, the shift from personal denial to personal responsibility? What will tip us toward addressing global warming with the urgency it deserves, as the mother of all threats to homeland security?

A 2005 study on Americans' perceptions of global warming found that most are moderately concerned, but 68 percent believe the greatest threats are to people far away or to nonhuman nature -- a dangerous and delusional misperception. Only 13 percent perceive risk to themselves, their families or their communities.

Many secretly perceive global warming to be an insoluble problem and respond by circling the family wagons and turning inward. Yet science shows that human beings are born with powerful tools for solving this quandary. We have the genetic smarts and the cultural smarts. We have the technological know-how. We even have the inclination.

The truth is we can change ourselves with breathtaking speed, sculpting even "immutable" human nature. Forty years ago many believed human nature mandated that blacks and whites live in segregation; 30 years ago human nature divided men and women into separate economies; 20 years ago human nature prevented us from defusing a global nuclear standoff, but in 1987 the U.S. and Soviet Union signed the INF agreement. Nowadays we blame human nature for the insolvable hazards of global warming.

Research out of the Max Planck Institute in Germany suggests how we might help ourselves evolve. We behave as better environmental citizens when educated about the science of global warming, and when our individual actions are visible to those around us -- a phenomenon known as "social facilitation." Perhaps if we're vigorously informed of how global warming endangers our neighborhoods, we'll individually forego the McMansions and the Hummers and make other sustainable choices. Anything less compromises our children's future.

Until then, our denial facilitates "social loafing": the tendency of individuals to slack when work is shared and individual performance is not assessed. There's no better example than the U.S. Congress, where members cloak their lethargy regarding global warming behind the stultifying inactivity of their fellows. And why not? After all, who's watching?

Not the media, which habitually squelch new science stories on global warming by rationalizing that we've heard that before , though they would never ignore another round of Middle East bloodletting. The growing body of scientific knowledge on climate change gains heft and power as it accumulates, but the public rarely hears about it, reinforcing our loafing.

Scientists don't help when they react to the terrifying dimensions of public ignorance by sheltering inside hallowed halls. At a recent meeting of the Society for Conservation Biology, 70 percent of members argued in favor of advocating real solutions to environmental problems directly to lethargic policymakers and the press. Yet most researchers remain sequestered at a time when we need their knowledge and expertise like never before.

The nature of tipping points is that they happen dizzyingly fast. The good news is that history proves we're capable of keeping up. Social scientists once believed it would take decades of government pressure and education for Americans to choose smaller families, since the desire to procreate is an absolute part of the human animal, or so they thought. Yet population growth radically declined over only three years in the 1970s -- one woman at a time -- without an ounce of government involvement.

Political leaders can help. But even without them we can help ourselves. Whether or not Marie Antoinette actually said, "Let them eat cake," she inspired change that reverberated far beyond Europe. Likewise, when George W. Bush says we can't act on global warming until we "fully understand the nature of the problem," we can use his callous disregard as a rallying cry.

The truth is, humans can change, and change fast. Our hallmark is adaptability. Long ago, we looked out from the trees and saw the savannas. Beyond the savannas we glimpsed further frontiers. History proves that when we behold a better world, we move toward it -- one person at a time -- leaving behind what no longer works. We know what to do. We know how to do it. We know the timeline. We are our own tipping point.

This piece is adapted from a longer article in the current issue of Mother Jones.

Julia Whitty is a contributing writer for Mother Jones and the author of the forthcoming book The Fragile Edge: Diving and Other Adventures in the South Pacific.

His study, based on air temperatures and past sea level changes rather than computer models, suggested seas could rise by 50-140 cms (19.69-55.12 inches) by 2100, well above the 9-88 cms (3.54-34.65 inches) projected by the scientific panel that advises the United Nations.

A rise of one meter, or over 3 feet, might swamp low-lying Pacific islands such as Tuvalu, flood large areas of Bangladesh or Florida and threaten cities from New York to Buenos Aires.

"The computer models underestimate the sea level rise that has already occurred," Rahmstorf told Reuters of a rise of about 20 cms (7.87 inches) since 1900. "There are aspects of the physics we don't understand very well."

Sea level changes hinge on poorly understood factors such as the pace of the melt of glaciers and of ice sheets in Greenland and Antarctica. Water also expands as it gets warmer but the rate of penetration of heat to the depths is uncertain.

"My main conclusion is not that my forecast is better but that the uncertainty is much larger because of the different results you get with reasonable methods," he said.

Almost all climate scientists reckon the world is warming because of emissions of greenhouse gases from human use of fossil fuels in factories, power plants and cars. Rising temperatures could bring more droughts, floods and heatwaves.

Rahmstorf likened his approach to predicting the height of tides along a coast, largely based on past observations.

He said seas were 120 meters (just under 400 feet) and below present levels during the last Ice Age 20,000 years ago. Seas are 25-35 metres (82-114.83 feet) higher than the present in the Pliocene epoch 3 million years ago.

In the Ice Age temperatures were 4-7 Celsius (7.2-12.6 Fahrenheit) cooler than today and 2-3 C (3.6-5.4F) warmer in the Pliocene. That suggested sea levels change 10-30 metres per rise or fall per degree Celsius (1.8F), over thousands of years.

The U.N. climate panel has projected temperatures will rise by 1.4-5.8C (2.5-10.4F) by 2100, mainly because of human influences.

"Sea level is a very slow component of the climate system so what we see by the year 2100 is just a small percentage of the total we are causing," Rahmstorf said.

There was still time for the world to cut greenhouse gas emissions but he said the slow pace of U.N. talks on extending the U.N.'s Kyoto Protocol beyond 2012 "gives you the impression that governments are not very well aware of how urgent the whole problem has become". Coastal cities in the North Atlantic - from New York to London - could be especially vulnerable because a possible slowdown of ocean currents could also raise sea levels in the North Atlantic and lower them in the southern hemisphere.

"Any time you change ocean currents you change the sea surface...if you slow down the North Atlantic current you get a rise in the North Atlantic," Rahmstorf said.