Final answer:
The Toba supereruption, a massive volcanic event that occurred around 74,000 years ago, is the major climate event that nearly wiped out Neanderthals, significantly affecting global climate and exacerbating their survival challenges.
Step-by-step explanation:
The major climate event that nearly wiped out Neanderthals was the C. Toba supereruption. This catastrophic event occurred about 74,000 years ago and had a profound impact on global climate. It was one of the Earth's most massive volcanic eruptions, leading to a volcanic winter and significantly affecting many species, including Neanderthals. The ash and aerosols released into the atmosphere would have blocked sunlight, causing a considerable drop in global temperatures and leading to harsh living conditions.
The Toba supereruption's effects on climate and ecosystems were so severe that they likely contributed to the decline of Neanderthal populations, exacerbating challenges they faced such as finding food and coping with the colder climate. Over time, these factors, combined with competition from modern humans, contributed to the eventual disappearance of Neanderthals.