Thursday, March 22, 2007

If global warming doesn't get you..............

Global warming is the hot issue of the year. Even, sceptics in the government have come around to changing their tune on it's dangers and the need for action even if it makes no difference and involves money making schemes such as carbon trading etc. However, there is a danger that is more urgent than GW (although probably not as deadly as the neocons being in charge for another decade) which is the Earth's magnetic field. The magnetic field is due to molten iron deep in the core of the Earth although there is yet no widely accepted model as to how it works. You may or may not know that the magnetic field switches polarity every now and again so that north becomes south and south becomes north. So what? It will confuse your compass but I doubt whether that leaves you quivering with fear. Now if this were to happen almost instantly then there would not be a problem. However, this is not the way of things in nature. The magnetic field weakens gradually, slowly decreasing to nothing and then builds up again with the opposite polarity. Although we cannot predict when this will happen (reversal occurs every few thousand years or a few million years depending on who is doing the estimating), we know it does happen at irregular periods from rock records.

Satellites in a low orbit over Southern Africa have already experienced radiation damage due to weakening of the protective effect of the magnetosphere. This could be due to random fluctuations but it has now been twice as long between the switch of polarity compared to last time and the consequences could be devastating. That may sound vague but according to an article in the NYT in 2004, the collapse of the field started around 150 years ago and it has now decreased by about 15% of its original strength. That decline is only accelerating.

In the absence of a protecting field not only will animals lose their way during migration, the Earth will be exposed to dangerous solar radiation that will do a lot more than top up your tan. The radiation will destroy ozone that protects us from UV and as well as leading to many species (probably) being wiped out. There is some evidence for small species extinctions being correlated with geomagnetic reversals. The USA has reacted with concern at these findings and has proposed several technological solutions to the problem. By 2050, they propose to have two giant magnets in place at the current positions of the magnetic poles. This will create a permanent fix, removing the instability of the current situation, with the only danger being to armour wearing polar adventurers and large steel hulled ships, wandering into the proximity of the new magnetic poles. Another technological fix is to flood the upper atmosphere with factor 3000 sun-screening chemicals. This will give the sky a permanent light brown look but experts reckon it is time we had a change from boring old light blue anyway. Shares in the sunscreen industry have rocketed, particularly since Halliburten-KBR group merged with Laboratoire Garnier. The Earth is 4.5 billion years old.


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