Estimation of the total oxygen loss from Earth with a semi-empirical model of atmospheric escape

Understanding atmospheric escape into space for stellar and planetary conditions differing from the current ones on Earth is an ongoing challenge. It helps us to assess the stability of planetary atmospheres, hence their habitability. Over geological time scales, despite the small changes in Earth’s magnetic field magnitude, the solar wind pressure, and EUV radiation from the Sun have evolved significantly, affecting the atmospheric erosion rate. On one hand, the solar wind pressure affects non-thermal processes, and on the other EUV radiation alters Earth’s atmospheric parameters, increasing the ion production rate and the exospheric temperature. Both jointly cause a significant effect on erosion.We developed a semi-empirical model to analyze seven different erosion mechanisms and their dependency on terrestrial and solar parameters, in order to estimate the oxygen escape rate for past conditions. Our model considers variations of the Earth’s magnetic moment, the solar wind pressure, and the solar EUV flux. We discuss the effect of different atmospheric factors and their impact on the oxygen loss for each escape process and provide an estimate of the total amount of oxygen lost by the Earth over the last ~2 billion years. In addition, such a model contributes to identifying the solar and planetary parameters that are critical for the stability of the planet’s atmosphere.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)