“There’s nothing like this anywhere in the world,” Alan Hogg, from New Zealand’s University of Waikato.
During an excavation of a geothermal power plant in Ngawha North Island, New Zealand, an ancient tree was found. The Tree contains a record of a reversal of Earth’s magnetic field.
The Tree, buried in 26 feet of soil, was 65 meters long. According to the carbon dating the Tree lived for 1500 years, between 41,000-42,500 years ago, this period is known as the Laschamp Excursion.
The lifespan of this unique Ngāwhā Kauri tree covers a significant point when the Earth’s magnetic field nearly reversed. At that point in time, the magnetic north and south went on a short journey but never completed a full reversal.
The Earth’s magnetic is generated by the iron in the Earth’s core. As it moves, electric currents get produced that extend into space.
The magnetic field acts as a shield in protecting Earth from the solar winds. The solar wind is a stream of particles that come from the Sun. The solar wind has the potential to rip away our ozone layer if it ever were to impact the Earth’s atmosphere.
When the magnetic field reverses or tries to, the safety barrier that it gives off gets weaker leading to more Sun radiation reaching through our atmosphere. Hence it shows up on tree rings.
Chris Turney, an expert in paleoclimatology and climate change from the University of New South Wales together with a group of scientists, are analyzing samples of the Tree.
By understanding what happened to the Tree during the process would give insight into what to expect the next time a polar shift happens. Experts believe when this happens, we might experience an increase in cosmic radiation that will take out satellites and potentially other communication infrastructure.
According to NASA, there is a pattern of magnetic field reversals in the last 20 million years. It appears to have been happening once every 200,000 to 300,000 years. The previous full magnetic field reversal took place around 780,000 years ago.
The Magnetic field change is of increasing interest to scientists after reports showed that the Earth’s northern magnetic pole moved at an unexpectedly fast rate towards Siberia in September 2018. As a result, the scientist had to update the World Magnetic Model (WMM). The WMM is used in navigation and many civilian systems. That why it is of paramount importance knowing where the northern and southern magnetic poles are.