Deeper Look – Episode 44
Part Two – Solar Minimum and Earth’s Magnetic Reversal
Watch, then continue reading below.
Before I get the flurry of questions, the 2017 call for being 50% down on our magnetic field is around the scarier end of the estimations. Here is what I mean:
If you simply extrapolate the trends then the magnetic field wouldn’t reach 50% lost strength until around 2030. The other end of the spectrum takes a bit of thinking. 2% lost field strength from 1600 to 1850 means it would take approximately 1250 years to lose 10% of the field. We know that in the next 150 years we lost 10% more (1850-2000). Then in 10 years from 2000 to 2010 we lost another 5%, meaning it would take only 20 years to lose the next ten percent. You can therefore loosely consider the trend in the following way-
We we’re losing 10% of our field in 1250 years, then 150, and 20, which puts us at 20% down here in 2015, but with the next 10% being lost in approximately 3 years, then 5 months, etc.
Another way to look at things is to consider the average rate of change per year during the aforementioned periods. From 1600 to 1850 we lost about 0.008% of the field each year. From 1850 to 200 we lost 0.067% of the field each year. From 2000 to 2010 we lost 0.5% of the field each year. We are accelerating ~8x as we jump from period to period – that’s 8 times faster weakening than the time period before. The periods are getting shorter as well, meaning that 5 years after the 2010 numbers we should be losing 1% every few months, and then 1% a month sometime late this year.
So depending on how you account for time and how you extrapolate going forward, we could have a bit more than a decade, or we could have only a few years left. If NOAA had given us another update or the ESA’s SWARM mission hadn’t gone cold we wouldn’t have to guess – but alas, welcome to the world of earth changes.