Impact of extreme solar particle events on Earth’s ozone and magnetic field

New research investigated the influence of extreme solar particle events on the Earth’s ozone layer and climate, concentrating on how these events interact with varying geomagnetic field strengths and providing crucial insights into possible hazards to human health and ecological stability.

• The ozone layer can be depleted by solar particle events, which are short-lived bursts of high-energy particles which can alter atmospheric chemistry.
• The Earth’s geomagnetic field currently deflects cosmic particles, limiting their impact to the polar regions, but geological records show periods of significant field weakening, allowing particles to penetrate at lower latitudes. This could lead to ozone layer damage, increased UV radiation, and consequential health, climatic, and evolutionary impacts.

According to a new study, Solar Particle Events (SPEs) can cause significant damage to the ozone layer, increase ultraviolet (UV) radiation, and deteriorate the climate and ecology in a variety of ways. This study, published in the Proceedings of the National Academy of Sciences (PNAS), brought to the forefront the increased risks that occur when Earth’s geomagnetic field is weak.

The Earth’s magnetic field serves as a protective shield, deflecting charged solar particles and cosmic radiation. Normally, this field plays a crucial part in defending the environment. However, the magnetic field isn’t consistent and has gone through entire phases of severe weakening and even complete absence. Historical geological records show such oscillations, with the most recent severe weakening occurring 42 000 years ago and lasting about another 1 000 years.

The Sun emits a stream of charged particles known as the solar wind, which generally contains photons and electrons. Occasionally, it also emits strong bursts of energy in the form of SPEs which are mainly proton emissions associated with solar flares. These high-energy protons can get into Earth’s atmosphere, when the geomagnetic field is weak, causing a string of atmospheric reactions.

The study used modern atmospheric models and concluded that SPEs are seriously harmful to the ozone layer and lead to its depletion. The ozone layer is useful in absorbing damaging UV radiation from the Sun. When SPEs occur, they deplete the ozone layer in the Earth’s atmosphere allowing more radiation to reach the Earth’s surface. Increased UV exposure can cause more DNA damage, raising the risk of skin cancer and other health problems.

Researchers utilized the SOCOL3-MPIOM atmosphere-ocean-chemistry-climate model and the LibRadtran radiation transfer model to understand the consequences of an extreme SPE under different geomagnetic field strengths. Under present geomagnetic conditions, an extreme SPE would increase nitrogen oxides (NOx) in the polar stratosphere and mesosphere, resulting in stratospheric ozone depletion lasting for about a year. This would in turn lead to a temporary yet large boost in UV radiation levels at the surface.

In scenarios when the geomagnetic field is completely missing, the results are even worse. The study discovered that NOx levels will grow throughout the atmosphere, causing severe and protracted ozone depletion lasting up to six years. Resultantly, ground-level UV radiation will increase by 25% while DNA damage rates will increase by 50%.

The interaction between SPEs and geomagnetic strengths can explain many significant events in the Earth’s history. The transient weakening of the geomagnetic field 42,000 years ago coincided with major evolutionary and extinction events, including the loss of Neanderthals and several large mammal species in Australia.

Understanding the effects of high SPEs on different geomagnetic conditions is critical for assessing future threats.

The study also showed there is a need for additional research on the potential health risks and long-term climate consequences of such incidents. As the Sun’s cycles continue and the geomagnetic field evolves, monitoring and preparing for these cosmic interactions will be critical to reducing their impact on modern society and life on Earth.

References:

¹ Global impacts of an extreme solar particle event under different geomagnetic field strengths – Pavle Arsenovic et al. – PNAS – July 1, 2024 – https://www.pnas.org/doi/10.1073/pnas.2321770121

Harsha Borah

Harsha Borah is an experienced content writer with a proven track record in the industry. Harsha has worked with LitSpark Solutions and Whateveryourdose, honing skills in creating engaging content across various platforms. A gold medalist in a state-level writing competition organized by Assam Tourism, Harsha’s travelogue on Tezpur was widely appreciated. Harsha’s article, "The Dark Tale of the Only Judge in India to Be Hanged," ranks second on Google and has garnered over 11 000 views and 8 900 reads on Medium. Outside of writing, Harsha enjoys reading books and solving jigsaw puzzles.

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