The rate at which Earth is losing water to space is influenced by various factors, including the escape of water vapor into the upper atmosphere and its subsequent loss into space. This process is primarily driven by solar radiation, which can heat the upper atmosphere and increase the kinetic energy of water molecules, allowing some of them to escape the planet’s gravitational pull. However, the loss of water to space is not expected to significantly accelerate near the end of Earth’s life before it gets sterilized.
Earth’s future is influenced by several factors, including the increasing luminosity of the Sun as it ages. In several billion years, as the Sun evolves into a red giant, it will expand and become hotter, causing the Earth’s surface temperatures to rise significantly. This could lead to increased evaporation of water, but the primary loss of water is not related to the end of Earth’s life.
Ultimately, over a very long timescale, as the Sun continues to evolve, it may lead to the loss of Earth’s atmosphere and water, ultimately rendering the planet inhospitable for life. However, this process occurs on a timescale of billions of years, and it’s not directly linked to the end of Earth’s life but rather a consequence of changes in the Sun’s lifecycle. Before that time, Earth could face other challenges such as changing climates and geological events, but it’s not an imminent concern on human timescales.