The collapse of the Earth's magnetic field, which both guards the planet and guides many of its creatures, appears to have started in earnest about 150 years ago. The field's strength has waned 10 to 15 percent, and the deterioration has accelerated of late, increasing debate over whether it portends a reversal of the lines of magnetic force that normally envelop the Earth.
During a reversal, the main field weakens, almost vanishes, then reappears with opposite polarity. Afterward, compass needles that normally point north would point south, and during the thousands of years of transition, much in the heavens and Earth would go askew.
A reversal could knock out power grids, hurt astronauts and satellites, widen atmospheric ozone holes, send polar auroras flashing to the equator and confuse birds, fish and migratory animals that rely on the steadiness of the magnetic field as a navigation aid. But experts said the repercussions would fall short of catastrophic, despite a few proclamations of doom and sketchy evidence of past links between field reversals and species extinctions.
Note that with sufficient planning a lot of the electrical effects could be ameliorated by better shielding and back-ups. Even satellites could be built to be better shielded. But maintaining a human presence in low Earth orbit would become a much riskier proposition.
Suppose the flip comes to pass. Should we respond by creating new maps that show the Southern Hemisphere on top?
Consider just one practical problem: If we continue to call the "North" the "North" then all compasses will be wrong. But if we make new compasses then they will have to be labelled as "Post-Collapse" compasses or else someone could use a compass, not know it was built before or after the collapse, and go off in the wrong direction. Likely the period of collapsed magnetic field would last so long before the field popped up firmly again that the use of compasses will have long been abandoned before their labelling becomes an issue.
Animals that have evolved to navigate by the magnetic field might be driven extinct.
When baby loggerhead turtles embark on an 8,000-mile trek around the Atlantic, they use invisible magnetic clues to check their bearings. So do salmon and whales, honeybees and homing pigeons, frogs and Zambian mole rats, scientists have found.
But within a hundred years we may well know all the species that have genetic adaptations to magnetic fields. We could use future advances in biotechnology to easily do genetic engineering to the most threatened of these species to adapt them to the change in magnetic fields. Therefore mass extinctions may be avoidable unless the collapse of the magnetic field causes holes in the ozone layer that cause extinctions via increases in UV radiation. Though even in that scenario we could save some of the species either by genetically engineering them to be more resistant to high UV or by doing climate engineering to create UV shields.
The flip of the magnetic poles may not happen for hundreds of thousands of years. But there may already be people alive today who will live to see the magnetic field collapse. Anyone who is still alive when Engineered Negligible Senescence (rejuvenation therapies that will make us young again) is achieved could conceivably live long enough to witness the magnetic field collapse. There may well already be people alive today who will live long enough to be around when rejuvenation becomes commonplace. Therefore some readers of this post may live through the future collapse of Earth's magnetic field.
The European Space Agency is going to launch a "Swing" cluster of 3 satellites in 2009 to collect enough data to perhaps allow magnetic field forecasting in a fashion analogous to weather and climate forecasting.
The objective of the Swarm mission is to provide the best ever survey of the geomagnetic field and its temporal evolution, in order to gain new insights into the Earth system by improving our understanding of the Earth’s interior and climate. The mission is scheduled for launch in 2009. After release from a single launcher, a side-by-side flying lower pair of satellites at an initial altitude of 450 km and a single higher satellite at 530 km will form the Swarm constellation.
High-precision and high-resolution measurements of the strength, direction and variation of the magnetic field, complemented by precise navigation, accelerometer and electric field measurements, will provide the necessary observations that are required to separate and model various sources of the geomagnetic field. This results in a unique “view” inside the Earth from space to study the composition and processes in the interior.
My guess is that we will be so technologically advanced by the time a magnetic field collapse becomes severe that we will be able to easily compensate for its effects. Climate engineering, UV shields over human habitats, genetic engineering of other species, and heavy shielding of electronics will be among the methods we use to protect human civilization and other species.
|Share |||Randall Parker, 2004 July 14 03:44 PM Dangers Natural General|