A positive feedback loop is a process where an initial change leads to further changes in the same direction. For example, when temperature rises, it can cause ice to melt, which reduces the Earth's reflectivity. This results in more heat absorption, leading to even higher temperatures. In biological systems, a positive feedback loop can occur during childbirth. When contractions begin, they push the baby toward the birth canal, triggering the release of the hormone oxytocin. This hormone increases the strength and frequency of contractions, further facilitating the birth process until delivery is complete.