What is the “Faint Young Sun Paradox” and why is it relevant to the study of climate change?

The ‘Faint Young Sun Paradox’: A Relevant Study for Climate Change

The ‘Faint Young Sun Paradox’ (FYSP) is a term used to describe the puzzling observation that the early sun was much weaker than today’s sun, yet the Earth had liquid water at the time – even though liquid water requires more energy than the early sun was able to provide. The paradox can be used to help understand climate changes in the past. Researchers have been studying the FYSP in detail since 1960s. They are looking into the origins of liquid water and how it was possible to be created despite the lackluster sun. It has been suggested that the Earth’s early atmosphere contained more greenhouse gases than it does today, which allowed it to trap more of the sun’s energy and maintain a warmer climate (Kasting, 2016). Outgassing by volcanic activity is thought to have caused an increase in greenhouse gas levels. This allowed for thicker, reflective atmosphere (Kasting 2019). The FYSP has been used to form hypotheses about the Earth’s climate in the past, which can then be tested with further research.