ABSTRACT:The rise of sea levels could have devastating consequences for coastal settlements, and it can easily be one of the most critical effects of climate change. Thus, all factors affecting sea levels need to be considered. One of the factors discussed in this paper is the natural variability of sea levels, which originates from the oscillation of the planets and solar activity. The effect of the Sun's activity on Earth's climate has been identified since the 1800s. However, there are still many unknowns regarding the mechanisms connecting the Earth's climate to the variation in solar irradiance. Climate modelling that implements the solar sciences is a novel approach that accounts for the considerable effect that natural factors have on the climate, especially at regional level. This paper discusses the noticeable effect that planet oscillations have on the Sun's activity, which gives a very good correlation with the observed patterns in global surface temperatures, rainfall records and sea levels. In agreement with many studies that have identified a 60-year cycle in the variation of Earth's temperature, it is expected that surface temperatures will reach a trough of the cycle around 2030-2040. Furthermore, considering the influence of the Solar Inertial Motion, a solar slowdown is predicted for Solar Cycles 24 and 25, which will create a weak grand minimum. It is anticipated that this weak grand minimum will be reflected in a dampening effect of global temperatures, and a subsequent moderation in the rate of sea level rise.