New Scientist has a longish summary of a recently-released National Academy of Sciences report on the dangers faced by industrial societies from anomalous space weather events. Consider, for example, the1859 Carrington event — the most extreme space weather incident we have records of. According to Wikipedia,
From August 28 until September 2, numerous sunspots and solar flares were observed on the sun. Just before noon on September 1, the British astronomer, Richard Carrington, observed the largest flare, which caused a massive coronal mass ejection (CME), to travel directly toward Earth, taking eighteen hours. This is remarkable because such a journey normally takes three to four days. It moved so quickly because an earlier CME had cleared its way.
From the 1st to the 2nd, the largest recorded geomagnetic storm occurred, causing the failure of telegraph systems all over Europe and North America. Auroras were seen all over the world, most notably over the Caribbean; also noteworthy were those over the Rocky Mountains that were so bright, the glow awoke gold miners, who began preparing breakfast because they thought it was morning.
Now imagine a storm like this hitting societies almost completely dependent on unhardened electrical transmission lines. The result would not be pretty,
There are two problems to face. The first is the modern electricity grid, which is designed to operate at ever higher voltages over ever larger areas. Though this provides a more efficient way to run the electricity networks, minimising power losses and wastage through overproduction, it has made them much more vulnerable to space weather. The high-power grids act as particularly efficient antennas, channelling enormous direct currents into the power transformers.
The second problem is the grid’s interdependence with the systems that support our lives: water and sewage treatment, supermarket delivery infrastructures, power station controls, financial markets and many others all rely on electricity. Put the two together, and it is clear that a repeat of the Carrington event could produce a catastrophe the likes of which the world has never seen. “It’s just the opposite of how we usually think of natural disasters,” says John Kappenman, a power industry analyst with the Metatech Corporation of Goleta, California, and an advisor to the NAS committee that produced the report. “Usually the less developed regions of the world are most vulnerable, not the highly sophisticated technological regions.”
According to the NAS report, a severe space weather event in the US could induce ground currents that would knock out 300 key transformers within about 90 seconds, cutting off the power for more than 130 million people (see map). From that moment, the clock is ticking for America.
Moreover, this would be a prolonged problem. The NAS report estimates it would take up to 4 – 10 years for the country. That’s a minimum of many months and the possibility of several years without electrical power for some parts of the country. In the US, that’s almost certainly millions of excess fatalities as people no longer have easy access to safe drinkable water, heating and cooling, and possibly drugs they rely on such as insulin.
One way to prevent such a disaster is to shut down the grid intentionally before the space storm reaches the Earth so as to avoid the damage to the physical infrastructure. And there is a system in place to help give some notice, but not surprisingly it isn’t all that well-funded and may be inadequate in truly anomalous conditions,
By far the most important indicator of incoming space weather is NASA’s Advanced Composition Explorer (ACE). The probe, launched in 1997, has a solar orbit that keeps it directly between the sun and Earth. Its uninterrupted view of the sun means it gives us continuous reports on the direction and velocity of the solar wind and other streams of charged particles that flow past its sensors. ACE can provide between 15 and 45 minutes’ warning of any incoming geomagnetic storms. The power companies need about 15 minutes to prepare their systems for a critical event, so that would seem passable.
However, observations of the sun and magnetometer readings during the Carrington event shows that the coronal mass ejection was travelling so fast it took less than 15 minutes to get from where ACE is positioned to Earth. “It arrived faster than we can do anything,” Hapgood says.
There is another problem. ACE is 11 years old, and operating well beyond its planned lifespan. The onboard detectors are not as sensitive as they used to be, and there is no telling when they will finally give up the ghost. Furthermore, its sensors become saturated in the event of a really powerful solar flare. “It was built to look at average conditions rather than extremes,” Baker says.
And there’s no real plan for anything to replace or supercede ACE. So, for now, just cross your fingers and hope for the best.
- May 4, 2009 @ 16:37:40 [Current Revision] by Brian Carnell
- May 4, 2009 @ 16:36:53 by Brian Carnell