The Earth's magnetic field can alter weather and global temperatures. In this article, I would like to continue the discussion by describing how the Earth's magnetic field is changing.
The process of magnetic pole reversal on Earth may follow a similar process observed in the Sun. The Sun undergoes a magnetic pole reversal every 11 years like clockwork. The same process occurs on Earth but is less regular, and the time interval between reversals are measured in thousands or even millions of years. The last reversal on Earth took place 740,000 years ago.
NASA recently published findings that showed for nearly a month beginning in
March 2000, the Sun's south magnetic pole faded away, and a north pole emerged
to take its place. The Sun had essentially two north poles. During this process,
the south magnetic pole migrated north and for a while became a band of south
magnetic flux smeared around the Sun's equator.
(http://science.nasa.gov/headlines/y2003/22apr_currentsheet.htm)
This anomaly preceded the Sun's magnetic pole reversal by a few months, which occurred in 2001. The Sun’s magnetic field is normally dipolar but during solar maximum, quadrupole and octupole components exist as well.
Satellite measurements show the Earth's magnetic field is weakening quite rapidly. Using the International Geomagnetic Reference Field (IGRF) data set, the magnetic field at the equator in open ocean has declined 1.7 percent in intensity since 1980, a decline from 34,824 to 34,246 nanoTesla (nT). In contrast, the entire decline over the period from 1900 to 1980 was 2.8 percent. The dramatic decline in Earth's magnetic field strength has led many to believe that the Earth may soon encounter a magnetic pole reversal.
Dr. Heikki Nevanlinna, Research Professor at Geophysics Research, Finnish Meteorological Institute, wrote an article in Helsingin Sanomat, the leading newspaper in Finland, July 27, 2002. In the article, he states that the North Hemisphere magnetic pole has moved 1500 kilometers in the past 100 years while the South Hemisphere magnetic pole has moved only 1000 kilometers during the same period. The structure of the Earth's magnetic field is currently asymmetric.
A South Atlantic Anomaly (SSA) has appeared, which is a major depression in the
magnetic field strength. The field strength within this depression approaches
only 20,000 nanoTesla (nT).
(http://www.dsri.dk/showpage.php3?id=65)
The fact that Earth's magnetic field is currently asymmetric combined with the fact that a magnetic field depression has formed would lead one to believe that the Earth's magnetic pole components are being restructured. The process of Earth magnetic pole reversals may be quite complex and studying changes in the Sun's magnetic pole reversals can provide very valuable insight that may directly apply to a similar process within the Earth.